diff options
| -rw-r--r-- | arch/x86/include/asm/mtrr.h | 2 | ||||
| -rw-r--r-- | arch/x86/mm/pat.c | 20 |
2 files changed, 15 insertions, 7 deletions
diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h index dbff1456d2152..3337d2233aefc 100644 --- a/arch/x86/include/asm/mtrr.h +++ b/arch/x86/include/asm/mtrr.h @@ -86,7 +86,7 @@ static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi) } static inline void mtrr_bp_init(void) { - pat_disable("MTRRs disabled, skipping PAT initialization too."); + pat_disable("PAT support disabled because CONFIG_MTRR is disabled in the kernel."); } #define mtrr_ap_init() do {} while (0) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 560ac5137a2f4..e26b81ca5b956 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -66,7 +66,11 @@ static bool __read_mostly pat_disabled = !IS_ENABLED(CONFIG_X86_PAT); static bool __read_mostly pat_initialized; static bool __read_mostly init_cm_done; -void pat_disable(const char *reason) +/* + * PAT support is enabled by default, but can be disabled for + * various user-requested or hardware-forced reasons: + */ +void pat_disable(const char *msg_reason) { if (pat_disabled) return; @@ -77,12 +81,12 @@ void pat_disable(const char *reason) } pat_disabled = true; - pr_info("x86/PAT: %s\n", reason); + pr_info("x86/PAT: %s\n", msg_reason); } static int __init nopat(char *str) { - pat_disable("PAT support disabled."); + pat_disable("PAT support disabled via boot option."); return 0; } early_param("nopat", nopat); @@ -238,13 +242,13 @@ static void pat_bsp_init(u64 pat) u64 tmp_pat; if (!boot_cpu_has(X86_FEATURE_PAT)) { - pat_disable("PAT not supported by CPU."); + pat_disable("PAT not supported by the CPU."); return; } rdmsrl(MSR_IA32_CR_PAT, tmp_pat); if (!tmp_pat) { - pat_disable("PAT MSR is 0, disabled."); + pat_disable("PAT support disabled by the firmware."); return; } @@ -314,7 +318,7 @@ void init_cache_modes(void) } /** - * pat_init - Initialize PAT MSR and PAT table + * pat_init - Initialize the PAT MSR and PAT table on the current CPU * * This function initializes PAT MSR and PAT table with an OS-defined value * to enable additional cache attributes, WC, WT and WP. @@ -328,6 +332,10 @@ void pat_init(void) u64 pat; struct cpuinfo_x86 *c = &boot_cpu_data; +#ifndef CONFIG_X86_PAT + pr_info_once("x86/PAT: PAT support disabled because CONFIG_X86_PAT is disabled in the kernel.\n"); +#endif + if (pat_disabled) return; |