powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.
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.kumar@linux.ibm.com> Reviewed-by: Sandipan Das <sandipan@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201127044424.40686-15-aneesh.kumar@linux.ibm.com
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@ -177,6 +177,27 @@ DECLARE_STATIC_KEY_FALSE(uaccess_flush_key);
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#include <asm/mmu.h>
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#include <asm/mmu.h>
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#include <asm/ptrace.h>
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#include <asm/ptrace.h>
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/*
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* For kernel thread that doesn't have thread.regs return
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* default AMR/IAMR values.
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*/
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static inline u64 current_thread_amr(void)
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{
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if (current->thread.regs)
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return current->thread.regs->amr;
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return AMR_KUAP_BLOCKED;
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}
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static inline u64 current_thread_iamr(void)
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{
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if (current->thread.regs)
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return current->thread.regs->iamr;
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return AMR_KUEP_BLOCKED;
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}
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#endif /* CONFIG_PPC_PKEY */
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#ifdef CONFIG_PPC_KUAP
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static inline void kuap_user_restore(struct pt_regs *regs)
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static inline void kuap_user_restore(struct pt_regs *regs)
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{
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{
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if (!mmu_has_feature(MMU_FTR_PKEY))
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if (!mmu_has_feature(MMU_FTR_PKEY))
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@ -226,10 +226,6 @@ struct thread_struct {
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struct thread_vr_state ckvr_state; /* Checkpointed VR state */
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struct thread_vr_state ckvr_state; /* Checkpointed VR state */
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unsigned long ckvrsave; /* Checkpointed VRSAVE */
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unsigned long ckvrsave; /* Checkpointed VRSAVE */
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#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
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#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
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#ifdef CONFIG_PPC_MEM_KEYS
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unsigned long amr;
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unsigned long iamr;
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#endif
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#ifdef CONFIG_KVM_BOOK3S_32_HANDLER
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#ifdef CONFIG_KVM_BOOK3S_32_HANDLER
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void* kvm_shadow_vcpu; /* KVM internal data */
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void* kvm_shadow_vcpu; /* KVM internal data */
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#endif /* CONFIG_KVM_BOOK3S_32_HANDLER */
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#endif /* CONFIG_KVM_BOOK3S_32_HANDLER */
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@ -589,7 +589,6 @@ static void save_all(struct task_struct *tsk)
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__giveup_spe(tsk);
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__giveup_spe(tsk);
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msr_check_and_clear(msr_all_available);
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msr_check_and_clear(msr_all_available);
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thread_pkey_regs_save(&tsk->thread);
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}
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}
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void flush_all_to_thread(struct task_struct *tsk)
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void flush_all_to_thread(struct task_struct *tsk)
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@ -1160,8 +1159,6 @@ static inline void save_sprs(struct thread_struct *t)
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t->tar = mfspr(SPRN_TAR);
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t->tar = mfspr(SPRN_TAR);
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}
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}
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#endif
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#endif
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thread_pkey_regs_save(t);
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}
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}
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static inline void restore_sprs(struct thread_struct *old_thread,
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static inline void restore_sprs(struct thread_struct *old_thread,
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@ -1202,7 +1199,6 @@ static inline void restore_sprs(struct thread_struct *old_thread,
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mtspr(SPRN_TIDR, new_thread->tidr);
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mtspr(SPRN_TIDR, new_thread->tidr);
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#endif
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#endif
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thread_pkey_regs_restore(new_thread, old_thread);
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}
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}
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struct task_struct *__switch_to(struct task_struct *prev,
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struct task_struct *__switch_to(struct task_struct *prev,
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@ -347,12 +347,6 @@ static bool exception_common(int signr, struct pt_regs *regs, int code,
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current->thread.trap_nr = code;
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current->thread.trap_nr = code;
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/*
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* Save all the pkey registers AMR/IAMR/UAMOR. Eg: Core dumps need
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* to capture the content, if the task gets killed.
