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From: Yunhui Cui <cuiyunhui@bytedance.com>
To: paul.walmsley@sifive.com, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, guoren@kernel.org, bjorn@rivosinc.com,
	conor.dooley@microchip.com, jszhang@kernel.org,
	andy.chiu@sifive.com, cuiyunhui@bytedance.com,
	dave.hansen@linux.intel.com, elver@google.com, glider@google.com,
	cyphar@cyphar.com, kirill.shutemov@linux.intel.com,
	keescook@chromium.org, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v5] riscv: add userland instruction dump to RISC-V splats
Date: Fri,  1 Sep 2023 20:30:43 +0800	[thread overview]
Message-ID: <20230901123043.73700-1-cuiyunhui@bytedance.com> (raw)

Add userland instruction dump and rename dump_kernel_instr()
to dump_instr().

An example:
[    0.822439] Freeing unused kernel image (initmem) memory: 6916K
[    0.823817] Run /init as init process
[    0.839411] init[1]: unhandled signal 4 code 0x1 at 0x000000000005be18 in bb[10000+5fb000]
[    0.840751] CPU: 0 PID: 1 Comm: init Not tainted 5.14.0-rc4-00049-gbd644290aa72-dirty #187
[    0.841373] Hardware name:  , BIOS
[    0.841743] epc : 000000000005be18 ra : 0000000000079e74 sp : 0000003fffcafda0
[    0.842271]  gp : ffffffff816e9dc8 tp : 0000000000000000 t0 : 0000000000000000
[    0.842947]  t1 : 0000003fffc9fdf0 t2 : 0000000000000000 s0 : 0000000000000000
[    0.843434]  s1 : 0000000000000000 a0 : 0000003fffca0190 a1 : 0000003fffcafe18
[    0.843891]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.844357]  a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000000
[    0.844803]  s2 : 0000000000000000 s3 : 0000000000000000 s4 : 0000000000000000
[    0.845253]  s5 : 0000000000000000 s6 : 0000000000000000 s7 : 0000000000000000
[    0.845722]  s8 : 0000000000000000 s9 : 0000000000000000 s10: 0000000000000000
[    0.846180]  s11: 0000000000d144e0 t3 : 0000000000000000 t4 : 0000000000000000
[    0.846616]  t5 : 0000000000000000 t6 : 0000000000000000
[    0.847204] status: 0000000200000020 badaddr: 00000000f0028053 cause: 0000000000000002
[    0.848219] Code: f06f ff5f 3823 fa11 0113 fb01 2e23 0201 0293 0000 (8053) f002
[    0.851016] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 arch/riscv/kernel/traps.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index f798c853bede..923b49c38985 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -33,7 +33,19 @@ int show_unhandled_signals = 1;
 
 static DEFINE_SPINLOCK(die_lock);
 
-static void dump_kernel_instr(const char *loglvl, struct pt_regs *regs)
+static int copy_code(struct pt_regs *regs, u16 *val, const u16 *insns)
+{
+	if (!user_mode(regs))
+		return get_kernel_nofault(*val, insns);
+
+	/* The user space code from other tasks cannot be accessed. */
+	if (regs != task_pt_regs(current))
+		return -EPERM;
+
+	return copy_from_user_nofault(val, insns, sizeof(*val));
+}
+
+static void dump_instr(const char *loglvl, struct pt_regs *regs)
 {
 	char str[sizeof("0000 ") * 12 + 2 + 1], *p = str;
 	const u16 *insns = (u16 *)instruction_pointer(regs);
@@ -42,7 +54,7 @@ static void dump_kernel_instr(const char *loglvl, struct pt_regs *regs)
 	int i;
 
 	for (i = -10; i < 2; i++) {
-		bad = get_kernel_nofault(val, &insns[i]);
+		bad = copy_code(regs, &val, &insns[i]);
 		if (!bad) {
 			p += sprintf(p, i == 0 ? "(%04hx) " : "%04hx ", val);
 		} else {
@@ -71,7 +83,7 @@ void die(struct pt_regs *regs, const char *str)
 	print_modules();
 	if (regs) {
 		show_regs(regs);
-		dump_kernel_instr(KERN_EMERG, regs);
+		dump_instr(KERN_EMERG, regs);
 	}
 
 	cause = regs ? regs->cause : -1;
@@ -104,6 +116,7 @@ void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
 		print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
 		pr_cont("\n");
 		__show_regs(regs);
+		dump_instr(KERN_EMERG, regs);
 	}
 
 	force_sig_fault(signo, code, (void __user *)addr);
-- 
2.20.1


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             reply	other threads:[~2023-09-01 12:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-01 12:30 Yunhui Cui [this message]
2023-09-07 11:43 ` [PATCH v5] riscv: add userland instruction dump to RISC-V splats yunhui cui
2023-09-07 18:45 ` Björn Töpel
2023-09-08 13:15   ` [External] " yunhui cui
2023-09-08 18:00     ` Björn Töpel
2023-09-12  2:13       ` yunhui cui

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