From e33416fca8a2313b8650bd5807aaf34354d39a4c Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Thu, 2 Feb 2023 21:27:35 +1100 Subject: [PATCH 1/3] powerpc: Don't select ARCH_WANTS_NO_INSTR Commit 41b7a347bf14 ("powerpc: Book3S 64-bit outline-only KASAN support") added a select of ARCH_WANTS_NO_INSTR, because it also added some uses of noinstr. However noinstr is always defined, regardless of ARCH_WANTS_NO_INSTR, so there's no need to select it just for that. As PeterZ says [1]: Note that by selecting ARCH_WANTS_NO_INSTR you effectively state to abide by its rules. As of now the powerpc code does not abide by those rules, and trips some new warnings added by Peter in linux-next. So until the code can be fixed to avoid those warnings, disable ARCH_WANTS_NO_INSTR. Note that ARCH_WANTS_NO_INSTR is also used to gate building KCOV and parts of KCSAN. However none of the noinstr annotations in powerpc were added for KCOV or KCSAN, instead instrumentation is blocked at the file level using KCOV_INSTRUMENT_foo.o := n. [1]: https://lore.kernel.org/linuxppc-dev/Y9t6yoafrO5YqVgM@hirez.programming.kicks-ass.net Reported-by: Sachin Sant Suggested-by: Peter Zijlstra Signed-off-by: Michael Ellerman --- arch/powerpc/Kconfig | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index b8c4ac56bddc..7a5f8dbfbdd0 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -163,7 +163,6 @@ config PPC select ARCH_WANT_IRQS_OFF_ACTIVATE_MM select ARCH_WANT_LD_ORPHAN_WARN select ARCH_WANTS_MODULES_DATA_IN_VMALLOC if PPC_BOOK3S_32 || PPC_8xx - select ARCH_WANTS_NO_INSTR select ARCH_WEAK_RELEASE_ACQUIRE select BINFMT_ELF select BUILDTIME_TABLE_SORT From 97e45d469eb180a7bd2809e4e079331552c73e42 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sat, 4 Feb 2023 09:22:06 -0800 Subject: [PATCH 2/3] powerpc/kexec_file: fix implicit decl error kexec (PPC64) code calls memory_hotplug_max(). Add the header declaration for it from . Using does not work since the #include for depends on CONFIG_NUMA=y, which is not always set. Fixes this build error/warning: arch/powerpc/kexec/file_load_64.c: In function 'kexec_extra_fdt_size_ppc64': arch/powerpc/kexec/file_load_64.c:993:33: error: implicit declaration of function 'memory_hotplug_max' 993 | usm_entries = ((memory_hotplug_max() / drmem_lmb_size()) + | ^~~~~~~~~~~~~~~~~~ Fixes: fc546faa5595 ("powerpc/kexec_file: Count hot-pluggable memory in FDT estimate") Signed-off-by: Randy Dunlap Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230204172206.7662-1-rdunlap@infradead.org --- arch/powerpc/kexec/file_load_64.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c index 52085751f5f4..9be3e818a240 100644 --- a/arch/powerpc/kexec/file_load_64.c +++ b/arch/powerpc/kexec/file_load_64.c @@ -26,6 +26,7 @@ #include #include #include +#include #include struct umem_info { From 2ea31e2e62bbc4d11c411eeb36f1b02841dbcab1 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Mon, 6 Feb 2023 14:22:40 +1000 Subject: [PATCH 3/3] powerpc/64s/interrupt: Fix interrupt exit race with security mitigation switch The RFI and STF security mitigation options can flip the interrupt_exit_not_reentrant static branch condition concurrently with the interrupt exit code which tests that branch. Interrupt exit tests this condition to set MSR[EE|RI] for exit, then again in the case a soft-masked interrupt is found pending, to recover the MSR so the interrupt can be replayed before attempting to exit again. If the condition changes between these two tests, the MSR and irq soft-mask state will become corrupted, leading to warnings and possible crashes. For example, if the branch is initially true then false, MSR[EE] will be 0 but PACA_IRQ_HARD_DIS clear and EE may not get enabled, leading to warnings in irq_64.c. Fixes: 13799748b957 ("powerpc/64: use interrupt restart table to speed up return from interrupt") Cc: stable@vger.kernel.org # v5.14+ Reported-by: Sachin Sant Tested-by: Sachin Sant Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230206042240.92103-1-npiggin@gmail.com --- arch/powerpc/kernel/interrupt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index fc6631a80527..0ec1581619db 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -50,16 +50,18 @@ static inline bool exit_must_hard_disable(void) */ static notrace __always_inline bool prep_irq_for_enabled_exit(bool restartable) { + bool must_hard_disable = (exit_must_hard_disable() || !restartable); + /* This must be done with RI=1 because tracing may touch vmaps */ trace_hardirqs_on(); - if (exit_must_hard_disable() || !restartable) + if (must_hard_disable) __hard_EE_RI_disable(); #ifdef CONFIG_PPC64 /* This pattern matches prep_irq_for_idle */ if (unlikely(lazy_irq_pending_nocheck())) { - if (exit_must_hard_disable() || !restartable) { + if (must_hard_disable) { local_paca->irq_happened |= PACA_IRQ_HARD_DIS; __hard_RI_enable(); }