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| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2019-10-23 11:01:53 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-16 10:29:41 +0100 |
| commit | 211278805ea59ef5b871d89f5688e50faf6ca68c (patch) | |
| tree | a5efb6eed49e458c6dd04c3efd47881d3fbf6eb6 /arch/x86/kernel/cpu/cpu.h | |
| parent | 919d56194a7fe18c8d67e873d6f71c9db2e00eea (diff) | |
| download | linux-stable-211278805ea59ef5b871d89f5688e50faf6ca68c.tar.gz linux-stable-211278805ea59ef5b871d89f5688e50faf6ca68c.tar.bz2 linux-stable-211278805ea59ef5b871d89f5688e50faf6ca68c.zip | |
x86/cpu: Add a "tsx=" cmdline option with TSX disabled by default
commit 95c5824f75f3ba4c9e8e5a4b1a623c95390ac266 upstream.
Add a kernel cmdline parameter "tsx" to control the Transactional
Synchronization Extensions (TSX) feature. On CPUs that support TSX
control, use "tsx=on|off" to enable or disable TSX. Not specifying this
option is equivalent to "tsx=off". This is because on certain processors
TSX may be used as a part of a speculative side channel attack.
Carve out the TSX controlling functionality into a separate compilation
unit because TSX is a CPU feature while the TSX async abort control
machinery will go to cpu/bugs.c.
[ bp: - Massage, shorten and clear the arg buffer.
- Clarifications of the tsx= possible options - Josh.
- Expand on TSX_CTRL availability - Pawan. ]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
[bwh: Backported to 4.9: adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kernel/cpu/cpu.h')
| -rw-r--r-- | arch/x86/kernel/cpu/cpu.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h index 1f2873ac32ca..4350f50b5deb 100644 --- a/arch/x86/kernel/cpu/cpu.h +++ b/arch/x86/kernel/cpu/cpu.h @@ -44,6 +44,22 @@ struct _tlb_table { extern const struct cpu_dev *const __x86_cpu_dev_start[], *const __x86_cpu_dev_end[]; +#ifdef CONFIG_CPU_SUP_INTEL +enum tsx_ctrl_states { + TSX_CTRL_ENABLE, + TSX_CTRL_DISABLE, + TSX_CTRL_NOT_SUPPORTED, +}; + +extern __ro_after_init enum tsx_ctrl_states tsx_ctrl_state; + +extern void __init tsx_init(void); +extern void tsx_enable(void); +extern void tsx_disable(void); +#else +static inline void tsx_init(void) { } +#endif /* CONFIG_CPU_SUP_INTEL */ + extern void get_cpu_cap(struct cpuinfo_x86 *c); extern void cpu_detect_cache_sizes(struct cpuinfo_x86 *c); extern int detect_extended_topology_early(struct cpuinfo_x86 *c); |