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x86/speculation: Move STIPB/IBPB string conditionals out of cpu_show_common() 

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>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181125185003.874479208@linutronix.de
This commit is contained in:
Tim Chen 2018-11-25 19:33:32 +01:00 committed by Thomas Gleixner
parent b86bda0426
commit a8f76ae41c
1 changed files with 18 additions and 2 deletions
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20
arch/x86/kernel/cpu/bugs.c
View File

@ -844,6 +844,22 @@ static ssize_t l1tf_show_state(char *buf)
}
#endif
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)
{
@ -865,9 +881,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
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());