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x86: c_p_a() fix: reorder TLB / cache flushes to follow Intel recommendation

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Intel recommends to first flush the TLBs and then the caches
on caching attribute changes. c_p_a() previously did it the
other way round. Reorder that.

The procedure is still not fully compliant to the Intel documentation
because Intel recommends a all CPU synchronization step between
the TLB flushes and the cache flushes.

However on all new Intel CPUs this is now meaningless anyways
because they support Self-Snoop and can skip the cache flush
step anyway.

[ mingo@elte.hu: decoupled from clflush and ported it to x86.git ]

Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Andi Kleen 2008-01-30 13:33:52 +01:00 committed by Ingo Molnar
parent 6ba9b7d8f0
commit 3c86882341
2 changed files with 8 additions and 7 deletions
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12
arch/x86/mm/pageattr_32.c
View File

@ -87,6 +87,12 @@ static void flush_kernel_map(void *arg)
struct list_head *lh = (struct list_head *)arg;
struct page *p;
/*
* Flush all to work around Errata in early athlons regarding
* large page flushing.
*/
__flush_tlb_all();
/* High level code is not ready for clflush yet */
if (0 && cpu_has_clflush) {
list_for_each_entry(p, lh, lru)
@ -95,12 +101,6 @@ static void flush_kernel_map(void *arg)
if (boot_cpu_data.x86_model >= 4)
wbinvd();
}
/*
* Flush all to work around Errata in early athlons regarding
* large page flushing.
*/
__flush_tlb_all();
}
static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)

3
arch/x86/mm/pageattr_64.c
View File

@ -82,6 +82,8 @@ static void flush_kernel_map(void *arg)
struct list_head *l = (struct list_head *)arg;
struct page *pg;
__flush_tlb_all();
/* When clflush is available always use it because it is
much cheaper than WBINVD. */
/* clflush is still broken. Disable for now. */
@ -94,7 +96,6 @@ static void flush_kernel_map(void *arg)
clflush_cache_range(addr, PAGE_SIZE);
}
}
__flush_tlb_all();
}
static inline void flush_map(struct list_head *l)