Before this patch, users need to do this to fetch vex.vvvv:
if (insn->vex_prefix.nbytes == 2) {
vex_vvvv = ((insn->vex_prefix.bytes[1] >> 3) & 0xf) ^ 0xf;
}
if (insn->vex_prefix.nbytes == 3) {
vex_vvvv = ((insn->vex_prefix.bytes[2] >> 3) & 0xf) ^ 0xf;
}
Make it so that insn->vex_prefix.bytes[2] always contains vex.wvvvvLpp bits.
Signed-off-by: Denys Vlasenko <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Frank Ch. Eigler <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Jim Keniston <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Ingo Molnar <[email protected]>
---
arch/x86/lib/insn.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 54fcffe..829ca4c 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -163,6 +163,12 @@ found:
/* VEX.W overrides opnd_size */
insn->opnd_bytes = 8;
} else {
+ /*
+ * For VEX2, fake VEX3-like byte#2.
+ * Makes it easier to decode vex.W, vex.vvvv,
+ * vex.L and vex.pp. Masking with 0x7f sets vex.W == 0.
+ */
+ insn->vex_prefix.bytes[2] = b2 & 0x7f;
insn->vex_prefix.nbytes = 2;
insn->next_byte += 2;
}
--
1.8.1.4
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