| From 41ff9aa49f6c54c66d0e6b37f265fd9cb0176057 Mon Sep 17 00:00:00 2001 |
| From: Paul Floyd <pjfloyd@wanadoo.fr> |
| Date: Sun, 17 Dec 2023 14:18:51 +0100 |
| Subject: [PATCH 4/4] Bug 478624 - Valgrind incompatibility with binutils-2.42 |
| on x86 with new nop patterns (unhandled instruction bytes: 0x2E 0x8D 0xB4 |
| 0x26) |
| |
| It was a bit of a struggle to get the testcase to build |
| with both clang and gcc (oddly enough gcc was more difficult) so |
| I just resorted to using .byte arrays. |
| |
| (cherry picked from commit d35005cef8ad8207542738812705ceabf137d7e0) |
| |
| Upstream-Status: Backport [https://sourceware.org/git/?p=valgrind.git;a=commit;h=41ff9aa49f6c54c66d0e6b37f265fd9cb0176057] |
| Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| --- |
| .gitignore | 1 + |
| NEWS | 2 ++ |
| VEX/priv/guest_x86_toIR.c | 22 +++++++++++++- |
| none/tests/x86/Makefile.am | 2 ++ |
| none/tests/x86/gnu_binutils_nop.c | 34 ++++++++++++++++++++++ |
| none/tests/x86/gnu_binutils_nop.stderr.exp | 0 |
| none/tests/x86/gnu_binutils_nop.vgtest | 2 ++ |
| 7 files changed, 62 insertions(+), 1 deletion(-) |
| create mode 100644 none/tests/x86/gnu_binutils_nop.c |
| create mode 100644 none/tests/x86/gnu_binutils_nop.stderr.exp |
| create mode 100644 none/tests/x86/gnu_binutils_nop.vgtest |
| |
| --- a/NEWS |
| +++ b/NEWS |
| @@ -9,6 +9,8 @@ The following bugs have been fixed or re |
| file produced by mold |
| 476708 valgrind-monitor.py regular expressions should use raw strings |
| 477198 Add fchmodat2 syscall on linux |
| +478624 Valgrind incompatibility with binutils-2.42 on x86 with new nop patterns |
| + (unhandled instruction bytes: 0x2E 0x8D 0xB4 0x26) |
| |
| To see details of a given bug, visit |
| https://bugs.kde.org/show_bug.cgi?id=XXXXXX |
| --- a/VEX/priv/guest_x86_toIR.c |
| +++ b/VEX/priv/guest_x86_toIR.c |
| @@ -8198,7 +8198,7 @@ DisResult disInstr_X86_WRK ( |
| delta += 5; |
| goto decode_success; |
| } |
| - /* Don't barf on recent binutils padding, |
| + /* Don't barf on recent (2010) binutils padding, |
| all variants of which are: nopw %cs:0x0(%eax,%eax,1) |
| 66 2e 0f 1f 84 00 00 00 00 00 |
| 66 66 2e 0f 1f 84 00 00 00 00 00 |
| @@ -8222,6 +8222,26 @@ DisResult disInstr_X86_WRK ( |
| goto decode_success; |
| } |
| } |
| + |
| + /* bug478624 GNU binutils uses a leal of esi into itself with |
| + a zero offset and CS prefix as an 8 byte no-op (Dec 2023). |
| + Since the CS prefix is hardly ever used we don't do much |
| + to decode it, just a few cases for conditional branches. |
| + So add handling here with other pseudo-no-ops. |
| + */ |
| + if (code[0] == 0x2E && code[1] == 0x8D) { |
| + if (code[2] == 0x74 && code[3] == 0x26 && code[4] == 0x00) { |
| + DIP("leal %%cs:0(%%esi,%%eiz,1),%%esi\n"); |
| + delta += 5; |
| + goto decode_success; |
| + } |
| + if (code[2] == 0xB4 && code[3] == 0x26 && code[4] == 0x00 |
| + && code[5] == 0x00 && code[6] == 0x00 && code[7] == 0x00) { |
| + DIP("leal %%cs:0(%%esi,%%eiz,1),%%esi\n"); |
| + delta += 8; |
| + goto decode_success; |
| + } |
| + } |
| |
| // Intel CET requires the following opcodes to be treated as NOPs |
| // with any prefix and ModRM, SIB and disp combination: |
| --- a/none/tests/x86/Makefile.am |
| +++ b/none/tests/x86/Makefile.am |
| @@ -52,6 +52,7 @@ EXTRA_DIST = \ |
| fxtract.stdout.exp fxtract.stderr.exp fxtract.vgtest \ |
| fxtract.stdout.exp-older-glibc \ |
| getseg.stdout.exp getseg.stderr.exp getseg.vgtest \ |
| + gnu_binutils_nop.stderr.exp gnu_binutils_nop.vgtest \ |
| incdec_alt.stdout.exp incdec_alt.stderr.exp incdec_alt.vgtest \ |
| int.stderr.exp int.stdout.exp int.disabled \ |
| $(addsuffix .stderr.exp,$(INSN_TESTS)) \ |
| @@ -100,6 +101,7 @@ check_PROGRAMS = \ |
| fpu_lazy_eflags \ |
| fxtract \ |
| getseg \ |
| + gnu_binutils_nop \ |
| incdec_alt \ |
| $(INSN_TESTS) \ |
| int \ |
| --- /dev/null |
| +++ b/none/tests/x86/gnu_binutils_nop.c |
| @@ -0,0 +1,34 @@ |
| +int main(void) |
| +{ |
| + // GNU binutils uses various opcodes as alternatives for nop |
| + // the idea is that it is faster to execute one large opcode |
| + // with no side-effects than multiple repetitions of the |
| + // single byte 'nop'. This gives more choice when code |
| + // needs to be padded. |
| + |
| + // the following is based on |
| + // https://sourceware.org/cgit/binutils-gdb/tree/gas/config/tc-i386.c#n1256 |
| + |
| + // one byte |
| + __asm__ __volatile__("nop"); |
| + // two bytes |
| + __asm__ __volatile__("xchg %ax,%ax"); |
| + // three bytes |
| + //__asm__ __volatile__("leal 0(%esi),%esi"); |
| + __asm__ __volatile__(".byte 0x8d,0x76,0x00"); |
| + // four bytes |
| + //__asm__ __volatile__("leal 0(%esi,%eiz),%esi"); |
| + __asm__ __volatile__(".byte 0x8d,0x74,0x26,0x00"); |
| + // five bytes |
| + //__asm__ __volatile__("leal %cs:0(%esi,%eiz),%esi"); |
| + __asm__ __volatile__(".byte 0x2e,0x8d,0x74,0x26,0x00"); |
| + // six bytes |
| + //__asm__ __volatile__("leal 0L(%esi),%esi"); |
| + __asm__ __volatile__(".byte 0x8d,0xb6,0x00,0x00,0x00,0x00"); |
| + // seven bytes |
| + //__asm__ __volatile__("leal 0L(%esi,%eiz),%esi"); |
| + __asm__ __volatile__(".byte 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00"); |
| + // eight bytes |
| + //__asm__ __volatile__("leal %cs:0L(%esi,%eiz),%esi"); |
| + __asm__ __volatile__(".byte 0x2e,0x8d,0xb4,0x26,0x00,0x00,0x00,0x00"); |
| +} |
| --- /dev/null |
| +++ b/none/tests/x86/gnu_binutils_nop.vgtest |
| @@ -0,0 +1,2 @@ |
| +prog: gnu_binutils_nop |
| +vgopts: -q |