[PATCH] powerpc64s: Print exception vector name alongside the trap number

[Christophe LEROY]

Le 18/04/2018 à 11:02, Naveen N. Rao a écrit :
> Print a small help text indicating the exception vector alongside the
> trap number to make it easier while analyzing back traces. As an
> example:
> 
>      Unable to handle kernel paging request for data at address 0x00000000
>      Faulting instruction address: 0xc0000000006e3728
>      Oops: Kernel access of bad area, sig: 11 [#1]
>      LE SMP NR_CPUS=2048 NUMA PowerNV
>      Modules linked in:
>      CPU: 0 PID: 1 Comm: bash Not tainted 4.16.0-nnr #226
>      NIP:  c0000000006e3728 LR: c0000000006e4774 CTR: c0000000006e3700
>      REGS: c0000000f0aa3980 TRAP: 0300 (DSI)  Not tainted  (4.16.0-nnr)
>      MSR:  9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 28222222  XER: 20000000
>      CFAR: c0000000006e4770 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 0
> 
> Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
> ---
> I find this useful to have in backtraces, instead of having to look it
> up. Some of the names could probably be tweaked a bit to be more
> sensible.
> 
> - Naveen
> 
>   arch/powerpc/kernel/process.c | 42 +++++++++++++++++++++++++++++++++++
>   1 file changed, 42 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 1237f13fed51..71bfe29af456 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -1414,6 +1414,42 @@ static void print_msr_bits(unsigned long val)
>   #define LAST_VOLATILE	12
>   #endif
>   
> +#ifdef CONFIG_PPC_BOOK3S_64

Why not make something generic applicable to all platforms ?

Christophe

> +static char *print_trap(unsigned long trapno)
> +{
> +	trapno &= 0xff0;
> +	switch (trapno) {
> +		case 0x100:	return "SRESET";
> +		case 0x200:	return "MCE";
> +		case 0x300:	return "DSI";
> +		case 0x380:	return "DSISLB";
> +		case 0x400:	return "ISI";
> +		case 0x480:	return "ISISLB";
> +		case 0x500:	return "EXT";
> +		case 0x600:	return "ALIGN";
> +		case 0x700:	return "PCHECK";
> +		case 0x800:	return "FP";
> +		case 0x900:	return "DEC";
> +		case 0x980:	return "HDEC";
> +		case 0xa00:	return "DBELL";
> +		case 0xc00:	return "SC";
> +		case 0xd00:	return "SSTEP";
> +		case 0xe00:	return "HDSI";
> +		case 0xe20:	return "HISI";
> +		case 0xe40:	return "HEMUL";
> +		case 0xe60:	return "HMI";
> +		case 0xe80:	return "HDBELL";
> +		case 0xea0:	return "HVIRT";
> +		case 0xf00:	return "PMI";
> +		case 0xf20:	return "ALTIVEC";
> +		case 0xf40:	return "VSX";
> +		case 0xf60:	return "UNAVAIL";
> +		case 0xf80:	return "HUNAVAIL";
> +	}
> +	return "UNKNOWN";
> +}
> +#endif
> +
>   void show_regs(struct pt_regs * regs)
>   {
>   	int i, trap;
> @@ -1422,8 +1458,14 @@ void show_regs(struct pt_regs * regs)
>   
>   	printk("NIP:  "REG" LR: "REG" CTR: "REG"\n",
>   	       regs->nip, regs->link, regs->ctr);
> +#ifdef CONFIG_PPC_BOOK3S_64
> +	printk("REGS: %px TRAP: %04lx (%s)  %s  (%s)\n",
> +	       regs, regs->trap, print_trap(regs->trap), print_tainted(),
> +	       init_utsname()->release);
> +#else
>   	printk("REGS: %px TRAP: %04lx   %s  (%s)\n",
>   	       regs, regs->trap, print_tainted(), init_utsname()->release);
> +#endif
>   	printk("MSR:  "REG" ", regs->msr);
>   	print_msr_bits(regs->msr);
>   	pr_cont("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
>