diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2018-07-20 10:56:27 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-07-22 14:27:41 +0200 |
| commit | 42f967dede3e8dbe34935fd7612e0eba0bc3a666 (patch) | |
| tree | a1e5e82253267de800206a247095d71928da3165 /arch/arm64/kernel/entry.S | |
| parent | 242bff3816ad7b48d3db5d7aa9b6c2c961e08d16 (diff) | |
arm64: ssbd: Skip apply_ssbd if not using dynamic mitigation
commit 986372c4367f46b34a3c0f6918d7fb95cbdf39d6 upstream.
In order to avoid checking arm64_ssbd_callback_required on each
kernel entry/exit even if no mitigation is required, let's
add yet another alternative that by default jumps over the mitigation,
and that gets nop'ed out if we're doing dynamic mitigation.
Think of it as a poor man's static key...
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 0f2510bd1ef9..75f1d9f051e8 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -100,6 +100,9 @@ alternative_else_nop_endif // to save/restore them if required. .macro apply_ssbd, state, targ, tmp1, tmp2 #ifdef CONFIG_ARM64_SSBD +alternative_cb arm64_enable_wa2_handling + b \targ +alternative_cb_end ldr_this_cpu \tmp2, arm64_ssbd_callback_required, \tmp1 cbz \tmp2, \targ mov w0, #ARM_SMCCC_ARCH_WORKAROUND_2 |