Commit f546769b authored by Mark Andrews's avatar Mark Andrews

arm: just use the compiler's default yield support

parent 9150e432
Pipeline #14476 passed with stages
in 11 minutes and 29 seconds
5234. [port] arm: just use the compiler's default support for
yield. [GL #981]
--- 9.15.0 released ---
5233. [bug] Negative trust anchors did not work with "forward only;"
......
......@@ -72,35 +72,6 @@ These are platforms on which BIND 9.15 is known *not* to build or run:
## Platform quirks
### ARM
If the compilation ends with following error:
```
Error: selected processor does not support `yield' in ARM mode
```
You will need to set `-march` compiler option to `native`, so the compiler
recognizes `yield` assembler instruction. The proper way to set `-march=native`
would be to put it into `CFLAGS`, e.g. run `./configure` like this:
`CFLAGS="-march=native -Os -g" ./configure` plus your usual options.
If that doesn't work, you can enforce the minimum CPU and FPU (taken from Debian
armhf documentation):
* The lowest worthwhile CPU implementation is Armv7-A, therefore the recommended
build option is `-march=armv7-a`.
* FPU should be set at VFPv3-D16 as they represent the minimum specification of
the processors to support here, therefore the recommended build option is
`-mfpu=vfpv3-d16`.
The `configure` command should look like this:
```
CFLAGS="-march=armv7-a -mfpu=vfpv3-d16 -Os -g" ./configure
```
### NetBSD 6 i386
The i386 build of NetBSD requires the `libatomic` library, available from
......
......@@ -45,6 +45,9 @@
/* Define to 1 if you have the `arc4random_uniform' function. */
#undef HAVE_ARC4RANDOM_UNIFORM
/* define if the ARM yield instruction is available */
#undef HAVE_ARM_YIELD
/* Define to 1 if the compiler supports __builtin_clz. */
#undef HAVE_BUILTIN_CLZ
......
......@@ -13831,17 +13831,15 @@ $as_echo "#define FLEXIBLE_ARRAY_MEMBER /**/" >>confdefs.h
#
case $host in #(
arm*) :
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for yield instruction support" >&5
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for yield instruction support" >&5
$as_echo_n "checking for yield instruction support... " >&6; }
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
main ()
{
__asm__ __volatile__ ("yield")
;
return 0;
}
......@@ -13849,8 +13847,12 @@ _ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
$as_echo "yes" >&6; }
$as_echo "#define HAVE_ARM_YIELD 1" >>confdefs.h
else
as_fn_error $? "no, try adding -march=native or -march=armv7-a to CFLAGS (see PLATFORMS.md for more information)" "$LINENO" 5
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
$as_echo "no" >&6; }
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext ;; #(
*) :
......
......@@ -424,15 +424,15 @@ AC_C_FLEXIBLE_ARRAY_MEMBER
# Check for yield support on ARM processors
#
AS_CASE([$host],
[arm*],[
AC_MSG_CHECKING([for yield instruction support])
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[]],
[[__asm__ __volatile__ ("yield")]]
)],
[AC_MSG_RESULT([yes])],
[AC_MSG_ERROR([no, try adding -march=native or -march=armv7-a to CFLAGS (see PLATFORMS.md for more information)])])])
[arm*],
[AC_MSG_CHECKING([for yield instruction support])
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([[]],
[[__asm__ __volatile__ ("yield")]])],
[AC_MSG_RESULT([yes])
AC_DEFINE([HAVE_ARM_YIELD], [1],
[define if the ARM yield instruction is available])],
[AC_MSG_RESULT([no])])])
AC_CHECK_FUNCS([sysctlbyname])
......
......@@ -52,7 +52,7 @@
# define isc_rwlock_pause() __asm__ __volatile__ ("rep; nop")
#elif defined(__ia64__)
# define isc_rwlock_pause() __asm__ __volatile__ ("hint @pause")
#elif defined(__arm__)
#elif defined(__arm__) && HAVE_ARM_YIELD
# define isc_rwlock_pause() __asm__ __volatile__ ("yield")
#elif defined(sun) && (defined(__sparc) || defined(__sparc__))
# define isc_rwlock_pause() smt_pause()
......
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