| Message ID | 20230413073429.40050-1-haibo.li@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ARM:unwind:fix unwind abort for uleb128 case | expand |
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
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
Il 13/04/23 09:34, Haibo Li ha scritto: > 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> > --- > v2: > - As Linus Walleij and Alexandre Mergnat suggested,add comments for unwind_decode_uleb128 > - As Alexandre Mergnat suggested,change variables declaration in Alphabetical order > --- > arch/arm/kernel/unwind.c | 25 ++++++++++++++++++++++++- > 1 file changed, 24 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c > index 53be7ea6181b..f37e55fcf81d 100644 > --- a/arch/arm/kernel/unwind.c > +++ b/arch/arm/kernel/unwind.c > @@ -308,6 +308,29 @@ static int unwind_exec_pop_subset_r0_to_r3(struct unwind_ctrl_block *ctrl, > return URC_OK; > } > > +static unsigned long unwind_decode_uleb128(struct unwind_ctrl_block *ctrl) > +{ > + unsigned long bytes = 0; > + unsigned long insn; > + unsigned long result = 0; > + > + /* unwind_get_byte() will advance ctrl one instruction at a time, > + * we loop until we get an instruction byte where bit 7 is not set. > + * Note:It decodes max 4 bytes to output 28bits data. > + * 28bits data(0xfffffff) covers vsp increments of 1073742336. > + * It is sufficent for unwinding stack. > + */ /* * unwind_get_byte() will advance `ctrl` one instruction at a time, so * loop until we get an instruction byte where bit 7 is not set. * * Note: This decodes a maximum of 4 bytes to output 28 bits data where * max is 0xfffffff: that will cover a vsp increment of 1073742336, hence * it is sufficient for unwinding the stack. */ > + do { > + insn = unwind_get_byte(ctrl); > + result |= (insn & 0x7f) << (bytes * 7); > + bytes++; also, I would do ... } while (!!(insn & 0x80) && bytes != sizeof(result)); ...compressing the code and not creating any human readability concern. after which, you can get my Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Il 13/04/23 09:34, Haibo Li ha scritto: > > 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> > > --- > > v2: > > - As Linus Walleij and Alexandre Mergnat suggested,add comments for > > unwind_decode_uleb128 > > - As Alexandre Mergnat suggested,change variables declaration in > > Alphabetical order > > --- > > arch/arm/kernel/unwind.c | 25 ++++++++++++++++++++++++- > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c index > > 53be7ea6181b..f37e55fcf81d 100644 > > --- a/arch/arm/kernel/unwind.c > > +++ b/arch/arm/kernel/unwind.c > > @@ -308,6 +308,29 @@ static int > unwind_exec_pop_subset_r0_to_r3(struct unwind_ctrl_block *ctrl, > > return URC_OK; > > } > > > > +static unsigned long unwind_decode_uleb128(struct unwind_ctrl_block > > +*ctrl) { > > + unsigned long bytes = 0; > > + unsigned long insn; > > + unsigned long result = 0; > > + > > + /* unwind_get_byte() will advance ctrl one instruction at a time, > > + * we loop until we get an instruction byte where bit 7 is not set. > > + * Note:It decodes max 4 bytes to output 28bits data. > > + * 28bits data(0xfffffff) covers vsp increments of 1073742336. > > + * It is sufficent for unwinding stack. > > + */ > > /* > * unwind_get_byte() will advance `ctrl` one instruction at a time, so > * loop until we get an instruction byte where bit 7 is not set. > * > * Note: This decodes a maximum of 4 bytes to output 28 bits data where > * max is 0xfffffff: that will cover a vsp increment of 1073742336, hence > * it is sufficient for unwinding the stack. > */ Looks much better.Thanks. > > > + do { > > + insn = unwind_get_byte(ctrl); > > + result |= (insn & 0x7f) << (bytes * 7); > > + bytes++; > > also, I would do ... > > } while (!!(insn & 0x80) && bytes != sizeof(result)); > > ...compressing the code and not creating any human readability concern. > > after which, you can get my > > Reviewed-by: AngeloGioacchino Del Regno > <angelogioacchino.delregno@collabora.com> get it.I will make a new patch.
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c index 53be7ea6181b..f37e55fcf81d 100644 --- a/arch/arm/kernel/unwind.c +++ b/arch/arm/kernel/unwind.c @@ -308,6 +308,29 @@ static int unwind_exec_pop_subset_r0_to_r3(struct unwind_ctrl_block *ctrl, return URC_OK; } +static unsigned long unwind_decode_uleb128(struct unwind_ctrl_block *ctrl) +{ + unsigned long bytes = 0; + unsigned long insn; + unsigned long result = 0; + + /* unwind_get_byte() will advance ctrl one instruction at a time, + * we loop until we get an instruction byte where bit 7 is not set. + * Note:It decodes max 4 bytes to output 28bits data. + * 28bits data(0xfffffff) covers vsp increments of 1073742336. + * It is sufficent for unwinding stack. + */ + do { + insn = unwind_get_byte(ctrl); + result |= (insn & 0x7f) << (bytes * 7); + bytes++; + if (bytes == sizeof(result)) + break; + } while (!!(insn & 0x80)); + + return result; +} + /* * Execute the current unwind instruction. */ @@ -361,7 +384,7 @@ static int unwind_exec_insn(struct unwind_ctrl_block *ctrl) if (ret) goto error; } else if (insn == 0xb2) { - unsigned long uleb128 = unwind_get_byte(ctrl); + unsigned long uleb128 = unwind_decode_uleb128(ctrl); ctrl->vrs[SP] += 0x204 + (uleb128 << 2); } else {
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> --- v2: - As Linus Walleij and Alexandre Mergnat suggested,add comments for unwind_decode_uleb128 - As Alexandre Mergnat suggested,change variables declaration in Alphabetical order --- arch/arm/kernel/unwind.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-)