diff options
| author | Joey Gouly <joey.gouly@arm.com> | 2024-08-22 16:11:01 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2024-09-04 12:54:04 +0100 |
| commit | 7f955be9f887d3ce77afb61ea74d907f06fe6f1e (patch) | |
| tree | 64ed14dae6ec546dc08e80191e9dbce9bb736c47 /arch/arm64/mm/mmu.c | |
| parent | fc2d9cd33040630f9d6ff819f1f326d51b354429 (diff) | |
arm64: implement PKEYS support
Implement the PKEYS interface, using the Permission Overlay Extension.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20240822151113.1479789-19-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/mm/mmu.c')
| -rw-r--r-- | arch/arm64/mm/mmu.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 353ea5dc32b8..e55b02fbddc8 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -25,6 +25,7 @@ #include <linux/vmalloc.h> #include <linux/set_memory.h> #include <linux/kfence.h> +#include <linux/pkeys.h> #include <asm/barrier.h> #include <asm/cputype.h> @@ -1549,3 +1550,47 @@ void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp) cpu_uninstall_idmap(); } + +#ifdef CONFIG_ARCH_HAS_PKEYS +int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) +{ + u64 new_por = POE_RXW; + u64 old_por; + u64 pkey_shift; + + if (!system_supports_poe()) + return -ENOSPC; + + /* + * This code should only be called with valid 'pkey' + * values originating from in-kernel users. Complain + * if a bad value is observed. + */ + if (WARN_ON_ONCE(pkey >= arch_max_pkey())) + return -EINVAL; + + /* Set the bits we need in POR: */ + new_por = POE_RXW; + if (init_val & PKEY_DISABLE_WRITE) + new_por &= ~POE_W; + if (init_val & PKEY_DISABLE_ACCESS) + new_por &= ~POE_RW; + if (init_val & PKEY_DISABLE_READ) + new_por &= ~POE_R; + if (init_val & PKEY_DISABLE_EXECUTE) + new_por &= ~POE_X; + + /* Shift the bits in to the correct place in POR for pkey: */ + pkey_shift = pkey * POR_BITS_PER_PKEY; + new_por <<= pkey_shift; + + /* Get old POR and mask off any old bits in place: */ + old_por = read_sysreg_s(SYS_POR_EL0); + old_por &= ~(POE_MASK << pkey_shift); + + /* Write old part along with new part: */ + write_sysreg_s(old_por | new_por, SYS_POR_EL0); + + return 0; +} +#endif |