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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <ak@linux.intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Michal Hocko <mhocko@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv2 03/10] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time
Date: Tue, 18 Jul 2017 17:15:10 +0300	[thread overview]
Message-ID: <20170718141517.52202-4-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20170718141517.52202-1-kirill.shutemov@linux.intel.com>

This patch prepare decompression code to boot-time switching between 4-
and 5-level paging.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/boot/compressed/head_64.S | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index fbf4c32d0b62..2e362aea3319 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -347,6 +347,28 @@ preferred_addr:
 	leaq	boot_stack_end(%rbx), %rsp
 
 #ifdef CONFIG_X86_5LEVEL
+	/* Preserve rbx across cpuid */
+	movq	%rbx, %r8
+
+	/* Check if leaf 7 is supported */
+	movl	$0, %eax
+	cpuid
+	cmpl	$7, %eax
+	jb	lvl5
+
+	/*
+	 * Check if la57 is supported.
+	 * The feature is enumerated with CPUID.(EAX=07H, ECX=0):ECX[bit 16]
+	 */
+	movl	$7, %eax
+	movl	$0, %ecx
+	cpuid
+	andl	$(1 << 16), %ecx
+	jz	lvl5
+
+	/* Restore rbx */
+	movq	%r8, %rbx
+
 	/* Check if 5-level paging has already enabled */
 	movq	%cr4, %rax
 	testl	$X86_CR4_LA57, %eax
@@ -386,6 +408,8 @@ preferred_addr:
 	pushq	%rax
 	lretq
 lvl5:
+	/* Restore rbx */
+	movq	%r8, %rbx
 #endif
 
 	/* Zero EFLAGS */
-- 
2.11.0

WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <ak@linux.intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Michal Hocko <mhocko@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv2 03/10] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time
Date: Tue, 18 Jul 2017 17:15:10 +0300	[thread overview]
Message-ID: <20170718141517.52202-4-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20170718141517.52202-1-kirill.shutemov@linux.intel.com>

This patch prepare decompression code to boot-time switching between 4-
and 5-level paging.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/boot/compressed/head_64.S | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index fbf4c32d0b62..2e362aea3319 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -347,6 +347,28 @@ preferred_addr:
 	leaq	boot_stack_end(%rbx), %rsp
 
 #ifdef CONFIG_X86_5LEVEL
+	/* Preserve rbx across cpuid */
+	movq	%rbx, %r8
+
+	/* Check if leaf 7 is supported */
+	movl	$0, %eax
+	cpuid
+	cmpl	$7, %eax
+	jb	lvl5
+
+	/*
+	 * Check if la57 is supported.
+	 * The feature is enumerated with CPUID.(EAX=07H, ECX=0):ECX[bit 16]
+	 */
+	movl	$7, %eax
+	movl	$0, %ecx
+	cpuid
+	andl	$(1 << 16), %ecx
+	jz	lvl5
+
+	/* Restore rbx */
+	movq	%r8, %rbx
+
 	/* Check if 5-level paging has already enabled */
 	movq	%cr4, %rax
 	testl	$X86_CR4_LA57, %eax
@@ -386,6 +408,8 @@ preferred_addr:
 	pushq	%rax
 	lretq
 lvl5:
+	/* Restore rbx */
+	movq	%r8, %rbx
 #endif
 
 	/* Zero EFLAGS */
-- 
2.11.0

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  parent reply	other threads:[~2017-07-18 14:16 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-18 14:15 [PATCHv2 00/10] Boot-time switching between 4- and 5-level paging Kirill A. Shutemov
2017-07-18 14:15 ` Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 01/10] x86/kasan: Use the same shadow offset for " Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 02/10] x86/xen: Provide pre-built page tables only for XEN_PV and XEN_PVH Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:15 ` Kirill A. Shutemov [this message]
2017-07-18 14:15   ` [PATCHv2 03/10] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 04/10] x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 05/10] x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 06/10] x86/mm: Handle boot-time paging mode switching at early boot Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 07/10] x86/mm: Fold p4d page table layer at runtime Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 08/10] x86/mm: Replace compile-time checks for 5-level with runtime-time Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:24   ` Juergen Gross
2017-07-18 14:24     ` Juergen Gross
2017-07-18 15:16     ` Kirill A. Shutemov
2017-07-18 15:16       ` Kirill A. Shutemov
2017-07-25  9:05     ` Kirill A. Shutemov
2017-07-25  9:05       ` Kirill A. Shutemov
2017-07-26  7:28       ` Juergen Gross
2017-07-26  7:28         ` Juergen Gross
2017-07-26 16:43         ` Kirill A. Shutemov
2017-07-26 16:43           ` Kirill A. Shutemov
2017-07-27  8:27           ` Juergen Gross
2017-07-27  8:27             ` Juergen Gross
2017-08-01  7:46           ` Juergen Gross
2017-08-01  7:46             ` Juergen Gross
2017-08-01 14:44             ` Kirill A. Shutemov
2017-08-01 14:44               ` Kirill A. Shutemov
2017-08-01 17:14               ` Juergen Gross
2017-08-01 17:14                 ` Juergen Gross
2017-08-01 19:11                 ` Kirill A. Shutemov
2017-08-01 19:11                   ` Kirill A. Shutemov
2017-08-02  7:44                   ` Juergen Gross
2017-08-02  7:44                     ` Juergen Gross
2017-08-02  8:17                     ` Kirill A. Shutemov
2017-08-02  8:17                       ` Kirill A. Shutemov
2017-08-02  8:30                       ` Juergen Gross
2017-08-02  8:30                         ` Juergen Gross
2017-07-18 14:15 ` [PATCHv2 09/10] x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov
2017-07-18 14:15 ` [PATCHv2 10/10] x86/mm: Offset boot-time paging mode switching cost Kirill A. Shutemov
2017-07-18 14:15   ` Kirill A. Shutemov

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