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authorSuresh Siddha <suresh.b.siddha@intel.com>2009-08-17 22:23:50 +0200
committerH. Peter Anvin <hpa@zytor.com>2009-08-17 23:12:44 +0200
commit1adcaafe7414c5731f758b158aa0525057225deb (patch)
treed4e1b96fea899a3adf376fc3590263954fbecdbb /arch/x86/include/asm/pgtable.h
parentx86, mce: Don't initialize MCEs on unknown CPUs (diff)
downloadlinux-1adcaafe7414c5731f758b158aa0525057225deb.tar.xz
linux-1adcaafe7414c5731f758b158aa0525057225deb.zip
x86, pat: Allow ISA memory range uncacheable mapping requests
Max Vozeler reported: > Bug 13877 - bogl-term broken with CONFIG_X86_PAT=y, works with =n > > strace of bogl-term: > 814 mmap2(NULL, 65536, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0) > = -1 EAGAIN (Resource temporarily unavailable) > 814 write(2, "bogl: mmaping /dev/fb0: Resource temporarily unavailable\n", > 57) = 57 PAT code maps the ISA memory range as WB in the PAT attribute, so that fixed range MTRR registers define the actual memory type (UC/WC/WT etc). But the upper level is_new_memtype_allowed() API checks are failing, as the request here is for UC and the return tracked type is WB (Tracked type is WB as MTRR type for this legacy range potentially will be different for each 4k page). Fix is_new_memtype_allowed() by always succeeding the ISA address range checks, as the null PAT (WB) and def MTRR fixed range register settings satisfy the memory type needs of the applications that map the ISA address range. Reported-and-Tested-by: Max Vozeler <xam@debian.org> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/pgtable.h')
-rw-r--r--arch/x86/include/asm/pgtable.h12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 3cc06e3fceb8..16748077559a 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -2,6 +2,7 @@
#define _ASM_X86_PGTABLE_H
#include <asm/page.h>
+#include <asm/e820.h>
#include <asm/pgtable_types.h>
@@ -269,10 +270,17 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
#define canon_pgprot(p) __pgprot(massage_pgprot(p))
-static inline int is_new_memtype_allowed(unsigned long flags,
- unsigned long new_flags)
+static inline int is_new_memtype_allowed(u64 paddr, unsigned long size,
+ unsigned long flags,
+ unsigned long new_flags)
{
/*
+ * PAT type is always WB for ISA. So no need to check.
+ */
+ if (is_ISA_range(paddr, paddr + size - 1))
+ return 1;
+
+ /*
* Certain new memtypes are not allowed with certain
* requested memtype:
* - request is uncached, return cannot be write-back