Messages in this thread | | | From | Linus Walleij <> | Date | Thu, 13 Apr 2023 09:39:00 +0200 | Subject | Re: [PATCH v2] ARM:unwind:fix unwind abort for uleb128 case |
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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>
Please put this into Russell's patch tracker once you feel it is finished! https://www.arm.linux.org.uk/developer/patches/
Yours, Linus Walleij
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