| Message ID | 20230116073834.333129-2-bjorn@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Palmer Dabbelt |
| Headers | show |
| Series | riscv: Dump faulting instructions in oops handler | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/patch_count | success | Link |
| 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: 4 this patch: 4 |
| conchuod/header_inline | success | No static functions without inline keyword in header files |
| conchuod/checkpatch | warning | 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 |
Hi Björn, On Mon, Jan 16, 2023 at 8:41 AM Björn Töpel <bjorn@kernel.org> wrote: > 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> Thanks for your patch! > --- 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; > + unsigned long addr = regs->epc; Given you never use this as an unsigned long, what about const u16 *insns = (u16 *)instruction_pointer(regs); so you no longer need casts below? > + long bad; > + u16 val; > + int i; > + > + for (i = -10; i < 2; i++) { > + bad = get_kernel_nofault(val, &((u16 *)addr)[i]); > + if (!bad) { > + p += sprintf(p, i == 0 ? "(%04hx) " : "%04hx ", val); > + } else { > + printk("%sCode: Unable to access instruction at 0x%lx.\n", %px, so you can drop the cast to long below. > + loglvl, (long)&((u16 *)addr)[i]); > + return; > + } > + } > + printk("%sCode: %s\n", loglvl, str); > +} > + > void die(struct pt_regs *regs, const char *str) > { > static int die_counter; Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Geert Uytterhoeven <geert@linux-m68k.org> writes: >> +static void dump_kernel_instr(const char *loglvl, struct pt_regs *regs) >> +{ >> + char str[sizeof("0000 ") * 12 + 2 + 1], *p = str; >> + unsigned long addr = regs->epc; > > Given you never use this as an unsigned long, what about > > const u16 *insns = (u16 *)instruction_pointer(regs); > > so you no longer need casts below? Indeed! Good suggestion, thank you! I'll do this change in v3. >> + long bad; >> + u16 val; >> + int i; >> + >> + for (i = -10; i < 2; i++) { >> + bad = get_kernel_nofault(val, &((u16 *)addr)[i]); >> + if (!bad) { >> + p += sprintf(p, i == 0 ? "(%04hx) " : "%04hx ", val); >> + } else { >> + printk("%sCode: Unable to access instruction at 0x%lx.\n", > > %px, so you can drop the cast to long below. Much cleaner. Thanks! Björn
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 549bde5c970a..b8f0ea8a9568 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; + unsigned long addr = regs->epc; + long bad; + u16 val; + int i; + + for (i = -10; i < 2; i++) { + bad = get_kernel_nofault(val, &((u16 *)addr)[i]); + if (!bad) { + p += sprintf(p, i == 0 ? "(%04hx) " : "%04hx ", val); + } else { + printk("%sCode: Unable to access instruction at 0x%lx.\n", + loglvl, (long)&((u16 *)addr)[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);