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| author | Borislav Petkov <bp@suse.de> | 2020-11-28 14:20:06 +0100 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2020-11-29 09:08:56 -0800 |
| commit | 632ee6fd822f8264edc5935c4e31955849df8ba2 (patch) | |
| tree | cb5f6b5f3ea89bbab67eaf48ecb4b965832e5f8a /opcodes | |
| parent | 568cbddc710f6cb6be752f390a1521cd5556ad9b (diff) | |
| download | gdb-632ee6fd822f8264edc5935c4e31955849df8ba2.zip gdb-632ee6fd822f8264edc5935c4e31955849df8ba2.tar.gz gdb-632ee6fd822f8264edc5935c4e31955849df8ba2.tar.bz2 | |
x86: Do not dump DS/CS segment overrides for branch hints
The previous change
"x86: Ignore CS/DS/ES/SS segment-override prefixes in 64-bit mode"
to ignore segment override prefixes in 64-bit mode lead to dumping
branch hints as excessive prefixes:
ffffffff8109d5a0 <vmx_get_rflags>:
...
ffffffff8109d601: 3e 77 0a ds ja,pt ffffffff8109d60e <vmx_get_rflags+0x6e>
^^^^^
In this particular case, those prefixes are not excessive but are used
to provide branch hints - taken/not-taken - to the CPU.
Assign active_seg_prefix in that particular case to consume them.
gas/
2002-11-29 Borislav Petkov <bp@suse.de>
* testsuite/gas/i386/branch.d: Add new branch insns test.
* testsuite/gas/i386/branch.s: Likewise.
* testsuite/gas/i386/i386.exp: Insert the new branch test.
* testsuite/gas/i386/x86-64-branch.d: Test for branch hints insns.
* testsuite/gas/i386/x86-64-branch.s: Likewise.
* testsuite/gas/i386/ilp32/x86-64-branch.d: Likewise.
opcodes/
2020-11-28 Borislav Petkov <bp@suse.de>
* i386-dis.c (print_insn): Set active_seg_prefix for branch hint insns
to not dump branch hint prefixes 0x2E and 0x3E as unused prefixes.
Diffstat (limited to 'opcodes')
| -rw-r--r-- | opcodes/ChangeLog | 5 | ||||
| -rw-r--r-- | opcodes/i386-dis.c | 13 |
2 files changed, 16 insertions, 2 deletions
diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog index 1e7e40f..02fd2f5 100644 --- a/opcodes/ChangeLog +++ b/opcodes/ChangeLog @@ -1,3 +1,8 @@ +2020-11-28 Borislav Petkov <bp@suse.de> + + * i386-dis.c (print_insn): Set active_seg_prefix for branch hint insns + to not dump branch hint prefixes 0x2E and 0x3E as unused prefixes. + 2020-11-16 Przemyslaw Wirkus <przemyslaw.wirkus@arm.com> * aarch64-tbl.h (FLAGM): Handle for FLAGM feature. diff --git a/opcodes/i386-dis.c b/opcodes/i386-dis.c index 58cf001..a1e47c5 100644 --- a/opcodes/i386-dis.c +++ b/opcodes/i386-dis.c @@ -10910,10 +10910,19 @@ putop (const char *in_template, int sizeflag) used_prefixes |= prefixes & (PREFIX_CS | PREFIX_DS); *obufp++ = ','; *obufp++ = 'p'; + + /* Set active_seg_prefix even if not set in 64-bit mode + because here it is a valid branch hint. */ if (prefixes & PREFIX_DS) - *obufp++ = 't'; + { + active_seg_prefix = PREFIX_DS; + *obufp++ = 't'; + } else - *obufp++ = 'n'; + { + active_seg_prefix = PREFIX_CS; + *obufp++ = 'n'; + } } break; case 'K': |