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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/include | |
| 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/include')
| -rw-r--r-- | arch/s390/include/asm/processor.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h index bfbfad482289..5f37f9ceef5e 100644 --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -91,6 +91,7 @@ void cpu_detect_mhz_feature(void); extern const struct seq_operations cpuinfo_op; extern int sysctl_ieee_emulation_warnings; extern void execve_tail(void); +extern void __bpon(void); /* * User space process size: 2GB for 31 bit, 4TB or 8PT for 64 bit. |