From 9865f1d46a68a5f58cb623054c8308484007d8a4 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Tue, 3 Jun 2014 19:48:10 +0100 Subject: [PATCH] ARM: 8070/1: Introduce arm_get_current_stack_frame() Currently there are numerous places where "struct pt_regs" are used to populate "struct stackframe", however all of those location do not consider the situation where the kernel might be compiled in THUMB2 mode, in which case the framepointer member of pt_regs become ARM_r7 instead of ARM_fp (r11). Document this idiosyncracy in the definition of "struct stackframe" The easiest solution is to introduce a new function (in the spirit of https://groups.google.com/forum/#!topic/linux.kernel/dA2YuUcSpZ4) which would hide the complexity of initializing the stackframe struct from pt_regs. Also implement a macro frame_pointer(regs) that would return the correct register so that we can use it in cases where we just require the frame pointer and not a whole struct stackframe Signed-off-by: Nikolay Borisov Acked-by: Will Deacon Acked-by: Robert Richter Signed-off-by: Russell King --- arch/arm/include/asm/ptrace.h | 6 ++++++ arch/arm/include/asm/stacktrace.h | 15 +++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h index c877654fe3bf..601264d983fa 100644 --- a/arch/arm/include/asm/ptrace.h +++ b/arch/arm/include/asm/ptrace.h @@ -84,6 +84,12 @@ static inline long regs_return_value(struct pt_regs *regs) #define instruction_pointer(regs) (regs)->ARM_pc +#ifdef CONFIG_THUMB2_KERNEL +#define frame_pointer(regs) (regs)->ARM_r7 +#else +#define frame_pointer(regs) (regs)->ARM_fp +#endif + static inline void instruction_pointer_set(struct pt_regs *regs, unsigned long val) { diff --git a/arch/arm/include/asm/stacktrace.h b/arch/arm/include/asm/stacktrace.h index 4d0a16441b29..7722201ead19 100644 --- a/arch/arm/include/asm/stacktrace.h +++ b/arch/arm/include/asm/stacktrace.h @@ -1,13 +1,28 @@ #ifndef __ASM_STACKTRACE_H #define __ASM_STACKTRACE_H +#include + struct stackframe { + /* + * FP member should hold R7 when CONFIG_THUMB2_KERNEL is enabled + * and R11 otherwise. + */ unsigned long fp; unsigned long sp; unsigned long lr; unsigned long pc; }; +static __always_inline +void arm_get_current_stackframe(struct pt_regs *regs, struct stackframe *frame) +{ + frame->fp = frame_pointer(regs); + frame->sp = regs->ARM_sp; + frame->lr = regs->ARM_lr; + frame->pc = regs->ARM_pc; +} + extern int unwind_frame(struct stackframe *frame); extern void walk_stackframe(struct stackframe *frame, int (*fn)(struct stackframe *, void *), void *data); -- 2.20.1