[PATCH 14/26] x86/asm: remove __VIRTUAL_MASK_SHIFT==47 assert

From: Kirill A. Shutemov
Date: Mon Mar 13 2017 - 01:53:26 EST


We don't need it 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 044d18ebc43c..f07b4efb34d5 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