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@us.ibm.com --- 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); +}