From 1adcaafe7414c5731f758b158aa0525057225deb Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 17 Aug 2009 13:23:50 -0700 Subject: [PATCH] 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 Signed-off-by: Suresh Siddha Signed-off-by: Venkatesh Pallipadi Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/pgtable.h | 12 ++++++++++-- arch/x86/mm/pat.c | 3 ++- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 3cc06e3fceb..16748077559 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 +#include #include @@ -269,9 +270,16 @@ 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: diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index e6718bb2806..352aa9e927e 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -623,7 +623,8 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot, return ret; if (flags != want_flags) { - if (strict_prot || !is_new_memtype_allowed(want_flags, flags)) { + if (strict_prot || + !is_new_memtype_allowed(paddr, size, want_flags, flags)) { free_memtype(paddr, paddr + size); printk(KERN_ERR "%s:%d map pfn expected mapping type %s" " for %Lx-%Lx, got %s\n", -- 2.20.1