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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-01-16 07:11:45 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-02-05 13:49:17 +0100 |
| commit | d768bd892fc8f066cd3aa000eb1867bcf32db0ee (patch) | |
| tree | 73856bebc552b175d71bef6859824d7ca8d8e051 /arch/s390/kernel/ipl.c | |
| parent | cf1489984641369611556bf00c48f945c77bcf02 (diff) | |
| download | linux-d768bd892fc8f066cd3aa000eb1867bcf32db0ee.tar.gz linux-d768bd892fc8f066cd3aa000eb1867bcf32db0ee.tar.bz2 linux-d768bd892fc8f066cd3aa000eb1867bcf32db0ee.zip | |
s390: add options to change branch prediction behaviour for the kernel
Add the PPA instruction to the system entry and exit path to switch
the kernel to a different branch prediction behaviour. The instructions
are added via CPU alternatives and can be disabled with the "nospec"
or the "nobp=0" kernel parameter. If the default behaviour selected
with CONFIG_KERNEL_NOBP is set to "n" then the "nobp=1" parameter can be
used to enable the changed kernel branch prediction.
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/ipl.c')
| -rw-r--r-- | arch/s390/kernel/ipl.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c index da5cc3b469aa..34477c1aee6d 100644 --- a/arch/s390/kernel/ipl.c +++ b/arch/s390/kernel/ipl.c @@ -543,6 +543,7 @@ static struct kset *ipl_kset; static void __ipl_run(void *unused) { + __bpon(); diag308(DIAG308_LOAD_CLEAR, NULL); if (MACHINE_IS_VM) __cpcmd("IPL", NULL, 0, NULL); |