diff mbox series

[v3,1/2] riscv: Add instruction dump to RISC-V splats

Message ID 20230119074738.708301-2-bjorn@kernel.org (mailing list archive)
State Accepted
Commit eb165bfa8eafc3d306e34b238e53aafb35dce102
Delegated to: Palmer Dabbelt
Headers show
Series riscv: Dump faulting instructions in oops handler | expand

Checks

Context Check Description
conchuod/cover_letter success Series has a cover letter
conchuod/tree_selection success Guessed tree name to be for-next
conchuod/fixes_present success Fixes tag not required for -next series
conchuod/maintainers_pattern success MAINTAINERS pattern errors before the patch: 13 and now 13
conchuod/verify_signedoff success Signed-off-by tag matches author and committer
conchuod/kdoc success Errors and warnings before: 0 this patch: 0
conchuod/module_param success Was 0 now: 0
conchuod/build_rv64_gcc_allmodconfig success Errors and warnings before: 0 this patch: 0
conchuod/alphanumeric_selects success Out of order selects before the patch: 57 and now 57
conchuod/build_rv32_defconfig success Build OK
conchuod/dtb_warn_rv64 success Errors and warnings before: 2 this patch: 2
conchuod/header_inline success No static functions without inline keyword in header files
conchuod/checkpatch warning WARNING: Using vsprintf specifier '%px' potentially exposes the kernel memory layout, if you don't really need the address please consider using '%p'. WARNING: printk() should include KERN_<LEVEL> facility level
conchuod/source_inline success Was 0 now: 0
conchuod/build_rv64_nommu_k210_defconfig success Build OK
conchuod/verify_fixes success No Fixes tag
conchuod/build_rv64_nommu_virt_defconfig success Build OK

Commit Message

Björn Töpel Jan. 19, 2023, 7:47 a.m. UTC 
From: Björn Töpel <bjorn@rivosinc.com>

Add instruction dump (Code:) output to RISC-V splats. Dump 16b
parcels.

An example:
  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
  Oops [#1]
  Modules linked in:
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc3-00302-g840ff44c571d-dirty #27
  Hardware name: riscv-virtio,qemu (DT)
  epc : kernel_init+0xc8/0x10e
   ra : kernel_init+0x70/0x10e
  epc : ffffffff80bd9a40 ra : ffffffff80bd99e8 sp : ff2000000060bec0
   gp : ffffffff81730b28 tp : ff6000007ff00000 t0 : 7974697275636573
   t1 : 0000000000000000 t2 : 3030303270393d6e s0 : ff2000000060bee0
   s1 : ffffffff81732028 a0 : 0000000000000000 a1 : ff60000080dd1780
   a2 : 0000000000000002 a3 : ffffffff8176a470 a4 : 0000000000000000
   a5 : 000000000000000a a6 : 0000000000000081 a7 : ff60000080dd1780
   s2 : 0000000000000000 s3 : 0000000000000000 s4 : 0000000000000000
   s5 : 0000000000000000 s6 : 0000000000000000 s7 : 0000000000000000
   s8 : 0000000000000000 s9 : 0000000000000000 s10: 0000000000000000
   s11: 0000000000000000 t3 : ffffffff81186018 t4 : 0000000000000022
   t5 : 000000000000003d t6 : 0000000000000000
  status: 0000000200000120 badaddr: 0000000000000000 cause: 000000000000000f
  [<ffffffff80003528>] ret_from_exception+0x0/0x16
  Code: 862a d179 608c a517 0069 0513 2be5 d0ef db2e 47a9 (c11c) a517
  ---[ end trace 0000000000000000 ]---
  Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
  SMP: stopping secondary CPUs
  ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---

Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
---
 arch/riscv/kernel/traps.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 549bde5c970a..fbdcdbc792d3 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -29,6 +29,27 @@  int show_unhandled_signals = 1;
 
 static DEFINE_SPINLOCK(die_lock);
 
+static void dump_kernel_instr(const char *loglvl, struct pt_regs *regs)
+{
+	char str[sizeof("0000 ") * 12 + 2 + 1], *p = str;
+	const u16 *insns = (u16 *)instruction_pointer(regs);
+	long bad;
+	u16 val;
+	int i;
+
+	for (i = -10; i < 2; i++) {
+		bad = get_kernel_nofault(val, &insns[i]);
+		if (!bad) {
+			p += sprintf(p, i == 0 ? "(%04hx) " : "%04hx ", val);
+		} else {
+			printk("%sCode: Unable to access instruction at 0x%px.\n",
+			       loglvl, &insns[i]);
+			return;
+		}
+	}
+	printk("%sCode: %s\n", loglvl, str);
+}
+
 void die(struct pt_regs *regs, const char *str)
 {
 	static int die_counter;
@@ -43,8 +64,10 @@  void die(struct pt_regs *regs, const char *str)
 
 	pr_emerg("%s [#%d]\n", str, ++die_counter);
 	print_modules();
-	if (regs)
+	if (regs) {
 		show_regs(regs);
+		dump_kernel_instr(KERN_EMERG, regs);
+	}
 
 	cause = regs ? regs->cause : -1;
 	ret = notify_die(DIE_OOPS, str, regs, 0, cause, SIGSEGV);