diff options
| author | Will Deacon <will.deacon@arm.com> | 2018-04-03 12:09:05 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-08 12:12:52 +0200 |
| commit | 1809afd71b9c419ab8b57c3ea5c870b5285f442a (patch) | |
| tree | 231a21294cd0e7c760c8dd000bd0a7d416d20275 /arch/arm64/include | |
| parent | 78a0cec5fe4399dced66e70cdec793618590d932 (diff) | |
arm64: mm: Map entry trampoline into trampoline and kernel page tables
commit 51a0048beb44 upstream.
The exception entry trampoline needs to be mapped at the same virtual
address in both the trampoline page table (which maps nothing else)
and also the kernel page table, so that we can swizzle TTBR1_EL1 on
exceptions from and return to EL0.
This patch maps the trampoline at a fixed virtual address in the fixmap
area of the kernel virtual address space, which allows the kernel proper
to be randomized with respect to the trampoline when KASLR is enabled.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com> [v4.9 backport]
Tested-by: Will Deacon <will.deacon@arm.com>
Tested-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/fixmap.h | 5 | ||||
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 1 |
2 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h index caf86be815ba..7b1d88c18143 100644 --- a/arch/arm64/include/asm/fixmap.h +++ b/arch/arm64/include/asm/fixmap.h @@ -51,6 +51,11 @@ enum fixed_addresses { FIX_EARLYCON_MEM_BASE, FIX_TEXT_POKE0, + +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 + FIX_ENTRY_TRAMP_TEXT, +#define TRAMP_VALIAS (__fix_to_virt(FIX_ENTRY_TRAMP_TEXT)) +#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ __end_of_permanent_fixed_addresses, /* diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 7acd3c5c7643..3a30a3994e4a 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -692,6 +692,7 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm, extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; +extern pgd_t tramp_pg_dir[PTRS_PER_PGD]; /* * Encode and decode a swap entry: |