diff options
| author | Benjamin Gray <bgray@linux.ibm.com> | 2024-04-17 14:23:18 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2024-05-03 13:46:51 +0300 |
| commit | 75171f06c4507c3b6b5a69d793879fb20d108bb1 (patch) | |
| tree | 82a5db6c1f962cb180135e9cec442e812ffbe028 /arch/powerpc/kernel | |
| parent | d7228a58d9438d6f219dc7f33eab0d1980b3bd2f (diff) | |
| download | linux-75171f06c4507c3b6b5a69d793879fb20d108bb1.tar.xz | |
powerpc/dexcr: Track the DEXCR per-process
Add capability to make the DEXCR act as a per-process SPR.
We do not yet have an interface for changing the values per task. We
also expect the kernel to use a single DEXCR value across all tasks
while in privileged state, so there is no need to synchronize after
changing it (the userspace aspects will synchronize upon returning to
userspace).
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240417112325.728010-3-bgray@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 10 | ||||
| -rw-r--r-- | arch/powerpc/kernel/ptrace/ptrace-view.c | 7 |
2 files changed, 11 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 9452a54d356c..d482c3fd81d7 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1185,6 +1185,9 @@ static inline void save_sprs(struct thread_struct *t) if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE)) t->hashkeyr = mfspr(SPRN_HASHKEYR); + + if (cpu_has_feature(CPU_FTR_ARCH_31)) + t->dexcr = mfspr(SPRN_DEXCR); #endif } @@ -1267,6 +1270,10 @@ static inline void restore_sprs(struct thread_struct *old_thread, if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE) && old_thread->hashkeyr != new_thread->hashkeyr) mtspr(SPRN_HASHKEYR, new_thread->hashkeyr); + + if (cpu_has_feature(CPU_FTR_ARCH_31) && + old_thread->dexcr != new_thread->dexcr) + mtspr(SPRN_DEXCR, new_thread->dexcr); #endif } @@ -1878,6 +1885,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) #ifdef CONFIG_PPC_BOOK3S_64 if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE)) p->thread.hashkeyr = current->thread.hashkeyr; + + if (cpu_has_feature(CPU_FTR_ARCH_31)) + p->thread.dexcr = mfspr(SPRN_DEXCR); #endif return 0; } diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c b/arch/powerpc/kernel/ptrace/ptrace-view.c index 584cf5c3df50..c1819e0a6684 100644 --- a/arch/powerpc/kernel/ptrace/ptrace-view.c +++ b/arch/powerpc/kernel/ptrace/ptrace-view.c @@ -469,12 +469,7 @@ static int dexcr_get(struct task_struct *target, const struct user_regset *regse if (!cpu_has_feature(CPU_FTR_ARCH_31)) return -ENODEV; - /* - * The DEXCR is currently static across all CPUs, so we don't - * store the target's value anywhere, but the static value - * will also be correct. - */ - membuf_store(&to, (u64)lower_32_bits(DEXCR_INIT)); + membuf_store(&to, (u64)lower_32_bits(target->thread.dexcr)); /* * Technically the HDEXCR is per-cpu, but a hypervisor can't reasonably |