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2021-08-18powerpc/32: Remove unneccessary calculations in load_up_{fpu/altivec}Christophe Leroy2-5/+2
No need to re-read SPRN_THREAD, we can calculate thread address from current (r2). And remove a reload of value 1 into r4 as r4 is already 1. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/c04cce578b97a76a9e69a096698b1d89f721768a.1629276437.git.christophe.leroy@csgroup.eu
2021-08-18powerpc: Remove duplicate includesWan Jiabing2-3/+1
interrupt.c: asm/interrupt.h has been included at line 12, so remove the duplicate one at line 10. time.c: linux/sched/clock.h has been included at line 33,so remove the duplicate one at line 56 and move sched/cputime.h under sched including segament. Signed-off-by: Wan Jiabing <wanjiabing@vivo.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210323062916.295346-1-wanjiabing@vivo.com
2021-08-15powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm gotoChristophe Leroy3-4/+9
Using asm goto in __WARN_FLAGS() and WARN_ON() allows more flexibility to GCC. For that add an entry to the exception table so that program_check_exception() knowns where to resume execution after a WARNING. Here are two exemples. The first one is done on PPC32 (which benefits from the previous patch), the second is on PPC64. unsigned long test(struct pt_regs *regs) { int ret; WARN_ON(regs->msr & MSR_PR); return regs->gpr[3]; } unsigned long test9w(unsigned long a, unsigned long b) { if (WARN_ON(!b)) return 0; return a / b; } Before the patch: 000003a8 <test>: 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc <test+0x14> 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 3c0: 80 63 00 0c lwz r3,12(r3) 3c4: 4e 80 00 20 blr 0000000000000bf0 <.test9w>: bf0: 7c 89 00 74 cntlzd r9,r4 bf4: 79 29 d1 82 rldicl r9,r9,58,6 bf8: 0b 09 00 00 tdnei r9,0 bfc: 2c 24 00 00 cmpdi r4,0 c00: 41 82 00 0c beq c0c <.test9w+0x1c> c04: 7c 63 23 92 divdu r3,r3,r4 c08: 4e 80 00 20 blr c0c: 38 60 00 00 li r3,0 c10: 4e 80 00 20 blr After the patch: 000003a8 <test>: 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc <test+0x14> 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 0000000000000c50 <.test9w>: c50: 7c 89 00 74 cntlzd r9,r4 c54: 79 29 d1 82 rldicl r9,r9,58,6 c58: 0b 09 00 00 tdnei r9,0 c5c: 7c 63 23 92 divdu r3,r3,r4 c60: 4e 80 00 20 blr c70: 38 60 00 00 li r3,0 c74: 4e 80 00 20 blr In the first exemple, we see GCC doesn't need to duplicate what happens after the trap. In the second exemple, we see that GCC doesn't need to emit a test and a branch in the likely path in addition to the trap. We've got some WARN_ON() in .softirqentry.text section so it needs to be added in the OTHER_TEXT_SECTIONS in modpost.c Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/389962b1b702e3c78d169e59bcfac56282889173.1618331882.git.christophe.leroy@csgroup.eu
2021-08-13powerpc/pseries: Add support for FORM2 associativityAneesh Kumar K.V1-1/+2
PAPR interface currently supports two different ways of communicating resource grouping details to the OS. These are referred to as Form 0 and Form 1 associativity grouping. Form 0 is the older format and is now considered deprecated. This patch adds another resource grouping named FORM2. Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210812132223.225214-6-aneesh.kumar@linux.ibm.com
2021-08-13powerpc/pseries: Rename TYPE1_AFFINITY to FORM1_AFFINITYAneesh Kumar K.V1-1/+1
Also make related code cleanup that will allow adding FORM2_AFFINITY in later patches. No functional change in this patch. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210812132223.225214-3-aneesh.kumar@linux.ibm.com
2021-08-13powerpc: rename powerpc_debugfs_root to arch_debugfs_dirAneesh Kumar K.V11-40/+39
No functional change in this patch. arch_debugfs_dir is the generic kernel name declared in linux/debugfs.h for arch-specific debugfs directory. Architectures like x86/s390 already use the name. Rename powerpc specific powerpc_debugfs_root to arch_debugfs_dir. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210812132831.233794-2-aneesh.kumar@linux.ibm.com
2021-08-12powerpc/interrupt: Do not call single_step_exception() from other exceptionsChristophe Leroy1-2/+7
single_step_exception() is called by emulate_single_step() which is called from (at least) alignment exception() handler and program_check_exception() handler. Redefine it as a regular __single_step_exception() which is called by both single_step_exception() handler and emulate_single_step() function. Fixes: 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers") Cc: stable@vger.kernel.org # v5.12+ Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/aed174f5cbc06f2cf95233c071d8aac948e46043.1628611921.git.christophe.leroy@csgroup.eu
2021-08-12powerpc/interrupt: Fix OOPS by not calling do_IRQ() from timer_interrupt()Christophe Leroy2-2/+7
An interrupt handler shall not be called from another interrupt handler otherwise this leads to problems like the following: Kernel attempted to write user page (afd4fa84) - exploit attempt? (uid: 1000) ------------[ cut here ]------------ Bug: Write fault blocked by KUAP! WARNING: CPU: 0 PID: 1617 at arch/powerpc/mm/fault.c:230 do_page_fault+0x484/0x720 Modules linked in: CPU: 0 PID: 1617 Comm: sshd Tainted: G W 5.13.0-pmac-00010-g8393422eb77 #7 NIP: c001b77c LR: c001b77c CTR: 00000000 REGS: cb9e5bc0 TRAP: 0700 Tainted: G W (5.13.0-pmac-00010-g8393422eb77) MSR: 00021032 <ME,IR,DR,RI> CR: 24942424 XER: 00000000 GPR00: c001b77c cb9e5c80 c1582c00 00000021 3ffffbff 085b0000 00000027 c8eb644c GPR08: 00000023 00000000 00000000 00000000 24942424 0063f8c8 00000000 000186a0 GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 c07640c4 cb9e5e98 cb9e5e90 GPR24: 00000040 afd4fa96 00000040 02000000 c1fda6c0 afd4fa84 00000300 cb9e5cc0 NIP [c001b77c] do_page_fault+0x484/0x720 LR [c001b77c] do_page_fault+0x484/0x720 Call Trace: [cb9e5c80] [c001b77c] do_page_fault+0x484/0x720 (unreliable) [cb9e5cb0] [c000424c] DataAccess_virt+0xd4/0xe4 --- interrupt: 300 at __copy_tofrom_user+0x110/0x20c NIP: c001f9b4 LR: c03250a0 CTR: 00000004 REGS: cb9e5cc0 TRAP: 0300 Tainted: G W (5.13.0-pmac-00010-g8393422eb77) MSR: 00009032 <EE,ME,IR,DR,RI> CR: 48028468 XER: 20000000 DAR: afd4fa84 DSISR: 0a000000 GPR00: 20726f6f cb9e5d80 c1582c00 00000004 cb9e5e3a 00000016 afd4fa80 00000000 GPR08: 3835202d 72777872 2d78722d 00000004 28028464 0063f8c8 00000000 000186a0 GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 c07640c4 cb9e5e98 cb9e5e90 GPR24: 00000040 afd4fa96 00000040 cb9e5e0c 00000daa a0000000 cb9e5e98 afd4fa56 NIP [c001f9b4] __copy_tofrom_user+0x110/0x20c LR [c03250a0] _copy_to_iter+0x144/0x990 --- interrupt: 300 [cb9e5d80] [c03e89c0] n_tty_read+0xa4/0x598 (unreliable) [cb9e5df0] [c03e2a0c] tty_read+0xdc/0x2b4 [cb9e5e80] [c0156bf8] vfs_read+0x274/0x340 [cb9e5f00] [c01571ac] ksys_read+0x70/0x118 [cb9e5f30] [c0016048] ret_from_syscall+0x0/0x28 --- interrupt: c00 at 0xa7855c88 NIP: a7855c88 LR: a7855c5c CTR: 00000000 REGS: cb9e5f40 TRAP: 0c00 Tainted: G W (5.13.0-pmac-00010-g8393422eb77) MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 2402446c XER: 00000000 GPR00: 00000003 afd4ec70 a72137d0 0000000b afd4ecac 00004000 0065a990 00000800 GPR08: 00000000 a7947930 00000000 