RE: [PATCH v2] powerpc/32: Don't use a struct based type for pte_t
From: David Laight <hidden>
Date: 2021-09-17 14:32:31
Also in:
lkml
From: Christophe Leroy
Sent: 17 September 2021 14:58 Long time ago we had a config item called STRICT_MM_TYPECHECKS to build the kernel with pte_t defined as a structure in order to perform additional build checks or build it with pte_t defined as a simple type in order to get simpler generated code.
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diff --git a/arch/powerpc/include/asm/pgtable-types.h b/arch/powerpc/include/asm/pgtable-types.h index d11b4c61d686..c60199fc6fa6 100644 --- a/arch/powerpc/include/asm/pgtable-types.h +++ b/arch/powerpc/include/asm/pgtable-types.h@@ -5,14 +5,26 @@ /* PTE level */ #if defined(CONFIG_PPC_8xx) && defined(CONFIG_PPC_16K_PAGES) typedef struct { pte_basic_t pte, pte1, pte2, pte3; } pte_t; -#else +#elif defined(__CHECKER__) || !defined(CONFIG_PPC32) typedef struct { pte_basic_t pte; } pte_t; +#else +typedef pte_basic_t pte_t; #endif + +#if defined(__CHECKER__) || !defined(CONFIG_PPC32) || \ + (defined(CONFIG_PPC_8xx) && defined(CONFIG_PPC_16K_PAGES)) #define __pte(x) ((pte_t) { (x) }) static inline pte_basic_t pte_val(pte_t x) { return x.pte; } +#else +#define __pte(x) ((pte_t)(x)) +static inline pte_basic_t pte_val(pte_t x) +{ + return x; +} +#endif
Would it be better to define:
static inline pte_basic_*pte_basic(pte_t *x)
{
#if xxx
return x;
#else
return &x->pte;
#endif
}
Then pte_val(x) is always *pt_basic(x)
and the casts like:
- pte_basic_t *entry = &ptep->pte; + pte_basic_t *entry = (pte_basic_t *)ptep;
can go away. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)