From bd2a13f32959a851d43d9681d9dc9b8bb3eec398 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Tue, 15 May 2018 19:42:23 +0200 Subject: [PATCH] arm: print instructions pointed to by pc If an exception occurs in a loaded image and the relocation offset is unknown, it is helful to know the instructions pointed to by the program counter. This patch adds the missing output. A possible output is: Code: e1c560d0 e12fff1e e120077b e12fff1e (e7f7defb) The parentheses indicate the instruction causing the exception. The output can be disassembled using the decodecode script provided by the Linux kernel project. Signed-off-by: Heinrich Schuchardt --- arch/arm/lib/interrupts.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/arm/lib/interrupts.c b/arch/arm/lib/interrupts.c index 28ba3f1..930b25c 100644 --- a/arch/arm/lib/interrupts.c +++ b/arch/arm/lib/interrupts.c @@ -56,6 +56,30 @@ static void show_efi_loaded_images(struct pt_regs *regs) efi_print_image_infos((void *)instruction_pointer(regs)); } +static void dump_instr(struct pt_regs *regs) +{ + unsigned long addr = instruction_pointer(regs); + const int thumb = thumb_mode(regs); + const int width = thumb ? 4 : 8; + int i; + + if (thumb) + addr &= ~1L; + else + addr &= ~3L; + printf("Code: "); + for (i = -4; i < 1 + !!thumb; i++) { + unsigned int val; + + if (thumb) + val = ((u16 *)addr)[i]; + else + val = ((u32 *)addr)[i]; + printf(i == 0 ? "(%0*x) " : "%0*x ", width, val); + } + printf("\n"); +} + void show_regs (struct pt_regs *regs) { unsigned long __maybe_unused flags; @@ -96,6 +120,7 @@ void show_regs (struct pt_regs *regs) fast_interrupts_enabled (regs) ? "on" : "off", processor_modes[processor_mode (regs)], thumb_mode (regs) ? " (T)" : ""); + dump_instr(regs); } /* fixup PC to point to the instruction leading to the exception */