From bd809af16e3ab1f8d55b3e2928c47c67e2a865d2 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 3 Nov 2014 14:02:03 +0100 Subject: [PATCH] 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/include/asm/pat.h | 1 + arch/x86/include/asm/pgtable_types.h | 4 +++ arch/x86/mm/init.c | 8 +++++ arch/x86/mm/mm_internal.h | 2 ++ arch/x86/mm/pat.c | 50 ++++++++++++++++++++++++++-- 5 files changed, 63 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h index 150407a7234..91bc4ba95f9 100644 --- a/arch/x86/include/asm/pat.h +++ b/arch/x86/include/asm/pat.h @@ -11,6 +11,7 @@ static const int pat_enabled; #endif extern void pat_init(void); +void pat_init_cache_modes(void); extern int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm); diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 6d5f6d15421..af447f95e3b 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -351,6 +351,10 @@ extern uint8_t __pte2cachemode_tbl[8]; ((((cb) >> (_PAGE_BIT_PAT - 2)) & 4) | \ (((cb) >> (_PAGE_BIT_PCD - 1)) & 2) | \ (((cb) >> _PAGE_BIT_PWT) & 1)) +#define __cm_idx2pte(i) \ + ((((i) & 4) << (_PAGE_BIT_PAT - 2)) | \ + (((i) & 2) << (_PAGE_BIT_PCD - 1)) | \ + (((i) & 1) << _PAGE_BIT_PWT)) static inline unsigned long cachemode2protval(enum page_cache_mode pcm) { diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index a9776ba475d..82b41d56bb9 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -716,3 +716,11 @@ void __init zone_sizes_init(void) free_area_init_nodes(max_zone_pfns); } +void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache) +{ + /* entry 0 MUST be WB (hardwired to speed up translations) */ + BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB); + + __cachemode2pte_tbl[cache] = __cm_idx2pte(entry); + __pte2cachemode_tbl[entry] = cache; +} diff --git a/arch/x86/mm/mm_internal.h b/arch/x86/mm/mm_internal.h index 6b563a11889..62474ba66c8 100644 --- a/arch/x86/mm/mm_internal.h +++ b/arch/x86/mm/mm_internal.h @@ -16,4 +16,6 @@ void zone_sizes_init(void); extern int after_bootmem; +void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache); + #endif /* __X86_MM_INTERNAL_H */ diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index ef75f3f8981..4c601276a55 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 -- 2.41.0