00000004 c15831b0 0063f8c8 00000000 000186a0 GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 0065a9e0 00000001 0065fac0 GPR24: 00000000 00000089 00664050 00000000 00668e30 a720c8dc a7943ff4 0065f9b0 NIP [a7855c88] 0xa7855c88 LR [a7855c5c] 0xa7855c5c --- interrupt: c00 Instruction dump: 3884aa88 38630178 48076861 807f0080 48042e45 2f830000 419e0148 3c80c079 3c60c076 38841be4 386301c0 4801f705 <0fe00000> 3860000b 4bfffe30 3c80c06b ---[ end trace fd69b91a8046c2e5 ]--- Here the problem is that by re-enterring an exception handler, kuap_save_and_lock() is called a second time with this time KUAP access locked, leading to regs->kuap being overwritten hence KUAP not being unlocked at exception exit as expected. Do not call do_IRQ() from timer_interrupt() directly. Instead, redefine do_IRQ() as a standard function named __do_IRQ(), and call it from both do_IRQ() and time_interrupt() handlers. Fixes: 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers") Cc: stable@vger.kernel.org # v5.12+ Reported-by: Stan Johnson <userm57@yahoo.com> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/c17d234f4927d39a1d7100864a8e1145323d33a0.1628611927.git.christophe.leroy@csgroup.eu
2021-08-10powerpc/pseries/pci: Add MSI domainsCédric Le Goater1-0/+6
Two IRQ domains are added on top of default machine IRQ domain. First, the top level "pSeries-PCI-MSI" domain deals with the MSI specificities. In this domain, the HW IRQ numbers are generated by the PCI MSI layer, they compose a unique ID for an MSI source with the PCI device identifier and the MSI vector number. These numbers can be quite large on a pSeries machine running under the IBM Hypervisor and /sys/kernel/irq/ and /proc/interrupts will require small fixes to show them correctly. Second domain is the in-the-middle "pSeries-MSI" domain which acts as a proxy between the PCI MSI subsystem and the machine IRQ subsystem. It usually allocate the MSI vector numbers but, on pSeries machines, this is done by the RTAS FW and RTAS returns IRQ numbers in the IRQ number space of the machine. This is why the in-the-middle "pSeries-MSI" domain has the same HW IRQ numbers as its parent domain. Only the XIVE (P9/P10) parent domain is supported for now. We still need to add support for IRQ domain hierarchy under XICS. Signed-off-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210701132750.1475580-6-clg@kaod.org
2021-08-10powerpc: Replace deprecated CPU-hotplug functions.Sebastian Andrzej Siewior1-2/+2
The functions get_online_cpus() and put_online_cpus() have been deprecated during the CPU hotplug rework. They map directly to cpus_read_lock() and cpus_read_unlock(). Replace deprecated CPU-hotplug functions with the official version. The behavior remains unchanged. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210803141621.780504-4-bigeasy@linutronix.de
2021-08-09powerpc/iommu: don't set failed sg dma_address to DMA_MAPPING_ERRORLogan Gunthorpe1-2/+0
Setting the ->dma_address to DMA_MAPPING_ERROR is not part of the ->map_sg calling convention, so remove it. Link: https://lore.kernel.org/linux-mips/20210716063241.GC13345@lst.de/ Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Geoff Levand <geoff@infradead.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2021-08-09powerpc/iommu: return error code from .map_sg() opsMartin Oliveira1-2/+2
The .map_sg() op now expects an error code instead of zero on failure. Propagate the error up if vio_dma_iommu_map_sg() fails. ppc_iommu_map_sg() may fail either because of iommu_range_alloc() or because of tbl->it_ops->set(). The former only supports returning an error with DMA_MAPPING_ERROR and an examination of the latter indicates that it may return arch-specific errors (for example, tce_buildmulti_pSeriesLP()). Hence, coalesce all of those errors into -EIO, per the documentation on dma_map_sgtable(). Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Geoff Levand <geoff@infradead.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2021-08-09powerpc/kprobes: Fix kprobe Oops happens in bookePu Lehui1-1/+2
When using kprobe on powerpc booke series processor, Oops happens as show bellow: / # echo "p:myprobe do_nanosleep" > /sys/kernel/debug/tracing/kprobe_events / # echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable / # sleep 1 [ 50.076730] Oops: Exception in kernel mode, sig: 5 [#1] [ 50.077017] BE PAGE_SIZE=4K SMP NR_CPUS=24 QEMU e500 [ 50.077221] Modules linked in: [ 50.077462] CPU: 0 PID: 77 Comm: sleep Not tainted 5.14.0-rc4-00022-g251a1524293d #21 [ 50.077887] NIP: c0b9c4e0 LR: c00ebecc CTR: 00000000 [ 50.078067] REGS: c3883de0 TRAP: 0700 Not tainted (5.14.0-rc4-00022-g251a1524293d) [ 50.078349] MSR: 00029000 <CE,EE,ME> CR: 24000228 XER: 20000000 [ 50.078675] [ 50.078675] GPR00: c00ebdf0 c3883e90 c313e300 c3883ea0 00000001 00000000 c3883ecc 00000001 [ 50.078675] GPR08: c100598c c00ea250 00000004 00000000 24000222 102490c2 bff4180c 101e60d4 [ 50.078675] GPR16: 00000000 102454ac 00000040 10240000 10241100 102410f8 10240000 00500000 [ 50.078675] GPR24: 00000002 00000000 c3883ea0 00000001 00000000 0000c350 3b9b8d50 00000000 [ 50.080151] NIP [c0b9c4e0] do_nanosleep+0x0/0x190 [ 50.080352] LR [c00ebecc] hrtimer_nanosleep+0x14c/0x1e0 [ 50.080638] Call Trace: [ 50.080801] [c3883e90] [c00ebdf0] hrtimer_nanosleep+0x70/0x1e0 (unreliable) [ 50.081110] [c3883f00] [c00ec004] sys_nanosleep_time32+0xa4/0x110 [ 50.081336] [c3883f40] [c001509c] ret_from_syscall+0x0/0x28 [ 50.081541] --- interrupt: c00 at 0x100a4d08 [ 50.081749] NIP: 100a4d08 LR: 101b5234 CTR: 00000003 [ 50.081931] REGS: c3883f50 TRAP: 0c00 Not tainted (5.14.0-rc4-00022-g251a1524293d) [ 50.082183] MSR: 0002f902 <CE,EE,PR,FP,ME> CR: 24000222 XER: 00000000 [ 50.082457] [ 50.082457] GPR00: 000000a2 bf980040 1024b4d0 bf980084 bf980084 64000000 00555345 fefefeff [ 50.082457] GPR08: 7f7f7f7f 101e0000 00000069 00000003 28000422 102490c2 bff4180c 101e60d4 [ 50.082457] GPR16: 00000000 102454ac 00000040 10240000 10241100 102410f8 10240000 00500000 [ 50.082457] GPR24: 00000002 bf9803f4 10240000 00000000 00000000 100039e0 00000000 102444e8 [ 50.083789] NIP [100a4d08] 0x100a4d08 [ 50.083917] LR [101b5234] 0x101b5234 [ 50.084042] --- interrupt: c00 [ 50.084238] Instruction dump: [ 50.084483] 4bfffc40 60000000 60000000 60000000 9421fff0 39400402 914200c0 38210010 [ 50.084841] 4bfffc20 00000000 00000000 00000000 <7fe00008> 7c0802a6 7c892378 93c10048 [ 50.085487] ---[ end trace f6fffe98e2fa8f3e ]--- [ 50.085678] Trace/breakpoint trap There is no real mode for booke arch and the MMU translation is always on. The corresponding MSR_IS/MSR_DS bit in booke is used to switch the address space, but not for real mode judgment. Fixes: 21f8b2fa3ca5 ("powerpc/kprobes: Ignore traps that happened in real mode") Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210809023658.218915-1-pulehui@huawei.com
2021-08-07powerpc/smp: Fix OOPS in topology_init()Christophe Leroy1-1/+1
