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>
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4cf30de..e89d248 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -555,12 +555,10 @@
if (!pte_val(old_pte)) {
if (!primary)
return 0;
-
- /*
- * Special error value returned, indicating that the mapping
- * did not exist at this address.
- */
- return -EFAULT;
+ WARN(1, KERN_WARNING "CPA: called for zero pte. "
+ "vaddr = %lx cpa->vaddr = %lx\n", address,
+ *cpa->vaddr);
+ return -EINVAL;
}
if (level == PG_LEVEL_4K) {
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 160c42d..8b08fb9 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -505,35 +505,6 @@
}
#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 @@
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 @@
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 @@
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 "