Commit 8a764a87 authored by Denys Vlasenko's avatar Denys Vlasenko Committed by Ingo Molnar

x86/asm/decoder: Create artificial 3rd byte for 2-byte VEX

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: default avatarDenys Vlasenko <dvlasenk@redhat.com>
Acked-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1423767879-31691-1-git-send-email-dvlasenk@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e07e0d4c
......@@ -164,6 +164,12 @@ void insn_get_prefixes(struct insn *insn)
/* 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;
}
......
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