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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2015-11-17 09:53:31 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2015-11-18 09:40:20 +0000
commit65da0a8e34a857f2ba9ccb91dc8f8f964cf938b7 (patch)
tree8dd46aee28e086b06249e65042b03db96631eca4 /arch/arm64
parentde818bd4522c40ea02a81b387d2fa86f989c9623 (diff)
downloadop-kernel-dev-65da0a8e34a857f2ba9ccb91dc8f8f964cf938b7.zip
op-kernel-dev-65da0a8e34a857f2ba9ccb91dc8f8f964cf938b7.tar.gz
arm64: use non-global mappings for UEFI runtime regions
As pointed out by Russell King in response to the proposed ARM version of this code, the sequence to switch between the UEFI runtime mapping and current's actual userland mapping (and vice versa) is potentially unsafe, since it leaves a time window between the switch to the new page tables and the TLB flush where speculative accesses may hit on stale global TLB entries. So instead, use non-global mappings, and perform the switch via the ordinary ASID-aware context switch routines. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/mmu_context.h2
-rw-r--r--arch/arm64/kernel/efi.c14
2 files changed, 6 insertions, 10 deletions
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index c0e8789..2416578 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -101,7 +101,7 @@ static inline void cpu_set_default_tcr_t0sz(void)
#define destroy_context(mm) do { } while(0)
void check_and_switch_context(struct mm_struct *mm, unsigned int cpu);
-#define init_new_context(tsk,mm) ({ atomic64_set(&mm->context.id, 0); 0; })
+#define init_new_context(tsk,mm) ({ atomic64_set(&(mm)->context.id, 0); 0; })
/*
* This is called when "tsk" is about to enter lazy TLB mode.
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index de46b50..fc5508e 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -224,6 +224,8 @@ static bool __init efi_virtmap_init(void)
{
efi_memory_desc_t *md;
+ init_new_context(NULL, &efi_mm);
+
for_each_efi_memory_desc(&memmap, md) {
u64 paddr, npages, size;
pgprot_t prot;
@@ -254,7 +256,8 @@ static bool __init efi_virtmap_init(void)
else
prot = PAGE_KERNEL;
- create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size, prot);
+ create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size,
+ __pgprot(pgprot_val(prot) | PTE_NG));
}
return true;
}
@@ -329,14 +332,7 @@ core_initcall(arm64_dmi_init);
static void efi_set_pgd(struct mm_struct *mm)
{
- if (mm == &init_mm)
- cpu_set_reserved_ttbr0();
- else
- cpu_switch_mm(mm->pgd, mm);
-
- local_flush_tlb_all();
- if (icache_is_aivivt())
- __local_flush_icache_all();
+ switch_mm(NULL, mm, NULL);
}
void efi_virtmap_load(void)
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