| Message ID | 20110727103546.7d4f2419@kryten (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Commit | c113a3aee2b68e311f2bc55f70fe56b64c3a476b |
| Delegated to: | Benjamin Herrenschmidt |
| Headers | show |
Index: linux-powerpc/arch/powerpc/include/asm/jump_label.h =================================================================== --- linux-powerpc.orig/arch/powerpc/include/asm/jump_label.h 2011-07-27 09:35:04.266872078 +1000 +++ linux-powerpc/arch/powerpc/include/asm/jump_label.h 2011-07-27 09:39:32.581719669 +1000 @@ -22,7 +22,6 @@ static __always_inline bool arch_static_ asm goto("1:\n\t" "nop\n\t" ".pushsection __jump_table, \"aw\"\n\t" - ".align 4\n\t" JUMP_ENTRY_TYPE "1b, %l[l_yes], %c0\n\t" ".popsection \n\t" : : "i" (key) : : l_yes); @@ -41,7 +40,6 @@ struct jump_entry { jump_label_t code; jump_label_t target; jump_label_t key; - jump_label_t pad; }; #endif /* _ASM_POWERPC_JUMP_LABEL_H */
I hit an oops at boot on the first instruction of timer_cpu_notify: NIP [c000000000722f88] .timer_cpu_notify+0x0/0x388 The code should look like: c000000000722f78: eb e9 00 30 ld r31,48(r9) c000000000722f7c: 2f bf 00 00 cmpdi cr7,r31,0 c000000000722f80: 40 9e ff 44 bne+ cr7,c000000000722ec4 c000000000722f84: 4b ff ff 74 b c000000000722ef8 c000000000722f88 <.timer_cpu_notify>: c000000000722f88: 7c 08 02 a6 mflr r0 c000000000722f8c: 2f a4 00 07 cmpdi cr7,r4,7 c000000000722f90: fb c1 ff f0 std r30,-16(r1) c000000000722f94: fb 61 ff d8 std r27,-40(r1) But the oops output shows: eb61ffd8 eb81ffe0 eba1ffe8 ebc1fff0 7c0803a6 ebe1fff8 4e800020 00000000 ebe90030 c0000000 00ad0a28 00000000 2fa40007 fbc1fff0 fb61ffd8 So we scribbled over our instructions with c000000000ad0a28, which is an address inside the jump_table ELF section. It turns out the jump_table section is only aligned to 8 bytes but we are aligning our entries within the section to 16 bytes. This means our entries are offset from the table: c000000000acd4a8 <__start___jump_table>: ... c000000000ad0a10: c0 00 00 00 lfs f0,0(0) c000000000ad0a14: 00 70 cd 5c .long 0x70cd5c c000000000ad0a18: c0 00 00 00 lfs f0,0(0) c000000000ad0a1c: 00 70 cd 90 .long 0x70cd90 c000000000ad0a20: c0 00 00 00 lfs f0,0(0) c000000000ad0a24: 00 ac a4 20 .long 0xaca420 And the jump table sort code gets very confused and writes into the wrong spot. Remove the alignment, and also remove the padding since we it saves some space and we shouldn't need it. Signed-off-by: Anton Blanchard <anton@samba.org> ---