Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [BUGFIX PATCH] x86/insn: Fix to decode bsr/bsf/jmpe with operand-size prefix | Date | Tue, 05 Jun 2012 00:09:11 +0900 |
| |
Fix x86 instruction decoder to decode bsr/bsf/jmpe with operand-size prefix (66h). This fixes below failure of the test case.
bsf/bsr/jmpe have a special encoding. Opcode map in Intel Software Developers Manual vol2 says they have TZCNT/LZCNT variants if it has F3h prefix. However, there is no information if it has other 66h or F2h prefixes. Current instruction decoder supposes that those are a bad instruction, but it actually accept at least operand-size prefix.
This fixes errors reported by test_get_len as below:
Warning: arch/x86/tools/test_get_len found difference at <em_bsf>:ffffffff81036d87 Warning: ffffffff81036de5: 66 0f bc c2 bsf %dx,%ax Warning: objdump says 4 bytes, but insn_get_length() says 3 Warning: arch/x86/tools/test_get_len found difference at <em_bsr>:ffffffff81036ea6 Warning: ffffffff81036f04: 66 0f bd c2 bsr %dx,%ax Warning: objdump says 4 bytes, but insn_get_length() says 3 Warning: decoded and checked 13298882 instructions with 2 warnings
Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Pekka Enberg <penberg@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> ---
arch/x86/lib/x86-opcode-map.txt | 8 ++++---- arch/x86/tools/gen-insn-attr-x86.awk | 14 +++++++++----- 2 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt index 8191379..5d7e51f 100644 --- a/arch/x86/lib/x86-opcode-map.txt +++ b/arch/x86/lib/x86-opcode-map.txt @@ -28,7 +28,7 @@ # - (66): the last prefix is 0x66 # - (F3): the last prefix is 0xF3 # - (F2): the last prefix is 0xF2 -# +# - (!F3) : the last prefix is not 0xF3 (including non-last prefix case) Table: one byte opcode Referrer: @@ -515,12 +515,12 @@ b4: LFS Gv,Mp b5: LGS Gv,Mp b6: MOVZX Gv,Eb b7: MOVZX Gv,Ew -b8: JMPE | POPCNT Gv,Ev (F3) +b8: JMPE (!F3) | POPCNT Gv,Ev (F3) b9: Grp10 (1A) ba: Grp8 Ev,Ib (1A) bb: BTC Ev,Gv -bc: BSF Gv,Ev | TZCNT Gv,Ev (F3) -bd: BSR Gv,Ev | LZCNT Gv,Ev (F3) +bc: BSF Gv,Ev (!F3) | TZCNT Gv,Ev (F3) +bd: BSR Gv,Ev (!F3) | LZCNT Gv,Ev (F3) be: MOVSX Gv,Eb bf: MOVSX Gv,Ew # 0x0f 0xc0-0xcf diff --git a/arch/x86/tools/gen-insn-attr-x86.awk b/arch/x86/tools/gen-insn-attr-x86.awk index 5f6a5b6..ddcf39b 100644 --- a/arch/x86/tools/gen-insn-attr-x86.awk +++ b/arch/x86/tools/gen-insn-attr-x86.awk @@ -66,9 +66,10 @@ BEGIN { rex_expr = "^REX(\\.[XRWB]+)*" fpu_expr = "^ESC" # TODO - lprefix1_expr = "\\(66\\)" + lprefix1_expr = "\\((66|!F3)\\)" lprefix2_expr = "\\(F3\\)" - lprefix3_expr = "\\(F2\\)" + lprefix3_expr = "\\((F2|!F3)\\)" + lprefix_expr = "\\((66|F2|F3)\\)" max_lprefix = 4 # All opcodes starting with lower-case 'v' or with (v1) superscript @@ -333,13 +334,16 @@ function convert_operands(count,opnd, i,j,imm,mod) if (match(ext, lprefix1_expr)) { lptable1[idx] = add_flags(lptable1[idx],flags) variant = "INAT_VARIANT" - } else if (match(ext, lprefix2_expr)) { + } + if (match(ext, lprefix2_expr)) { lptable2[idx] = add_flags(lptable2[idx],flags) variant = "INAT_VARIANT" - } else if (match(ext, lprefix3_expr)) { + } + if (match(ext, lprefix3_expr)) { lptable3[idx] = add_flags(lptable3[idx],flags) variant = "INAT_VARIANT" - } else { + } + if (!match(ext, lprefix_expr)){ table[idx] = add_flags(table[idx],flags) } }
| |