From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@amacapital.net>,
Dmitry Safonov <dsafonov@virtuozzo.com>,
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: [PATCHv5 06/19] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time
Date: Mon, 21 Aug 2017 18:29:03 +0300 [thread overview]
Message-ID: <20170821152916.40124-7-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20170821152916.40124-1-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 */
--
2.14.1
--
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next prev parent reply other threads:[~2017-08-21 15:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-21 15:28 [PATCHv5 00/19] Boot-time switching between 4- and 5-level paging Kirill A. Shutemov
2017-08-21 15:28 ` [PATCHv5 01/19] mm/sparsemem: Allocate mem_section at runtime for SPARSEMEM_EXTREME Kirill A. Shutemov
2017-08-22 16:28 ` Borislav Petkov
2017-08-22 17:50 ` Kirill A. Shutemov
2017-08-21 15:28 ` [PATCHv5 02/19] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 03/19] x86/kasan: Use the same shadow offset for 4- and 5-level paging Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 04/19] x86/xen: Provide pre-built page tables only for XEN_PV and XEN_PVH Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 05/19] x86/xen: Drop 5-level paging support code from XEN_PV code Kirill A. Shutemov
2017-08-21 15:29 ` Kirill A. Shutemov [this message]
2017-08-27 11:29 ` [PATCHv5 06/19] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time Cyrill Gorcunov
2017-09-04 13:02 ` Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 07/19] x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 08/19] x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 09/19] x86/mm: Make MAX_PHYSADDR_BITS and MAX_PHYSMEM_BITS dynamic Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 10/19] x86/mm: Make __PHYSICAL_MASK_SHIFT and __VIRTUAL_MASK_SHIFT dynamic Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 11/19] x86/mm: Make STACK_TOP_MAX dynamic Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 12/19] x86/mm: Adjust virtual address space layout in early boot Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 13/19] x86/mm: Make early boot code support boot-time switching of paging modes Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 14/19] x86/mm: Fold p4d page table layer at runtime Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 15/19] x86/mm: Replace compile-time checks for 5-level with runtime-time Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 16/19] x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 17/19] x86/xen: Allow XEN_PV and XEN_PVH to be enabled with X86_5LEVEL Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 18/19] x86/mm: Redefine some of page table helpers as macros Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 19/19] x86/mm: Offset boot-time paging mode switching cost Kirill A. Shutemov
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