[PATCH 7/7] powerpc/traps: Show instructions on exceptions
From: Murilo Opsfelder Araujo <hidden>
Date: 2018-07-24 19:28:25
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Move show_instructions() declaration to arch/powerpc/include/asm/stacktrace.h
and include asm/stracktrace.h in arch/powerpc/kernel/process.c, which contains
the implementation.
Modify show_instructions() not to call __kernel_text_address(), allowing
userspace instruction dump. probe_kernel_address(), which returns -EFAULT if
something goes wrong, is still being called.
Call show_instructions() in arch/powerpc/kernel/traps.c to dump instructions at
faulty location, useful to debugging.
Before this patch, an unhandled signal message looked like:
Jul 24 09:57:00 localhost kernel: pandafault[10524]: segfault (11) at 00000000100007d0 nip 000000001000061c lr 00007fffbd295100 code 2 in pandafault[10000000+10000]
After this patch, it looks like:
Jul 24 09:57:00 localhost kernel: pandafault[10524]: segfault (11) at 00000000100007d0 nip 000000001000061c lr 00007fffbd295100 code 2 in pandafault[10000000+10000]
Jul 24 09:57:00 localhost kernel: Instruction dump:
Jul 24 09:57:00 localhost kernel: 4bfffeec 4bfffee8 3c401002 38427f00 fbe1fff8 f821ffc1 7c3f0b78 3d22fffe
Jul 24 09:57:00 localhost kernel: 392988d0 f93f0020 e93f0020 39400048 <99490000> 39200000 7d234b78 383f0040
Signed-off-by: Murilo Opsfelder Araujo <redacted>
---
arch/powerpc/include/asm/stacktrace.h | 7 +++++++
arch/powerpc/kernel/process.c | 6 +++---
arch/powerpc/kernel/traps.c | 3 +++
3 files changed, 13 insertions(+), 3 deletions(-)
create mode 100644 arch/powerpc/include/asm/stacktrace.h
diff --git a/arch/powerpc/include/asm/stacktrace.h b/arch/powerpc/include/asm/stacktrace.h
new file mode 100644
index 000000000000..46e5ef451578
--- /dev/null
+++ b/arch/powerpc/include/asm/stacktrace.h@@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_STACKTRACE_H +#define _ASM_POWERPC_STACKTRACE_H + +void show_instructions(struct pt_regs *regs); + +#endif /* _ASM_POWERPC_STACKTRACE_H */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index b1af3390249c..ee1d63e03c52 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c@@ -52,6 +52,7 @@ #include <asm/machdep.h> #include <asm/time.h> #include <asm/runlatch.h> +#include <asm/stacktrace.h> #include <asm/syscalls.h> #include <asm/switch_to.h> #include <asm/tm.h>
@@ -1261,7 +1262,7 @@ struct task_struct *__switch_to(struct task_struct *prev, static int instructions_to_print = 16; -static void show_instructions(struct pt_regs *regs) +void show_instructions(struct pt_regs *regs) { int i; unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
@@ -1283,8 +1284,7 @@ static void show_instructions(struct pt_regs *regs) pc = (unsigned long)phys_to_virt(pc); #endif - if (!__kernel_text_address(pc) || - probe_kernel_address((unsigned int __user *)pc, instr)) { + if (probe_kernel_address((unsigned int __user *)pc, instr)) { pr_cont("XXXXXXXX "); } else { if (regs->nip == pc)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index e55ee639d010..3beca17ac1b1 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c@@ -70,6 +70,7 @@ #include <asm/hmi.h> #include <sysdev/fsl_pci.h> #include <asm/kprobes.h> +#include <asm/stacktrace.h> #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC_CORE) int (*__debugger)(struct pt_regs *regs) __read_mostly;
@@ -357,6 +358,8 @@ static void show_signal_msg(int signr, struct pt_regs *regs, int code, print_vma_addr(KERN_CONT " in ", regs->nip); pr_cont("\n"); + + show_instructions(regs); } void _exception_pkey(int signr, struct pt_regs *regs, int code,
--
2.17.1