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Subject: Re: [PATCH] powerpc/process: Enhance readability for trap types.
From:   Xiongwei Song <sxwjean@me.com>
In-Reply-To: <8de71b45-efea-b493-ee90-b89062e8e30f@csgroup.eu>
Date:   Mon, 29 Mar 2021 07:11:29 +0800
Cc:     mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org,
        npiggin@gmail.com, ravi.bangoria@linux.ibm.com, mikey@neuling.org,
        aneesh.kumar@linux.ibm.com, haren@linux.ibm.com,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Xiongwei Song <sxwjean@gmail.com>
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Message-Id: <9C228D50-4378-4477-857A-D34D46BDEF5D@me.com>
References: <20210328143545.24324-1-sxwjean@me.com>
 <8de71b45-efea-b493-ee90-b89062e8e30f@csgroup.eu>
To:     Christophe Leroy <christophe.leroy@csgroup.eu>
Precedence: bulk


> On Mar 28, 2021, at 11:21 PM, Christophe Leroy =
<christophe.leroy@csgroup.eu> wrote:
>=20
>=20
>=20
> Le 28/03/2021 =C3=A0 16:35, Xiongwei Song a =C3=A9crit :
>> From: Xiongwei Song <sxwjean@gmail.com>
>> Define macros to enhance the code readability on ppc trap types.
>=20
> Good idea
>=20
>> Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
>> ---
>>  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 */
>=20
> I think usually we use MCE, so TRAP_MCE would be better

Ok.
>=20
>> +#define TRAP_DSI 0x300 /* DSI exception */
>> +#define TRAP_AM  0x600 /* Alignment exception */
>=20
> Don't know what AM means. TRAP_ALIGN would be more explicit.

No Problem.
>=20
>> +
>=20
> The defines should go in a header file, for instance asm/ptrace.h in =
order to be re-used in other files.

Agree.
>=20
> You should do more. You can find other places to improve with:
>=20
> git grep "trap =3D=3D" arch/powerpc/
> git grep "TRAP(regs) =3D=3D" arch/powerpc/

Just ran =E2=80=9Cgit grep=E2=80=9D, looks like the work is much bigger =
than what I imagined.
>=20
>>  static void __show_regs(struct pt_regs *regs)
>>  {
>>  	int i, trap;
>> @@ -1465,7 +1469,7 @@ static void __show_regs(struct pt_regs *regs)
>>  	trap =3D TRAP(regs);
>>  	if (!trap_is_syscall(regs) && cpu_has_feature(CPU_FTR_CFAR))
>>  		pr_cont("CFAR: "REG" ", regs->orig_gpr3);
>> -	if (trap =3D=3D 0x200 || trap =3D=3D 0x300 || trap =3D=3D 0x600) =
{
>> +	if (trap =3D=3D TRAP_MC || trap =3D=3D TRAP_DSI || trap =3D=3D =
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=