Now that kernel correctly store/restore userspace AMR/IAMR values, avoid manipulating AMR and IAMR from the kernel on behalf of userspace.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com> --- arch/powerpc/include/asm/book3s/64/kup.h | 23 ++++++++ arch/powerpc/include/asm/processor.h | 5 -- arch/powerpc/kernel/process.c | 4 -- arch/powerpc/kernel/traps.c | 6 -- arch/powerpc/mm/book3s64/pkeys.c | 71 ++++-------------------- 5 files changed, 34 insertions(+), 75 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h index fe1818954e51..31eb0acddea9 100644 --- a/arch/powerpc/include/asm/book3s/64/kup.h +++ b/arch/powerpc/include/asm/book3s/64/kup.h @@ -174,6 +174,29 @@ extern u64 default_uamor; extern u64 default_amr; extern u64 default_iamr; +/* + * For kernel thread that doesn't have thread.regs return + * default AMR/IAMR values. + */ +static inline u64 current_thread_amr(void) +{ + if (current->thread.regs) + return current->thread.regs->kuap; + return AMR_KUAP_BLOCKED; +} + +static inline u64 current_thread_iamr(void) +{ + if (current->thread.regs) + return current->thread.regs->kuep; + return AMR_KUEP_BLOCKED; +} + +static inline u64 read_uamor(void) +{ + return default_uamor; +} + static inline void kuap_restore_user_amr(struct pt_regs *regs) { if (!mmu_has_feature(MMU_FTR_PKEY)) diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index a51964b4ec42..591987da44e2 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -234,11 +234,6 @@ struct thread_struct { struct thread_vr_state ckvr_state; /* Checkpointed VR state */ unsigned long ckvrsave; /* Checkpointed VRSAVE */ #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ -#ifdef CONFIG_PPC_MEM_KEYS - unsigned long amr; - unsigned long iamr; - unsigned long uamor; -#endif #ifdef CONFIG_KVM_BOOK3S_32_HANDLER void* kvm_shadow_vcpu; /* KVM internal data */ #endif /* CONFIG_KVM_BOOK3S_32_HANDLER */ diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 0ab9a8cf1bcb..682deeee421f 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -585,7 +585,6 @@ static void save_all(struct task_struct *tsk) __giveup_spe(tsk); msr_check_and_clear(msr_all_available); - thread_pkey_regs_save(&tsk->thread); } void flush_all_to_thread(struct task_struct *tsk) @@ -1097,8 +1096,6 @@ static inline void save_sprs(struct thread_struct *t) t->tar = mfspr(SPRN_TAR); } #endif - - thread_pkey_regs_save(t); } static inline void restore_sprs(struct thread_struct *old_thread, @@ -1139,7 +1136,6 @@ static inline void restore_sprs(struct thread_struct *old_thread, mtspr(SPRN_TIDR, new_thread->tidr); #endif - thread_pkey_regs_restore(new_thread, old_thread); } struct task_struct *__switch_to(struct task_struct *prev, diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 3fca22276bb1..a47fb49b7af8 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -348,12 +348,6 @@ static bool exception_common(int signr, struct pt_regs *regs, int code, current->thread.trap_nr = code; - /* - * Save all the pkey registers AMR/IAMR/UAMOR. Eg: Core dumps need - * to capture the content, if the task gets killed. - */ - thread_pkey_regs_save(¤t->thread); - return true; } diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c index 5012b57af808..0f4fc2876fc8 100644 --- a/arch/powerpc/mm/book3s64/pkeys.c +++ b/arch/powerpc/mm/book3s64/pkeys.c @@ -264,40 +264,17 @@ void pkey_mm_init(struct mm_struct *mm) mm->context.execute_only_pkey = execute_only_key; } -static inline u64 read_amr(void) +static inline void update_current_thread_amr(u64 value) { - return mfspr(SPRN_AMR); + current->thread.regs->kuap = value; } -static inline void write_amr(u64 value) -{ - mtspr(SPRN_AMR, value); -} - -static inline u64 read_iamr(void) -{ - if (static_branch_unlikely(&execute_pkey_disabled)) - return 0x0UL; - - return mfspr(SPRN_IAMR); -} - -static inline void write_iamr(u64 value) +static inline void update_current_thread_iamr(u64 value) { if (static_branch_unlikely(&execute_pkey_disabled)) return; - mtspr(SPRN_IAMR, value); -} - -static inline u64 read_uamor(void) -{ - return mfspr(SPRN_UAMOR); -} - -static inline void write_uamor(u64 value) -{ - mtspr(SPRN_UAMOR, value); + current->thread.regs->kuep = value; } static bool is_pkey_enabled(int pkey) @@ -314,20 +291,21 @@ static bool is_pkey_enabled(int pkey) return !!(uamor_pkey_bits); } +/* FIXME!! what happens to other threads AMR value? */ static inline void init_amr(int pkey, u8 init_bits) { u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey)); - u64 old_amr = read_amr() & ~((u64)(0x3ul) << pkeyshift(pkey)); + u64 old_amr = current_thread_amr() & ~((u64)(0x3ul) << pkeyshift(pkey)); - write_amr(old_amr | new_amr_bits); + update_current_thread_amr(old_amr | new_amr_bits); } static inline void init_iamr(int pkey, u8 init_bits) { u64 new_iamr_bits = (((u64)init_bits & 0x1UL) << pkeyshift(pkey)); - u64 old_iamr = read_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey)); + u64 old_iamr = current_thread_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey)); - write_iamr(old_iamr | new_iamr_bits); + update_current_thread_iamr(old_iamr | new_iamr_bits); } /* @@ -360,33 +338,6 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, return 0; } -void thread_pkey_regs_save(struct thread_struct *thread) -{ - if (!mmu_has_feature(MMU_FTR_PKEY)) - return; - - /* - * TODO: Skip saving registers if @thread hasn't used any keys yet. - */ - thread->amr = read_amr(); - thread->iamr = read_iamr(); - thread->uamor = read_uamor(); -} - -void thread_pkey_regs_restore(struct thread_struct *new_thread, - struct thread_struct *old_thread) -{ - if (!mmu_has_feature(MMU_FTR_PKEY)) - return; - - if (old_thread->amr != new_thread->amr) - write_amr(new_thread->amr); - if (old_thread->iamr != new_thread->iamr) - write_iamr(new_thread->iamr); - if (old_thread->uamor != new_thread->uamor) - write_uamor(new_thread->uamor); -} - int execute_only_pkey(struct mm_struct *mm) { if (static_branch_likely(&execute_pkey_disabled)) @@ -440,10 +391,10 @@ static bool pkey_access_permitted(int pkey, bool write, bool execute) return true; pkey_shift = pkeyshift(pkey); - if (execute && !(read_iamr() & (IAMR_EX_BIT << pkey_shift))) + if (execute && !(current_thread_iamr() & (IAMR_EX_BIT << pkey_shift))) return true; - amr = read_amr(); /* Delay reading amr until absolutely needed */ + amr = current_thread_amr(); return ((!write && !(amr & (AMR_RD_BIT << pkey_shift))) || (write && !(amr & (AMR_WR_BIT << pkey_shift)))); } -- 2.26.2