On Fri, 8 Sep 2017 15:44:58 -0700 Ram Pai <linux...@us.ibm.com> wrote:
> 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 <linux...@us.ibm.com> > --- > arch/powerpc/include/asm/pkeys.h | 4 +++ > arch/powerpc/include/asm/processor.h | 5 ++++ > arch/powerpc/kernel/process.c | 10 ++++++++ > arch/powerpc/mm/pkeys.c | 39 > ++++++++++++++++++++++++++++++++++ > 4 files changed, 58 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/include/asm/pkeys.h > b/arch/powerpc/include/asm/pkeys.h > index 7fd48a4..78c5362 100644 > --- a/arch/powerpc/include/asm/pkeys.h > +++ b/arch/powerpc/include/asm/pkeys.h > @@ -143,5 +143,9 @@ static inline void pkey_mm_init(struct mm_struct *mm) > mm_pkey_allocation_map(mm) = initial_allocation_mask; > } > > +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); > extern void pkey_initialize(void); > #endif /*_ASM_PPC64_PKEYS_H */ > diff --git a/arch/powerpc/include/asm/processor.h > b/arch/powerpc/include/asm/processor.h > index fab7ff8..de9d9ba 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_PPC64_MEMORY_PROTECTION_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 a0c74bb..ba80002 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> > @@ -1085,6 +1086,9 @@ static inline void save_sprs(struct thread_struct *t) > t->tar = mfspr(SPRN_TAR); > } > #endif > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS > + thread_pkey_regs_save(t); > +#endif Just define two variants of thread_pkey_regs_save() based on CONFIG_PPC64_MEMORY_PROTECTION_KEYS and remove the #ifdefs from process.c Ditto for the lines below > } > > static inline void restore_sprs(struct thread_struct *old_thread, > @@ -1120,6 +1124,9 @@ static inline void restore_sprs(struct thread_struct > *old_thread, > mtspr(SPRN_TAR, new_thread->tar); > } > #endif > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS > + thread_pkey_regs_restore(new_thread, old_thread); > +#endif > } > > #ifdef CONFIG_PPC_BOOK3S_64 > @@ -1705,6 +1712,9 @@ 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 */ > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS > + thread_pkey_regs_init(¤t->thread); > +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ > } > EXPORT_SYMBOL(start_thread); > > diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c > index 2282864..7cd1be4 100644 > --- a/arch/powerpc/mm/pkeys.c > +++ b/arch/powerpc/mm/pkeys.c > @@ -149,3 +149,42 @@ 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 (!pkey_inited) > + return; > + > + /* @TODO skip saving any registers if the thread > + * has not used any keys yet. > + */ Comment style is broken > + > + 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 (!pkey_inited) > + return; > + > + /* @TODO just reset uamor to zero if the new_thread > + * has not used any keys yet. > + */ Comment style is broken. > + > + 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); Is this order correct? Ideally, You want to write the uamor first but since we are in supervisor state, I think we can get away with this order. Do we want to expose the uamor to user space for it to modify the AMR directly? > +} > + > +void thread_pkey_regs_init(struct thread_struct *thread) > +{ > + write_amr(0x0ul); > + write_iamr(0x0ul); > + write_uamor(0x0ul); This is not correct, reserved keys should not be set to 0's Balbir Singh.