diff options
Diffstat (limited to 'arch/x86/mm/pat.c')
-rw-r--r-- | arch/x86/mm/pat.c | 54 |
1 files changed, 24 insertions, 30 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 277446cd30b..bcb1a8e4b2d 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -25,31 +25,24 @@ #include <asm/mtrr.h> #include <asm/io.h> -int pat_wc_enabled = 1; +#ifdef CONFIG_X86_PAT +int __read_mostly pat_wc_enabled = 1; -static u64 __read_mostly boot_pat_state; - -static int nopat(char *str) +void __init pat_disable(char *reason) { pat_wc_enabled = 0; - printk(KERN_INFO "x86: PAT support disabled.\n"); - - return 0; + printk(KERN_INFO "%s\n", reason); } -early_param("nopat", nopat); -static int pat_known_cpu(void) +static int nopat(char *str) { - if (!pat_wc_enabled) - return 0; - - if (cpu_has_pat) - return 1; - - pat_wc_enabled = 0; - printk(KERN_INFO "CPU and/or kernel does not support PAT.\n"); + pat_disable("PAT support disabled."); return 0; } +early_param("nopat", nopat); +#endif + +static u64 __read_mostly boot_pat_state; enum { PAT_UC = 0, /* uncached */ @@ -66,17 +59,19 @@ void pat_init(void) { u64 pat; -#ifndef CONFIG_X86_PAT - nopat(NULL); -#endif - - /* Boot CPU enables PAT based on CPU feature */ - if (!smp_processor_id() && !pat_known_cpu()) + if (!pat_wc_enabled) return; - /* APs enable PAT iff boot CPU has enabled it before */ - if (smp_processor_id() && !pat_wc_enabled) - return; + /* Paranoia check. */ + if (!cpu_has_pat) { + printk(KERN_ERR "PAT enabled, but CPU feature cleared\n"); + /* + * Panic if this happens on the secondary CPU, and we + * switched to PAT on the boot CPU. We have no way to + * undo PAT. + */ + BUG_ON(boot_pat_state); + } /* Set PWT to Write-Combining. All other bits stay the same */ /* @@ -95,9 +90,8 @@ void pat_init(void) PAT(4,WB) | PAT(5,WC) | PAT(6,UC_MINUS) | PAT(7,UC); /* Boot CPU check */ - if (!smp_processor_id()) { + if (!boot_pat_state) rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); - } wrmsrl(MSR_IA32_CR_PAT, pat); printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n", @@ -561,7 +555,7 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, "%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n", current->comm, current->pid, cattr_name(flags), - offset, offset + size); + offset, (unsigned long long)(offset + size)); return 0; } @@ -582,7 +576,7 @@ void map_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot) "%s:%d /dev/mem expected mapping type %s for %Lx-%Lx, got %s\n", current->comm, current->pid, cattr_name(want_flags), - addr, addr + size, + addr, (unsigned long long)(addr + size), cattr_name(flags)); } } |