diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2020-11-03 10:22:29 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-11-10 17:30:40 +0000 |
| commit | 833be850f1cabd0e3b5337c0fcab20a6e936dd48 (patch) | |
| tree | f19034fb5146f82b4fc2944ec86fef62581335aa /arch/arm64/kernel/entry.S | |
| parent | ba090f9cafd53dbabe0f0a8c4ccae44203d3731b (diff) | |
arm64: consistently use reserved_pg_dir
Depending on configuration options and specific code paths, we either
use the empty_zero_page or the configuration-dependent reserved_ttbr0
as a reserved value for TTBR{0,1}_EL1.
To simplify this code, let's always allocate and use the same
reserved_pg_dir, replacing reserved_ttbr0. Note that this is allocated
(and hence pre-zeroed), and is also marked as read-only in the kernel
Image mapping.
Keeping this separate from the empty_zero_page potentially helps with
robustness as the empty_zero_page is used in a number of cases where a
failure to map it read-only could allow it to become corrupted.
The (presently unused) swapper_pg_end symbol is also removed, and
comments are added wherever we rely on the offsets between the
pre-allocated pg_dirs to keep these cases easily identifiable.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201103102229.8542-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index b295fb912b12..6f31c2c06788 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -807,9 +807,10 @@ SYM_CODE_END(ret_to_user) */ .pushsection ".entry.tramp.text", "ax" + // Move from tramp_pg_dir to swapper_pg_dir .macro tramp_map_kernel, tmp mrs \tmp, ttbr1_el1 - add \tmp, \tmp, #(PAGE_SIZE + RESERVED_TTBR0_SIZE) + add \tmp, \tmp, #(2 * PAGE_SIZE) bic \tmp, \tmp, #USER_ASID_FLAG msr ttbr1_el1, \tmp #ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003 @@ -826,9 +827,10 @@ alternative_else_nop_endif #endif /* CONFIG_QCOM_FALKOR_ERRATUM_1003 */ .endm + // Move from swapper_pg_dir to tramp_pg_dir .macro tramp_unmap_kernel, tmp mrs \tmp, ttbr1_el1 - sub \tmp, \tmp, #(PAGE_SIZE + RESERVED_TTBR0_SIZE) + sub \tmp, \tmp, #(2 * PAGE_SIZE) orr \tmp, \tmp, #USER_ASID_FLAG msr ttbr1_el1, \tmp /* |