From bee4e1fdc31223f8e0569370635ced223a1dd2ce Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 10 Mar 2022 18:05:28 +0100 Subject: [PATCH] ARM: Revert "unwind: dump exception stack from calling frame" After simplifying the stack switch code in the IRQ exception handler by deferring the actual stack switch to call_with_stack(), we no longer need to special case the way we dump the exception stack, since it will always be at the top of whichever stack was active when the exception was taken. So revert this special handling for the ARM unwinder. This reverts commit 4ab6827081c63b83011a18d8e27f621ed34b1194. Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King (Oracle) --- arch/arm/include/asm/stacktrace.h | 10 ---------- arch/arm/kernel/traps.c | 3 +-- arch/arm/kernel/unwind.c | 9 +-------- 3 files changed, 2 insertions(+), 20 deletions(-) diff --git a/arch/arm/include/asm/stacktrace.h b/arch/arm/include/asm/stacktrace.h index e56503fd9447..3e78f921b8b2 100644 --- a/arch/arm/include/asm/stacktrace.h +++ b/arch/arm/include/asm/stacktrace.h @@ -21,16 +21,6 @@ struct stackframe { struct llist_node *kr_cur; struct task_struct *tsk; #endif -#ifdef CONFIG_ARM_UNWIND - /* - * This field is used to track the stack pointer value when calling - * __entry routines. This is needed when IRQ stacks and overflow stacks - * are used, because in that case, the struct pt_regs passed to these - * __entry routines may be at the top of the task stack, while we are - * executing from another stack. - */ - unsigned long sp_low; -#endif }; static __always_inline diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 08612032aefe..a4938b699b49 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -87,8 +87,7 @@ void dump_backtrace_entry(unsigned long where, unsigned long from, loglvl, where, from); #endif - if (!IS_ENABLED(CONFIG_UNWINDER_ARM) && - in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE)) + if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE)) dump_mem(loglvl, "Exception stack", frame + 4, end); } diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c index 3cd8892ed52b..e619ec7856b7 100644 --- a/arch/arm/kernel/unwind.c +++ b/arch/arm/kernel/unwind.c @@ -29,7 +29,6 @@ #include #include -#include #include #include #include @@ -424,7 +423,6 @@ int unwind_frame(struct stackframe *frame) */ if (frame->pc == frame->lr) return -URC_FAILURE; - frame->sp_low = frame->sp; frame->pc = frame->lr; return URC_OK; } else if ((idx->insn & 0x80000000) == 0) @@ -476,7 +474,6 @@ int unwind_frame(struct stackframe *frame) frame->sp = ctrl.vrs[SP]; frame->lr = ctrl.vrs[LR]; frame->pc = ctrl.vrs[PC]; - frame->sp_low = ctrl.sp_low; frame->lr_addr = ctrl.lr_addr; return URC_OK; @@ -526,11 +523,7 @@ here: urc = unwind_frame(&frame); if (urc < 0) break; - if (in_entry_text(where)) - dump_mem(loglvl, "Exception stack", frame.sp_low, - frame.sp_low + sizeof(struct pt_regs)); - - dump_backtrace_entry(where, frame.pc, 0, loglvl); + dump_backtrace_entry(where, frame.pc, frame.sp - 4, loglvl); } }