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Diffstat (limited to 'results/classifier/gemma3:12b/kernel/1922887')
| -rw-r--r-- | results/classifier/gemma3:12b/kernel/1922887 | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/results/classifier/gemma3:12b/kernel/1922887 b/results/classifier/gemma3:12b/kernel/1922887 new file mode 100644 index 000000000..d459d45c2 --- /dev/null +++ b/results/classifier/gemma3:12b/kernel/1922887 @@ -0,0 +1,31 @@ + +STR in Thumb 32 decode problem + +Hi + +It seems that QEMU does not have a proper check on the STR instruction in Thumb32 mode. + +Specifically, the machine code is 0xf84f0ddd, which is 0b1111 1000 0100 1111 0000 1101 1101 1101. +This is an STR (immediate, Thumb) instruction with a T4 encoding scheme. + +The symbols is + +Rn = 1111 +Rt = 0000 +P = 1 +U = 0 +W = 1 + +The decode ASL is below: + +if P == ‘1’ && U == ‘1’ && W == ‘0’ then SEE STRT; +if Rn == ‘1101’ && P == ‘1’ && U == ‘0’ && W == ‘1’ && imm8 == ‘00000100’ then SEE PUSH; +if Rn == ‘1111’ || (P == ‘0’ && W == ‘0’) then UNDEFINED; +t = UInt(Rt); n = UInt(Rn); imm32 = ZeroExtend(imm8, 32); +index = (P == ‘1’); add = (U == ‘1’); wback = (W == ‘1’); +if t == 15 || (wback && n == t) then UNPREDICTABLE; + +When Rn == 1111, it should be an undefined instruction, which should raise SEGILL signal. However, it seems that QEMU does not check this constraint, which should be a bug. Many thanks + +Regards +Muhui \ No newline at end of file |