[PATCH v2] arm64: rename dump_instr as dump_kernel_instr

[PATCH v2] arm64: rename dump_instr as dump_kernel_instr

[jinho lim]

[v2]
dump_kernel_instr does not work for user mode.
rename dump_instr function and remove __dump_instr.

Signed-off-by: jinho lim <jordan.lim@samsung.com>
---

Thanks for review, I rename dump_instr function and merge __dump_instr in it.

 arch/arm64/kernel/traps.c | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index ccc13b45d9b1..7053165cb31a 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -66,11 +66,20 @@ static void dump_backtrace_entry(unsigned long where)
 	printk(" %pS\n", (void *)where);
 }
 
-static void __dump_instr(const char *lvl, struct pt_regs *regs)
+static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
 {
-	unsigned long addr = instruction_pointer(regs);
+	unsigned long addr;
 	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
 	int i;
+	mm_segment_t fs;
+
+	if (user_mode(regs))
+		return;
+
+	addr = instruction_pointer(regs);
+
+	fs = get_fs();
+	set_fs(KERNEL_DS);
 
 	for (i = -4; i < 1; i++) {
 		unsigned int val, bad;
@@ -84,19 +93,10 @@ static void __dump_instr(const char *lvl, struct pt_regs *regs)
 			break;
 		}
 	}
+
 	printk("%sCode: %s\n", lvl, str);
-}
 
-static void dump_instr(const char *lvl, struct pt_regs *regs)
-{
-	if (!user_mode(regs)) {
-		mm_segment_t fs = get_fs();
-		set_fs(KERNEL_DS);
-		__dump_instr(lvl, regs);
-		set_fs(fs);
-	} else {
-		__dump_instr(lvl, regs);
-	}
+	set_fs(fs);
 }
 
 void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
@@ -182,8 +182,7 @@ static int __die(const char *str, int err, struct pt_regs *regs)
 	print_modules();
 	show_regs(regs);
 
-	if (!user_mode(regs))
-		dump_instr(KERN_EMERG, regs);
+	dump_kernel_instr(KERN_EMERG, regs);
 
 	return ret;
 }
-- 
2.17.1

Re: [PATCH v2] arm64: rename dump_instr as dump_kernel_instr

[Will Deacon]

On Thu, Jun 20, 2019 at 03:52:49PM +0900, jinho lim wrote:
> [v2]

The version information is not usually part of the commit message. Please
drop that...

> dump_kernel_instr does not work for user mode.
> rename dump_instr function and remove __dump_instr.

... and rewrite this so it explains the problem that you're solving.

> Signed-off-by: jinho lim <jordan.lim@samsung.com>
> ---
> 
> Thanks for review, I rename dump_instr function and merge __dump_instr in it.
> 
>  arch/arm64/kernel/traps.c | 29 ++++++++++++++---------------
>  1 file changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index ccc13b45d9b1..7053165cb31a 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -66,11 +66,20 @@ static void dump_backtrace_entry(unsigned long where)
>  	printk(" %pS\n", (void *)where);
>  }
>  
> -static void __dump_instr(const char *lvl, struct pt_regs *regs)
> +static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
>  {
> -	unsigned long addr = instruction_pointer(regs);
> +	unsigned long addr;
>  	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
>  	int i;
> +	mm_segment_t fs;
> +
> +	if (user_mode(regs))
> +		return;
> +
> +	addr = instruction_pointer(regs);
> +
> +	fs = get_fs();
> +	set_fs(KERNEL_DS);

Actually, if we use aarch64_insn_read() instead of get_user() then we can
avoid having to mess directly with the fs and we'll also get endianness
correction for free when running a big-endian kernel.

Will