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[PATCHv4 1/9] x86/asm: Fix comment in return_from_SYSCALL_64

From "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCHv4 1/9] x86/asm: Fix comment in return_from_SYSCALL_64
Date 2017-04-13 13:40 +0200
Message-ID <tvLgu-2jU-27@gated-at.bofh.it> (permalink)
References <ttEj8-G4-25@gated-at.bofh.it> <tvLgt-2jU-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On x86-64 __VIRTUAL_MASK_SHIFT depends on paging mode now.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/entry/entry_64.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 607d72c4a485..edec30584eb8 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -266,7 +266,8 @@ return_from_SYSCALL_64:
 	 * If width of "canonical tail" ever becomes variable, this will need
 	 * to be updated to remain correct on both old and new CPUs.
 	 *
-	 * Change top 16 bits to be the sign-extension of 47th bit
+	 * Change top bits to match most significant bit (47th or 56th bit
+	 * depending on paging mode) in the address.
 	 */
 	shl	$(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx
 	sar	$(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx
-- 
2.11.0

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[PATCHv4 0/9] x86: 5-level paging enabling for v4.12, Part 4 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-13 13:40 +0200
  [PATCHv4 9/9] x86/mm: Allow to have userspace mappings above 47-bits "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-13 13:40 +0200
  [PATCHv4 2/9] x86/boot/64: Rewrite startup_64 in C "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-13 13:40 +0200
  [PATCHv4 1/9] x86/asm: Fix comment in return_from_SYSCALL_64 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-13 13:40 +0200
  [PATCHv4 3/9] x86/boot/64: Rename init_level4_pgt and early_level4_pgt "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-13 13:40 +0200
  [PATCHv4 6/9] x86/mm: Make kernel_physical_mapping_init() support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-13 13:40 +0200
  [PATCHv4 5/9] x86/mm: Add sync_global_pgds() for configuration with 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-13 13:40 +0200

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