x86: Fix to decode grouped AVX with VEX pp bits

Fix to decode grouped AVX with VEX pp bits which should be
handled as same as last-prefixes. This fixes below warnings
in posttest with CONFIG_CRYPTO_SHA1_SSSE3=y.

 Warning: arch/x86/tools/test_get_len found difference at <sha1_transform_avx>:ffffffff810d5fc0
 Warning: ffffffff810d6069:	c5 f9 73 de 04       	vpsrldq $0x4,%xmm6,%xmm0
 Warning: objdump says 5 bytes, but insn_get_length() says 4
 ...

With this change, test_get_len can decode it correctly.

 $ arch/x86/tools/test_get_len -v -y
 ffffffff810d6069:       c5 f9 73 de 04          vpsrldq $0x4,%xmm6,%xmm0
 Succeed: decoded and checked 1 instructions

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20120210053340.30429.73410.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 40 insertions, 32 deletions

diff --git a/arch/x86/include/asm/inat.h b/arch/x86/include/asm/inat.h
index 205b063e3e32..74a2e312e8a2 100644
--- a/arch/x86/include/asm/inat.h
+++ b/arch/x86/include/asm/inat.h
@@ -97,11 +97,12 @@
 
 /* Attribute search APIs */
 extern insn_attr_t inat_get_opcode_attribute(insn_byte_t opcode);
+extern int inat_get_last_prefix_id(insn_byte_t last_pfx);
 extern insn_attr_t inat_get_escape_attribute(insn_byte_t opcode,
-                                             insn_byte_t last_pfx,
+                                             int lpfx_id,
                                              insn_attr_t esc_attr);
 extern insn_attr_t inat_get_group_attribute(insn_byte_t modrm,
-                                            insn_byte_t last_pfx,
+                                            int lpfx_id,
                                             insn_attr_t esc_attr);
 extern insn_attr_t inat_get_avx_attribute(insn_byte_t opcode,
                                           insn_byte_t vex_m,
diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h
index 74df3f1eddfd..48eb30a86062 100644
--- a/arch/x86/include/asm/insn.h
+++ b/arch/x86/include/asm/insn.h
@@ -96,12 +96,6 @@ struct insn {
 #define X86_VEX_P(vex)  ((vex) & 0x03)          /* VEX3 Byte2, VEX2 Byte1 */
 #define X86_VEX_M_MAX   0x1f                    /* VEX3.M Maximum value */
 
-/* The last prefix is needed for two-byte and three-byte opcodes */
-static inline insn_byte_t insn_last_prefix(struct insn *insn)
-{
-        return insn->prefixes.bytes[3];
-}
-
 extern void insn_init(struct insn *insn, const void *kaddr, int x86_64);
 extern void insn_get_prefixes(struct insn *insn);
 extern void insn_get_opcode(struct insn *insn);
@@ -160,6 +154,18 @@ static inline insn_byte_t insn_vex_p_bits(struct insn *insn)
                 return X86_VEX_P(insn->vex_prefix.bytes[2]);
 }
 
+/* Get the last prefix id from last prefix or VEX prefix */
+static inline int insn_last_prefix_id(struct insn *insn)
+{
+        if (insn_is_avx(insn))
+                return insn_vex_p_bits(insn);   /* VEX_p is a SIMD prefix id */
+
+        if (insn->prefixes.bytes[3])
+                return inat_get_last_prefix_id(insn->prefixes.bytes[3]);
+
+        return 0;
+}
+
 /* Offset of each field from kaddr */
 static inline int insn_offset_rex_prefix(struct insn *insn)
 {
diff --git a/arch/x86/lib/inat.c b/arch/x86/lib/inat.c
index 88ad5fbda6e1..c1f01a8e9f65 100644
--- a/arch/x86/lib/inat.c
+++ b/arch/x86/lib/inat.c
@@ -29,46 +29,46 @@ insn_attr_t inat_get_opcode_attribute(insn_byte_t opcode)
         return inat_primary_table[opcode];
 }
 
