From 75a048119e76540d73132cfc8e0fa0c0a8bb6c83 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Thu, 22 Jan 2009 16:17:05 -0800 Subject: x86: handle PAT more like other CPU features Impact: Cleanup When PAT was originally introduced, it was handled specially for a few reasons: - PAT bugs are hard to track down, so we wanted to maintain a whitelist of CPUs. - The i386 and x86-64 CPUID code was not yet unified. Both of these are now obsolete, so handle PAT like any other features, including ordinary feature blacklisting due to known bugs. Signed-off-by: H. Peter Anvin --- arch/x86/mm/pat.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) (limited to 'arch/x86/mm/pat.c') diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 8b08fb9..430cb44 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -30,7 +30,7 @@ #ifdef CONFIG_X86_PAT int __read_mostly pat_enabled = 1; -void __cpuinit pat_disable(char *reason) +void __cpuinit pat_disable(const char *reason) { pat_enabled = 0; printk(KERN_INFO "%s\n", reason); @@ -42,6 +42,11 @@ static int __init nopat(char *str) return 0; } early_param("nopat", nopat); +#else +static inline void pat_disable(const char *reason) +{ + (void)reason; +} #endif @@ -78,16 +83,20 @@ void pat_init(void) if (!pat_enabled) return; - /* Paranoia check. */ - if (!cpu_has_pat && boot_pat_state) { - /* - * If this happens we are on a secondary CPU, but - * switched to PAT on the boot CPU. We have no way to - * undo PAT. - */ - printk(KERN_ERR "PAT enabled, " - "but not supported by secondary CPU\n"); - BUG(); + if (!cpu_has_pat) { + if (!boot_pat_state) { + pat_disable("PAT not supported by CPU."); + return; + } else { + /* + * If this happens we are on a secondary CPU, but + * switched to PAT on the boot CPU. We have no way to + * undo PAT. + */ + printk(KERN_ERR "PAT enabled, " + "but not supported by secondary CPU\n"); + BUG(); + } } /* Set PWT to Write-Combining. All other bits stay the same */ -- cgit v1.1 From 7880f7464546842ee14179bef16a6e14381ea638 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Tue, 24 Feb 2009 17:35:13 -0800 Subject: gpu/drm, x86, PAT: routine to keep identity map in sync Add a function to check and keep identity maps in sync, when changing any memory type. One of the follow on patches will also use this routine. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Cc: Dave Airlie Cc: Jesse Barnes Cc: Eric Anholt Cc: Keith Packard Signed-off-by: Ingo Molnar --- arch/x86/mm/pat.c | 46 +++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 17 deletions(-) (limited to 'arch/x86/mm/pat.c') diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index aebbf67..399383c 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -625,6 +625,33 @@ void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot) } /* + * Change the memory type for the physial address range in kernel identity + * mapping space if that range is a part of identity map. + */ +int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags) +{ + unsigned long id_sz; + + if (!pat_enabled || base >= __pa(high_memory)) + return 0; + + id_sz = (__pa(high_memory) < base + size) ? + __pa(high_memory) - base : + size; + + if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) { + printk(KERN_INFO + "%s:%d ioremap_change_attr failed %s " + "for %Lx-%Lx\n", + current->comm, current->pid, + cattr_name(flags), + base, (unsigned long long)(base + size)); + return -EINVAL; + } + return 0; +} + +/* * Internal interface to reserve a range of physical memory with prot. * Reserved non RAM regions only and after successful reserve_memtype, * this func also keeps identity mapping (if any) in sync with this new prot. @@ -633,7 +660,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot, int strict_prot) { int is_ram = 0; - int id_sz, ret; + int ret; unsigned long flags; unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK); @@ -670,23 +697,8 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot, 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) { + if (kernel_map_sync_memtype(paddr, size, flags) < 0) { free_memtype(paddr, paddr + size); - printk(KERN_ERR - "%s:%d reserve_pfn_range ioremap_change_attr failed %s " - "for %Lx-%Lx\n", - current->comm, current->pid, - cattr_name(flags), - (unsigned long long)paddr, - (unsigned long long)(paddr + size)); return -EINVAL; } return 0; -- cgit v1.1