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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Ingo Molnar <mingo@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Cyrill Gorcunov <gorcunov@openvz.org>,
	Borislav Petkov <bp@suse.de>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv7 06/19] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time
Date: Mon, 18 Sep 2017 13:55:40 +0300	[thread overview]
Message-ID: <20170918105553.27914-7-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20170918105553.27914-1-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 b4a5d284391c..09c85e8558eb 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -288,6 +288,28 @@ ENTRY(startup_64)
 	leaq	boot_stack_end(%rbx), %rsp
 
 #ifdef CONFIG_X86_5LEVEL
+	/* Preserve rbx across cpuid */
+	movq	%rbx, %r8
+
+	/* Check if leaf 7 is supported */
+	xorl	%eax, %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
+	xorl	%ecx, %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
@@ -327,6 +349,8 @@ ENTRY(startup_64)
 	pushq	%rax
 	lretq
 lvl5:
+	/* Restore rbx */
+	movq	%r8, %rbx
 #endif
 
 	/* Zero EFLAGS */
-- 
2.14.1

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  parent reply	other threads:[~2017-09-18 10:56 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-18 10:55 [PATCHv7 00/19] Boot-time switching between 4- and 5-level paging for 4.15 Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 01/19] mm/sparsemem: Allocate mem_section at runtime for SPARSEMEM_EXTREME Kirill A. Shutemov
2017-09-28  8:07   ` Ingo Molnar
2017-09-28  9:08     ` Kirill A. Shutemov
2017-09-28  9:39       ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 02/19] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS Kirill A. Shutemov
2017-09-28  8:10   ` Ingo Molnar
2017-09-28  9:19     ` Kirill A. Shutemov
2017-09-28  9:44       ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 03/19] x86/kasan: Use the same shadow offset for 4- and 5-level paging Kirill A. Shutemov
2017-09-28  8:15   ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 04/19] x86/xen: Provide pre-built page tables only for XEN_PV and XEN_PVH Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 05/19] x86/xen: Drop 5-level paging support code from XEN_PV code Kirill A. Shutemov
2017-09-18 10:55 ` Kirill A. Shutemov [this message]
2017-09-28  8:18   ` [PATCHv7 06/19] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 07/19] x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL Kirill A. Shutemov
2017-09-28  8:19   ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 08/19] x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable Kirill A. Shutemov
2017-09-19 14:03   ` Kirill A. Shutemov
2017-09-28  8:21   ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 09/19] x86/mm: Make MAX_PHYSADDR_BITS and MAX_PHYSMEM_BITS dynamic Kirill A. Shutemov
2017-09-28  8:25   ` Ingo Molnar
2017-09-28 10:17     ` Kirill A. Shutemov
2017-09-28 10:40       ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 10/19] x86/mm: Make __PHYSICAL_MASK_SHIFT and __VIRTUAL_MASK_SHIFT dynamic Kirill A. Shutemov
2017-09-28  8:28   ` Ingo Molnar
2017-09-28 10:22     ` Kirill A. Shutemov
2017-09-28 10:42       ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 11/19] x86/mm: Make STACK_TOP_MAX dynamic Kirill A. Shutemov
2017-09-28  8:29   ` Ingo Molnar
2017-09-28 13:19     ` Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 12/19] x86/mm: Adjust virtual address space layout in early boot Kirill A. Shutemov
2017-09-28  8:31   ` Ingo Molnar
2017-09-28 13:26     ` Kirill A. Shutemov
2017-09-28 13:38       ` Ingo Molnar
2017-09-28 14:28         ` Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 13/19] x86/mm: Make early boot code support boot-time switching of paging modes Kirill A. Shutemov
2017-09-28  8:33   ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 14/19] x86/mm: Fold p4d page table layer at runtime Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 15/19] x86/mm: Replace compile-time checks for 5-level with runtime-time Kirill A. Shutemov
2017-09-28  8:35   ` Ingo Molnar
2017-09-18 10:55 ` [PATCHv7 16/19] x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 17/19] x86/xen: Allow XEN_PV and XEN_PVH to be enabled with X86_5LEVEL Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 18/19] x86/mm: Redefine some of page table helpers as macros Kirill A. Shutemov
2017-09-18 10:55 ` [PATCHv7 19/19] x86/mm: Offset boot-time paging mode switching cost Kirill A. Shutemov
2017-09-25 13:16 ` [PATCHv7 00/19] Boot-time switching between 4- and 5-level paging for 4.15 Kirill A. Shutemov
2017-09-28  8:36 ` Ingo Molnar

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