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x86/speculation: Fix firmware entry SPEC_CTRL handling

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commit e6aa13622e upstream.

The firmware entry code may accidentally clear STIBP or SSBD. Fix that.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Josh Poimboeuf
2022-06-14 23:16:06 +02:00
committed by Greg Kroah-Hartman
parent f1b01ace81
commit d29c07912a
1 changed files with 4 additions and 6 deletions
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10
arch/x86/include/asm/nospec-branch.h
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@@ -286,18 +286,16 @@ extern u64 spec_ctrl_current(void);
*/
#define firmware_restrict_branch_speculation_start() \
do { \
u64 val = x86_spec_ctrl_base | SPEC_CTRL_IBRS; \
\
preempt_disable(); \
alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \
alternative_msr_write(MSR_IA32_SPEC_CTRL, \
spec_ctrl_current() | SPEC_CTRL_IBRS, \
X86_FEATURE_USE_IBRS_FW); \
} while (0)
#define firmware_restrict_branch_speculation_end() \
do { \
u64 val = x86_spec_ctrl_base; \
\
alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \
alternative_msr_write(MSR_IA32_SPEC_CTRL, \
spec_ctrl_current(), \
X86_FEATURE_USE_IBRS_FW); \
preempt_enable(); \
} while (0)