Running an SMP kernel on an UP platform not prepared for it, I encountered the following OOPS: BUG: Kernel NULL pointer dereference on read at 0x00000034 Faulting instruction address: 0xc0a04110 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=4K SMP NR_CPUS=2 CMPCPRO Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-pmac-00001-g230fedfaad21 #5234 NIP: c0a04110 LR: c0a040d8 CTR: c0a04084 REGS: e100dda0 TRAP: 0300 Not tainted (5.13.0-pmac-00001-g230fedfaad21) MSR: 00009032 <EE,ME,IR,DR,RI> CR: 84000284 XER: 00000000 DAR: 00000034 DSISR: 20000000 GPR00: c0006bd4 e100de60 c1033320 00000000 00000000 c0942274 00000000 00000000 GPR08: 00000000 00000000 00000001 00000063 00000007 00000000 c0006f30 00000000 GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000005 GPR24: c0c67d74 c0c67f1c c0c60000 c0c67d70 c0c0c558 1efdf000 c0c00020 00000000 NIP [c0a04110] topology_init+0x8c/0x138 LR [c0a040d8] topology_init+0x54/0x138 Call Trace: [e100de60] [80808080] 0x80808080 (unreliable) [e100de90] [c0006bd4] do_one_initcall+0x48/0x1bc [e100def0] [c0a0150c] kernel_init_freeable+0x1c8/0x278 [e100df20] [c0006f44] kernel_init+0x14/0x10c [e100df30] [c00190fc] ret_from_kernel_thread+0x14/0x1c Instruction dump: 7c692e70 7d290194 7c035040 7c7f1b78 5529103a 546706fe 5468103a 39400001 7c641b78 40800054 80c690b4 7fb9402e <81060034> 7fbeea14 2c080000 7fa3eb78 ---[ end trace b246ffbc6bbbb6fb ]--- Fix it by checking smp_ops before using it, as already done in several other places in the arch/powerpc/kernel/smp.c Fixes: 39f87561454d ("powerpc/smp: Move ppc_md.cpu_die() to smp_ops.cpu_offline_self()") Cc: stable@vger.kernel.org Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/75287841cbb8740edd44880fe60be66d489160d9.1628097995.git.christophe.leroy@csgroup.eu
2021-08-07powerpc/32: Fix critical and debug interrupts on BOOKEChristophe Leroy2-41/+17
32 bits BOOKE have special interrupts for debug and other critical events. When handling those interrupts, dedicated registers are saved in the stack frame in addition to the standard registers, leading to a shift of the pt_regs struct. Since commit db297c3b07af ("powerpc/32: Don't save thread.regs on interrupt entry"), the pt_regs struct is expected to be at the same place all the time. Instead of handling a special struct in addition to pt_regs, just add those special registers to struct pt_regs. Fixes: db297c3b07af ("powerpc/32: Don't save thread.regs on interrupt entry") Cc: stable@vger.kernel.org Reported-by: Radu Rendec <radu.rendec@gmail.com> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/028d5483b4851b01ea4334d0751e7f260419092b.1625637264.git.christophe.leroy@csgroup.eu
2021-08-07powerpc/32s: Fix napping restore in data storage interrupt (DSI)Christophe Leroy1-1/+1
When a DSI (Data Storage Interrupt) is taken while in NAP mode, r11 doesn't survive the call to power_save_ppc32_restore(). So use r1 instead of r11 as they both contain the virtual stack pointer at that point. Fixes: 4c0104a83fc3 ("powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE") Cc: stable@vger.kernel.org # v5.13+ Reported-by: Finn Thain <fthain@linux-m68k.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/731694e0885271f6ee9ffc179eb4bcee78313682.1628003562.git.christophe.leroy@csgroup.eu
2021-08-04powerpc/smp: Use existing L2 cache_map cpumask to find L3 cache siblingsParth Shah2-21/+48
On POWER10 systems, the "ibm,thread-groups" property "2" indicates the cpus in thread-group share both L2 and L3 caches. Hence, use cache_property = 2 itself to find both the L2 and L3 cache siblings. Hence, create a new thread_group_l3_cache_map to keep list of L3 siblings, but fill the mask using same property "2" array. Signed-off-by: Parth Shah <parth@linux.ibm.com> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210728175607.591679-4-parth@linux.ibm.com
2021-08-04powerpc/cacheinfo: Remove the redundant get_shared_cpu_map()Gautham R. Shenoy1-40/+1
The helper function get_shared_cpu_map() was added in 'commit 500fe5f550ec ("powerpc/cacheinfo: Report the correct shared_cpu_map on big-cores")' and subsequently expanded upon in 'commit 0be47634db0b ("powerpc/cacheinfo: Print correct cache-sibling map/list for L2 cache")' in order to help report the correct groups of threads sharing these caches on big-core systems where groups of threads within a core can share different sets of caches. Now that powerpc/cacheinfo is aware of "ibm,thread-groups" property, cache->shared_cpu_map contains the correct set of thread-siblings sharing the cache. Hence we no longer need the functions get_shared_cpu_map(). This patch removes this function. We also remove the helper function index_dir_to_cpu() which was only called by get_shared_cpu_map(). With these functions removed, we can still see the correct cache-sibling map/list for L1 and L2 caches on systems with L1 and L2 caches distributed among groups of threads in a core. With this patch, on a SMT8 POWER10 system where the L1 and L2 caches are split between the two groups of threads in a core, for CPUs 8,9, the L1-Data, L1-Instruction, L2, L3 cache CPU sibling list is as follows: $ grep . /sys/devices/system/cpu/cpu[89]/cache/index[0123]/shared_cpu_list /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list:8,10,12,14 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list:8,10,12,14 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list:8,10,12,14 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list:8-15 /sys/devices/system/cpu/cpu9/cache/index0/shared_cpu_list:9,11,13,15 /sys/devices/system/cpu/cpu9/cache/index1/shared_cpu_list:9,11,13,15 /sys/devices/system/cpu/cpu9/cache/index2/shared_cpu_list:9,11,13,15 /sys/devices/system/cpu/cpu9/cache/index3/shared_cpu_list:8-15 $ ppc64_cpu --smt=4 $ grep . /sys/devices/system/cpu/cpu[89]/cache/index[0123]/shared_cpu_list /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list:8,10 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list:8,10 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list:8,10 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list:8-11 /sys/devices/system/cpu/cpu9/cache/index0/shared_cpu_list:9,11 /sys/devices/system/cpu/cpu9/cache/index1/shared_cpu_list:9,11 /sys/devices/system/cpu/cpu9/cache/index2/shared_cpu_list:9,11 /sys/devices/system/cpu/cpu9/cache/index3/shared_cpu_list:8-11 $ ppc64_cpu --smt=2 $ grep . /sys/devices/system/cpu/cpu[89]/cache/index[0123]/shared_cpu_list /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list:8 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list:8 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list:8 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list:8-9 /sys/devices/system/cpu/cpu9/cache/index0/shared_cpu_list:9 /sys/devices/system/cpu/cpu9/cache/index1/shared_cpu_list:9 /sys/devices/system/cpu/cpu9/cache/index2/shared_cpu_list:9 /sys/devices/system/cpu/cpu9/cache/index3/shared_cpu_list:8-9 $ ppc64_cpu --smt=1 $ grep . /sys/devices/system/cpu/cpu[89]/cache/index[0123]/shared_cpu_list /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list:8 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list:8 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list:8 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list:8 Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210728175607.591679-3-parth@linux.ibm.com
2021-08-04powerpc/cacheinfo: Lookup cache by dt node and thread-group idGautham R. Shenoy2-24/+60
