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| author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2011-12-05 16:05:39 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-12-05 17:53:15 +0400 |
| commit | 130b78b2bf16d5d89091db38374faef896360cf9 (patch) | |
| tree | 46f1f553aba35de8e2ffea42128e2237da479dc6 /arch/x86/lib/inat.c | |
| parent | 1056c3e916f12cdd8042ab27dfccbb3a9e871df0 (diff) | |
| download | linux-130b78b2bf16d5d89091db38374faef896360cf9.tar.xz | |
x86: Fix instruction decoder to handle grouped AVX instructions
For reducing memory usage of attribute table, x86 instruction
decoder puts "Group" attribute only on "no-last-prefix"
attribute table (same as vex_p == 0 case).
Thus, the decoder should look no-last-prefix table first, and
then only if it is not a group, move on to "with-last-prefix"
table (vex_p != 0).
However, current implementation, inat_get_avx_attribute()
looks with-last-prefix directly. So, when decoding
a grouped AVX instruction, the decoder fails to find correct
group because there is no "Group" attribute on the table.
This ends up with the mis-decoding of instructions, as Ingo
reported in http://thread.gmane.org/gmane.linux.kernel/1214103
This patch fixes it to check no-last-prefix table first
even if that is an AVX instruction, and get an attribute from
"with last-prefix" table only if that is not a group.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20111205120539.15475.91428.stgit@cloud
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/inat.c')
| -rw-r--r-- | arch/x86/lib/inat.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/lib/inat.c b/arch/x86/lib/inat.c index 46fc4ee09fc4..88ad5fbda6e1 100644 --- a/arch/x86/lib/inat.c +++ b/arch/x86/lib/inat.c @@ -82,9 +82,16 @@ insn_attr_t inat_get_avx_attribute(insn_byte_t opcode, insn_byte_t vex_m, const insn_attr_t *table; if (vex_m > X86_VEX_M_MAX || vex_p > INAT_LSTPFX_MAX) return 0; - table = inat_avx_tables[vex_m][vex_p]; + /* At first, this checks the master table */ + table = inat_avx_tables[vex_m][0]; if (!table) return 0; + if (!inat_is_group(table[opcode]) && vex_p) { + /* If this is not a group, get attribute directly */ + table = inat_avx_tables[vex_m][vex_p]; + if (!table) + return 0; + } return table[opcode]; } |