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| author | Rich Felker <dalias@aerifal.cx> | 2016-04-25 19:37:06 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2016-04-25 19:37:06 -0400 |
| commit | be999f7a54e81656ea0409030205177327a7450c (patch) | |
| tree | 0468c4862b449a48c28c3b2e3441f65b213a0c76 | |
| parent | e7d05c7894aa15ea6decdeca481ffed3f14cb521 (diff) | |
| download | musl-be999f7a54e81656ea0409030205177327a7450c.tar.gz musl-be999f7a54e81656ea0409030205177327a7450c.tar.xz musl-be999f7a54e81656ea0409030205177327a7450c.zip | |
fix thread structure/dtv-pointer corruption on powerpc
per the powerpc psabi, offset 4 of the stack at call time belongs to the callee and is used for spilling lr (return address). in addition, offset 0 on the stack must contain a pointer to the previous stack frame, or a null pointer for the initial stack frame of a thread. __clone failed to setup any stack frame on the new thread's stack, thereby allowing the start function it called to clobber offset 4 of the new thread's struct __pthread, which contains the dtv pointer. add code to setup a proper stack frame and align the stack pointer to a multiple of 16 (also an abi requirement) if it was not already aligned.
| -rw-r--r-- | src/thread/powerpc/clone.s | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/thread/powerpc/clone.s b/src/thread/powerpc/clone.s index dc5c74c6..a57dbcce 100644 --- a/src/thread/powerpc/clone.s +++ b/src/thread/powerpc/clone.s @@ -22,6 +22,11 @@ stw 31, 4(1) mr 30, 3 mr 31, 6 +# create initial stack frame for new thread +clrrwi 4, 4, 4 +li 0, 0 +stwu 0, -16(4) + #move c into first arg mr 3, 5 #mr 4, 4 |