Currently the cacheinfo code on powerpc indexes the "cache" objects (modelling the L1/L2/L3 caches) where the key is device-tree node corresponding to that cache. On some of the POWER server platforms thread-groups within the core share different sets of caches (Eg: On SMT8 POWER9 systems, threads 0,2,4,6 of a core share L1 cache and threads 1,3,5,7 of the same core share another L1 cache). On such platforms, there is a single device-tree node corresponding to that cache and the cache-configuration within the threads of the core is indicated via "ibm,thread-groups" device-tree property. Since the current code is not aware of the "ibm,thread-groups" property, on the aforementoined systems, cacheinfo code still treats all the threads in the core to be sharing the cache because of the single device-tree node (In the earlier example, the cacheinfo code would says CPUs 0-7 share L1 cache). In this patch, we make the powerpc cacheinfo code aware of the "ibm,thread-groups" property. We indexe the "cache" objects by the key-pair (device-tree node, thread-group id). For any CPUX, for a given level of cache, the thread-group id is defined to be the first CPU in the "ibm,thread-groups" cache-group containing CPUX. For levels of cache which are not represented in "ibm,thread-groups" property, the thread-group id is -1. [parth: Remove "static" keyword for the definition of "thread_group_l1_cache_map" and "thread_group_l2_cache_map" to get rid of the compile error.] Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Parth Shah <parth@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210728175607.591679-2-parth@linux.ibm.com
2021-08-03powerpc/stacktrace: Include linux/delay.hMichal Suchanek1-0/+1
commit 7c6986ade69e ("powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi()") introduces udelay() call without including the linux/delay.h header. This may happen to work on master but the header that declares the functionshould be included nonetheless. Fixes: 7c6986ade69e ("powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi()") Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210729180103.15578-1-msuchanek@suse.de
2021-07-29powerpc/vdso: Don't use r30 to avoid breaking Go langMichael Ellerman1-0/+7
The Go runtime uses r30 for some special value called 'g'. It assumes that value will remain unchanged even when calling VDSO functions. Although r30 is non-volatile across function calls, the callee is free to use it, as long as the callee saves the value and restores it before returning. It used to be true by accident that the VDSO didn't use r30, because the VDSO was hand-written asm. When we switched to building the VDSO from C the compiler started using r30, at least in some builds, leading to crashes in Go. eg: ~/go/src$ ./all.bash Building Go cmd/dist using /usr/lib/go-1.16. (go1.16.2 linux/ppc64le) Building Go toolchain1 using /usr/lib/go-1.16. go build os/exec: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault go build reflect: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault go tool dist: FAILED: /usr/lib/go-1.16/bin/go install -gcflags=-l -tags=math_big_pure_go compiler_bootstrap bootstrap/cmd/...: exit status 1 There are patches in flight to fix Go[1], but until they are released and widely deployed we can workaround it in the VDSO by avoiding use of r30. Note this only works with GCC, clang does not support -ffixed-rN. 1: https://go-review.googlesource.com/c/go/+/328110 Fixes: ab037dd87a2f ("powerpc/vdso: Switch VDSO to generic C implementation.") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> Tested-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210729131244.2595519-1-mpe@ellerman.id.au
2021-07-26printk: remove safe buffersJohn Ogness2-6/+0
With @logbuf_lock removed, the high level printk functions for storing messages are lockless. Messages can be stored from any context, so there is no need for the NMI and safe buffers anymore. Remove the NMI and safe buffers. Although the safe buffers are removed, the NMI and safe context tracking is still in place. In these contexts, store the message immediately but still use irq_work to defer the console printing. Since printk recursion tracking is in place, safe context tracking for most of printk is not needed. Remove it. Only safe context tracking relating to the console and console_owner locks is left in place. This is because the console and console_owner locks are needed for the actual printing. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210715193359.25946-4-john.ogness@linutronix.de
2021-07-26powerpc/kexec: blacklist functions called in real mode for kprobeHari Bathini1-0/+2
As kprobe does not handle events happening in real mode, blacklist the functions that only get called in real mode or in kexec sequence with MMU turned off. Signed-off-by: Hari Bathini <hbathini@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/162626687834.155313.4692863392927831843.stgit@hbathini-workstation.ibm.com
2021-07-19printk: Userspace format indexing supportChris Down1-1/+1
We have a number of systems industry-wide that have a subset of their functionality that works as follows: 1. Receive a message from local kmsg, serial console, or netconsole; 2. Apply a set of rules to classify the message; 3. Do something based on this classification (like scheduling a remediation for the machine), rinse, and repeat. As a couple of examples of places we have this implemented just inside Facebook, although this isn't a Facebook-specific problem, we have this inside our netconsole processing (for alarm classification), and as part of our machine health checking. We use these messages to determine fairly important metrics around production health, and it's important that we get them right. While for some kinds of issues we have counters, tracepoints, or metrics with a stable interface which can reliably indicate the issue, in order to react to production issues quickly we need to work with the interface which most kernel developers naturally use when developing: printk. Most production issues come from unexpected phenomena, and as such usually the code in question doesn't have easily usable tracepoints or other counters available for the specific problem being mitigated. We have a number of lines of monitoring defence against problems in production (host metrics, process metrics, service metrics, etc), and where it's not feasible to reliably monitor at another level, this kind of pragmatic netconsole monitoring is essential. As one would expect, monitoring using printk is rather brittle for a number of reasons -- most notably that the message might disappear entirely in a new version of the kernel, or that the message may change in some way that the regex or other classification methods start to silently fail. One factor that makes this even harder is that, under normal operation, many of these messages are never expected to be hit. For example, there may be a rare hardware bug which one wants to detect if it was to ever happen again, but its recurrence is not likely or anticipated. This precludes using something like checking whether the printk in question was printed somewhere fleetwide recently to determine whether the message in question is still present or not, since we don't anticipate that it should be printed anywhere, but still need to monitor for its