Re: [RFC v2 07/12] powerpc: Macro the mask used for checking DSI exception

From: Aneesh Kumar K.V
Date: Wed Jun 21 2017 - 03:26:07 EST


Ram Pai <linuxram@xxxxxxxxxx> writes:

> Replace the magic number used to check for DSI exception
> with a meaningful value.
>
> Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
> ---
> arch/powerpc/include/asm/reg.h | 9 ++++++++-
> arch/powerpc/kernel/exceptions-64s.S | 2 +-
> 2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
> index 7e50e47..2dcb8a1 100644
> --- a/arch/powerpc/include/asm/reg.h
> +++ b/arch/powerpc/include/asm/reg.h
> @@ -272,16 +272,23 @@
> #define SPRN_DAR 0x013 /* Data Address Register */
> #define SPRN_DBCR 0x136 /* e300 Data Breakpoint Control Reg */
> #define SPRN_DSISR 0x012 /* Data Storage Interrupt Status Register */
> +#define DSISR_BIT32 0x80000000 /* not defined */
> #define DSISR_NOHPTE 0x40000000 /* no translation found */
> +#define DSISR_PAGEATTR_CONFLT 0x20000000 /* page attribute conflict */
> +#define DSISR_BIT35 0x10000000 /* not defined */
> #define DSISR_PROTFAULT 0x08000000 /* protection fault */
> #define DSISR_BADACCESS 0x04000000 /* bad access to CI or G */
> #define DSISR_ISSTORE 0x02000000 /* access was a store */
> #define DSISR_DABRMATCH 0x00400000 /* hit data breakpoint */
> -#define DSISR_NOSEGMENT 0x00200000 /* SLB miss */
> #define DSISR_KEYFAULT 0x00200000 /* Key fault */
> +#define DSISR_BIT43 0x00100000 /* not defined */
> #define DSISR_UNSUPP_MMU 0x00080000 /* Unsupported MMU config */
> #define DSISR_SET_RC 0x00040000 /* Failed setting of R/C bits */
> #define DSISR_PGDIRFAULT 0x00020000 /* Fault on page directory */
> +#define DSISR_PAGE_FAULT_MASK (DSISR_BIT32 | \
> + DSISR_PAGEATTR_CONFLT | \
> + DSISR_BADACCESS | \
> + DSISR_BIT43)
> #define SPRN_TBRL 0x10C /* Time Base Read Lower Register (user, R/O) */
> #define SPRN_TBRU 0x10D /* Time Base Read Upper Register (user, R/O) */
> #define SPRN_CIR 0x11B /* Chip Information Register (hyper, R/0) */
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index ae418b8..3fd0528 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -1411,7 +1411,7 @@ USE_TEXT_SECTION()
> .balign IFETCH_ALIGN_BYTES
> do_hash_page:
> #ifdef CONFIG_PPC_STD_MMU_64
> - andis. r0,r4,0xa410 /* weird error? */
> + andis. r0,r4,DSISR_PAGE_FAULT_MASK@h
> bne- handle_page_fault /* if not, try to insert a HPTE */
> andis. r0,r4,DSISR_DABRMATCH@h
> bne- handle_dabr_fault


Thanks for doing this. I always wondered what that 0xa410 indicates. Now
tha it is documented, I am wondering are those the only DSISR values
that we want to check early ? You also added few bit positions that is
expected to carry value 0 ? But then excluded BIT35. Any reason ?

-aneesh