From 6282e916f774e37845c65d1eae9f8c649004f033 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 5 Nov 2018 14:54:56 +0100 Subject: ARM: 8809/1: proc-v7: fix Thumb annotation of cpu_v7_hvc_switch_mm Due to what appears to be a copy/paste error, the opening ENTRY() of cpu_v7_hvc_switch_mm() lacks a matching ENDPROC(), and instead, the one for cpu_v7_smc_switch_mm() is duplicated. Given that it is ENDPROC() that emits the Thumb annotation, the cpu_v7_hvc_switch_mm() routine will be called in ARM mode on a Thumb2 kernel, resulting in the following splat: Internal error: Oops - undefined instruction: 0 [#1] SMP THUMB2 Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-rc1-00030-g4d28ad89189d-dirty #488 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 PC is at cpu_v7_hvc_switch_mm+0x12/0x18 LR is at flush_old_exec+0x31b/0x570 pc : [] lr : [] psr: 00000013 sp : ee899e50 ip : 00000000 fp : 00000001 r10: eda28f34 r9 : eda31800 r8 : c12470e0 r7 : eda1fc00 r6 : eda53000 r5 : 00000000 r4 : ee88c000 r3 : c0316eec r2 : 00000001 r1 : eda53000 r0 : 6da6c000 Flags: nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Note the 'ISA ARM' in the last line. Fix this by using the correct name in ENDPROC(). Cc: Fixes: 10115105cb3a ("ARM: spectre-v2: add firmware based hardening") Reviewed-by: Dave Martin Acked-by: Marc Zyngier Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King --- arch/arm/mm/proc-v7.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/mm') diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index b78d59a1cc05..fccd4d99f505 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -112,7 +112,7 @@ ENTRY(cpu_v7_hvc_switch_mm) hvc #0 ldmfd sp!, {r0 - r3} b cpu_v7_switch_mm -ENDPROC(cpu_v7_smc_switch_mm) +ENDPROC(cpu_v7_hvc_switch_mm) #endif ENTRY(cpu_v7_iciallu_switch_mm) mov r3, #0 -- cgit v1.2.3 From 383fb3ee8024d596f488d2dbaf45e572897acbdb Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 19 Jul 2018 12:21:31 +0100 Subject: ARM: spectre-v2: per-CPU vtables to work around big.Little systems In big.Little systems, some CPUs require the Spectre workarounds in paths such as the context switch, but other CPUs do not. In order to handle these differences, we need per-CPU vtables. We are unable to use the kernel's per-CPU variables to support this as per-CPU is not initialised at times when we need access to the vtables, so we have to use an array indexed by logical CPU number. We use an array-of-pointers to avoid having function pointers in the kernel's read/write .data section. Reviewed-by: Julien Thierry Signed-off-by: Russell King --- arch/arm/mm/proc-v7-bugs.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) (limited to 'arch/arm/mm') diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c index 5544b82a2e7a..9a07916af8dd 100644 --- a/arch/arm/mm/proc-v7-bugs.c +++ b/arch/arm/mm/proc-v7-bugs.c @@ -52,8 +52,6 @@ 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"; @@ -61,8 +59,6 @@ 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"; @@ -88,11 +84,9 @@ 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; + cpu_do_switch_mm = cpu_v7_hvc_switch_mm; spectre_v2_method = "hypervisor"; break; @@ -101,11 +95,9 @@ 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; + cpu_do_switch_mm = cpu_v7_smc_switch_mm; spectre_v2_method = "firmware"; break; @@ -119,11 +111,6 @@ 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) -- cgit v1.2.3