future presence in the long-term. This class of issue has happened on a number of occasions, causing unhealthy machines with hardware issues to remain in production for longer than ideal. As a recent example, some monitoring around blk_update_request fell out of date and caused semi-broken machines to remain in production for longer than would be desirable. Searching through the codebase to find the message is also extremely fragile, because many of the messages are further constructed beyond their callsite (eg. btrfs_printk and other module-specific wrappers, each with their own functionality). Even if they aren't, guessing the format and formulation of the underlying message based on the aesthetics of the message emitted is not a recipe for success at scale, and our previous issues with fleetwide machine health checking demonstrate as much. This provides a solution to the issue of silently changed or deleted printks: we record pointers to all printk format strings known at compile time into a new .printk_index section, both in vmlinux and modules. At runtime, this can then be iterated by looking at <debugfs>/printk/index/<module>, which emits the following format, both readable by humans and able to be parsed by machines: $ head -1 vmlinux; shuf -n 5 vmlinux # <level[,flags]> filename:line function "format" <5> block/blk-settings.c:661 disk_stack_limits "%s: Warning: Device %s is misaligned\n" <4> kernel/trace/trace.c:8296 trace_create_file "Could not create tracefs '%s' entry\n" <6> arch/x86/kernel/hpet.c:144 _hpet_print_config "hpet: %s(%d):\n" <6> init/do_mounts.c:605 prepare_namespace "Waiting for root device %s...\n" <6> drivers/acpi/osl.c:1410 acpi_no_auto_serialize_setup "ACPI: auto-serialization disabled\n" This mitigates the majority of cases where we have a highly-specific printk which we want to match on, as we can now enumerate and check whether the format changed or the printk callsite disappeared entirely in userspace. This allows us to catch changes to printks we monitor earlier and decide what to do about it before it becomes problematic. There is no additional runtime cost for printk callers or printk itself, and the assembly generated is exactly the same. Signed-off-by: Chris Down <chris@chrisdown.name> Cc: Petr Mladek <pmladek@suse.com> Cc: Jessica Yu <jeyu@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kees Cook <keescook@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Tested-by: Petr Mladek <pmladek@suse.com> Reported-by: kernel test robot <lkp@intel.com> Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> # for module.{c,h} Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/e42070983637ac5e384f17fbdbe86d19c7b212a5.1623775748.git.chris@chrisdown.name
2021-07-12exit/bdflush: Remove the deprecated bdflush system callEric W. Biederman1-1/+1
The bdflush system call has been deprecated for a very long time. Recently Michael Schmitz tested[1] and found that the last known caller of of the bdflush system call is unaffected by it's removal. Since the code is not needed delete it. [1] https://lkml.kernel.org/r/36123b5d-daa0-6c2b-f2d4-a942f069fd54@gmail.com Link: https://lkml.kernel.org/r/87sg10quue.fsf_-_@disp2133 Tested-by: Michael Schmitz <schmitzmic@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Cyril Hrubis <chrubis@suse.cz> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-07-09Merge tag 'powerpc-5.14-2' of ↵Linus Torvalds1-1/+5
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Michael Ellerman: "Fix crashes on 64-bit Book3E due to use of Book3S only mtmsrd instruction. Fix "scheduling while atomic" warnings at boot due to preempt count underflow. Two commits fixing our handling of BPF atomic instructions. Fix error handling in xive when allocating an IPI. Fix lockup on kernel exec fault on 603. Thanks to Bharata B Rao, Cédric Le Goater, Christian Zigotzky, Christophe Leroy, Guenter Roeck, Jiri Olsa, Naveen N. Rao, Nicholas Piggin, and Valentin Schneider" * tag 'powerpc-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/preempt: Don't touch the idle task's preempt_count during hotplug powerpc/64e: Fix system call illegal mtmsrd instruction powerpc/xive: Fix error handling when allocating an IPI powerpc/bpf: Reject atomic ops in ppc32 JIT powerpc/bpf: Fix detecting BPF atomic instructions powerpc/mm: Fix lockup on kernel exec fault
2021-07-08powerpc: convert to setup_initial_init_mm()Kefeng Wang1-4/+1
Use setup_initial_init_mm() helper to simplify code. Link: https://lkml.kernel.org/r/20210608083418.137226-12-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-06powerpc/64e: Fix system call illegal mtmsrd instructionNicholas Piggin1-1/+5
BookE does not have mtmsrd, switch to use wrteei to enable MSR[EE]. Fixes: dd152f70bdc1 ("powerpc/64s: system call avoid setting MSR[RI] until we set MSR[EE]") Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210706051310.608992-1-npiggin@gmail.com
2021-07-02Merge tag 'powerpc-5.14-1' of ↵Linus Torvalds61-1764/+2071
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: - A big series refactoring parts of our KVM code, and converting some to C. - Support for ARCH_HAS_SET_MEMORY, and ARCH_HAS_STRICT_MODULE_RWX on some CPUs. - Support for the Microwatt soft-core. - Optimisations to our interrupt return path on 64-bit. - Support for userspace access to the NX GZIP accelerator on PowerVM on Power10. - Enable KUAP and KUEP by default on 32-bit Book3S CPUs. - Other smaller features, fixes & cleanups. Thanks to: Andy Shevchenko, Aneesh Kumar K.V, Arnd Bergmann, Athira Rajeev, Baokun Li, Benjamin Herrenschmidt, Bharata B Rao, Christophe Leroy, Daniel Axtens, Daniel Henrique Barboza, Finn Thain, Geoff Levand, Haren Myneni, Jason Wang, Jiapeng Chong, Joel Stanley, Jordan Niethe, Kajol Jain, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Paul Mackerras, Russell Currey, Sathvika Vasireddy, Shaokun Zhang, Stephen Rothwell, Sudeep Holla, Suraj Jitindar Singh, Tom Rix, Vaibhav Jain, YueHaibing, Zhang Jianhua, and Zhen Lei. * tag 'powerpc-5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (218 commits) powerpc: Only build restart_table.c for 64s powerpc/64s: move ret_from_fork etc above __end_soft_masked powerpc/64s/interrupt: clean up interrupt return labels powerpc/64/interrupt: add missing kprobe annotations on interrupt exit symbols powerpc/64: enable MSR[EE] in irq replay pt_regs powerpc/64s/interrupt: preserve regs->softe for NMI interrupts powerpc/64s: add a table of implicit soft-masked addresses powerpc/64e: remove implicit soft-masking and interrupt exit restart logic powerpc/64e: fix CONFIG_RELOCATABLE build warnings powerpc/64s: fix hash page fault interrupt handler powerpc/4xx: Fix setup_kuep() on SMP powerpc/32s: Fix setup_{kuap/kuep}() on SMP powerpc/interrupt: Use names in check_return_regs_valid() powerpc/interrupt: Also use exit_must_hard_disable() on PPC32 powerpc/sysfs: Replace sizeof(arr)/sizeof(arr[0]) with ARRAY_SIZE powerpc/ptrace: Refactor regs_set_return_{msr/ip} powerpc/ptrace: Move set_return_regs_changed() before regs_set_return_{msr/ip} powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi() powerpc/pseries/vas: Include irqdomain.h powerpc: mark local variables around longjmp as volatile ...
