Messages in this thread | | | From | Haibo Li <> | Subject | Re: [PATCH v3] ARM:unwind:fix unwind abort for uleb128 case | Date | Mon, 17 Apr 2023 17:46:38 +0800 |
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> On Fri, Apr 14, 2023 at 8:10 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> > > Way to go, remember to collect all the Reviewed-by tags before you put the > patch into Russell's patch tracker. > > Yours, > Linus Walleij Thanks for reminding.I put the patch into Russell's patch tracker just now, together with the three Reviewed-by tags from you, Alexandre Mergnat and AngeloGioacchino Del Regno. Thank you all.
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