kernel/linux.git/arch/powerpc/include/asm/paca.h, branch linux-7.0.y

powerpc: Remove duplicate/unnecessary ifdefs

2024-02-21T04:15:40+00:00

When an ifdef is used in the below manner, second one could be considered as duplicate. ifdef DEFINE_A ...code block... ifdef DEFINE_A <-- This is a duplicate. ...code block... endif else ifndef DEFINE_A <-- This is also duplicate. ...code block... endif endif More details about the script and methods used to find these code patterns are in cover letter of [1]. Few places in arch/powerpc where this pattern was seen: paca.h: Hunk1: Code is under check of CONFIG_PPC64 from line 13, hence the second CONFIG_PPC64 at line 166 is a duplicate. Hunk2: CONFIG_PPC_BOOK3S_64 was defined back to back. Merged the two ifdefs. asm-offsets.c: Code is under check of CONFIG_PPC64 from line 176 hence second CONFIG_PPC64 at line 249 is a duplicate. powermac/feature.c: #ifndef CONFIG_PPC64 is used at line 2066. And then in #else again #ifdef CONFIG_PPC64 is used. Which is a duplicate since in #else means CONFIG_PPC64 is defined. xmon.c: Code is under the check of CONFIG_SMP from line 521 hence the same check of CONFIG_SMP at line 646 is a duplicate. No functional change is intended here. It only aims to improve code readability. [1] https://lore.kernel.org/all/20240118080326.13137-1-sshegde@linux.ibm.com/ Signed-off-by: Shrikanth Hegde Signed-off-by: Michael Ellerman Link: https://msgid.link/20240216053016.528906-1-sshegde@linux.ibm.com

powerpc: Don't include lppaca.h in paca.h

2023-08-24T12:33:16+00:00

By adding a forward declaration for struct lppaca we can untangle paca.h and lppaca.h. Also move get_lppaca() into lppaca.h for consistency. Add includes of lppaca.h to some files that need it. Signed-off-by: Michael Ellerman Link: https://msgid.link/20230823055317.751786-3-mpe@ellerman.id.au

powerpc: powernv: Fix KCSAN datarace warnings on idle_state contention

2023-06-21T05:13:57+00:00

The idle_state entry in the PACA on PowerNV features a bit which is atomically tested and set through ldarx/stdcx. to be used as a spinlock. This lock then guards access to other bit fields of idle_state. KCSAN cannot differentiate between any of these bitfield accesses as they all are implemented by 8-byte store/load instructions, thus cores contending on the bit-lock appear to data race with modifications to idle_state. Separate the bit-lock entry from the data guarded by the lock to avoid the possibility of data races being detected by KCSAN. Suggested-by: Nicholas Piggin Signed-off-by: Rohan McLure Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230510033117.1395895-7-rmclure@linux.ibm.com

powerpc/64: vmlinux support building with PCREL addresing

2023-04-20T02:59:21+00:00

PC-Relative or PCREL addressing is an extension to the ELF ABI which uses Power ISA v3.1 PC-relative instructions to calculate addresses, rather than the traditional TOC scheme. Add an option to build vmlinux using pcrel addressing. Modules continue to use TOC addressing. - TOC address helpers and r2 are poisoned with -1 when running vmlinux. r2 could be used for something useful once things are ironed out. - Assembly must call C functions with @notoc annotation, or the linker complains aobut a missing nop after the call. This is done with the CFUNC macro introduced earlier. - Boot: with the exception of prom_init, the execution branches to the kernel virtual address early in boot, before any addresses are generated, which ensures 34-bit pcrel addressing does not miss the high PAGE_OFFSET bits. TOC relative addressing has a similar requirement. prom_init does not go to the virtual address and its addresses should not carry over to the post-prom kernel. - Ftrace trampolines are converted from TOC addressing to pcrel addressing, including module ftrace trampolines that currently use the kernel TOC to find ftrace target functions. - BPF function prologue and function calling generation are converted from TOC to pcrel. - copypage_64.S has an interesting problem, prefixed instructions have alignment restrictions so the linker can add padding, which makes the assembler treat the difference between two local labels as non-constant even if alignment is arranged so padding is not required. This may need toolchain help to solve nicely, for now move the prefix instruction out of the alternate patch section to work around it. This reduces kernel text size by about 6%. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230408021752.862660-6-npiggin@gmail.com

powerpc/64: Move paca allocation to early_setup()