2021-07-02Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-0/+1
Merge more updates from Andrew Morton: "190 patches. Subsystems affected by this patch series: mm (hugetlb, userfaultfd, vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock, migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap, zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc, core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs, signals, exec, kcov, selftests, compress/decompress, and ipc" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits) ipc/util.c: use binary search for max_idx ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock ipc: use kmalloc for msg_queue and shmid_kernel ipc sem: use kvmalloc for sem_undo allocation lib/decompressors: remove set but not used variabled 'level' selftests/vm/pkeys: exercise x86 XSAVE init state selftests/vm/pkeys: refill shadow register after implicit kernel write selftests/vm/pkeys: handle negative sys_pkey_alloc() return code selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random kcov: add __no_sanitize_coverage to fix noinstr for all architectures exec: remove checks in __register_bimfmt() x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned hfsplus: report create_date to kstat.btime hfsplus: remove unnecessary oom message nilfs2: remove redundant continue statement in a while-loop kprobes: remove duplicated strong free_insn_page in x86 and s390 init: print out unknown kernel parameters checkpatch: do not complain about positive return values starting with EPOLL checkpatch: improve the indented label test checkpatch: scripts/spdxcheck.py now requires python3 ...
2021-07-01Merge tag 'fs_for_v5.14-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull misc fs updates from Jan Kara: "The new quotactl_fd() syscall (remake of quotactl_path() syscall that got introduced & disabled in 5.13 cycle), and couple of udf, reiserfs, isofs, and writeback fixes and cleanups" * tag 'fs_for_v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: writeback: fix obtain a reference to a freeing memcg css quota: remove unnecessary oom message isofs: remove redundant continue statement quota: Wire up quotactl_fd syscall quota: Change quotactl_path() systcall to an fd-based one reiserfs: Remove unneed check in reiserfs_write_full_page() udf: Fix NULL pointer dereference in udf_symlink function reiserfs: add check for invalid 1st journal block
2021-07-01kernel.h: split out panic and oops helpersAndy Shevchenko1-0/+1
kernel.h is being used as a dump for all kinds of stuff for a long time. Here is the attempt to start cleaning it up by splitting out panic and oops helpers. There are several purposes of doing this: - dropping dependency in bug.h - dropping a loop by moving out panic_notifier.h - unload kernel.h from something which has its own domain At the same time convert users tree-wide to use new headers, although for the time being include new header back to kernel.h to avoid twisted indirected includes for existing users. [akpm@linux-foundation.org: thread_info.h needs limits.h] [andriy.shevchenko@linux.intel.com: ia64 fix] Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Co-developed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Corey Minyard <cminyard@mvista.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Wei Liu <wei.liu@kernel.org> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Sebastian Reichel <sre@kernel.org> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Stephen Boyd <sboyd@kernel.org> Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Acked-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30powerpc/64s: move ret_from_fork etc above __end_soft_maskedNicholas Piggin1-26/+26
Code which runs with interrupts enabled should be moved above __end_soft_masked where possible, because maskable interrupts that hit below that symbol will need to consult the soft mask table, which is an extra cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-10-npiggin@gmail.com
2021-06-30powerpc/64s/interrupt: clean up interrupt return labelsNicholas Piggin1-3/+5
Normal kernel-interrupt exits can get interrupt_return_srr_user_restart in their backtrace, which is an unusual and notable function, and it is part of the user-interrupt exit path, which is doubly confusing. Add non-local labels for both user and kernel interrupt exit cases to address this and make the user and kernel cases more symmetric. Also get rid of an unused label. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-9-npiggin@gmail.com
2021-06-30powerpc/64/interrupt: add missing kprobe annotations on interrupt exit symbolsNicholas Piggin1-0/+6
If one interrupt exit symbol must not be kprobed, none of them can be, without more justification for why it's safe. Disallow kprobing on any of the (non-local) labels in the exit paths. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-8-npiggin@gmail.com
2021-06-30powerpc/64: enable MSR[EE] in irq replay pt_regsNicholas Piggin1-0/+1
Similar to commit 2b48e96be2f9f ("powerpc/64: fix irq replay pt_regs->softe value"), enable MSR_EE in pt_regs->msr. This makes the regs look more normal. It also allows some extra debug checks to be added to interrupt handler entry. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-7-npiggin@gmail.com
2021-06-30powerpc/64s: add a table of implicit soft-masked addressesNicholas Piggin3-10/+71
Commit 9d1988ca87dd ("powerpc/64: treat low kernel text as irqs soft-masked") ends up catching too much code, including ret_from_fork, and parts of interrupt and syscall return that do not expect to be interrupts to be soft-masked. If an interrupt gets marked pending, and then the code proceeds out of the implicit soft-masked region it will fail to deal with the pending interrupt. Fix this by adding a new table of addresses which explicitly marks the regions of code that are soft masked. This table is only checked for interrupts that below __end_soft_masked, so most kernel interrupts will not have the overhead of the table search. Fixes: 9d1988ca87dd ("powerpc/64: treat low kernel text as irqs soft-masked") Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-5-npiggin@gmail.com
2021-06-30powerpc/64e: remove implicit soft-masking and interrupt exit restart logicNicholas Piggin3-14/+16
The implicit soft-masking to speed up interrupt return was going to be used by 64e as well, but it has not been extensively tested on that platform and is not considered ready. It was intended to be disabled before merge. Disable it for now. Most of the restart code is common with 64s, so with more correctness and performance testing this could be re-enabled again by adding the extra soft-mask checks to interrupt handlers and flipping exit_must_hard_disable(). Fixes: 9d1988ca87dd ("powerpc/64: treat low kernel text as irqs soft-masked") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-4-npiggin@gmail.com
2021-06-30powerpc/64e: fix CONFIG_RELOCATABLE build warningsNicholas Piggin1-0/+11
CONFIG_RELOCATABLE=y causes build warnings from unresolved relocations. Fix these by using TOC addressing for these cases. Commit 24d33ac5b8ff ("powerpc/64s: Make prom_init require RELOCATABLE") caused some 64e configs to select RELOCATABLE resulting in these warnings, but the underlying issue was already there. This passes basic qemu testing. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-3-npiggin@gmail.com
2021-06-30Merge branch 'akpm' (patches from Andrew)Linus Torvalds2-2/+2
Merge misc updates from Andrew Morton: "191 patches. Subsystems affected by this patch series: kthread, ia64, scripts, ntfs, squashfs, ocfs2, kernel/watchdog, and mm (gup, pagealloc, slab, slub, kmemleak, dax, debug, pagecache, gup, swap, memcg, pagemap, mprotect, bootmem, dma, tracing, vmalloc, kasan, initialization, pagealloc, and memory-failure)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (191 commits) mm,hwpoison: make get_hwpoison_page() call get_any_page() mm,hwpoison: send SIGBUS with error virutal address mm/page_alloc: split pcp->high across all online CPUs for cpuless nodes mm/page_alloc: allow high-order pages to be stored on the per-cpu lists mm: replace CONFIG_FLAT_NODE_MEM_MAP with CONFIG_FLATMEM mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA docs: remove description of DISCONTIGMEM arch, mm: remove stale mentions of DISCONIGMEM mm: remove CONFIG_DISCONTIGMEM m68k: remove support for DISCONTIGMEM arc: remove support for DISCONTIGMEM arc: update comment about HIGHMEM implementation alpha: remove DISCONTIGMEM and NUMA mm/page_alloc: move free_the_page mm/page_alloc: fix counting of managed_pages mm/page_alloc: improve memmap_pages dbg msg mm: drop SECTION_SHIFT in code comments mm/page_alloc: introduce vm.percpu_pagelist_high_fraction mm/page_alloc: limit the number of pages on PCP lists when reclaim is active mm/page_alloc: scale the number of pages that are batch freed ...
