diff options
| author | Will Deacon <will.deacon@arm.com> | 2018-02-05 18:34:20 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2018-02-07 01:53:35 +0300 |
| commit | 6314d90e64936c584f300a52ef173603fb2461b5 (patch) | |
| tree | fb62ec15844bee34626b37a80ec6d82d6ee3f26a /arch/arm64/include/asm | |
| parent | 4d8efc2d5ee4c9ccfeb29ee8afd47a8660d0c0ce (diff) | |
| download | linux-6314d90e64936c584f300a52ef173603fb2461b5.tar.xz | |
arm64: entry: Ensure branch through syscall table is bounded under speculation
In a similar manner to array_index_mask_nospec, this patch introduces an
assembly macro (mask_nospec64) which can be used to bound a value under
speculation. This macro is then used to ensure that the indirect branch
through the syscall table is bounded under speculation, with out-of-range
addresses speculating as calls to sys_io_setup (0).
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 1f44b4255a28..1241fb211293 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -123,6 +123,17 @@ .endm /* + * Sanitise a 64-bit bounded index wrt speculation, returning zero if out + * of bounds. + */ + .macro mask_nospec64, idx, limit, tmp + sub \tmp, \idx, \limit + bic \tmp, \tmp, \idx + and \idx, \idx, \tmp, asr #63 + csdb + .endm + +/* * NOP sequence */ .macro nops, num |