BMC/Intel-BMC/linux.git/arch/arm64, branch dev-5.2

arm64: cpufeature: Don't treat granule sizes as strict

2019-09-06T08:23:23+00:00

[ Upstream commit 5717fe5ab38f9ccb32718bcb03bea68409c9cce4 ] If a CPU doesn't support the page size for which the kernel is configured, then we will complain and refuse to bring it online. For secondary CPUs (and the boot CPU on a system booting with EFI), we will also print an error identifying the mismatch. Consequently, the only time that the cpufeature code can detect a granule size mismatch is for a granule other than the one that is currently being used. Although we would rather such systems didn't exist, we've unfortunately lost that battle and Kevin reports that on his amlogic S922X (odroid-n2 board) we end up warning and taining with defconfig because 16k pages are not supported by all of the CPUs. In such a situation, we don't actually care about the feature mismatch, particularly now that KVM only exposes the sanitised view of the CPU registers (commit 93390c0a1b20 - "arm64: KVM: Hide unsupported AArch64 CPU features from guests"). Treat the granule fields as non-strict and let Kevin run without a tainted kernel. Cc: Marc Zyngier Reported-by: Kevin Hilman Tested-by: Kevin Hilman Acked-by: Mark Rutland Acked-by: Suzuki K Poulose Signed-off-by: Will Deacon [catalin.marinas@arm.com: changelog updated with KVM sanitised regs commit] Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin

KVM: arm64: Don't write junk to sysregs on reset

2019-08-29T06:30:19+00:00

[ Upstream commit 03fdfb2690099c19160a3f2c5b77db60b3afeded ] At the moment, the way we reset system registers is mildly insane: We write junk to them, call the reset functions, and then check that we have something else in them. The "fun" thing is that this can happen while the guest is running (PSCI, for example). If anything in KVM has to evaluate the state of a system register while junk is in there, bad thing may happen. Let's stop doing that. Instead, we track that we have called a reset function for that register, and assume that the reset function has done something. This requires fixing a couple of sysreg refinition in the trap table. In the end, the very need of this reset check is pretty dubious, as it doesn't check everything (a lot of the sysregs leave outside of the sys_regs[] array). It may well be axed in the near future. Tested-by: Zenghui Yu Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin

arm64: KVM: regmap: Fix unexpected switch fall-through

2019-08-25T14:10:34+00:00

commit 3d584a3c85d6fe2cf878f220d4ad7145e7f89218 upstream. When fall-through warnings was enabled by default, commit d93512ef0f0e ("Makefile: Globally enable fall-through warning"), the following warnings was starting to show up: In file included from ../arch/arm64/include/asm/kvm_emulate.h:19, from ../arch/arm64/kvm/regmap.c:13: ../arch/arm64/kvm/regmap.c: In function ‘vcpu_write_spsr32’: ../arch/arm64/include/asm/kvm_hyp.h:31:3: warning: this statement may fall through [-Wimplicit-fallthrough=] asm volatile(ALTERNATIVE(__msr_s(r##nvh, "%x0"), \ ^~~ ../arch/arm64/include/asm/kvm_hyp.h:46:31: note: in expansion of macro ‘write_sysreg_elx’ #define write_sysreg_el1(v,r) write_sysreg_elx(v, r, _EL1, _EL12) ^~~~~~~~~~~~~~~~ ../arch/arm64/kvm/regmap.c:180:3: note: in expansion of macro ‘write_sysreg_el1’ write_sysreg_el1(v, SYS_SPSR); ^~~~~~~~~~~~~~~~ ../arch/arm64/kvm/regmap.c:181:2: note: here case KVM_SPSR_ABT: ^~~~ In file included from ../arch/arm64/include/asm/cputype.h:132, from ../arch/arm64/include/asm/cache.h:8, from ../include/linux/cache.h:6, from ../include/linux/printk.h:9, from ../include/linux/kernel.h:15, from ../include/asm-generic/bug.h:18, from ../arch/arm64/include/asm/bug.h:26, from ../include/linux/bug.h:5, from ../include/linux/mmdebug.h:5, from ../include/linux/mm.h:9, from ../arch/arm64/kvm/regmap.c:11: ../arch/arm64/include/asm/sysreg.h:837:2: warning: this statement may fall through [-Wimplicit-fallthrough=] asm volatile("msr " __stringify(r) ", %x0" \ ^~~ ../arch/arm64/kvm/regmap.c:182:3: note: in expansion of macro ‘write_sysreg’ write_sysreg(v, spsr_abt); ^~~~~~~~~~~~ ../arch/arm64/kvm/regmap.c:183:2: note: here case KVM_SPSR_UND: ^~~~ Rework to add a 'break;' in the swich-case since it didn't have that, leading to an interresting set of bugs. Cc: stable@vger.kernel.org # v4.17+ Fixes: a892819560c4 ("KVM: arm64: Prepare to handle deferred save/restore of 32-bit registers") Signed-off-by: Anders Roxell [maz: reworked commit message, fixed stable range] Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