2021-06-29Merge tag 'irq-core-2021-06-29' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq updates from Thomas Gleixner: "Updates for the interrupt subsystem: Core changes: - Cleanup and simplification of common code to invoke the low level interrupt flow handlers when this invocation requires irqdomain resolution. Add the necessary core infrastructure. - Provide a proper interface for modular PMU drivers to set the interrupt affinity. - Add a request flag which allows to exclude interrupts from spurious interrupt detection. Useful especially for IPI handlers which always return IRQ_HANDLED which turns the spurious interrupt detection into a pointless waste of CPU cycles. Driver changes: - Bulk convert interrupt chip drivers to the new irqdomain low level flow handler invocation mechanism. - Add device tree bindings for the Renesas R-Car M3-W+ SoC - Enable modular build of the Qualcomm PDC driver - The usual small fixes and improvements" * tag 'irq-core-2021-06-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) dt-bindings: interrupt-controller: arm,gic-v3: Describe GICv3 optional properties irqchip: gic-pm: Remove redundant error log of clock bulk irqchip/sun4i: Remove unnecessary oom message irqchip/irq-imx-gpcv2: Remove unnecessary oom message irqchip/imgpdc: Remove unnecessary oom message irqchip/gic-v3-its: Remove unnecessary oom message irqchip/gic-v2m: Remove unnecessary oom message irqchip/exynos-combiner: Remove unnecessary oom message irqchip: Bulk conversion to generic_handle_domain_irq() genirq: Move non-irqdomain handle_domain_irq() handling into ARM's handle_IRQ() genirq: Add generic_handle_domain_irq() helper irqchip/nvic: Convert from handle_IRQ() to handle_domain_irq() irqdesc: Fix __handle_domain_irq() comment genirq: Use irq_resolve_mapping() to implement __handle_domain_irq() and co irqdomain: Introduce irq_resolve_mapping() irqdomain: Protect the linear revmap with RCU irqdomain: Cache irq_data instead of a virq number in the revmap irqdomain: Use struct_size() helper when allocating irqdomain irqdomain: Make normal and nomap irqdomains exclusive powerpc: Move the use of irq_domain_add_nomap() behind a config option ...
2021-06-29mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMAMike Rapoport2-2/+2
After removal of DISCINTIGMEM the NEED_MULTIPLE_NODES and NUMA configuration options are equivalent. Drop CONFIG_NEED_MULTIPLE_NODES and use CONFIG_NUMA instead. Done with $ sed -i 's/CONFIG_NEED_MULTIPLE_NODES/CONFIG_NUMA/' \ $(git grep -wl CONFIG_NEED_MULTIPLE_NODES) $ sed -i 's/NEED_MULTIPLE_NODES/NUMA/' \ $(git grep -wl NEED_MULTIPLE_NODES) with manual tweaks afterwards. [rppt@linux.ibm.com: fix arm boot crash] Link: https://lkml.kernel.org/r/YMj9vHhHOiCVN4BF@linux.ibm.com Link: https://lkml.kernel.org/r/20210608091316.3622-9-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David Hildenbrand <david@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds4-223/+43
Pull kvm updates from Paolo Bonzini: "This covers all architectures (except MIPS) so I don't expect any other feature pull requests this merge window. ARM: - Add MTE support in guests, complete with tag save/restore interface - Reduce the impact of CMOs by moving them in the page-table code - Allow device block mappings at stage-2 - Reduce the footprint of the vmemmap in protected mode - Support the vGIC on dumb systems such as the Apple M1 - Add selftest infrastructure to support multiple configuration and apply that to PMU/non-PMU setups - Add selftests for the debug architecture - The usual crop of PMU fixes PPC: - Support for the H_RPT_INVALIDATE hypercall - Conversion of Book3S entry/exit to C - Bug fixes S390: - new HW facilities for guests - make inline assembly more robust with KASAN and co x86: - Allow userspace to handle emulation errors (unknown instructions) - Lazy allocation of the rmap (host physical -> guest physical address) - Support for virtualizing TSC scaling on VMX machines - Optimizations to avoid shattering huge pages at the beginning of live migration - Support for initializing the PDPTRs without loading them from memory - Many TLB flushing cleanups - Refuse to load if two-stage paging is available but NX is not (this has been a requirement in practice for over a year) - A large series that separates the MMU mode (WP/SMAP/SMEP etc.) from CR0/CR4/EFER, using the MMU mode everywhere once it is computed from the CPU registers - Use PM notifier to notify the guest about host suspend or hibernate - Support for passing arguments to Hyper-V hypercalls using XMM registers - Support for Hyper-V TLB flush hypercalls and enlightened MSR bitmap on AMD processors - Hide Hyper-V hypercalls that are not included in the guest CPUID - Fixes for live migration of virtual machines that use the Hyper-V "enlightened VMCS" optimization of nested virtualization - Bugfixes (not many) Generic: - Support for retrieving statistics without debugfs - Cleanups for the KVM selftests API" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (314 commits) KVM: x86: rename apic_access_page_done to apic_access_memslot_enabled kvm: x86: disable the narrow guest module parameter on unload selftests: kvm: Allows userspace to handle emulation errors. kvm: x86: Allow userspace to handle emulation errors KVM: x86/mmu: Let guest use GBPAGES if supported in hardware and TDP is on KVM: x86/mmu: Get CR4.SMEP from MMU, not vCPU, in shadow page fault KVM: x86/mmu: Get CR0.WP from MMU, not vCPU, in shadow page fault KVM: x86/mmu: Drop redundant rsvd bits reset for nested NPT KVM: x86/mmu: Optimize and clean up so called "last nonleaf level" logic KVM: x86: Enhance comments for MMU roles and nested transition trickiness KVM: x86/mmu: WARN on any reserved SPTE value when making a valid SPTE KVM: x86/mmu: Add helpers to do full reserved SPTE checks w/ generic MMU KVM: x86/mmu: Use MMU's role to determine PTTYPE KVM: x86/mmu: Collapse 32-bit PAE and 64-bit statements for helpers KVM: x86/mmu: Add a helper to calculate root from role_regs KVM: x86/mmu: Add helper to update paging metadata KVM: x86/mmu: Don't update nested guest's paging bitmasks if CR0.PG=0 KVM: x86/mmu: Consolidate reset_rsvds_bits_mask() calls KVM: x86/mmu: Use MMU role_regs to get LA57, and drop vCPU LA57 helper KVM: x86/mmu: Get nested MMU's root level from the MMU's role ...
