Messages in this thread | | | Date | Thu, 13 Apr 2023 15:10:02 +0200 | Subject | Re: [PATCH v2] ARM:unwind:fix unwind abort for uleb128 case | From | Alexandre Mergnat <> |
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On 13/04/2023 09:39, Linus Walleij wrote: > On Thu, Apr 13, 2023 at 9:34 AM Haibo Li<haibo.li@mediatek.com> wrote: > >> When unwind instruction is 0xb2,the subsequent instructions >> are uleb128 bytes. >> For now,it uses only the first uleb128 byte in code. >> >> For vsp increments of 0x204~0x400,use one uleb128 byte like below: >> 0xc06a00e4 <unwind_test_work>: 0x80b27fac >> Compact model index: 0 >> 0xb2 0x7f vsp = vsp + 1024 >> 0xac pop {r4, r5, r6, r7, r8, r14} >> >> For vsp increments larger than 0x400,use two uleb128 bytes like below: >> 0xc06a00e4 <unwind_test_work>: @0xc0cc9e0c >> Compact model index: 1 >> 0xb2 0x81 0x01 vsp = vsp + 1032 >> 0xac pop {r4, r5, r6, r7, r8, r14} >> The unwind works well since the decoded uleb128 byte is also 0x81. >> >> For vsp increments larger than 0x600,use two uleb128 bytes like below: >> 0xc06a00e4 <unwind_test_work>: @0xc0cc9e0c >> Compact model index: 1 >> 0xb2 0x81 0x02 vsp = vsp + 1544 >> 0xac pop {r4, r5, r6, r7, r8, r14} >> In this case,the decoded uleb128 result is 0x101(vsp=0x204+(0x101<<2)). >> While the uleb128 used in code is 0x81(vsp=0x204+(0x81<<2)). >> The unwind aborts at this frame since it gets incorrect vsp. >> >> To fix this,add uleb128 decode to cover all the above case. >> >> Signed-off-by: Haibo Li<haibo.li@mediatek.com> > Thanks Haibo, > Reviewed-by: Linus Walleij<linus.walleij@linaro.org>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Regards, Alexandre
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