[PATCH 2/8] x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert

From: Kirill A. Shutemov
Date: Mon Mar 27 2017 - 12:30:53 EST


We don't need the assert anymore. 17be0aec74fb ("x86/asm/entry/64:
Implement better check for canonical addresses") made canonical
address check generic wrt. address width.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
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 d2b2a2948ffe..607d72c4a485 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

--
2.11.0