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| author | Joey Gouly <joey.gouly@arm.com> | 2023-06-06 17:58:50 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2023-06-06 18:52:41 +0300 |
| commit | f0af339fc408a55c9f48f5d9ca47059ef1eb36b8 (patch) | |
| tree | f71ee516598e602503bfcfea30789697cfdbcbca /arch/arm64/mm/proc.S | |
| parent | 8ef67c67e637809a28f0efeb045aa454c7799a51 (diff) | |
| download | linux-f0af339fc408a55c9f48f5d9ca47059ef1eb36b8.tar.xz | |
arm64: add PTE_UXN/PTE_WRITE to SWAPPER_*_FLAGS
With PIE enabled, the swapper PTEs would have a Permission Indirection Index
(PIIndex) of 0. A PIIndex of 0 is not currently used by any other PTEs.
To avoid using index 0 specifically for the swapper PTEs, mark them as
PTE_UXN and PTE_WRITE, so that they map to a PAGE_KERNEL_EXEC equivalent.
This also adds PTE_WRITE to KPTI_NG_PTE_FLAGS, which was tested by booting
with kpti=on.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230606145859.697944-12-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm/proc.S')
| -rw-r--r-- | arch/arm64/mm/proc.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index c2cb437821ca..9513a8d2ce0e 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -199,7 +199,7 @@ SYM_FUNC_END(idmap_cpu_replace_ttbr1) #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 -#define KPTI_NG_PTE_FLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) +#define KPTI_NG_PTE_FLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS | PTE_WRITE) .pushsection ".idmap.text", "a" @@ -290,7 +290,7 @@ SYM_TYPED_FUNC_START(idmap_kpti_install_ng_mappings) isb mov temp_pte, x5 - mov pte_flags, #KPTI_NG_PTE_FLAGS + mov_q pte_flags, KPTI_NG_PTE_FLAGS /* Everybody is enjoying the idmap, so we can rewrite swapper. */ /* PGD */ |