Re: [PATCH] powerpc/process: Enhance readability for trap types.

On Mar 28, 2021, at 11:21 PM, Christophe Leroy [off-list ref] wrote:



Le 28/03/2021 à 16:35, Xiongwei Song a écrit :

quoted

From: Xiongwei Song <redacted>
Define macros to enhance the code readability on ppc trap types.

Good idea

quoted

Signed-off-by: Xiongwei Song <redacted>
---
 arch/powerpc/kernel/process.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 3231c2df9e26..3bbd3cf353a7 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -1451,6 +1451,10 @@ static void print_msr_bits(unsigned long val)
 #define LAST_VOLATILE	12
 #endif
 +#define TRAP_MC  0x200 /* Machine Check */

I think usually we use MCE, so TRAP_MCE would be better

Ok.

quoted

+#define TRAP_DSI 0x300 /* DSI exception */
+#define TRAP_AM  0x600 /* Alignment exception */

Don't know what AM means. TRAP_ALIGN would be more explicit.

No Problem.

quoted

+

The defines should go in a header file, for instance asm/ptrace.h in order to be re-used in other files.

Agree.

You should do more. You can find other places to improve with:

git grep "trap ==" arch/powerpc/
git grep "TRAP(regs) ==" arch/powerpc/

Just ran “git grep”, looks like the work is much bigger than what I imagined.

quoted

 static void __show_regs(struct pt_regs *regs)
 {
 	int i, trap;

@@ -1465,7 +1469,7 @@ static void __show_regs(struct pt_regs *regs)
 	trap = TRAP(regs);
 	if (!trap_is_syscall(regs) && cpu_has_feature(CPU_FTR_CFAR))
 		pr_cont("CFAR: "REG" ", regs->orig_gpr3);
-	if (trap == 0x200 || trap == 0x300 || trap == 0x600) {
+	if (trap == TRAP_MC || trap == TRAP_DSI || trap == TRAP_AM) {
 		if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE))
 			pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr);
 		else

Thanks for the response. I will send v2.

 Regards,
Xiongwei