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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2017-09-12 17:37:33 +0300
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2018-10-09 12:20:57 +0300
commitce3dc447493ff4186b192b38d723ab5e8c1eb52f (patch)
treef93f58afcd85087876a1ab9badcdaed76b5a37fe /arch/s390/kernel/asm-offsets.c
parentff340d2472ec7618443913928af9fb85a7009270 (diff)
downloadlinux-ce3dc447493ff4186b192b38d723ab5e8c1eb52f.tar.xz
s390: add support for virtually mapped kernel stacks
With virtually mapped kernel stacks the kernel stack overflow detection is now fault based, every stack has a guard page in the vmalloc space. The panic_stack is renamed to nodat_stack and is used for all function that need to run without DAT, e.g. memcpy_real or do_start_kdump. The main effect is a reduction in the kernel image size as with vmap stacks the old style overflow checking that adds two instructions per function is not needed anymore. Result from bloat-o-meter: add/remove: 20/1 grow/shrink: 13/26854 up/down: 2198/-216240 (-214042) In regard to performance the micro-benchmark for fork has a hit of a few microseconds, allocating 4 pages in vmalloc space is more expensive compare to an order-2 page allocation. But with real workload I could not find a noticeable difference. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/asm-offsets.c')
-rw-r--r--arch/s390/kernel/asm-offsets.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 66e830f1c7bf..164bec175628 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -159,7 +159,7 @@ int main(void)
OFFSET(__LC_CURRENT, lowcore, current_task);
OFFSET(__LC_KERNEL_STACK, lowcore, kernel_stack);
OFFSET(__LC_ASYNC_STACK, lowcore, async_stack);
- OFFSET(__LC_PANIC_STACK, lowcore, panic_stack);
+ OFFSET(__LC_NODAT_STACK, lowcore, nodat_stack);
OFFSET(__LC_RESTART_STACK, lowcore, restart_stack);
OFFSET(__LC_RESTART_FN, lowcore, restart_fn);
OFFSET(__LC_RESTART_DATA, lowcore, restart_data);