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ARM: spectre-v2: warn about incorrect context switching functions

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Warn at error level if the context switching function is not what we
are expecting.  This can happen with big.Little systems, which we
currently do not support.

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>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Russell King 2018-05-25 14:40:14 +01:00
parent 10115105cb
commit c44f366ea7
1 changed files with 15 additions and 0 deletions
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15
arch/arm/mm/proc-v7-bugs.c
View file

@ -12,6 +12,8 @@
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
DEFINE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn);
extern void cpu_v7_iciallu_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
extern void cpu_v7_bpiall_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
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);
@ -50,6 +52,8 @@ static void cpu_v7_spectre_init(void)
case ARM_CPU_PART_CORTEX_A17:
case ARM_CPU_PART_CORTEX_A73:
case ARM_CPU_PART_CORTEX_A75:
if (processor.switch_mm != cpu_v7_bpiall_switch_mm)
goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
harden_branch_predictor_bpiall;
spectre_v2_method = "BPIALL";
@ -57,6 +61,8 @@ static void cpu_v7_spectre_init(void)
case ARM_CPU_PART_CORTEX_A15:
case ARM_CPU_PART_BRAHMA_B15:
if (processor.switch_mm != cpu_v7_iciallu_switch_mm)
goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
harden_branch_predictor_iciallu;
spectre_v2_method = "ICIALLU";
@ -82,6 +88,8 @@ static void cpu_v7_spectre_init(void)
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
if ((int)res.a0 != 0)
break;
if (processor.switch_mm != cpu_v7_hvc_switch_mm && cpu)
goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
call_hvc_arch_workaround_1;
processor.switch_mm = cpu_v7_hvc_switch_mm;
@ -93,6 +101,8 @@ static void cpu_v7_spectre_init(void)
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
if ((int)res.a0 != 0)
break;
if (processor.switch_mm != cpu_v7_smc_switch_mm && cpu)
goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
call_smc_arch_workaround_1;
processor.switch_mm = cpu_v7_smc_switch_mm;
@ -109,6 +119,11 @@ static void cpu_v7_spectre_init(void)
if (spectre_v2_method)
pr_info("CPU%u: Spectre v2: using %s workaround\n",
smp_processor_id(), spectre_v2_method);
return;
bl_error:
pr_err("CPU%u: Spectre v2: incorrect context switching function, system vulnerable\n",
cpu);
}
#else
static void cpu_v7_spectre_init(void)