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[tip:x86/mm] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert

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Commit-ID:  361b4b58ec4cf123e12a773909c6454dbd5e6dbc
Gitweb:     http://git.kernel.org/tip/361b4b58ec4cf123e12a773909c6454dbd5e6dbc
Author:     Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
AuthorDate: Thu, 30 Mar 2017 11:07:26 +0300
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 4 Apr 2017 08:22:33 +0200

x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert

We don't need the assert anymore, as:

  17be0aec74fb ("x86/asm/entry/64: Implement better check for canonical addresses")

made canonical address checks generic wrt. address width.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170330080731.65421-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/entry/entry_64.S | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 044d18e..f07b4ef 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -265,12 +265,9 @@ 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
 	 */
-	.ifne __VIRTUAL_MASK_SHIFT - 47
-	.error "virtual address width changed -- SYSRET checks need update"
-	.endif
-
-	/* Change top 16 bits to be the sign-extension of 47th bit */
 	shl	$(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx
 	sar	$(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx
 

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[PATCHv3 0/7] x86: 5-level paging enabling for v4.12, Part 3 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-30 10:10 +0200
  [PATCHv3 2/7] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-30 10:10 +0200
    [tip:x86/mm] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert "tip-bot for Kirill A. Shutemov" <tipbot@zytor.com> - 2017-04-04 10:40 +0200
      Re: [tip:x86/mm] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert Denys Vlasenko <dvlasenk@redhat.com> - 2017-04-04 17:40 +0200
        Re: [tip:x86/mm] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-05 13:20 +0200
          Re: [tip:x86/mm] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert Denys Vlasenko <dvlasenk@redhat.com> - 2017-04-05 14:00 +0200
            Re: [tip:x86/mm] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-05 14:10 +0200
  [PATCHv3 3/7] x86/mm: Define virtual memory map for 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-30 10:10 +0200
    [tip:x86/mm] x86/mm: Define virtual memory map for 5-level paging "tip-bot for Kirill A. Shutemov" <tipbot@zytor.com> - 2017-04-04 10:40 +0200
  [PATCHv3 5/7] x86/mm: Add basic defines/helpers for CONFIG_X86_5LEVEL "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-30 10:10 +0200
    [tip:x86/mm] x86/mm: Add basic defines/helpers for  CONFIG_X86_5LEVEL=y "tip-bot for Kirill A. Shutemov" <tipbot@zytor.com> - 2017-04-04 10:40 +0200
  [PATCHv3 7/7] x86/espfix: Add support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-30 10:20 +0200
    [tip:x86/mm] x86/espfix: Add support for 5-level paging "tip-bot for Kirill A. Shutemov" <tipbot@zytor.com> - 2017-04-04 10:40 +0200
  [PATCHv3 6/7] x86/kasan: Extend to support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-30 10:20 +0200
    [tip:x86/mm] x86/kasan: Extend KASAN to support 5-level paging "tip-bot for Kirill A. Shutemov" <tipbot@zytor.com> - 2017-04-04 10:40 +0200

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