# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxxxxx>
# Date 1183478690 -3600
# Node ID f1b62eb7f8be42485356382ac0f6bf5f5a430c22
# Parent 56da8753ba8d958e29262a45052a72dd7cfbaa79
[x86/32] Support two byte CMOVcc opcodes in 4G segment fixup.
These are present in Debian Etch's libc6-i686 package.
Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxxxxx>
---
xen/arch/x86/x86_32/seg_fixup.c | 84 ++++++++++++++++++++++++++++++++++++++--
1 files changed, 80 insertions(+), 4 deletions(-)
diff -r 56da8753ba8d -r f1b62eb7f8be xen/arch/x86/x86_32/seg_fixup.c
--- a/xen/arch/x86/x86_32/seg_fixup.c Tue Jul 03 16:02:31 2007 +0100
+++ b/xen/arch/x86/x86_32/seg_fixup.c Tue Jul 03 17:04:50 2007 +0100
@@ -93,6 +93,57 @@ static unsigned char insn_decode[256] =
X, X, X, X, X, X, O|M, O|M
};
+static unsigned char twobyte_decode[256] = {
+ /* 0x00 - 0x0F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x10 - 0x1F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x20 - 0x2F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x30 - 0x3F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x40 - 0x4F */
+ O|M, O|M, O|M, O|M, O|M, O|M, O|M, O|M,
+ O|M, O|M, O|M, O|M, O|M, O|M, O|M, O|M,
+ /* 0x50 - 0x5F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x60 - 0x6F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x70 - 0x7F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x80 - 0x8F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0x90 - 0x9F */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0xA0 - 0xAF */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0xB0 - 0xBF */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0xC0 - 0xCF */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0xD0 - 0xDF */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0xE0 - 0xEF */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X,
+ /* 0xF0 - 0xFF */
+ X, X, X, X, X, X, X, X,
+ X, X, X, X, X, X, X, X
+};
+
/*
* Obtain the base and limit associated with the given segment selector.
* The selector must identify a 32-bit code or data segment. Any segment that
@@ -275,6 +326,7 @@ int gpf_emulate_4gb(struct cpu_user_regs
u8 *eip; /* ptr to instruction start */
u8 *pb, b; /* ptr into instr. / current instr. byte */
int gs_override = 0;
+ int twobyte = 0;
/* WARNING: We only work for ring-3 segments. */
if ( unlikely(vm86_mode(regs)) || unlikely(!ring_3(regs)) )
@@ -337,12 +389,36 @@ int gpf_emulate_4gb(struct cpu_user_regs
decode = insn_decode[b]; /* opcode byte */
pb++;
+ if ( decode == 0 && b == 0x0f )
+ {
+ twobyte = 1;
+
+ if ( get_user(b, pb) )
+ {
+ dprintk(XENLOG_DEBUG,
+ "Fault while accessing byte %ld of instruction\n",
+ (long)(pb-eip));
+ goto page_fault;
+ }
+
+ if ( (pb - eip) >= 15 )
+ {
+ dprintk(XENLOG_DEBUG, "Too many opcode bytes for a "
+ "legal instruction\n");
+ goto fail;
+ }
+
+ decode = twobyte_decode[b];
+ pb++;
+ }
+
if ( decode == 0 )
{
- dprintk(XENLOG_DEBUG, "Unsupported opcode %02x\n", b);
- goto fail;
- }
-
+ dprintk(XENLOG_DEBUG, "Unsupported %sopcode %02x\n",
+ twobyte ? "two byte " : "", b);
+ goto fail;
+ }
+
if ( !(decode & HAS_MODRM) )
{
/* Must be a <disp32>, or bail. */
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