-insn_attr_t inat_get_escape_attribute(insn_byte_t opcode, insn_byte_t last_pfx,
+int inat_get_last_prefix_id(insn_byte_t last_pfx)
+{
+        insn_attr_t lpfx_attr;
+
+        lpfx_attr = inat_get_opcode_attribute(last_pfx);
+        return inat_last_prefix_id(lpfx_attr);
+}
+
+insn_attr_t inat_get_escape_attribute(insn_byte_t opcode, int lpfx_id,
                                       insn_attr_t esc_attr)
 {
         const insn_attr_t *table;
-        insn_attr_t lpfx_attr;
-        int n, m = 0;
+        int n;
 
         n = inat_escape_id(esc_attr);
-        if (last_pfx) {
-                lpfx_attr = inat_get_opcode_attribute(last_pfx);
-                m = inat_last_prefix_id(lpfx_attr);
-        }
+
         table = inat_escape_tables[n][0];
         if (!table)
                 return 0;
-        if (inat_has_variant(table[opcode]) && m) {
-                table = inat_escape_tables[n][m];
+        if (inat_has_variant(table[opcode]) && lpfx_id) {
+                table = inat_escape_tables[n][lpfx_id];
                 if (!table)
                         return 0;
         }
         return table[opcode];
 }
 
-insn_attr_t inat_get_group_attribute(insn_byte_t modrm, insn_byte_t last_pfx,
+insn_attr_t inat_get_group_attribute(insn_byte_t modrm, int lpfx_id,
                                      insn_attr_t grp_attr)
 {
         const insn_attr_t *table;
-        insn_attr_t lpfx_attr;
-        int n, m = 0;
+        int n;
 
         n = inat_group_id(grp_attr);
-        if (last_pfx) {
-                lpfx_attr = inat_get_opcode_attribute(last_pfx);
-                m = inat_last_prefix_id(lpfx_attr);
-        }
+
         table = inat_group_tables[n][0];
         if (!table)
                 return inat_group_common_attribute(grp_attr);
-        if (inat_has_variant(table[X86_MODRM_REG(modrm)]) && m) {
-                table = inat_group_tables[n][m];
+        if (inat_has_variant(table[X86_MODRM_REG(modrm)]) && lpfx_id) {
+                table = inat_group_tables[n][lpfx_id];
                 if (!table)
                         return inat_group_common_attribute(grp_attr);
         }
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 5a1f9f3e3fbb..25feb1ae71c5 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -185,7 +185,8 @@ err_out:
 void insn_get_opcode(struct insn *insn)
 {
         struct insn_field *opcode = &insn->opcode;
-        insn_byte_t op, pfx;
+        insn_byte_t op;
+        int pfx_id;
         if (opcode->got)
                 return;
         if (!insn->prefixes.got)
@@ -212,8 +213,8 @@ void insn_get_opcode(struct insn *insn)
                 /* Get escaped opcode */
                 op = get_next(insn_byte_t, insn);
                 opcode->bytes[opcode->nbytes++] = op;
-                pfx = insn_last_prefix(insn);
-                insn->attr = inat_get_escape_attribute(op, pfx, insn->attr);
+                pfx_id = insn_last_prefix_id(insn);
+                insn->attr = inat_get_escape_attribute(op, pfx_id, insn->attr);
         }
         if (inat_must_vex(insn->attr))
                 insn->attr = 0; /* This instruction is bad */
@@ -235,7 +236,7 @@ err_out:
 void insn_get_modrm(struct insn *insn)
 {
         struct insn_field *modrm = &insn->modrm;
-        insn_byte_t pfx, mod;
+        insn_byte_t pfx_id, mod;
         if (modrm->got)
                 return;
         if (!insn->opcode.got)
@@ -246,8 +247,8 @@ void insn_get_modrm(struct insn *insn)
                 modrm->value = mod;
                 modrm->nbytes = 1;
                 if (inat_is_group(insn->attr)) {
-                        pfx = insn_last_prefix(insn);
-                        insn->attr = inat_get_group_attribute(mod, pfx,
+                        pfx_id = insn_last_prefix_id(insn);
+                        insn->attr = inat_get_group_attribute(mod, pfx_id,
                                                               insn->attr);
                         if (insn_is_avx(insn) && !inat_accept_vex(insn->attr))
                                 insn->attr = 0; /* This is bad */