| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 204/266] x86/speculation: Move STIPB/IBPB string conditionals out of cpu_show_common() | Date | Wed, 15 May 2019 12:55:11 +0200 |
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From: Tim Chen <tim.c.chen@linux.intel.com>
commit a8f76ae41cd633ac00be1b3019b1eb4741be3828 upstream.
The Spectre V2 printout in cpu_show_common() handles conditionals for the various mitigation methods directly in the sprintf() argument list. That's hard to read and will become unreadable if more complex decisions need to be made for a particular method.
Move the conditionals for STIBP and IBPB string selection into helper functions, so they can be extended later on.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Casey Schaufler <casey.schaufler@intel.com> Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Jon Masters <jcm@redhat.com> Cc: Waiman Long <longman9394@gmail.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Dave Stewart <david.c.stewart@intel.com> Cc: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20181125185003.874479208@linutronix.de Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/x86/kernel/cpu/bugs.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -759,6 +759,22 @@ static void __init l1tf_select_mitigatio #ifdef CONFIG_SYSFS +static char *stibp_state(void) +{ + if (x86_spec_ctrl_base & SPEC_CTRL_STIBP) + return ", STIBP"; + else + return ""; +} + +static char *ibpb_state(void) +{ + if (boot_cpu_has(X86_FEATURE_USE_IBPB)) + return ", IBPB"; + else + return ""; +} + static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr, char *buf, unsigned int bug) { @@ -777,9 +793,9 @@ static ssize_t cpu_show_common(struct de case X86_BUG_SPECTRE_V2: return sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled], - boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "", + ibpb_state(), boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "", - (x86_spec_ctrl_base & SPEC_CTRL_STIBP) ? ", STIBP" : "", + stibp_state(), boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "", spectre_v2_module_string());
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