* [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler
@ 2023-01-19 7:47 Björn Töpel
2023-01-19 7:47 ` [PATCH v3 1/2] riscv: Add instruction dump to RISC-V splats Björn Töpel
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Björn Töpel @ 2023-01-19 7:47 UTC (permalink / raw)
To: Paul Walmsley, Palmer Dabbelt, Albert Ou, linux-riscv
Cc: Björn Töpel, Andreas Schwab, Geert Uytterhoeven, linux-kernel
From: Björn Töpel <bjorn@rivosinc.com>
RISC-V does not dump faulting instructions in the oops handler. This
series adds "Code:" dumps to the oops output together with
scripts/decodecode support.
Thanks,
Björn
v2->v3: Simplifications/getting rid of casts (Geert)
v1->v2: Dump instructions in 16b parcels (Andreas)
Björn Töpel (2):
riscv: Add instruction dump to RISC-V splats
scripts/decodecode: Add support for RISC-V
arch/riscv/kernel/traps.c | 25 ++++++++++++++++++++++++-
scripts/decodecode | 12 +++++++++++-
2 files changed, 35 insertions(+), 2 deletions(-)
base-commit: 7287904c8771b77b9504f53623bb477065c19a58
--
2.37.2
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^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3 1/2] riscv: Add instruction dump to RISC-V splats
2023-01-19 7:47 [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler Björn Töpel
@ 2023-01-19 7:47 ` Björn Töpel
2023-01-19 7:47 ` [PATCH v3 2/2] scripts/decodecode: Add support for RISC-V Björn Töpel
2023-02-22 15:00 ` [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler patchwork-bot+linux-riscv
2 siblings, 0 replies; 5+ messages in thread
From: Björn Töpel @ 2023-01-19 7:47 UTC (permalink / raw)
To: Paul Walmsley, Palmer Dabbelt, Albert Ou, linux-riscv
Cc: Björn Töpel, Andreas Schwab, Geert Uytterhoeven, linux-kernel
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 --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);
--
2.37.2
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v3 2/2] scripts/decodecode: Add support for RISC-V
2023-01-19 7:47 [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler Björn Töpel
2023-01-19 7:47 ` [PATCH v3 1/2] riscv: Add instruction dump to RISC-V splats Björn Töpel
@ 2023-01-19 7:47 ` Björn Töpel
2023-02-21 15:18 ` Alexandre Ghiti
2023-02-22 15:00 ` [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler patchwork-bot+linux-riscv
2 siblings, 1 reply; 5+ messages in thread
From: Björn Töpel @ 2023-01-19 7:47 UTC (permalink / raw)
To: Paul Walmsley, Palmer Dabbelt, Albert Ou, linux-riscv
Cc: Björn Töpel, Andreas Schwab, Geert Uytterhoeven, linux-kernel
From: Björn Töpel <bjorn@rivosinc.com>
RISC-V has some GNU disassembly quirks, e.g. it requires '-D' to
properly disassemble .2byte directives similar to Arm [1]. Further,
GNU objdump groups RISC-V instruction by 2 or 4 byte chunks, instead
doing byte-for-byte.
Add the required switches, and translate from short/word to bytes when
ARCH is "riscv".
An example how to invoke decodecode for RISC-V:
$ echo 'Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7)
6140' | AFLAGS="-march=rv64imac_zicbom_zihintpause" \
ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- ./scripts/decodecode
Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7) 6140
All code
========
0: bf45 c.j 0xffffffffffffffb0
2: 1007f793 andi a5,a5,256
6: f7d9 c.bnez a5,0xffffffffffffff94
8: 37af50ef jal ra,0xf5382
c: d541 c.beqz a0,0xffffffffffffff94
e: b7d9 c.j 0xffffffffffffffd4
10: 00c87097 auipc ra,0xc87
14:* 614080e7 jalr ra,1556(ra) # 0xc87624 <-- trapping instruction
Code starting with the faulting instruction
===========================================
0: 614080e7 jalr ra,1556(ra)
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=10263
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
---
scripts/decodecode | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/scripts/decodecode b/scripts/decodecode
index b28fd2686561..8fe71c292381 100755
--- a/scripts/decodecode
+++ b/scripts/decodecode
@@ -93,6 +93,11 @@ disas() {
${CROSS_COMPILE}strip $t.o
fi
+ if [ "$ARCH" = "riscv" ]; then
+ OBJDUMPFLAGS="-M no-aliases --section=.text -D"
+ ${CROSS_COMPILE}strip $t.o
+ fi
+
if [ $pc_sub -ne 0 ]; then
if [ $PC ]; then
adj_vma=$(( $PC - $pc_sub ))
@@ -126,8 +131,13 @@ get_substr_opcode_bytes_num()
do
substr+="$opc"
+ opcode="$substr"
+ if [ "$ARCH" = "riscv" ]; then
+ opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')
+ fi
+
# return if opcode bytes do not match @opline anymore
- if ! echo $opline | grep -q "$substr";
+ if ! echo $opline | grep -q "$opcode";
then
break
fi
--
2.37.2
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3 2/2] scripts/decodecode: Add support for RISC-V
2023-01-19 7:47 ` [PATCH v3 2/2] scripts/decodecode: Add support for RISC-V Björn Töpel
@ 2023-02-21 15:18 ` Alexandre Ghiti
0 siblings, 0 replies; 5+ messages in thread
From: Alexandre Ghiti @ 2023-02-21 15:18 UTC (permalink / raw)
To: Björn Töpel, Paul Walmsley, Palmer Dabbelt, Albert Ou,
linux-riscv
Cc: Björn Töpel, Andreas Schwab, Geert Uytterhoeven, linux-kernel
Hi Björn,
On 1/19/23 08:47, Björn Töpel wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
>
> RISC-V has some GNU disassembly quirks, e.g. it requires '-D' to
> properly disassemble .2byte directives similar to Arm [1]. Further,
> GNU objdump groups RISC-V instruction by 2 or 4 byte chunks, instead
> doing byte-for-byte.
