On 09/18/2012 01:09 PM, Benjamin Herrenschmidt wrote:
On Tue, 2012-09-18 at 15:05 +1000, Benjamin Herrenschmidt wrote:
On Mon, 2012-09-17 at 17:54 +0800, Tiejun Chen wrote:
-#ifdef CONFIG_PREEMPT
b restore
/* N.B. the only way to get here is from the beq following ret_from_except. */
resume_kernel:
- /* check current_thread_info->preempt_count */
+ /* check current_thread_info, _TIF_EMULATE_STACK_STORE */
CURRENT_THREAD_INFO(r9, r1)
+ lwz r8,TI_FLAGS(r9)
+ andis. r8,r8,_TIF_EMULATE_STACK_STORE@h
+ beq+ 1f
+
+ addi r8,r1,INT_FRAME_SIZE /* Get the kprobed function entry */
+
+ lwz r3,GPR1(r1)
+ subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception
frame */
+ mr r4,r1 /* src: current exception frame */
+ li r5,INT_FRAME_SIZE /* size: INT_FRAME_SIZE */
+ li r6,0 /* start offset: 0 */
+ mr r1,r3 /* Reroute the trampoline frame to r1 */
+
+ /* Copy from the original to the trampoline. */
+ li r6,0
You just did that li r6,0 2 lines above :-) I'll fix it up manually
while applying.
In fact the srwi can be dropped completely, we can just load r5 with the
divided value. Committed, will push later today, please test.
I retest to kprobe do_fork() and show_interrupts() with/without enabling
CONFIG_PREEMPT, separately, looks still work.
For 32-bit:
------------
+ /* Copy from the original to the trampoline. */
+ lwz r3,GPR1(r1)
+ subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception
frame */
+ mr r4,r1 /* src: current exception frame */
+ li r5,INT_FRAME_SIZE/4 /* size: INT_FRAME_SIZE */
+ li r6,0 /* start offset: 0 */
+ mr r1,r3 /* Reroute the trampoline frame to r1 */
+ mtctr r5
+2: lwzx r0,r6,r4
+ stwx r0,r6,r3
+ addi r6,r6,4
+ bdnz 2b
And for 64-bit:
---------------
+ /* Copy from the original to the trampoline. */
+ lwz r3,GPR1(r1)
+ subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception
frame */
+ mr r4,r1 /* src: current exception frame */
+ li r5,INT_FRAME_SIZE/8 /* size: INT_FRAME_SIZE */
+ li r6,0 /* start offset: 0 */
+ mr r1,r3 /* Reroute the trampoline frame to r1 */
+ mtctr r5
+2: ldx r0,r6,r4
+ stdx r0,r6,r3
+ addi r6,r6,8
+ bdnz 2b
Thanks
Tiejun
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