From e0ffcf3fe18e0310221461c08969edec2cc7628c Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 30 May 2022 14:20:50 +0200 Subject: [PATCH] s390/stack: add union to reflect kvm stack slot usages Add a union which describes how the empty stack slots are being used by kvm and perf. This should help to avoid another bug like the one which was fixed with commit c9bfb460c3e4 ("s390/perf: obtain sie_block from the right address"). Reviewed-by: Nico Boehr Tested-by: Nico Boehr Signed-off-by: Heiko Carstens --- arch/s390/include/asm/stacktrace.h | 10 +++++++++- arch/s390/kernel/asm-offsets.c | 8 ++++---- arch/s390/kernel/perf_event.c | 2 +- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h index 7e0e15bee18d..b23c658dce77 100644 --- a/arch/s390/include/asm/stacktrace.h +++ b/arch/s390/include/asm/stacktrace.h @@ -39,7 +39,15 @@ static inline bool on_stack(struct stack_info *info, * Kernel uses the packed stack layout (-mpacked-stack). */ struct stack_frame { - unsigned long empty[9]; + union { + unsigned long empty[9]; + struct { + unsigned long sie_control_block; + unsigned long sie_savearea; + unsigned long sie_reason; + unsigned long sie_flags; + }; + }; unsigned long gprs[10]; unsigned long back_chain; }; diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index 0e10d7ff4203..d8ce965c0a97 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -58,10 +58,10 @@ int main(void) OFFSET(__SF_BACKCHAIN, stack_frame, back_chain); OFFSET(__SF_GPRS, stack_frame, gprs); OFFSET(__SF_EMPTY, stack_frame, empty[0]); - OFFSET(__SF_SIE_CONTROL, stack_frame, empty[1]); - OFFSET(__SF_SIE_SAVEAREA, stack_frame, empty[2]); - OFFSET(__SF_SIE_REASON, stack_frame, empty[3]); - OFFSET(__SF_SIE_FLAGS, stack_frame, empty[4]); + OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block); + OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea); + OFFSET(__SF_SIE_REASON, stack_frame, sie_reason); + OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags); DEFINE(STACK_FRAME_OVERHEAD, sizeof(struct stack_frame)); BLANK(); /* idle data offsets */ diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c index e259ff1f5ad3..c27321cb0969 100644 --- a/arch/s390/kernel/perf_event.c +++ b/arch/s390/kernel/perf_event.c @@ -30,7 +30,7 @@ static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs) if (!stack) return NULL; - return (struct kvm_s390_sie_block *)stack->empty[1]; + return (struct kvm_s390_sie_block *)stack->sie_control_block; } static bool is_in_guest(struct pt_regs *regs)