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| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-14 15:38:55 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-31 11:09:01 +0100 |
| commit | 10115105cb3aa17b5da1cb726ae8dd5f6854bd93 (patch) | |
| tree | d032bf3acc75e49cb9336990881d0d4e4dad3d26 /arch | |
| parent | f5fe12b1eaee220ce62ff9afb8b90929c396595f (diff) | |
| download | linux-10115105cb3aa17b5da1cb726ae8dd5f6854bd93.tar.bz2 | |
ARM: spectre-v2: add firmware based hardening
Add firmware based hardening for cores that require more complex
handling in firmware.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/mm/proc-v7-bugs.c | 60 | ||||
| -rw-r--r-- | arch/arm/mm/proc-v7.S | 21 |
2 files changed, 81 insertions, 0 deletions
diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c index 85a2e3d6263c..da25a38e1897 100644 --- a/arch/arm/mm/proc-v7-bugs.c +++ b/arch/arm/mm/proc-v7-bugs.c @@ -1,14 +1,20 @@ // SPDX-License-Identifier: GPL-2.0 +#include <linux/arm-smccc.h> #include <linux/kernel.h> +#include <linux/psci.h> #include <linux/smp.h> #include <asm/cp15.h> #include <asm/cputype.h> +#include <asm/proc-fns.h> #include <asm/system_misc.h> #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR DEFINE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn); +extern void cpu_v7_smc_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm); +extern void cpu_v7_hvc_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm); + static void harden_branch_predictor_bpiall(void) { write_sysreg(0, BPIALL); @@ -19,6 +25,16 @@ static void harden_branch_predictor_iciallu(void) write_sysreg(0, ICIALLU); } +static void __maybe_unused call_smc_arch_workaround_1(void) +{ + arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL); +} + +static void __maybe_unused call_hvc_arch_workaround_1(void) +{ + arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL); +} + static void cpu_v7_spectre_init(void) { const char *spectre_v2_method = NULL; @@ -45,7 +61,51 @@ static void cpu_v7_spectre_init(void) harden_branch_predictor_iciallu; spectre_v2_method = "ICIALLU"; break; + +#ifdef CONFIG_ARM_PSCI + default: + /* Other ARM CPUs require no workaround */ + if (read_cpuid_implementor() == ARM_CPU_IMP_ARM) + break; + /* fallthrough */ + /* Cortex A57/A72 require firmware workaround */ + case ARM_CPU_PART_CORTEX_A57: + case ARM_CPU_PART_CORTEX_A72: { + struct arm_smccc_res res; + + if (psci_ops.smccc_version == SMCCC_VERSION_1_0) + break; + + switch (psci_ops.conduit) { + case PSCI_CONDUIT_HVC: + arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, + ARM_SMCCC_ARCH_WORKAROUND_1, &res); + if ((int)res.a0 != 0) + break; + per_cpu(harden_branch_predictor_fn, cpu) = + call_hvc_arch_workaround_1; + processor.switch_mm = cpu_v7_hvc_switch_mm; + spectre_v2_method = "hypervisor"; + break; + + case PSCI_CONDUIT_SMC: + arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, + ARM_SMCCC_ARCH_WORKAROUND_1, &res); + if ((int)res.a0 != 0) + break; + per_cpu(harden_branch_predictor_fn, cpu) = + call_smc_arch_workaround_1; + processor.switch_mm = cpu_v7_smc_switch_mm; + spectre_v2_method = "firmware"; + break; + + default: + break; + } } +#endif + } + if (spectre_v2_method) pr_info("CPU%u: Spectre v2: using %s workaround\n", smp_processor_id(), spectre_v2_method); diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 79510011e7eb..b78d59a1cc05 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -9,6 +9,7 @@ * * This is the "shell" of the ARMv7 processor support. */ +#include <linux/arm-smccc.h> #include <linux/init.h> #include <linux/linkage.h> #include <asm/assembler.h> @@ -93,6 +94,26 @@ ENTRY(cpu_v7_dcache_clean_area) ret lr ENDPROC(cpu_v7_dcache_clean_area) +#ifdef CONFIG_ARM_PSCI + .arch_extension sec +ENTRY(cpu_v7_smc_switch_mm) + stmfd sp!, {r0 - r3} + movw r0, #:lower16:ARM_SMCCC_ARCH_WORKAROUND_1 + movt r0, #:upper16:ARM_SMCCC_ARCH_WORKAROUND_1 + smc #0 + ldmfd sp!, {r0 - r3} + b cpu_v7_switch_mm +ENDPROC(cpu_v7_smc_switch_mm) + .arch_extension virt +ENTRY(cpu_v7_hvc_switch_mm) + stmfd sp!, {r0 - r3} + movw r0, #:lower16:ARM_SMCCC_ARCH_WORKAROUND_1 + movt r0, #:upper16:ARM_SMCCC_ARCH_WORKAROUND_1 + hvc #0 + ldmfd sp!, {r0 - r3} + b cpu_v7_switch_mm +ENDPROC(cpu_v7_smc_switch_mm) +#endif ENTRY(cpu_v7_iciallu_switch_mm) mov r3, #0 mcr p15, 0, r3, c7, c5, 0 @ ICIALLU |