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| author | Jiri Kosina <jkosina@suse.cz> | 2018-07-13 16:23:23 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-15 18:12:56 +0200 |
| commit | 8e41ddda308f9ac29fb9dd85d6e6bde7d3a29910 (patch) | |
| tree | cd1e4dab5e013a0fe0214084b9bd9c2758371b83 /kernel/cpu.c | |
| parent | e25726b1d30247589f36101c7e1e0a9b378fe407 (diff) | |
| download | linux-stable-8e41ddda308f9ac29fb9dd85d6e6bde7d3a29910.tar.gz linux-stable-8e41ddda308f9ac29fb9dd85d6e6bde7d3a29910.tar.bz2 linux-stable-8e41ddda308f9ac29fb9dd85d6e6bde7d3a29910.zip | |
cpu/hotplug: Expose SMT control init function
commit 8e1b706b6e819bed215c0db16345568864660393 upstream
The L1TF mitigation will gain a commend line parameter which allows to set
a combination of hypervisor mitigation and SMT control.
Expose cpu_smt_disable() so the command line parser can tweak SMT settings.
[ tglx: Split out of larger patch and made it preserve an already existing
force off state ]
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142323.039715135@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 7e4c788163cd..e41d453e98a5 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -351,13 +351,23 @@ EXPORT_SYMBOL_GPL(cpu_hotplug_enable); enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; EXPORT_SYMBOL_GPL(cpu_smt_control); -static int __init smt_cmdline_disable(char *str) +void __init cpu_smt_disable(bool force) { - cpu_smt_control = CPU_SMT_DISABLED; - if (str && !strcmp(str, "force")) { + if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || + cpu_smt_control == CPU_SMT_NOT_SUPPORTED) + return; + + if (force) { pr_info("SMT: Force disabled\n"); cpu_smt_control = CPU_SMT_FORCE_DISABLED; + } else { + cpu_smt_control = CPU_SMT_DISABLED; } +} + +static int __init smt_cmdline_disable(char *str) +{ + cpu_smt_disable(str && !strcmp(str, "force")); return 0; } early_param("nosmt", smt_cmdline_disable); |