Commit 165eb13e authored by Jonathan Marek's avatar Jonathan Marek Committed by Will Deacon
Browse files

arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY 



The "drop print" commit removed the whole branch and not just the print.
For some ARM64 cpus, this leads to hard lockup when
CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY is not enabled.

Fixes: 62e72463 ("arm64: proton-pack: Drop print when !CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY")
Signed-off-by: default avatarJonathan Marek <jonathan@marek.ca>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 7c16c02e

arch/arm64/kernel/proton-pack.c

+2 −0
Original line number Diff line number Diff line
@@ -1032,6 +1032,8 @@ void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry) 


	if (arm64_get_spectre_v2_state() == SPECTRE_VULNERABLE) {

		/* No point mitigating Spectre-BHB alone. */

	} else if (!IS_ENABLED(CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY)) {

		/* Do nothing */

	} else if (supports_ecbhb(SCOPE_LOCAL_CPU)) {

		state = SPECTRE_MITIGATED;

		set_bit(BHB_HW, &system_bhb_mitigations);