>
> Add the required switches, and translate from short/word to bytes when
> ARCH is "riscv".
>
> An example how to invoke decodecode for RISC-V:
> $ echo 'Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7)
> 6140' | AFLAGS="-march=rv64imac_zicbom_zihintpause" \
> ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- ./scripts/decodecode
> Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7) 6140
> All code
> ========
> 0: bf45 c.j 0xffffffffffffffb0
> 2: 1007f793 andi a5,a5,256
> 6: f7d9 c.bnez a5,0xffffffffffffff94
> 8: 37af50ef jal ra,0xf5382
> c: d541 c.beqz a0,0xffffffffffffff94
> e: b7d9 c.j 0xffffffffffffffd4
> 10: 00c87097 auipc ra,0xc87
> 14:* 614080e7 jalr ra,1556(ra) # 0xc87624 <-- trapping instruction
>
> Code starting with the faulting instruction
> ===========================================
> 0: 614080e7 jalr ra,1556(ra)
>
> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=10263
>
> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
> ---
> scripts/decodecode | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/decodecode b/scripts/decodecode
> index b28fd2686561..8fe71c292381 100755
> --- a/scripts/decodecode
> +++ b/scripts/decodecode
> @@ -93,6 +93,11 @@ disas() {
> ${CROSS_COMPILE}strip $t.o
> fi
>
> + if [ "$ARCH" = "riscv" ]; then
> + OBJDUMPFLAGS="-M no-aliases --section=.text -D"
> + ${CROSS_COMPILE}strip $t.o
> + fi
> +
> if [ $pc_sub -ne 0 ]; then
> if [ $PC ]; then
> adj_vma=$(( $PC - $pc_sub ))
> @@ -126,8 +131,13 @@ get_substr_opcode_bytes_num()
> do
> substr+="$opc"
>
> + opcode="$substr"
> + if [ "$ARCH" = "riscv" ]; then
> + opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')
> + fi
> +
> # return if opcode bytes do not match @opline anymore
> - if ! echo $opline | grep -q "$substr";
> + if ! echo $opline | grep -q "$opcode";
> then
> break
> fi
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Thanks, that's very useful!
Alex
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler
2023-01-19 7:47 [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler Björn Töpel
2023-01-19 7:47 ` [PATCH v3 1/2] riscv: Add instruction dump to RISC-V splats Björn Töpel
2023-01-19 7:47 ` [PATCH v3 2/2] scripts/decodecode: Add support for RISC-V Björn Töpel
@ 2023-02-22 15:00 ` patchwork-bot+linux-riscv
2 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+linux-riscv @ 2023-02-22 15:00 UTC (permalink / raw)
To: =?utf-8?b?QmrDtnJuIFTDtnBlbCA8Ympvcm5Aa2VybmVsLm9yZz4=?=
Cc: linux-riscv, paul.walmsley, palmer, aou, bjorn, schwab, geert,
linux-kernel
Hello:
This series was applied to riscv/linux.git (for-next)
by Palmer Dabbelt <palmer@rivosinc.com>:
On Thu, 19 Jan 2023 08:47:36 +0100 you wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
>
> RISC-V does not dump faulting instructions in the oops handler. This
> series adds "Code:" dumps to the oops output together with
> scripts/decodecode support.
>
> Thanks,
> Björn
>
> [...]
Here is the summary with links:
- [v3,1/2] riscv: Add instruction dump to RISC-V splats
https://git.kernel.org/riscv/c/eb165bfa8eaf
- [v3,2/2] scripts/decodecode: Add support for RISC-V
https://git.kernel.org/riscv/c/00b242509c8f
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
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2023-01-19 7:47 [PATCH v3 0/2] riscv: Dump faulting instructions in oops handler Björn Töpel
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2023-01-19 7:47 ` [PATCH v3 2/2] scripts/decodecode: Add support for RISC-V Björn Töpel
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