Store and restore the AMR, IAMR and UAMOR register state of the task
before scheduling out and after scheduling in, respectively.
Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
---
arch/powerpc/include/asm/mmu_context.h | 3 ++
arch/powerpc/include/asm/pkeys.h | 4 ++
arch/powerpc/include/asm/processor.h | 5 +++
arch/powerpc/kernel/process.c | 7 ++++
arch/powerpc/mm/pkeys.c | 52 +++++++++++++++++++++++++++++++-
5 files changed, 70 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 7d0f2d0..4d69223 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -195,6 +195,9 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
#ifndef CONFIG_PPC_MEM_KEYS
#define pkey_mm_init(mm)
+#define thread_pkey_regs_save(thread)
+#define thread_pkey_regs_restore(new_thread, old_thread)
+#define thread_pkey_regs_init(thread)
#endif /* CONFIG_PPC_MEM_KEYS */
#endif /* __KERNEL__ */
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 2500a90..3def5af 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -150,4 +150,8 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
}
extern void pkey_mm_init(struct mm_struct *mm);
+extern void thread_pkey_regs_save(struct thread_struct *thread);
+extern void thread_pkey_regs_restore(struct thread_struct *new_thread,
+ struct thread_struct *old_thread);
+extern void thread_pkey_regs_init(struct thread_struct *thread);
#endif /*_ASM_POWERPC_KEYS_H */
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index bdab3b7..01299cd 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -309,6 +309,11 @@ 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 5acb5a1..6447f80 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -42,6 +42,7 @@
#include <linux/hw_breakpoint.h>
#include <linux/uaccess.h>
#include <linux/elf-randomize.h>
+#include <linux/pkeys.h>
#include <asm/pgtable.h>
#include <asm/io.h>
@@ -1102,6 +1103,8 @@ 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,
@@ -1141,6 +1144,8 @@ static inline void restore_sprs(struct thread_struct *old_thread,
old_thread->tidr != new_thread->tidr)
mtspr(SPRN_TIDR, new_thread->tidr);
#endif
+
+ thread_pkey_regs_restore(new_thread, old_thread);
}
#ifdef CONFIG_PPC_BOOK3S_64
@@ -1865,6 +1870,8 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
current->thread.tm_tfiar = 0;
current->thread.load_tm = 0;
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
+
+ thread_pkey_regs_init(¤t->thread);
}
EXPORT_SYMBOL(start_thread);
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index 39e9814..7dfcf2d 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -16,6 +16,8 @@
bool pkey_execute_disable_supported;
int pkeys_total; /* Total pkeys as per device tree */
u32 initial_allocation_mask; /* Bits set for reserved keys */
+u64 pkey_amr_uamor_mask; /* Bits in AMR/UMOR not to be touched */
+u64 pkey_iamr_mask; /* Bits in AMR not to be touched */
#define AMR_BITS_PER_PKEY 2
#define AMR_RD_BIT 0x1UL
@@ -74,8 +76,16 @@ int pkey_initialize(void)
* programming note.
*/
initial_allocation_mask = ~0x0;
- for (i = 2; i < (pkeys_total - os_reserved); i++)
+
+ /* register mask is in BE format */
+ pkey_amr_uamor_mask = ~0x0ul;
+ pkey_iamr_mask = ~0x0ul;
+
+ for (i = 2; i < (pkeys_total - os_reserved); i++) {
initial_allocation_mask &= ~(0x1 << i);
+ pkey_amr_uamor_mask &= ~(0x3ul << pkeyshift(i));
+ pkey_iamr_mask &= ~(0x1ul << pkeyshift(i));
+ }
return 0;
}
@@ -210,3 +220,43 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
init_amr(pkey, new_amr_bits);
return 0;
}
+
+void thread_pkey_regs_save(struct thread_struct *thread)
+{
+ if (static_branch_likely(&pkey_disabled))
+ 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 (static_branch_likely(&pkey_disabled))
+ return;
+
+ /*
+ * TODO: Just set UAMOR to zero if @new_thread hasn't used any keys yet.
+ */
+ 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);
+}
+
+void thread_pkey_regs_init(struct thread_struct *thread)
+{
+ if (static_branch_likely(&pkey_disabled))
+ return;
+
+ write_amr(read_amr() & pkey_amr_uamor_mask);
+ write_iamr(read_iamr() & pkey_iamr_mask);
+ write_uamor(read_uamor() & pkey_amr_uamor_mask);
+}
--
1.7.1
