Now that kernel correctly store/restore userspace AMR/IAMR values, avoid
manipulating AMR and IAMR from the kernel on behalf of userspace.
Reviewed-by: Sandipan Das <sandi...@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
arch/powerpc/include/asm/book3s/64/kup.h | 21 +++++++++
arch/powerpc/include/asm/processor.h | 4 --
arch/powerpc/kernel/process.c | 4 --
arch/powerpc/kernel/traps.c | 6 ---
arch/powerpc/mm/book3s64/pkeys.c | 57 +++++-------------------
5 files changed, 31 insertions(+), 61 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h
b/arch/powerpc/include/asm/book3s/64/kup.h
index 1b2047202a85..97e81fd820be 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -175,6 +175,27 @@ DECLARE_STATIC_KEY_FALSE(uaccess_flush_key);
#include <asm/mmu.h>
#include <asm/ptrace.h>
+/*
+ * 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->amr;
+ return AMR_KUAP_BLOCKED;
+}
+
+static inline u64 current_thread_iamr(void)
+{
+ if (current->thread.regs)
+ return current->thread.regs->iamr;
+ return AMR_KUEP_BLOCKED;
+}
+#endif /* CONFIG_PPC_PKEY */
+
+#ifdef CONFIG_PPC_KUAP
+
static inline void kuap_user_restore(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 c61c859b51a8..c3df3a420c92 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -230,10 +230,6 @@ 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;
-#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 7ea53aac0478..136dcb901861 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -589,7 +589,6 @@ 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)
@@ -1160,8 +1159,6 @@ 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,
@@ -1202,7 +1199,6 @@ 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 5006dcbe1d9f..419028d53fd6 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -347,12 +347,6 @@ 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 355d001fa155..8d1bf2f18ca4 100644
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -281,30 +281,17 @@ void __init setup_kuap(bool disabled)
}
#endif
-static inline u64 read_amr(void)
+static inline void update_current_thread_amr(u64 value)
{
- return mfspr(SPRN_AMR);
+ current->thread.regs->amr = value;
}
-static inline void write_amr(u64 value)
-{
- mtspr(SPRN_AMR, value);
-}
-
-static inline u64 read_iamr(void)
-{
- if (!likely(pkey_execute_disable_supported))
- return 0x0UL;
-
- return mfspr(SPRN_IAMR);
-}
-
-static inline void write_iamr(u64 value)
+static inline void update_current_thread_iamr(u64 value)
{
if (!likely(pkey_execute_disable_supported))
return;
- mtspr(SPRN_IAMR, value);
+ current->thread.regs->iamr = value;
}
#ifdef CONFIG_PPC_MEM_KEYS
@@ -319,17 +306,17 @@ void pkey_mm_init(struct mm_struct *mm)
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);
}
/*
@@ -372,30 +359,6 @@ 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();
-}
-
-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);
-}
-
int execute_only_pkey(struct mm_struct *mm)
{
return mm->context.execute_only_pkey;
@@ -444,9 +407,9 @@ static bool pkey_access_permitted(int pkey, bool write,
bool execute)
pkey_shift = pkeyshift(pkey);
if (execute)
- return !(read_iamr() & (IAMR_EX_BIT << pkey_shift));
+ return !(current_thread_iamr() & (IAMR_EX_BIT << pkey_shift));
- amr = read_amr();
+ amr = current_thread_amr();
if (write)
return !(amr & (AMR_WR_BIT << pkey_shift));
--
2.28.0