2023-02-10T11:19:56+00:00

The early paca and boot cpuid dance is complicated and currently does not quite work as expected for boot cpuid != 0 cases. early_init_devtree() currently allocates the paca_ptrs and boot cpuid paca, but until that returns and early_setup() calls setup_paca(), this thread is currently still executing with smp_processor_id() == 0. One problem this causes is the paca_ptrs[smp_processor_id()] pointer is poisoned, so valid_emergency_stack() (any backtrace) and any similar users will crash. Another is that the hardware id which is set here will not be returned by get_hard_smp_processor_id(smp_processor_id()), but it would work correctly for boot_cpuid == 0, which could lead to difficult to reproduce or find bugs. The hard id does not seem to be used by the rest of early_init_devtree(), it just looks like all this code might have been put here to allocate somewhere to store boot CPU hardware id while scanning the devtree. Rearrange things so the hwid is put in a global variable like boot_cpuid, and do all the paca allocation and boot paca setup in the 64-bit early_setup() after we have everything ready to go. The paca_ptrs[0] re-poisoning code in early_setup does not seem to have ever worked, because paca_ptrs[0] was never not-poisoned when boot_cpuid is not 0. Signed-off-by: Nicholas Piggin [mpe: Fix build error on 32-bit] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221216115930.2667772-4-npiggin@gmail.com

powerpc: Remove CONFIG_PPC_BOOK3E

2022-09-26T13:00:13+00:00

CONFIG_PPC_BOOK3E is redundant with CONFIG_PPC_BOOK3E_64. The later is more explicit about the fact that it's a 64 bits target. Remove CONFIG_PPC_BOOK3E. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/5d0891490813c19cdcfc04678f512ea68cba3e64.1663606876.git.christophe.leroy@csgroup.eu

Revert "powerpc/rtas: Implement reentrant rtas call"

2022-09-14T12:43:13+00:00

At the time this was submitted by Leonardo, I confirmed -- or thought I had confirmed -- with PowerVM partition firmware development that the following RTAS functions: - ibm,get-xive - ibm,int-off - ibm,int-on - ibm,set-xive were safe to call on multiple CPUs simultaneously, not only with respect to themselves as indicated by PAPR, but with arbitrary other RTAS calls: https://lore.kernel.org/linuxppc-dev/875zcy2v8o.fsf@linux.ibm.com/ Recent discussion with firmware development makes it clear that this is not true, and that the code in commit b664db8e3f97 ("powerpc/rtas: Implement reentrant rtas call") is unsafe, likely explaining several strange bugs we've seen in internal testing involving DLPAR and LPM. These scenarios use ibm,configure-connector, whose internal state can be corrupted by the concurrent use of the "reentrant" functions, leading to symptoms like endless busy statuses from RTAS. Fixes: b664db8e3f97 ("powerpc/rtas: Implement reentrant rtas call") Cc: stable@vger.kernel.org # v5.8+ Signed-off-by: Nathan Lynch Reviewed-by: Laurent Dufour Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220907220111.223267-1-nathanl@linux.ibm.com

powerpc/64: Include cache.h directly in paca.h

2022-05-27T12:20:09+00:00

paca.h uses ____cacheline_aligned without directly including cache.h, where it's defined. For Book3S builds that's OK because paca.h includes lppaca.h, and it does include cache.h. But Book3E builds have been getting cache.h indirectly via printk.h, which is dicey, and in fact that include was recently removed, leading to build errors such as: ld: fs/isofs/dir.o:(.bss+0x0): multiple definition of `____cacheline_aligned'; fs/isofs/namei.o:(.bss+0x0): first defined here So include cache.h directly to fix the build error. Fixes: 534aa1dc975a ("printk: stop including cache.h from printk.h") Reported-by: Guenter Roeck Signed-off-by: Michael Ellerman

powerpc/mm: Remove CONFIG_PPC_MM_SLICES

2022-05-05T12:11:57+00:00

CONFIG_PPC_MM_SLICES is always selected by hash book3s/64. CONFIG_PPC_MM_SLICES is never selected by other platforms. Remove it. Signed-off-by: Christophe Leroy Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/dc2cdc204de8978574bf7c02329b6cfc4db0bce7.1649523076.git.christophe.leroy@csgroup.eu

powerpc/mce: Avoid using irq_work_queue() in realmode

2022-03-07T13:05:00+00:00

In realmode mce handler we use irq_work_queue() to defer the processing of mce events, irq_work_queue() can only be called when translation is enabled because it touches memory outside RMA, hence we enable translation before calling irq_work_queue and disable on return, though it is not safe to do in realmode. To avoid this, program the decrementer and call the event processing functions from timer handler. Signed-off-by: Ganesh Goudar Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220120121931.517974-1-ganeshgr@linux.ibm.com