Re: [PATCH v4 5/6] powerpc: Add show_user_instructions()
From: Christophe LEROY <hidden>
Date: 2018-08-02 05:26:26
Also in:
lkml
Le 01/08/2018 à 23:33, Murilo Opsfelder Araujo a écrit :
quoted hunk ↗ jump to hunk
show_user_instructions() is a slightly modified version of show_instructions() that allows userspace instruction dump. This will be useful within show_signal_msg() to dump userspace instructions of the faulty location. Here is a sample of what show_user_instructions() outputs: pandafault[10850]: code: 4bfffeec 4bfffee8 3c401002 38427f00 fbe1fff8 f821ffc1 7c3f0b78 3d22fffe pandafault[10850]: code: 392988d0 f93f0020 e93f0020 39400048 <99490000> 39200000 7d234b78 383f0040 The current->comm and current->pid printed can serve as a glue that links the instructions dump to its originator, allowing messages to be interleaved in the logs. Signed-off-by: Murilo Opsfelder Araujo <redacted> --- arch/powerpc/include/asm/stacktrace.h | 13 +++++++++ arch/powerpc/kernel/process.c | 40 +++++++++++++++++++++++++++ 2 files changed, 53 insertions(+) create mode 100644 arch/powerpc/include/asm/stacktrace.hdiff --git a/arch/powerpc/include/asm/stacktrace.h b/arch/powerpc/include/asm/stacktrace.h new file mode 100644 index 000000000000..6149b53b3bc8 --- /dev/null +++ b/arch/powerpc/include/asm/stacktrace.h@@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Stack trace functions. + * + * Copyright 2018, Murilo Opsfelder Araujo, IBM Corporation. + */ + +#ifndef _ASM_POWERPC_STACKTRACE_H +#define _ASM_POWERPC_STACKTRACE_H + +void show_user_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 e9533b4d2f08..364645ac732c 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c@@ -1299,6 +1299,46 @@ static void show_instructions(struct pt_regs *regs) pr_cont("\n"); } +void show_user_instructions(struct pt_regs *regs) +{ + int i; + const char *prefix = KERN_INFO "%s[%d]: code: "; + unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 * + sizeof(int)); + + printk(prefix, current->comm, current->pid);
Why not use pr_info() and remove KERN_INFO from *prefix ?
+
+ for (i = 0; i < instructions_to_print; i++) {
+ int instr;
+
+ if (!(i % 8) && (i > 0)) {
+ pr_cont("\n");
+ printk(prefix, current->comm, current->pid);
+ }
+
+#if !defined(CONFIG_BOOKE)
+ /* If executing with the IMMU off, adjust pc rather
+ * than print XXXXXXXX.
+ */
+ if (!(regs->msr & MSR_IR))
+ pc = (unsigned long)phys_to_virt(pc);Shouldn't this be done outside of the loop, only once ? Christophe
+#endif
+
+ if (probe_kernel_address((unsigned int __user *)pc, instr)) {
+ pr_cont("XXXXXXXX ");
+ } else {
+ if (regs->nip == pc)
+ pr_cont("<%08x> ", instr);
+ else
+ pr_cont("%08x ", instr);
+ }
+
+ pc += sizeof(int);
+ }
+
+ pr_cont("\n");
+}
+
struct regbit {
unsigned long bit;
const char *name;