bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 06:44:00 -04:00
Code Issues Packages Projects Releases Wiki Activity

s390/cpufeature: Convert MACHINE_HAS_NX to cpu_has_nx()

Browse Source 
Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the feature is present.

test_facility() generates better code since it results in a static branch
without accessing memory. The branch is patched via alternatives by the
decompressor depending on the availability of the required facility.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens
2025-02-07 15:48:50 +01:00
committed by Vasily Gorbik
parent 42805261fc
commit b49ee5b386
8 changed files with 11 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
arch/s390/mm/init.c
View File

@@ -8,6 +8,7 @@
* Copyright (C) 1995 Linus Torvalds
*/
#include <linux/cpufeature.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
@@ -117,7 +118,7 @@ void mark_rodata_ro(void)
{
unsigned long size = __end_ro_after_init - __start_ro_after_init;
if (MACHINE_HAS_NX)
if (cpu_has_nx())
system_ctl_set_bit(0, CR0_INSTRUCTION_EXEC_PROTECTION_BIT);
__set_memory_ro(__start_ro_after_init, __end_ro_after_init);
pr_info("Write protected read-only-after-init data: %luk\n", size >> 10);