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| author | Kumar Gala <galak@kernel.crashing.org> | 2011-10-06 02:53:40 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-11-17 16:26:07 +1100 |
| commit | 187b9f2aa769198daa7cf8054abb65a08b8d8b47 (patch) | |
| tree | 722bbeb3aa73e59b1b6b3fb883c287adb7583a53 | |
| parent | b95bc2191412f5ecf2781c966110a13fa82a80d3 (diff) | |
| download | linux-187b9f2aa769198daa7cf8054abb65a08b8d8b47.tar.bz2 | |
powerpc/book3e-64: Fix debug support for userspace
With the introduction of CONFIG_PPC_ADV_DEBUG_REGS user space debug is
broken on Book-E 64-bit parts that support delayed debug events. When
switch_booke_debug_regs() sets DBCR0 we'll start getting debug events as
MSR_DE is also set and we aren't able to handle debug events from kernel
space.
We can remove the hack that always enables MSR_DE and loads up DBCR0 and
just utilize switch_booke_debug_regs() to get user space debug working
again.
We still need to handle critical/debug exception stacks & proper
save/restore of state for those exception levles to support debug events
from kernel space like we have on 32-bit.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/include/asm/reg_booke.h | 2 | ||||
| -rw-r--r-- | arch/powerpc/kernel/process.c | 22 |
2 files changed, 1 insertions, 23 deletions
diff --git a/arch/powerpc/include/asm/reg_booke.h b/arch/powerpc/include/asm/reg_booke.h index 28cdbd9f399c..03c48e819c8e 100644 --- a/arch/powerpc/include/asm/reg_booke.h +++ b/arch/powerpc/include/asm/reg_booke.h @@ -31,7 +31,7 @@ #define MSR_ MSR_ME | MSR_CE #define MSR_KERNEL MSR_ | MSR_64BIT -#define MSR_USER32 MSR_ | MSR_PR | MSR_EE | MSR_DE +#define MSR_USER32 MSR_ | MSR_PR | MSR_EE #define MSR_USER64 MSR_USER32 | MSR_64BIT #elif defined (CONFIG_40x) #define MSR_KERNEL (MSR_ME|MSR_RI|MSR_IR|MSR_DR|MSR_CE) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index ad3612af0a04..6457574c0b2f 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -486,28 +486,6 @@ 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 |