Re: [v6,2/5] powerpc/book3e: store crit/mc/dbg exception thread info
From: Scott Wood <hidden>
Date: 2014-01-15 01:27:35
Also in:
lkml
On Wed, Oct 23, 2013 at 05:31:22PM +0800, Tiejun Chen wrote:
quoted hunk ↗ jump to hunk
We need to store thread info to these exception thread info like something we already did for PPC32. Signed-off-by: Tiejun Chen <redacted> --- arch/powerpc/kernel/exceptions-64e.S | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-)diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index 68d74b4..a55cf62 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S@@ -36,6 +36,19 @@ */ #define SPECIAL_EXC_FRAME_SIZE INT_FRAME_SIZE +/* Now we only store something to exception thread info */
Now as opposed to when? Only as opposed to what else?
+#define EXC_LEVEL_EXCEPTION_PROLOG(type) \
I'd prefer .macro over #define.
+ ld r14,PACAKSAVE(r13); \ + CURRENT_THREAD_INFO(r14, r14); \ + CURRENT_THREAD_INFO(r15, r1); \ + ld r10,TI_FLAGS(r14); \ + std r10,TI_FLAGS(r15); \ + ld r10,TI_PREEMPT(r14); \ + std r10,TI_PREEMPT(r15); \ + ld r10,TI_TASK(r14); \ + std r10,TI_TASK(r15);
This is a start, but we'll also need to save some more context to allow TLB misses from within the exception (e.g. if a machine check handler or GDB stub writes to a serial port, and the I/O registers aren't in the TLB). At a minimum I think we need to save SRR0, SRR1, SPRN_SPRG_GEN_SCRATCH, SPRN_SPRG_TLB_SCRATCH, and the MAS registers. We'll also need to make the bolted TLB miss handlers capable of pointing to different extables (though they won't need to auto-advance as the original TLB miss handlers do -- we would advance SPRN_SPRG_TLB_EXFRAME from this code), and the original TLB miss handlers will now need to support more than 3 levels of nesting. For the e6500 tablewalk TLB miss handler, we'll need to do something special if we interrupt it when the lock is held, to revoke the lock and return to code that retries. Is there anything else I'm missing? -Scott