[Xen-changelog] [xen master] x86emul: relax asm() constraints

[patchbot@xxxxxxx]

commit 5644ce014223a6dbd087c0a5e18b5abe37b91c8d
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Feb 17 16:20:01 2016 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Feb 17 16:20:01 2016 +0100

    x86emul: relax asm() constraints
    
    Let's give the compiler as much liberty at picking instruction operands
    as possible. Also drop unnecessary size modifiers when the correct size
    can already be derived from the asm() operands. Finally also drop an
    "unsigned" from idiv_dbl()'s second parameter, allowing a cast to be
    eliminated.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 36 ++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 7a74ab7..028b3f6 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -611,7 +611,7 @@ do {                                                    \
  */
 static bool_t even_parity(uint8_t v)
 {
-    asm ( "test %b0,%b0; setp %b0" : "=a" (v) : "0" (v) );
+    asm ( "test %1,%1; setp %0" : "=qm" (v) : "q" (v) );
     return v;
 }
 
@@ -813,9 +813,9 @@ static int read_ulong(
  */
 static bool_t mul_dbl(unsigned long m[2])
 {
-    bool_t rc = 0;
-    asm ( "mul %1; seto %b2"
-          : "+a" (m[0]), "+d" (m[1]), "+q" (rc) );
+    bool_t rc;
+    asm ( "mul %1; seto %2"
+          : "+a" (m[0]), "+d" (m[1]), "=qm" (rc) );
     return rc;
 }
 
@@ -826,9 +826,9 @@ static bool_t mul_dbl(unsigned long m[2])
  */
 static bool_t imul_dbl(unsigned long m[2])
 {
-    bool_t rc = 0;
-    asm ( "imul %1; seto %b2"
-          : "+a" (m[0]), "+d" (m[1]), "+q" (rc) );
+    bool_t rc;
+    asm ( "imul %1; seto %2"
+          : "+a" (m[0]), "+d" (m[1]), "=qm" (rc) );
     return rc;
 }
 
@@ -842,7 +842,7 @@ static bool_t div_dbl(unsigned long u[2], unsigned long v)
 {
     if ( (v == 0) || (u[1] >= v) )
         return 1;
-    asm ( "div %2" : "+a" (u[0]), "+d" (u[1]) : "r" (v) );
+    asm ( "divq %2" : "+a" (u[0]), "+d" (u[1]) : "rm" (v) );
     return 0;
 }
 
@@ -854,9 +854,9 @@ static bool_t div_dbl(unsigned long u[2], unsigned long v)
  * NB. We don't use idiv directly as it's moderately hard to work out
  *     ahead of time whether it will #DE, which we cannot allow to happen.
  */
-static bool_t idiv_dbl(unsigned long u[2], unsigned long v)
+static bool_t idiv_dbl(unsigned long u[2], long v)
 {
-    bool_t negu = (long)u[1] < 0, negv = (long)v < 0;
+    bool_t negu = (long)u[1] < 0, negv = v < 0;
 
     /* u = abs(u) */
     if ( negu )
@@ -4521,9 +4521,10 @@ x86_emulate(
 
     case 0xbc: /* bsf or tzcnt */ {
         bool_t zf;
-        asm ( "bsf %2,%0; setz %b1"
-              : "=r" (dst.val), "=q" (zf)
-              : "r" (src.val) );
+
+        asm ( "bsf %2,%0; setz %1"
+              : "=r" (dst.val), "=qm" (zf)
+              : "rm" (src.val) );
         _regs.eflags &= ~EFLG_ZF;
         if ( (vex.pfx == vex_f3) && vcpu_has_bmi1() )
         {
@@ -4546,9 +4547,10 @@ x86_emulate(
 
     case 0xbd: /* bsr or lzcnt */ {
         bool_t zf;
-        asm ( "bsr %2,%0; setz %b1"
-              : "=r" (dst.val), "=q" (zf)
-              : "r" (src.val) );
+
+        asm ( "bsr %2,%0; setz %1"
+              : "=r" (dst.val), "=qm" (zf)
+              : "rm" (src.val) );
         _regs.eflags &= ~EFLG_ZF;
         if ( (vex.pfx == vex_f3) && vcpu_has_lzcnt() )
         {
@@ -4677,7 +4679,7 @@ x86_emulate(
             break;
         case 4:
 #ifdef __x86_64__
-            asm ( "bswap %k0" : "=r" (dst.val) : "0" (*dst.reg) );
+            asm ( "bswap %k0" : "=r" (dst.val) : "0" (*(uint32_t *)dst.reg) );
             break;
         case 8:
 #endif
--
generated by git-patchbot for /home/xen/git/xen.git#master

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