Commit 06bb53b3 authored by Ram Pai's avatar Ram Pai Committed by Michael Ellerman

powerpc: store and restore the pkey state across context switches

Store and restore the AMR, IAMR and UAMOR register state of the task
before scheduling out and after scheduling in, respectively.
Signed-off-by: default avatarRam Pai <linuxram@us.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent dcf87295
...@@ -195,6 +195,9 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, ...@@ -195,6 +195,9 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
#ifndef CONFIG_PPC_MEM_KEYS #ifndef CONFIG_PPC_MEM_KEYS
#define pkey_mm_init(mm) #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 /* CONFIG_PPC_MEM_KEYS */
#endif /* __KERNEL__ */ #endif /* __KERNEL__ */
......
...@@ -139,4 +139,8 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, ...@@ -139,4 +139,8 @@ 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 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 */ #endif /*_ASM_POWERPC_KEYS_H */
...@@ -309,6 +309,11 @@ struct thread_struct { ...@@ -309,6 +309,11 @@ struct thread_struct {
struct thread_vr_state ckvr_state; /* Checkpointed VR state */ struct thread_vr_state ckvr_state; /* Checkpointed VR state */
unsigned long ckvrsave; /* Checkpointed VRSAVE */ unsigned long ckvrsave; /* Checkpointed VRSAVE */
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ #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 #ifdef CONFIG_KVM_BOOK3S_32_HANDLER
void* kvm_shadow_vcpu; /* KVM internal data */ void* kvm_shadow_vcpu; /* KVM internal data */
#endif /* CONFIG_KVM_BOOK3S_32_HANDLER */ #endif /* CONFIG_KVM_BOOK3S_32_HANDLER */
......
...@@ -42,6 +42,7 @@ ...@@ -42,6 +42,7 @@
#include <linux/hw_breakpoint.h> #include <linux/hw_breakpoint.h>
#include <linux/uaccess.h> #include <linux/uaccess.h>
#include <linux/elf-randomize.h> #include <linux/elf-randomize.h>
#include <linux/pkeys.h>
#include <asm/pgtable.h> #include <asm/pgtable.h>
#include <asm/io.h> #include <asm/io.h>
...@@ -1103,6 +1104,8 @@ static inline void save_sprs(struct thread_struct *t) ...@@ -1103,6 +1104,8 @@ static inline void save_sprs(struct thread_struct *t)
t->tar = mfspr(SPRN_TAR); t->tar = mfspr(SPRN_TAR);
} }
#endif #endif
thread_pkey_regs_save(t);
} }
static inline void restore_sprs(struct thread_struct *old_thread, static inline void restore_sprs(struct thread_struct *old_thread,
...@@ -1142,6 +1145,8 @@ static inline void restore_sprs(struct thread_struct *old_thread, ...@@ -1142,6 +1145,8 @@ static inline void restore_sprs(struct thread_struct *old_thread,
old_thread->tidr != new_thread->tidr) old_thread->tidr != new_thread->tidr)
mtspr(SPRN_TIDR, new_thread->tidr); mtspr(SPRN_TIDR, new_thread->tidr);
#endif #endif
thread_pkey_regs_restore(new_thread, old_thread);
} }
#ifdef CONFIG_PPC_BOOK3S_64 #ifdef CONFIG_PPC_BOOK3S_64
...@@ -1867,6 +1872,8 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) ...@@ -1867,6 +1872,8 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
current->thread.tm_tfiar = 0; current->thread.tm_tfiar = 0;
current->thread.load_tm = 0; current->thread.load_tm = 0;
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
thread_pkey_regs_init(&current->thread);
} }
EXPORT_SYMBOL(start_thread); EXPORT_SYMBOL(start_thread);
......
...@@ -12,6 +12,8 @@ DEFINE_STATIC_KEY_TRUE(pkey_disabled); ...@@ -12,6 +12,8 @@ DEFINE_STATIC_KEY_TRUE(pkey_disabled);
bool pkey_execute_disable_supported; bool pkey_execute_disable_supported;
int pkeys_total; /* Total pkeys as per device tree */ int pkeys_total; /* Total pkeys as per device tree */
u32 initial_allocation_mask; /* Bits set for reserved keys */ 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_BITS_PER_PKEY 2
#define AMR_RD_BIT 0x1UL #define AMR_RD_BIT 0x1UL
...@@ -70,8 +72,16 @@ int pkey_initialize(void) ...@@ -70,8 +72,16 @@ int pkey_initialize(void)
* programming note. * programming note.
*/ */
initial_allocation_mask = ~0x0; 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); initial_allocation_mask &= ~(0x1 << i);
pkey_amr_uamor_mask &= ~(0x3ul << pkeyshift(i));
pkey_iamr_mask &= ~(0x1ul << pkeyshift(i));
}
return 0; return 0;
} }
...@@ -206,3 +216,43 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, ...@@ -206,3 +216,43 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
init_amr(pkey, new_amr_bits); init_amr(pkey, new_amr_bits);
return 0; 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);
}
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