diff options
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 |