| From ac11de3c592a76b4cd8124016f3efa1eaf26bc3e Mon Sep 17 00:00:00 2001 |
| From: Paul Burton <paul.burton@imgtec.com> |
| Date: Mon, 7 Nov 2016 15:07:02 +0000 |
| Subject: [PATCH] MIPS: Clear ISA bit correctly in get_frame_info() |
| |
| commit ccaf7caf2c73c6db920772bf08bf1d47b2170634 upstream. |
| |
| get_frame_info() can be called in microMIPS kernels with the ISA bit |
| already clear. For example this happens when unwind_stack_by_address() |
| is called because we begin with a PC that has the ISA bit set & subtract |
| the (odd) offset from the preceding symbol (which does not have the ISA |
| bit set). Since get_frame_info() unconditionally subtracts 1 from the PC |
| in microMIPS kernels it incorrectly misaligns the address it then |
| attempts to access code at, leading to an address error exception. |
| |
| Fix this by using msk_isa16_mode() to clear the ISA bit, which allows |
| get_frame_info() to function regardless of whether it is provided with a |
| PC that has the ISA bit set or not. |
| |
| Signed-off-by: Paul Burton <paul.burton@imgtec.com> |
| Fixes: 34c2f668d0f6 ("MIPS: microMIPS: Add unaligned access support.") |
| Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> |
| Cc: linux-mips@linux-mips.org |
| Cc: <stable@vger.kernel.org> # v3.10+ |
| Patchwork: https://patchwork.linux-mips.org/patch/14528/ |
| Signed-off-by: Ralf Baechle <ralf@linux-mips.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c |
| index d2d061520a23..19b4e57105da 100644 |
| --- a/arch/mips/kernel/process.c |
| +++ b/arch/mips/kernel/process.c |
| @@ -303,17 +303,14 @@ static inline int is_sp_move_ins(union mips_instruction *ip) |
| |
| static int get_frame_info(struct mips_frame_info *info) |
| { |
| -#ifdef CONFIG_CPU_MICROMIPS |
| - union mips_instruction *ip = (void *) (((char *) info->func) - 1); |
| -#else |
| - union mips_instruction *ip = info->func; |
| -#endif |
| + union mips_instruction *ip; |
| unsigned max_insns = info->func_size / sizeof(union mips_instruction); |
| unsigned i; |
| |
| info->pc_offset = -1; |
| info->frame_size = 0; |
| |
| + ip = (void *)msk_isa16_mode((ulong)info->func); |
| if (!ip) |
| goto err; |
| |
| -- |
| 2.12.0 |
| |