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*/
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thread_pkey_regs_save(¤t->thread);
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return true;
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return true;
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}
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}
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@ -281,30 +281,17 @@ void __init setup_kuap(bool disabled)
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}
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}
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#endif
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#endif
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static inline u64 read_amr(void)
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static inline void update_current_thread_amr(u64 value)
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{
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{
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return mfspr(SPRN_AMR);
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current->thread.regs->amr = value;
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}
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}
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static inline void write_amr(u64 value)
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static inline void update_current_thread_iamr(u64 value)
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{
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mtspr(SPRN_AMR, value);
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}
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static inline u64 read_iamr(void)
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{
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if (!likely(pkey_execute_disable_supported))
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return 0x0UL;
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return mfspr(SPRN_IAMR);
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}
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static inline void write_iamr(u64 value)
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{
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{
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if (!likely(pkey_execute_disable_supported))
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if (!likely(pkey_execute_disable_supported))
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return;
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return;
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mtspr(SPRN_IAMR, value);
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current->thread.regs->iamr = value;
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}
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}
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#ifdef CONFIG_PPC_MEM_KEYS
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#ifdef CONFIG_PPC_MEM_KEYS
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@ -319,17 +306,17 @@ void pkey_mm_init(struct mm_struct *mm)
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static inline void init_amr(int pkey, u8 init_bits)
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static inline void init_amr(int pkey, u8 init_bits)
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{
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{
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u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey));
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u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey));
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u64 old_amr = read_amr() & ~((u64)(0x3ul) << pkeyshift(pkey));
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u64 old_amr = current_thread_amr() & ~((u64)(0x3ul) << pkeyshift(pkey));
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write_amr(old_amr | new_amr_bits);
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update_current_thread_amr(old_amr | new_amr_bits);
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}
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}
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static inline void init_iamr(int pkey, u8 init_bits)
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static inline void init_iamr(int pkey, u8 init_bits)
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{
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{
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u64 new_iamr_bits = (((u64)init_bits & 0x1UL) << pkeyshift(pkey));
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u64 new_iamr_bits = (((u64)init_bits & 0x1UL) << pkeyshift(pkey));
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u64 old_iamr = read_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey));
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u64 old_iamr = current_thread_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey));
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write_iamr(old_iamr | new_iamr_bits);
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update_current_thread_iamr(old_iamr | new_iamr_bits);
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}
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}
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/*
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/*
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@ -372,30 +359,6 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
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return 0;
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return 0;
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}
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}
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void thread_pkey_regs_save(struct thread_struct *thread)
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{
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if (!mmu_has_feature(MMU_FTR_PKEY))
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return;
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/*
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* TODO: Skip saving registers if @thread hasn't used any keys yet.
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*/
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thread->amr = read_amr();
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thread->iamr = read_iamr();
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}
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void thread_pkey_regs_restore(struct thread_struct *new_thread,
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struct thread_struct *old_thread)
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{
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if (!mmu_has_feature(MMU_FTR_PKEY))
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return;
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if (old_thread->amr != new_thread->amr)
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write_amr(new_thread->amr);
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if (old_thread->iamr != new_thread->iamr)
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write_iamr(new_thread->iamr);
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}
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int execute_only_pkey(struct mm_struct *mm)
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int execute_only_pkey(struct mm_struct *mm)
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{
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{
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return mm->context.execute_only_pkey;
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return mm->context.execute_only_pkey;
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@ -444,9 +407,9 @@ static bool pkey_access_permitted(int pkey, bool write, bool execute)
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pkey_shift = pkeyshift(pkey);
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pkey_shift = pkeyshift(pkey);
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if (execute)
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if (execute)
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return !(read_iamr() & (IAMR_EX_BIT << pkey_shift));
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return !(current_thread_iamr() & (IAMR_EX_BIT << pkey_shift));
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amr = read_amr();
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amr = current_thread_amr();
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if (write)
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if (write)
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return !(amr & (AMR_WR_BIT << pkey_shift));
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return !(amr & (AMR_WR_BIT << pkey_shift));
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