[for-stable-v4.19,09/16] arm64: Always enable ssb vulnerability detection

Message ID 20191008153930.15386-10-ard.biesheuvel@linaro.org
State New
Headers show
Series
  • arm64 spec mitigation backports
Related show

Commit Message

Ard Biesheuvel Oct. 8, 2019, 3:39 p.m.
From: Jeremy Linton <jeremy.linton@arm.com>


[ Upstream commit d42281b6e49510f078ace15a8ea10f71e6262581 ]

Ensure we are always able to detect whether or not the CPU is affected
by SSB, so that we can later advertise this to userspace.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Tested-by: Stefan Wahren <stefan.wahren@i2se.com>

[will: Use IS_ENABLED instead of #ifdef]
Signed-off-by: Will Deacon <will.deacon@arm.com>

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

---
 arch/arm64/include/asm/cpufeature.h | 4 ----
 arch/arm64/kernel/cpu_errata.c      | 9 +++++----
 2 files changed, 5 insertions(+), 8 deletions(-)

-- 
2.20.1

Patch

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 510f687d269a..dda6e5056810 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -525,11 +525,7 @@  static inline int arm64_get_ssbd_state(void)
 #endif
 }
 
-#ifdef CONFIG_ARM64_SSBD
 void arm64_set_ssbd_mitigation(bool state);
-#else
-static inline void arm64_set_ssbd_mitigation(bool state) {}
-#endif
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 3758ba538a43..10571a378f4c 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -239,7 +239,6 @@  enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
 }
 #endif	/* CONFIG_HARDEN_BRANCH_PREDICTOR */
 
-#ifdef CONFIG_ARM64_SSBD
 DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
 
 int ssbd_state __read_mostly = ARM64_SSBD_KERNEL;
@@ -312,6 +311,11 @@  void __init arm64_enable_wa2_handling(struct alt_instr *alt,
 
 void arm64_set_ssbd_mitigation(bool state)
 {
+	if (!IS_ENABLED(CONFIG_ARM64_SSBD)) {
+		pr_info_once("SSBD disabled by kernel configuration\n");
+		return;
+	}
+
 	if (this_cpu_has_cap(ARM64_SSBS)) {
 		if (state)
 			asm volatile(SET_PSTATE_SSBS(0));
@@ -431,7 +435,6 @@  static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
 
 	return required;
 }
-#endif	/* CONFIG_ARM64_SSBD */
 
 #ifdef CONFIG_ARM64_ERRATUM_1463225
 DEFINE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
@@ -710,14 +713,12 @@  const struct arm64_cpu_capabilities arm64_errata[] = {
 		ERRATA_MIDR_RANGE_LIST(arm64_harden_el2_vectors),
 	},
 #endif
-#ifdef CONFIG_ARM64_SSBD
 	{
 		.desc = "Speculative Store Bypass Disable",
 		.capability = ARM64_SSBD,
 		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
 		.matches = has_ssbd_mitigation,
 	},
-#endif
 #ifdef CONFIG_ARM64_ERRATUM_1463225
 	{
 		.desc = "ARM erratum 1463225",