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raw | patch | inline | side by side (parent: 3a0e673)
author | Will Deacon <will.deacon@arm.com> | |
Fri, 15 Jun 2018 10:37:34 +0000 (11:37 +0100) | ||
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
Fri, 11 Oct 2019 16:21:10 +0000 (18:21 +0200) |
commit d71be2b6c0e19180b5f80a6d42039cc074a693a2 upstream.
Armv8.5 introduces a new PSTATE bit known as Speculative Store Bypass
Safe (SSBS) which can be used as a mitigation against Spectre variant 4.
Additionally, a CPU may provide instructions to manipulate PSTATE.SSBS
directly, so that userspace can toggle the SSBS control without trapping
to the kernel.
This patch probes for the existence of SSBS and advertise the new instructions
to userspace if they exist.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Armv8.5 introduces a new PSTATE bit known as Speculative Store Bypass
Safe (SSBS) which can be used as a mitigation against Spectre variant 4.
Additionally, a CPU may provide instructions to manipulate PSTATE.SSBS
directly, so that userspace can toggle the SSBS control without trapping
to the kernel.
This patch probes for the existence of SSBS and advertise the new instructions
to userspace if they exist.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
index 25ce9056cf641806ce8dd0a45f2392b546f47e78..c3de0bbf0e9a2d783b1b9cdfd2b5c6b66b23f0b5 100644 (file)
#define ARM64_MISMATCHED_CACHE_TYPE 31
#define ARM64_HAS_STAGE2_FWB 32
#define ARM64_WORKAROUND_1463225 33
+#define ARM64_SSBS 34
-#define ARM64_NCAPS 34
+#define ARM64_NCAPS 35
#endif /* __ASM_CPUCAPS_H */
index c1470931b8974936ed2a86fb231c15764d08f573..2fc6242baf11bc11167da5184378cf34fe3770d5 100644 (file)
#define SYS_ICH_LR15_EL2 __SYS__LR8_EL2(7)
/* Common SCTLR_ELx flags. */
+#define SCTLR_ELx_DSSBS (1UL << 44)
#define SCTLR_ELx_EE (1 << 25)
#define SCTLR_ELx_IESB (1 << 21)
#define SCTLR_ELx_WXN (1 << 19)
(1 << 10) | (1 << 13) | (1 << 14) | (1 << 15) | \
(1 << 17) | (1 << 20) | (1 << 24) | (1 << 26) | \
(1 << 27) | (1 << 30) | (1 << 31) | \
- (0xffffffffUL << 32))
+ (0xffffefffUL << 32))
#ifdef CONFIG_CPU_BIG_ENDIAN
#define ENDIAN_SET_EL2 SCTLR_ELx_EE
#define SCTLR_EL2_SET (SCTLR_ELx_IESB | ENDIAN_SET_EL2 | SCTLR_EL2_RES1)
#define SCTLR_EL2_CLEAR (SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C | \
SCTLR_ELx_SA | SCTLR_ELx_I | SCTLR_ELx_WXN | \
- ENDIAN_CLEAR_EL2 | SCTLR_EL2_RES0)
+ SCTLR_ELx_DSSBS | ENDIAN_CLEAR_EL2 | SCTLR_EL2_RES0)
#if (SCTLR_EL2_SET ^ SCTLR_EL2_CLEAR) != 0xffffffffffffffff
#error "Inconsistent SCTLR_EL2 set/clear bits"
(1 << 29))
#define SCTLR_EL1_RES0 ((1 << 6) | (1 << 10) | (1 << 13) | (1 << 17) | \
(1 << 27) | (1 << 30) | (1 << 31) | \
- (0xffffffffUL << 32))
+ (0xffffefffUL << 32))
#ifdef CONFIG_CPU_BIG_ENDIAN
#define ENDIAN_SET_EL1 (SCTLR_EL1_E0E | SCTLR_ELx_EE)
ENDIAN_SET_EL1 | SCTLR_EL1_UCI | SCTLR_EL1_RES1)
#define SCTLR_EL1_CLEAR (SCTLR_ELx_A | SCTLR_EL1_CP15BEN | SCTLR_EL1_ITD |\
SCTLR_EL1_UMA | SCTLR_ELx_WXN | ENDIAN_CLEAR_EL1 |\
- SCTLR_EL1_RES0)
+ SCTLR_ELx_DSSBS | SCTLR_EL1_RES0)
#if (SCTLR_EL1_SET ^ SCTLR_EL1_CLEAR) != 0xffffffffffffffff
#error "Inconsistent SCTLR_EL1 set/clear bits"
#define ID_AA64PFR0_EL0_64BIT_ONLY 0x1
#define ID_AA64PFR0_EL0_32BIT_64BIT 0x2
+/* id_aa64pfr1 */
+#define ID_AA64PFR1_SSBS_SHIFT 4
+
+#define ID_AA64PFR1_SSBS_PSTATE_NI 0
+#define ID_AA64PFR1_SSBS_PSTATE_ONLY 1
+#define ID_AA64PFR1_SSBS_PSTATE_INSNS 2
+
/* id_aa64mmfr0 */
#define ID_AA64MMFR0_TGRAN4_SHIFT 28
#define ID_AA64MMFR0_TGRAN64_SHIFT 24
index 17c65c8f33cb6073acda182e7b1c943e08730870..2bcd6e4f34740337c0d122fef5a2b513dcb75dd1 100644 (file)
#define HWCAP_USCAT (1 << 25)
#define HWCAP_ILRCPC (1 << 26)
#define HWCAP_FLAGM (1 << 27)
+#define HWCAP_SSBS (1 << 28)
#endif /* _UAPI__ASM_HWCAP_H */
index a897efdb3ddddca72b8c3231b934f76f400be667..d7552bbdf9634458e4394624bc02ab02938b4344 100644 (file)
ARM64_FTR_END,
};
+static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SSBS_SHIFT, 4, ID_AA64PFR1_SSBS_PSTATE_NI),
+ ARM64_FTR_END,
+};
+
static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
/*
* We already refuse to boot CPUs that don't support our configured
/* Op1 = 0, CRn = 0, CRm = 4 */
ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
- ARM64_FTR_REG(SYS_ID_AA64PFR1_EL1, ftr_raz),
+ ARM64_FTR_REG(SYS_ID_AA64PFR1_EL1, ftr_id_aa64pfr1),
ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_raz),
/* Op1 = 0, CRn = 0, CRm = 5 */
/*
* EL3 is not our concern.
- * ID_AA64PFR1 is currently RES0.
*/
taint |= check_update_ftr_reg(SYS_ID_AA64PFR0_EL1, cpu,
info->reg_id_aa64pfr0, boot->reg_id_aa64pfr0);
.cpu_enable = cpu_enable_hw_dbm,
},
#endif
+ {
+ .desc = "Speculative Store Bypassing Safe (SSBS)",
+ .capability = ARM64_SSBS,
+ .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64PFR1_EL1,
+ .field_pos = ID_AA64PFR1_SSBS_SHIFT,
+ .sign = FTR_UNSIGNED,
+ .min_field_value = ID_AA64PFR1_SSBS_PSTATE_ONLY,
+ },
{},
};
#ifdef CONFIG_ARM64_SVE
HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE),
#endif
+ HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, HWCAP_SSBS),
{},
};
index e9ab7b3ed31765e2a915c9841d515679f8e8749a..dce971f2c1673ed8dd0dca5e6d4833d8a16d086f 100644 (file)
"uscat",
"ilrcpc",
"flagm",
+ "ssbs",
NULL
};