[PATCH v11 1/12] x86, mm, pat: Cleanup init flags in pat_init()
From: Toshi Kani pat_init() uses two flags, 'boot_cpu' and 'boot_pat_state', for tracking the boot CPU's initialization status. 'boot_pat_state' is also overloaded to carry the boot PAT value. This patch cleans this up by replacing them with a new single flag, 'boot_cpu_done', to track the boot CPU's initialization status. 'boot_pat_state' is only used to carry the boot PAT value as a result. Suggested-by: Thomas Gleixner Signed-off-by: Toshi Kani --- arch/x86/mm/pat.c | 40 +++- 1 file changed, 19 insertions(+), 21 deletions(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index a1c9654..e1ec6a7 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -197,24 +197,29 @@ void pat_init_cache_modes(void) void pat_init(void) { u64 pat; - bool boot_cpu = !boot_pat_state; + static bool boot_cpu_done; if (!pat_enabled()) return; - if (!cpu_has_pat) { - if (!boot_pat_state) { + if (!boot_cpu_done) { + if (!cpu_has_pat) { 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. -*/ - pr_err("x86/PAT: PAT enabled, but not supported by secondary CPU\n"); - BUG(); } + + rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); + if (!boot_pat_state) { + pat_disable("PAT read returns always zero, disabled."); + return; + } + } else if (!cpu_has_pat) { + /* +* If this happens we are on a secondary CPU, but +* switched to PAT on the boot CPU. We have no way to +* undo PAT. +*/ + panic("PAT enabled, but not supported by secondary CPU\n"); } /* Set PWT to Write-Combining. All other bits stay the same */ @@ -233,19 +238,12 @@ void pat_init(void) pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) | PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC); - /* Boot CPU check */ - if (!boot_pat_state) { - rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); - if (!boot_pat_state) { - pat_disable("PAT read returns always zero, disabled."); - return; - } - } - wrmsrl(MSR_IA32_CR_PAT, pat); - if (boot_cpu) + if (!boot_cpu_done) { pat_init_cache_modes(); + boot_cpu_done = true; + } } #undef PAT -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v11 1/12] x86, mm, pat: Cleanup init flags in pat_init()
From: Toshi Kani toshi.k...@hp.com pat_init() uses two flags, 'boot_cpu' and 'boot_pat_state', for tracking the boot CPU's initialization status. 'boot_pat_state' is also overloaded to carry the boot PAT value. This patch cleans this up by replacing them with a new single flag, 'boot_cpu_done', to track the boot CPU's initialization status. 'boot_pat_state' is only used to carry the boot PAT value as a result. Suggested-by: Thomas Gleixner t...@linutronix.de Signed-off-by: Toshi Kani toshi.k...@hp.com --- arch/x86/mm/pat.c | 40 +++- 1 file changed, 19 insertions(+), 21 deletions(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index a1c9654..e1ec6a7 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -197,24 +197,29 @@ void pat_init_cache_modes(void) void pat_init(void) { u64 pat; - bool boot_cpu = !boot_pat_state; + static bool boot_cpu_done; if (!pat_enabled()) return; - if (!cpu_has_pat) { - if (!boot_pat_state) { + if (!boot_cpu_done) { + if (!cpu_has_pat) { 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. -*/ - pr_err(x86/PAT: PAT enabled, but not supported by secondary CPU\n); - BUG(); } + + rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); + if (!boot_pat_state) { + pat_disable(PAT read returns always zero, disabled.); + return; + } + } else if (!cpu_has_pat) { + /* +* If this happens we are on a secondary CPU, but +* switched to PAT on the boot CPU. We have no way to +* undo PAT. +*/ + panic(PAT enabled, but not supported by secondary CPU\n); } /* Set PWT to Write-Combining. All other bits stay the same */ @@ -233,19 +238,12 @@ void pat_init(void) pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) | PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC); - /* Boot CPU check */ - if (!boot_pat_state) { - rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); - if (!boot_pat_state) { - pat_disable(PAT read returns always zero, disabled.); - return; - } - } - wrmsrl(MSR_IA32_CR_PAT, pat); - if (boot_cpu) + if (!boot_cpu_done) { pat_init_cache_modes(); + boot_cpu_done = true; + } } #undef PAT -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/