arm64: Make debug exception handlers visible from RCU

2019-08-25T14:10:33+00:00

[ Upstream commit d8bb6718c4db9bcd075dde7ff55d46091ccfae15 ] Make debug exceptions visible from RCU so that synchronize_rcu() correctly track the debug exception handler. This also introduces sanity checks for user-mode exceptions as same as x86's ist_enter()/ist_exit(). The debug exception can interrupt in idle task. For example, it warns if we put a kprobe on a function called from idle task as below. The warning message showed that the rcu_read_lock() caused this problem. But actually, this means the RCU is lost the context which is already in NMI/IRQ. /sys/kernel/debug/tracing # echo p default_idle_call >> kprobe_events /sys/kernel/debug/tracing # echo 1 > events/kprobes/enable /sys/kernel/debug/tracing # [ 135.122237] [ 135.125035] ============================= [ 135.125310] WARNING: suspicious RCU usage [ 135.125581] 5.2.0-08445-g9187c508bdc7 #20 Not tainted [ 135.125904] ----------------------------- [ 135.126205] include/linux/rcupdate.h:594 rcu_read_lock() used illegally while idle! [ 135.126839] [ 135.126839] other info that might help us debug this: [ 135.126839] [ 135.127410] [ 135.127410] RCU used illegally from idle CPU! [ 135.127410] rcu_scheduler_active = 2, debug_locks = 1 [ 135.128114] RCU used illegally from extended quiescent state! [ 135.128555] 1 lock held by swapper/0/0: [ 135.128944] #0: (____ptrval____) (rcu_read_lock){....}, at: call_break_hook+0x0/0x178 [ 135.130499] [ 135.130499] stack backtrace: [ 135.131192] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0-08445-g9187c508bdc7 #20 [ 135.131841] Hardware name: linux,dummy-virt (DT) [ 135.132224] Call trace: [ 135.132491] dump_backtrace+0x0/0x140 [ 135.132806] show_stack+0x24/0x30 [ 135.133133] dump_stack+0xc4/0x10c [ 135.133726] lockdep_rcu_suspicious+0xf8/0x108 [ 135.134171] call_break_hook+0x170/0x178 [ 135.134486] brk_handler+0x28/0x68 [ 135.134792] do_debug_exception+0x90/0x150 [ 135.135051] el1_dbg+0x18/0x8c [ 135.135260] default_idle_call+0x0/0x44 [ 135.135516] cpu_startup_entry+0x2c/0x30 [ 135.135815] rest_init+0x1b0/0x280 [ 135.136044] arch_call_rest_init+0x14/0x1c [ 135.136305] start_kernel+0x4d4/0x500 [ 135.136597] So make debug exception visible to RCU can fix this warning. Reported-by: Naresh Kamboju Acked-by: Paul E. McKenney Signed-off-by: Masami Hiramatsu Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: kprobes: Recover pstate.D in single-step exception handler

