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From: Borislav Petkov <bp@alien8.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 01/20] x86/mm/pat: Untangle pat_init()
Date: Thu,  4 Jun 2015 18:55:09 +0200
Message-ID: <1433436928-31903-2-git-send-email-bp@alien8.de> (raw)
In-Reply-To: <1433436928-31903-1-git-send-email-bp@alien8.de>

From: Borislav Petkov <bp@suse.de>

Split it into a BSP and AP version which makes the PAT initialization
path actually readable again.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: arnd@arndb.de
Cc: Elliott@hp.com
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: stefan.bader@canonical.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Cc: yigal@plexistor.com
---
 arch/x86/mm/pat.c | 69 ++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 40 insertions(+), 29 deletions(-)

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index a1c96544099d..476d0780560f 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -36,6 +36,8 @@
 #undef pr_fmt
 #define pr_fmt(fmt) "" fmt
 
+static bool boot_cpu_done;
+
 static int __read_mostly __pat_enabled = IS_ENABLED(CONFIG_X86_PAT);
 
 static inline void pat_disable(const char *reason)
@@ -194,31 +196,47 @@ void pat_init_cache_modes(void)
 
 #define PAT(x, y)	((u64)PAT_ ## y << ((x)*8))
 
-void pat_init(void)
+static void pat_bsp_init(u64 pat)
 {
-	u64 pat;
-	bool boot_cpu = !boot_pat_state;
+	if (!cpu_has_pat) {
+		pat_disable("PAT not supported by CPU.");
+		return;
+	}
 
-	if (!pat_enabled())
+	rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
+	if (!boot_pat_state) {
+		pat_disable("PAT MSR is 0, disabled.");
 		return;
+	}
 
+	wrmsrl(MSR_IA32_CR_PAT, pat);
+
+	pat_init_cache_modes();
+}
+
+static void pat_ap_init(u64 pat)
+{
 	if (!cpu_has_pat) {
-		if (!boot_pat_state) {
-			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();
-		}
+		/*
+		 * 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("x86/PAT: PAT enabled, but not supported by secondary CPU\n");
 	}
 
-	/* Set PWT to Write-Combining. All other bits stay the same */
+	wrmsrl(MSR_IA32_CR_PAT, pat);
+}
+
+void pat_init(void)
+{
+	u64 pat;
+
+	if (!pat_enabled())
+		return;
+
 	/*
+	 * Set PWT to Write-Combining. All other bits stay the same:
+	 *
 	 * PTE encoding used in Linux:
 	 *      PAT
 	 *      |PCD
@@ -233,19 +251,12 @@ 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;
-		}
+	if (!boot_cpu_done) {
+		pat_bsp_init(pat);
+		boot_cpu_done = true;
+	} else {
+		pat_ap_init(pat);
 	}
-
-	wrmsrl(MSR_IA32_CR_PAT, pat);
-
-	if (boot_cpu)
-		pat_init_cache_modes();
 }
 
 #undef PAT
-- 
2.3.5


  reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-04 16:55 [PATCH 00/20] tip queue 2015-06-04 Borislav Petkov
2015-06-04 16:55 ` Borislav Petkov [this message]
2015-06-07 17:39   ` [tip:x86/mm] x86/mm/pat: Untangle pat_init() tip-bot for Borislav Petkov
2015-06-04 16:55 ` [PATCH 02/20] x86/mm/pat: Emulate PAT when it is disabled Borislav Petkov
2015-06-07 17:39   ` [tip:x86/mm] " tip-bot for Borislav Petkov
2015-06-04 16:55 ` [PATCH 03/20] x86/mm/pat: Remove pat_enabled() checks Borislav Petkov
2015-06-07 17:40   ` [tip:x86/mm] " tip-bot for Borislav Petkov
2015-06-04 16:55 ` [PATCH 04/20] x86/mm/pat: Use 7th PAT MSR slot for Write-Through PAT type Borislav Petkov
2015-06-04 16:55 ` [PATCH 05/20] x86/mm/pat: Change reserve_memtype() for Write-Through type Borislav Petkov
2015-06-07 17:40   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 06/20] x86/mm: Teach is_new_memtype_allowed() about " Borislav Petkov
2015-06-07 17:41   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 07/20] x86/mm, asm-generic: Add ioremap_wt() for creating Write-Through mappings Borislav Petkov
2015-06-07 17:41   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 08/20] arch/*/io.h: Add ioremap_wt() to all architectures Borislav Petkov
2015-06-07 17:41   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 09/20] video/fbdev, asm/io.h: Remove ioremap_writethrough() Borislav Petkov
2015-06-07 17:41   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 10/20] x86/mm/pat: Add pgprot_writethrough() Borislav Petkov
2015-06-07 17:42   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 11/20] x86/mm/pat: Extend set_page_memtype() to support Write-Through type Borislav Petkov
2015-06-07 17:42   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 12/20] x86/mm: Add set_memory_wt() for " Borislav Petkov
2015-06-07 17:42   ` [tip:x86/mm] x86/mm/pat: " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 13/20] drivers/block/pmem: Map NVDIMM in Write-Through mode Borislav Petkov
2015-06-07 17:43   ` [tip:x86/mm] " tip-bot for Toshi Kani
2015-06-04 16:55 ` [PATCH 14/20] x86/mce: Add Local MCE definitions Borislav Petkov
2015-06-07 17:43   ` [tip:x86/core] " tip-bot for Ashok Raj
2015-06-04 16:55 ` [PATCH 15/20] x86/mce: Add infrastructure to support Local MCE Borislav Petkov
2015-06-07 17:43   ` [tip:x86/core] " tip-bot for Ashok Raj
2015-06-04 16:55 ` [PATCH 16/20] x86/mce: Handle Local MCE events Borislav Petkov
2015-06-07 17:44   ` [tip:x86/core] " tip-bot for Ashok Raj
2015-06-04 16:55 ` [PATCH 17/20] x86: Kill CONFIG_X86_HT Borislav Petkov
2015-06-07 17:44   ` [tip:x86/core] " tip-bot for Borislav Petkov
2015-06-04 16:55 ` [PATCH 18/20] x86/uapi: Do not export <asm/msr-index.h> as part of the user API headers Borislav Petkov
2015-06-07 17:44   ` [tip:x86/core] " tip-bot for Borislav Petkov
2015-06-04 16:55 ` [PATCH 19/20] x86/microcode: Disable builtin microcode loading on 32-bit for now Borislav Petkov
2015-06-07 17:45   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2015-06-04 16:55 ` [PATCH 20/20] x86/microcode: Correct variables type Borislav Petkov
2015-06-07 17:45   ` [tip:x86/microcode] x86/microcode: Correct CPU family related variable types tip-bot for Andy Shevchenko

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