On 22/06/2026 15:16, David Hildenbrand (Arm) wrote: > On 5/26/26 13:15, Kevin Brodsky wrote: >> Introduce a helper that sets the permissions of a given pkey >> (POIndex) in the POR_ELx format, and make use of it in >> arch_set_user_pkey_access(). >> >> Signed-off-by: Kevin Brodsky <[email protected]> >> --- >> arch/arm64/include/asm/por.h | 7 +++++++ >> arch/arm64/mm/mmu.c | 26 ++++++++++---------------- >> 2 files changed, 17 insertions(+), 16 deletions(-) >> >> diff --git a/arch/arm64/include/asm/por.h b/arch/arm64/include/asm/por.h >> index d913d5b529e4..bffb4d2b1246 100644 >> --- a/arch/arm64/include/asm/por.h >> +++ b/arch/arm64/include/asm/por.h >> @@ -31,4 +31,11 @@ static inline bool por_elx_allows_exec(u64 por, u8 pkey) >> return perm & POE_X; >> } >> >> +static inline u64 por_elx_set_pkey_perms(u64 por, u8 pkey, u64 perms) >> +{ >> + u64 shift = POR_ELx_PERM_SHIFT(pkey); >> + >> + return (por & ~(POE_MASK << shift)) | (perms << shift); >> +} >> + >> #endif /* _ASM_ARM64_POR_H */ >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index dd85e093ffdb..493310cf0486 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -2339,8 +2339,8 @@ void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp) >> #ifdef CONFIG_ARCH_HAS_PKEYS >> int arch_set_user_pkey_access(int pkey, unsigned long init_val) >> { >> - u64 new_por; >> - u64 old_por; >> + u64 new_perms; > You should spell out the renaming of the variable.
Sure, will do. > Given that perms is 4bit per key, should we use a u8 for it instead? We could, in fact I'm just noticing that this all very inconsistent right now: the POE_* constants are defined as UL, but por_elx_allows_* and other functions use u8. I'll clean that up in a separate patch and use u8 here. >> + u64 por; >> >> if (!system_supports_poe()) >> return -ENOSPC; >> @@ -2354,25 +2354,19 @@ int arch_set_user_pkey_access(int pkey, unsigned >> long init_val) >> return -EINVAL; >> >> /* Set the bits we need in POR: */ >> - new_por = POE_RWX; >> + new_perms = POE_RWX; >> if (init_val & PKEY_DISABLE_WRITE) >> - new_por &= ~POE_W; >> + new_perms &= ~POE_W; >> if (init_val & PKEY_DISABLE_ACCESS) >> - new_por &= ~POE_RW; >> + new_perms &= ~POE_RW; >> if (init_val & PKEY_DISABLE_READ) >> - new_por &= ~POE_R; >> + new_perms &= ~POE_R; >> if (init_val & PKEY_DISABLE_EXECUTE) >> - new_por &= ~POE_X; >> + new_perms &= ~POE_X; >> >> - /* Shift the bits in to the correct place in POR for pkey: */ >> - new_por = POR_ELx_PERM_PREP(pkey, new_por); >> - >> - /* Get old POR and mask off any old bits in place: */ >> - old_por = read_sysreg_s(SYS_POR_EL0); >> - old_por &= ~(POE_MASK << POR_ELx_PERM_SHIFT(pkey)); >> - >> - /* Write old part along with new part: */ >> - write_sysreg_s(old_por | new_por, SYS_POR_EL0); >> + por = read_sysreg_s(SYS_POR_EL0); >> + por = por_elx_set_pkey_perms(por, pkey, new_perms); >> + write_sysreg_s(por, SYS_POR_EL0); > Was wondering whether to move reading+writing of the register into the same > helper, but you cannot reuse this exactly the same way for SYS_POR_EL1 as it > seems. It wouldn't be useful because the new user of the helper, por_set_kpkeys_context(), doesn't itself read or write the register. > Reviewed-by: David Hildenbrand (Arm) <[email protected]> Thanks! - Kevin
