lkml.org 
[lkml]   [2017]   [Apr]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCHv5 1/9] x86/asm: Fix comment in return_from_SYSCALL_64
Date
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
\
 
 \ /
  Last update: 2017-04-20 18:23    [W:0.058 / U:5.520 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site