[updating Christoffer's email address]
On 16/05/18 12:01, Russell King wrote:
> Add PSCI based hardening for cores that require more complex handling in
> firmware.
>
> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
> ---
> arch/arm/mm/proc-v7-bugs.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++
> arch/arm/mm/proc-v7.S | 21 +++++++++++++++++++
> 2 files changed, 71 insertions(+)
>
> diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
> index 65a9b8141f86..81de4a8e74c6 100644
> --- a/arch/arm/mm/proc-v7-bugs.c
> +++ b/arch/arm/mm/proc-v7-bugs.c
> @@ -1,9 +1,12 @@
> // 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>
>
> void cpu_v7_bugs_init(void);
> @@ -39,6 +42,9 @@ void cpu_v7_ca15_ibe(void)
> #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
> void (*harden_branch_predictor)(void);
>
> +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);
> @@ -49,6 +55,18 @@ static void harden_branch_predictor_iciallu(void)
> write_sysreg(0, ICIALLU);
> }
>
> +#ifdef CONFIG_ARM_PSCI
> +static void call_smc_arch_workaround_1(void)
> +{
> + arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
> +}
> +
> +static void call_hvc_arch_workaround_1(void)
> +{
> + arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
> +}
> +#endif
> +
> void cpu_v7_bugs_init(void)
> {
> const char *spectre_v2_method = NULL;
> @@ -73,6 +91,38 @@ void cpu_v7_bugs_init(void)
> spectre_v2_method = "ICIALLU";
> break;
> }
> +
> +#ifdef CONFIG_ARM_PSCI
> + if (psci_ops.smccc_version != SMCCC_VERSION_1_0) {
> + struct arm_smccc_res res;
> +
> + 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;
> + harden_branch_predictor = call_hvc_arch_workaround_1;
> + processor.switch_mm = cpu_v7_hvc_switch_mm;
> + spectre_v2_method = "hypervisor PSCI";
nit: strictly speaking, this is not provided by PSCI, but by
ARCH_WORKAROUND_1. We just use the same conduit as PSCI to discover it.
> + 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;
> + harden_branch_predictor = call_smc_arch_workaround_1;
> + processor.switch_mm = cpu_v7_smc_switch_mm;
> + spectre_v2_method = "firmware PSCI";
> + break;
> +
> + default:
> + break;
> + }
> + }
> +#endif
> +
> if (spectre_v2_method)
> pr_info("CPU: Spectre v2: using %s workaround\n",
> spectre_v2_method);
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> index 989864676f8b..7e6719a0eada 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
>
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
M.
--
Jazz is not dead. It just smells funny...
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