[Qemu-devel] [PATCH v3 25/27] tcg-ppc64: Use getauxval for ISA detection

[Richard Henderson <rth@twiddle.net>]

Glibc 2.16 includes an easy way to get feature bits previously
buried in /proc or the program startup auxiliary vector.  Use it.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 configure              | 18 ++++++++++++++++++
 tcg/ppc64/tcg-target.c | 16 +++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index fbea75e..e675b9d 100755
--- a/configure
+++ b/configure
@@ -3252,6 +3252,20 @@ if compile_prog "" "" ; then
     int128=yes
 fi
 
+########################################
+# check if getauxval is available.
+
+getauxval=no
+cat > $TMPC << EOF
+#include <sys/auxv.h>
+int main(void) {
+  return getauxval(AT_HWCAP) == 0;
+}
+EOF
+if compile_prog "" "" ; then
+    getauxval=yes
+fi
+
 ##########################################
 # End of CC checks
 # After here, no more $cc or $ld runs
@@ -3809,6 +3823,10 @@ if test "$int128" = "yes" ; then
   echo "CONFIG_INT128=y" >> $config_host_mak
 fi
 
+if test "$getauxval" = "yes" ; then
+  echo "CONFIG_GETAUXVAL=y" >> $config_host_mak
+fi
+
 if test "$glusterfs" = "yes" ; then
   echo "CONFIG_GLUSTERFS=y" >> $config_host_mak
 fi
diff --git a/tcg/ppc64/tcg-target.c b/tcg/ppc64/tcg-target.c
index 4ade501..cc1161a 100644
--- a/tcg/ppc64/tcg-target.c
+++ b/tcg/ppc64/tcg-target.c
@@ -44,8 +44,15 @@ static uint8_t *tb_ret_addr;
 #define GUEST_BASE 0
 #endif
 
+#ifdef CONFIG_GETAUXVAL
+#include <sys/auxv.h>
+static bool have_isa_2_06;
+#define HAVE_ISA_2_06  have_isa_2_06
+#define HAVE_ISEL      have_isa_2_06
+#else
 #define HAVE_ISA_2_06  0
-#define HAVE_ISEL      0
+#define HAVE_ISA_ISEL  0
+#endif
 
 #ifdef CONFIG_USE_GUEST_BASE
 #define TCG_GUEST_BASE_REG 30
@@ -2084,6 +2091,13 @@ static const TCGTargetOpDef ppc_op_defs[] = {
 
 static void tcg_target_init (TCGContext *s)
 {
+#ifdef CONFIG_GETAUXVAL
+    unsigned long hwcap = getauxval(AT_HWCAP);
+    if (hwcap & PPC_FEATURE_ARCH_2_06) {
+        have_isa_2_06 = true;
+    }
+#endif
+
     tcg_regset_set32 (tcg_target_available_regs[TCG_TYPE_I32], 0, 0xffffffff);
     tcg_regset_set32 (tcg_target_available_regs[TCG_TYPE_I64], 0, 0xffffffff);
     tcg_regset_set32 (tcg_target_call_clobber_regs, 0,
-- 
1.8.1.4