diff options
Diffstat (limited to 'arch/powerpc/kernel/process.c')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 1e78453645be..551f6713ff42 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -477,6 +477,28 @@ struct task_struct *__switch_to(struct task_struct *prev, new_thread = &new->thread; old_thread = ¤t->thread; +#if defined(CONFIG_PPC_BOOK3E_64) + /* XXX Current Book3E code doesn't deal with kernel side DBCR0, + * we always hold the user values, so we set it now. + * + * However, we ensure the kernel MSR:DE is appropriately cleared too + * to avoid spurrious single step exceptions in the kernel. + * + * This will have to change to merge with the ppc32 code at some point, + * but I don't like much what ppc32 is doing today so there's some + * thinking needed there + */ + if ((new_thread->dbcr0 | old_thread->dbcr0) & DBCR0_IDM) { + u32 dbcr0; + + mtmsr(mfmsr() & ~MSR_DE); + isync(); + dbcr0 = mfspr(SPRN_DBCR0); + dbcr0 = (dbcr0 & DBCR0_EDM) | new_thread->dbcr0; + mtspr(SPRN_DBCR0, dbcr0); + } +#endif /* CONFIG_PPC64_BOOK3E */ + #ifdef CONFIG_PPC64 /* * Collect processor utilization data per process |