2021-06-28Merge tag 'sched-core-2021-06-28' of ↵Linus Torvalds2-3/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler udpates from Ingo Molnar: - Changes to core scheduling facilities: - Add "Core Scheduling" via CONFIG_SCHED_CORE=y, which enables coordinated scheduling across SMT siblings. This is a much requested feature for cloud computing platforms, to allow the flexible utilization of SMT siblings, without exposing untrusted domains to information leaks & side channels, plus to ensure more deterministic computing performance on SMT systems used by heterogenous workloads. There are new prctls to set core scheduling groups, which allows more flexible management of workloads that can share siblings. - Fix task->state access anti-patterns that may result in missed wakeups and rename it to ->__state in the process to catch new abuses. - Load-balancing changes: - Tweak newidle_balance for fair-sched, to improve 'memcache'-like workloads. - "Age" (decay) average idle time, to better track & improve workloads such as 'tbench'. - Fix & improve energy-aware (EAS) balancing logic & metrics. - Fix & improve the uclamp metrics. - Fix task migration (taskset) corner case on !CONFIG_CPUSET. - Fix RT and deadline utilization tracking across policy changes - Introduce a "burstable" CFS controller via cgroups, which allows bursty CPU-bound workloads to borrow a bit against their future quota to improve overall latencies & batching. Can be tweaked via /sys/fs/cgroup/cpu/<X>/cpu.cfs_burst_us. - Rework assymetric topology/capacity detection & handling. - Scheduler statistics & tooling: - Disable delayacct by default, but add a sysctl to enable it at runtime if tooling needs it. Use static keys and other optimizations to make it more palatable. - Use sched_clock() in delayacct, instead of ktime_get_ns(). - Misc cleanups and fixes. * tag 'sched-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits) sched/doc: Update the CPU capacity asymmetry bits sched/topology: Rework CPU capacity asymmetry detection sched/core: Introduce SD_ASYM_CPUCAPACITY_FULL sched_domain flag psi: Fix race between psi_trigger_create/destroy sched/fair: Introduce the burstable CFS controller sched/uclamp: Fix uclamp_tg_restrict() sched/rt: Fix Deadline utilization tracking during policy change sched/rt: Fix RT utilization tracking during policy change sched: Change task_struct::state sched,arch: Remove unused TASK_STATE offsets sched,timer: Use __set_current_state() sched: Add get_current_state() sched,perf,kvm: Fix preemption condition sched: Introduce task_is_running() sched: Unbreak wakeups sched/fair: Age the average idle time sched/cpufreq: Consider reduced CPU capacity in energy calculation sched/fair: Take thermal pressure into account while estimating energy thermal/cpufreq_cooling: Update offline CPUs per-cpu thermal_pressure sched/fair: Return early from update_tg_cfs_load() if delta == 0 ...
2021-06-28Merge tag 'perf-core-2021-06-28' of ↵Linus Torvalds1-17/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf events updates from Ingo Molnar: - Platform PMU driver updates: - x86 Intel uncore driver updates for Skylake (SNR) and Icelake (ICX) servers - Fix RDPMC support - Fix [extended-]PEBS-via-PT support - Fix Sapphire Rapids event constraints - Fix :ppp support on Sapphire Rapids - Fix fixed counter sanity check on Alder Lake & X86_FEATURE_HYBRID_CPU - Other heterogenous-PMU fixes - Kprobes: - Remove the unused and misguided kprobe::fault_handler callbacks. - Warn about kprobes taking a page fault. - Fix the 'nmissed' stat counter. - Misc cleanups and fixes. * tag 'perf-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix task context PMU for Hetero perf/x86/intel: Fix instructions:ppp support in Sapphire Rapids perf/x86/intel: Add more events requires FRONTEND MSR on Sapphire Rapids perf/x86/intel: Fix fixed counter check warning for some Alder Lake perf/x86/intel: Fix PEBS-via-PT reload base value for Extended PEBS perf/x86: Reset the dirty counter to prevent the leak for an RDPMC task kprobes: Do not increment probe miss count in the fault handler x86,kprobes: WARN if kprobes tries to handle a fault kprobes: Remove kprobe::fault_handler uprobes: Update uprobe_write_opcode() kernel-doc comment perf/hw_breakpoint: Fix DocBook warnings in perf hw_breakpoint perf/core: Fix DocBook warnings perf/core: Make local function perf_pmu_snapshot_aux() static perf/x86/intel/uncore: Enable I/O stacks to IIO PMON mapping on ICX perf/x86/intel/uncore: Enable I/O stacks to IIO PMON mapping on SNR perf/x86/intel/uncore: Generalize I/O stacks to PMON mapping procedure perf/x86/intel/uncore: Drop unnecessary NULL checks after container_of()
2021-06-26powerpc/interrupt: Use names in check_return_regs_valid()Christophe Leroy1-2/+2
trap->regs == 0x3000 is trap_is_scv() trap 0x500 is INTERRUPT_EXTERNAL Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/d48bf0184a1de185eb0ed3282247f8a294710674.1624632537.git.christophe.leroy@csgroup.eu
2021-06-26powerpc/interrupt: Also use exit_must_hard_disable() on PPC32Christophe Leroy1-5/+3
Reduce #ifdefs a bit by making exit_must_hard_disable() return true on PPC32. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/52531029563c1fc823b790058e799d0ca71b028c.1624631463.git.christophe.leroy@csgroup.eu
2021-06-25Merge tag 'kvmarm-5.14' of ↵Paolo Bonzini2-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for v5.14. - Add MTE support in guests, complete with tag save/restore interface - Reduce the impact of CMOs by moving them in the page-table code - Allow device block mappings at stage-2 - Reduce the footprint of the vmemmap in protected mode - Support the vGIC on dumb systems such as the Apple M1 - Add selftest infrastructure to support multiple configuration and apply that to PMU/non-PMU setups - Add selftests for the debug architecture - The usual crop of PMU fixes
2021-06-25powerpc/sysfs: Replace sizeof(arr)/sizeof(arr[0]) with ARRAY_SIZEJason Wang1-6/+6
The ARRAY_SIZE macro is more compact and more formal in linux source. Signed-off-by: Jason Wang <wangborong@cdjrlc.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210624063632.25632-1-wangborong@cdjrlc.com
2021-06-25powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi()Michael Ellerman1-6/+20
In raise_backtrace_ipi() we iterate through the cpumask of CPUs, sending each an IPI asking them to do a backtrace, but we don't wait for the backtrace to happen. We then iterate through the CPU mask again, and if any CPU hasn't done the backtrace and cleared itself from the mask, we print a trace on its behalf, noting that the trace may be "stale". This works well enough when a CPU is not responding, because in that case it doesn't receive the IPI and the sending CPU is left to print the trace. But when all CPUs are responding we are left with a race between the sending and receiving CPUs, if the sending CPU wins the race then it will erroneously print a trace. This leads to spurious "stale" traces from the sending CPU, which can then be interleaved messily with the receiving CPU, note the CPU numbers, eg: [ 1658.929157][ C7] rcu: Stack dump where RCU GP kthread last ran: [ 1658.929223][ C7] Sending NMI from CPU 7 to CPUs 1: [ 1658.929303][ C1] NMI backtrace for cpu 1 [ 1658.929303][ C7] CPU 1 didn't respond to backtrace IPI, inspecting paca. [ 1658.929362][ C1] CPU: 1 PID: 325 Comm: kworker/1:1H Tainted: G W E 5.13.0-rc2+ #46 [ 1658.929405][ C7] irq_soft_mask: 0x01 in_mce: 0 in_nmi: 0 current: 325 (kworker/1:1H) [ 1658.929465][ C1] Workqueue: events_highpri test_work_fn [test_lockup] [ 1658.929549][ C7] Back trace of paca->saved_r1 (0xc0000000057fb400) (possibly stale): [ 1658.929592][ C1] NIP: c00000000002cf50 LR: c008000000820178 CTR: c00000000002cfa0 To fix it, change the logic so that the sending CPU waits 5s for the receiving CPU to print its trace. If the receiving CPU prints its trace successfully then the sending CPU just continues, avoiding any spurious "stale" trace. This has the added benefit of allowing all CPUs to print their traces in order and avoids any interleaving of their output. Fixes: 5cc05910f26e ("powerpc/64s: Wire up arch_trigger_cpumask_backtrace()") Cc: stable@vger.kernel.org # v4.18+ Reported-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210625140408.3351173-1-mpe@ellerman.id.au
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