2019-08-25T14:10:33+00:00

[ Upstream commit b3980e48528c4d2a9e70b145a5bba328b73a0f93 ] kprobes manipulates the interrupted PSTATE for single step, and doesn't restore it. Thus, if we put a kprobe where the pstate.D (debug) masked, the mask will be cleared after the kprobe hits. Moreover, in the most complicated case, this can lead a kernel crash with below message when a nested kprobe hits. [ 152.118921] Unexpected kernel single-step exception at EL1 When the 1st kprobe hits, do_debug_exception() will be called. At this point, debug exception (= pstate.D) must be masked (=1). But if another kprobes hits before single-step of the first kprobe (e.g. inside user pre_handler), it unmask the debug exception (pstate.D = 0) and return. Then, when the 1st kprobe setting up single-step, it saves current DAIF, mask DAIF, enable single-step, and restore DAIF. However, since "D" flag in DAIF is cleared by the 2nd kprobe, the single-step exception happens soon after restoring DAIF. This has been introduced by commit 7419333fa15e ("arm64: kprobe: Always clear pstate.D in breakpoint exception handler") To solve this issue, this stores all DAIF bits and restore it after single stepping. Reported-by: Naresh Kamboju Fixes: 7419333fa15e ("arm64: kprobe: Always clear pstate.D in breakpoint exception handler") Reviewed-by: James Morse Tested-by: James Morse Signed-off-by: Masami Hiramatsu Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64/mm: fix variable 'tag' set but not used

2019-08-25T14:10:32+00:00

[ Upstream commit 7732d20a160c76006c7fe7bca5178aea6af1d2e8 ] When CONFIG_KASAN_SW_TAGS=n, set_tag() is compiled away. GCC throws a warning, mm/kasan/common.c: In function '__kasan_kmalloc': mm/kasan/common.c:464:5: warning: variable 'tag' set but not used [-Wunused-but-set-variable] u8 tag = 0xff; ^~~ Fix it by making __tag_set() a static inline function the same as arch_kasan_set_tag() in mm/kasan/kasan.h for consistency because there is a macro in arch/arm64/include/asm/kasan.h, #define arch_kasan_set_tag(addr, tag) __tag_set(addr, tag) However, when CONFIG_DEBUG_VIRTUAL=n and CONFIG_SPARSEMEM_VMEMMAP=y, page_to_virt() will call __tag_set() with incorrect type of a parameter, so fix that as well. Also, still let page_to_virt() return "void *" instead of "const void *", so will not need to add a similar cast in lowmem_page_address(). Signed-off-by: Qian Cai Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64/mm: fix variable 'pud' set but not used

2019-08-25T14:10:32+00:00

[ Upstream commit 7d4e2dcf311d3b98421d1f119efe5964cafa32fc ] GCC throws a warning, arch/arm64/mm/mmu.c: In function 'pud_free_pmd_page': arch/arm64/mm/mmu.c:1033:8: warning: variable 'pud' set but not used [-Wunused-but-set-variable] pud_t pud; ^~~ because pud_table() is a macro and compiled away. Fix it by making it a static inline function and for pud_sect() as well. Signed-off-by: Qian Cai Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: unwind: Prohibit probing on return_address()

2019-08-25T14:10:32+00:00

[ Upstream commit ee07b93e7721ccd5d5b9fa6f0c10cb3fe2f1f4f9 ] Prohibit probing on return_address() and subroutines which is called from return_address(), since the it is invoked from trace_hardirqs_off() which is also kprobe blacklisted. Reported-by: Naresh Kamboju Signed-off-by: Masami Hiramatsu Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: Lower priority mask for GIC_PRIO_IRQON

2019-08-25T14:10:31+00:00

[ Upstream commit 677379bc9139ac24b310a281fcb21a2f04288353 ] On a system with two security states, if SCR_EL3.FIQ is cleared, non-secure IRQ priorities get shifted to fit the secure view but priority masks aren't. On such system, it turns out that GIC_PRIO_IRQON masks the priority of normal interrupts, which obviously ends up in a hang. Increase GIC_PRIO_IRQON value (i.e. lower priority) to make sure interrupts are not blocked by it. Cc: Oleg Nesterov Fixes: bd82d4bd21880b7c ("arm64: Fix incorrect irqflag restore for priority masking") Acked-by: Marc Zyngier Signed-off-by: Julien Thierry Signed-off-by: Catalin Marinas [will: fixed Fixes: tag] Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64/efi: fix variable 'si' set but not used

2019-08-25T14:10:31+00:00

[ Upstream commit f1d4836201543e88ebe70237e67938168d5fab19 ] GCC throws out this warning on arm64. drivers/firmware/efi/libstub/arm-stub.c: In function 'efi_entry': drivers/firmware/efi/libstub/arm-stub.c:132:22: warning: variable 'si' set but not used [-Wunused-but-set-variable] Fix it by making free_screen_info() a static inline function. Acked-by: Will Deacon Signed-off-by: Qian Cai Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin