diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2022-06-24 17:06:42 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2022-06-24 17:18:10 +0100 |
| commit | c3cee924bd855184d15bc4aa6088dcf8e2c1394c (patch) | |
| tree | afe531afe391eadbcdf03355a5c2e5b97df39a64 /arch/arm64/mm/proc.S | |
| parent | b013c1e1c659b0742f81cc4a95fe61faf6929ae5 (diff) | |
| download | linux-c3cee924bd855184d15bc4aa6088dcf8e2c1394c.tar.bz2 | |
arm64: head: cover entire kernel image in initial ID map
As a first step towards avoiding the need to create, tear down and
recreate the kernel virtual mapping with MMU and caches disabled, start
by expanding the ID map so it covers the page tables as well as all
executable code. This will allow us to populate the page tables with the
MMU and caches on, and call KASLR init code before setting up the
virtual mapping.
Since this ID map is only needed at boot, create it as a temporary set
of page tables, and populate the permanent ID map after enabling the MMU
and caches. While at it, switch to read-only attributes for the where
possible, as writable permissions are only needed for the initial kernel
page tables. Note that on 4k granule configurations, the permanent ID
map will now be reduced to a single page rather than a 2M block mapping.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-13-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/mm/proc.S')
| -rw-r--r-- | arch/arm64/mm/proc.S | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index e802badf9ac0..605c6640f94b 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -222,8 +222,10 @@ SYM_FUNC_END(idmap_cpu_replace_ttbr1) * * Called exactly once from stop_machine context by each CPU found during boot. */ -__idmap_kpti_flag: - .long 1 + .pushsection ".data", "aw", %progbits +SYM_DATA(__idmap_kpti_flag, .long 1) + .popsection + SYM_FUNC_START(idmap_kpti_install_ng_mappings) cpu .req w0 num_cpus .req w1 @@ -245,7 +247,7 @@ SYM_FUNC_START(idmap_kpti_install_ng_mappings) mrs swapper_ttb, ttbr1_el1 restore_ttbr1 swapper_ttb - adr flag_ptr, __idmap_kpti_flag + adr_l flag_ptr, __idmap_kpti_flag cbnz cpu, __idmap_kpti_secondary |