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authorLinus Torvalds <torvalds@linux-foundation.org>2009-01-15 15:32:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-15 16:25:09 -0800
commitb5db0e38653bfada34a92f360b4111566ede3842 (patch)
tree0ebc72a544e3d879ea5f9f57d5f65448d6bf3250 /arch/x86/mm/pat.c
parent647df5189fecb2c2fa811421a3f28bf9034e3a70 (diff)
Revert "x86 PAT: remove CPA WARN_ON for zero pte"
This reverts commit 58dab916dfb57328d50deb0aa9b3fc92efa248ff, which makes my Nehalem come to a nasty crawling almost-halt. It looks like it turns off caching of regular kernel RAM, with the understandable slowdown of a few orders of magnitude as a result. Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Peter Anvin <hpa@zytor.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/mm/pat.c')
-rw-r--r--arch/x86/mm/pat.c45
1 files changed, 13 insertions, 32 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 160c42d3eb8f..8b08fb955274 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -505,35 +505,6 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
}
#endif /* CONFIG_STRICT_DEVMEM */
-/*
- * Change the memory type for the physial address range in kernel identity
- * mapping space if that range is a part of identity map.
- */
-static int kernel_map_sync_memtype(u64 base, unsigned long size,
- unsigned long flags)
-{
- unsigned long id_sz;
- int ret;
-
- if (!pat_enabled || base >= __pa(high_memory))
- return 0;
-
- id_sz = (__pa(high_memory) < base + size) ?
- __pa(high_memory) - base :
- size;
-
- ret = ioremap_change_attr((unsigned long)__va(base), id_sz, flags);
- /*
- * -EFAULT return means that the addr was not valid and did not have
- * any identity mapping. That case is a success for
- * kernel_map_sync_memtype.
- */
- if (ret == -EFAULT)
- ret = 0;
-
- return ret;
-}
-
int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t *vma_prot)
{
@@ -584,7 +555,9 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
if (retval < 0)
return 0;
- if (kernel_map_sync_memtype(offset, size, flags)) {
+ if (((pfn < max_low_pfn_mapped) ||
+ (pfn >= (1UL<<(32 - PAGE_SHIFT)) && pfn < max_pfn_mapped)) &&
+ ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
free_memtype(offset, offset + size);
printk(KERN_INFO
"%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
@@ -632,7 +605,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
int strict_prot)
{
int is_ram = 0;
- int ret;
+ int id_sz, ret;
unsigned long flags;
unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
@@ -673,7 +646,15 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
flags);
}
- if (kernel_map_sync_memtype(paddr, size, flags)) {
+ /* Need to keep identity mapping in sync */
+ if (paddr >= __pa(high_memory))
+ return 0;
+
+ id_sz = (__pa(high_memory) < paddr + size) ?
+ __pa(high_memory) - paddr :
+ size;
+
+ if (ioremap_change_attr((unsigned long)__va(paddr), id_sz, flags) < 0) {
free_memtype(paddr, paddr + size);
printk(KERN_ERR
"%s:%d reserve_pfn_range ioremap_change_attr failed %s "