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x86/mm/pae: Get rid of set_64bit()

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Recognise that set_64bit() is a special case of our previously
introduced pxx_xchg64(), so use that and get rid of set_64bit().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221022114425.233481884%40infradead.org
This commit is contained in:
Peter Zijlstra 2022-10-21 13:36:24 +02:00 committed by Dave Hansen
parent 9ee850acd2
commit d4a72e7fe6
2 changed files with 12 additions and 39 deletions
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28
arch/x86/include/asm/cmpxchg_32.h
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@ -7,34 +7,6 @@
* you need to test for the feature in boot_cpu_data.
*/
/*
* CMPXCHG8B only writes to the target if we had the previous
* value in registers, otherwise it acts as a read and gives us the
* "new previous" value. That is why there is a loop. Preloading
* EDX:EAX is a performance optimization: in the common case it means
* we need only one locked operation.
*
* A SIMD/3DNOW!/MMX/FPU 64-bit store here would require at the very
* least an FPU save and/or %cr0.ts manipulation.
*
* cmpxchg8b must be used with the lock prefix here to allow the
* instruction to be executed atomically. We need to have the reader
* side to see the coherent 64bit value.
*/
static inline void set_64bit(volatile u64 *ptr, u64 value)
{
u32 low = value;
u32 high = value >> 32;
u64 prev = *ptr;
asm volatile("\n1:\t"
LOCK_PREFIX "cmpxchg8b %0\n\t"
"jnz 1b"
: "=m" (*ptr), "+A" (prev)
: "b" (low), "c" (high)
: "memory");
}
#ifdef CONFIG_X86_CMPXCHG64
#define arch_cmpxchg64(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \

23
arch/x86/include/asm/pgtable-3level.h
View File

@ -19,7 +19,15 @@
pr_err("%s:%d: bad pgd %p(%016Lx)\n", \
__FILE__, __LINE__, &(e), pgd_val(e))
/* Rules for using set_pte: the pte being assigned *must* be
#define pxx_xchg64(_pxx, _ptr, _val) ({ \
_pxx##val_t *_p = (_pxx##val_t *)_ptr; \
_pxx##val_t _o = *_p; \
do { } while (!try_cmpxchg64(_p, &_o, (_val))); \
native_make_##_pxx(_o); \
})
/*
* Rules for using set_pte: the pte being assigned *must* be
* either not present or in a state where the hardware will
* not attempt to update the pte. In places where this is
* not possible, use pte_get_and_clear to obtain the old pte
@ -34,12 +42,12 @@ static inline void native_set_pte(pte_t *ptep, pte_t pte)
static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
{
set_64bit((unsigned long long *)(ptep), native_pte_val(pte));
pxx_xchg64(pte, ptep, native_pte_val(pte));
}
static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
{
set_64bit((unsigned long long *)(pmdp), native_pmd_val(pmd));
pxx_xchg64(pmd, pmdp, native_pmd_val(pmd));
}
static inline void native_set_pud(pud_t *pudp, pud_t pud)
@ -47,7 +55,7 @@ static inline void native_set_pud(pud_t *pudp, pud_t pud)
#ifdef CONFIG_PAGE_TABLE_ISOLATION
pud.p4d.pgd = pti_set_user_pgtbl(&pudp->p4d.pgd, pud.p4d.pgd);
#endif
set_64bit((unsigned long long *)(pudp), native_pud_val(pud));
pxx_xchg64(pud, pudp, native_pud_val(pud));
}
/*
@ -91,13 +99,6 @@ static inline void pud_clear(pud_t *pudp)
}
#define pxx_xchg64(_pxx, _ptr, _val) ({ \
_pxx##val_t *_p = (_pxx##val_t *)_ptr; \
_pxx##val_t _o = *_p; \
do { } while (!try_cmpxchg64(_p, &_o, (_val))); \
native_make_##_pxx(_o); \
})
#ifdef CONFIG_SMP
static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
{