From bd809af16e3ab1f8d55b3e2928c47c67e2a865d2 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 3 Nov 2014 14:02:03 +0100 Subject: x86: Enable PAT to use cache mode translation tables Update the translation tables from cache mode to pgprot values according to the PAT settings. This enables changing the cache attributes of a PAT index in just one place without having to change at the users side. With this change it is possible to use the same kernel with different PAT configurations, e.g. supporting Xen. Signed-off-by: Juergen Gross Reviewed-by: Toshi Kani Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Thomas Gleixner Cc: stefan.bader@canonical.com Cc: xen-devel@lists.xensource.com Cc: ville.syrjala@linux.intel.com Cc: david.vrabel@citrix.com Cc: jbeulich@suse.com Cc: plagnioj@jcrosoft.com Cc: tomi.valkeinen@ti.com Cc: bhelgaas@google.com Link: http://lkml.kernel.org/r/1415019724-4317-18-git-send-email-jgross@suse.com Signed-off-by: Thomas Gleixner --- arch/x86/mm/pat.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 48 insertions(+), 2 deletions(-) (limited to 'arch/x86/mm/pat.c') diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index ef75f3f89810..4c601276a556 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -31,6 +31,7 @@ #include #include "pat_internal.h" +#include "mm_internal.h" #ifdef CONFIG_X86_PAT int __read_mostly pat_enabled = 1; @@ -75,6 +76,52 @@ enum { PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */ }; +#define CM(c) (_PAGE_CACHE_MODE_ ## c) + +static enum page_cache_mode pat_get_cache_mode(unsigned pat_val, char *msg) +{ + enum page_cache_mode cache; + char *cache_mode; + + switch (pat_val) { + case PAT_UC: cache = CM(UC); cache_mode = "UC "; break; + case PAT_WC: cache = CM(WC); cache_mode = "WC "; break; + case PAT_WT: cache = CM(WT); cache_mode = "WT "; break; + case PAT_WP: cache = CM(WP); cache_mode = "WP "; break; + case PAT_WB: cache = CM(WB); cache_mode = "WB "; break; + case PAT_UC_MINUS: cache = CM(UC_MINUS); cache_mode = "UC- "; break; + default: cache = CM(WB); cache_mode = "WB "; break; + } + + memcpy(msg, cache_mode, 4); + + return cache; +} + +#undef CM + +/* + * Update the cache mode to pgprot translation tables according to PAT + * configuration. + * Using lower indices is preferred, so we start with highest index. + */ +void pat_init_cache_modes(void) +{ + int i; + enum page_cache_mode cache; + char pat_msg[33]; + u64 pat; + + rdmsrl(MSR_IA32_CR_PAT, pat); + pat_msg[32] = 0; + for (i = 7; i >= 0; i--) { + cache = pat_get_cache_mode((pat >> (i * 8)) & 7, + pat_msg + 4 * i); + update_cache_mode_entry(i, cache); + } + pr_info("PAT configuration [0-7]: %s\n", pat_msg); +} + #define PAT(x, y) ((u64)PAT_ ## y << ((x)*8)) void pat_init(void) @@ -124,8 +171,7 @@ void pat_init(void) wrmsrl(MSR_IA32_CR_PAT, pat); if (boot_cpu) - printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n", - smp_processor_id(), boot_pat_state, pat); + pat_init_cache_modes(); } #undef PAT -- cgit v1.2.3