Merged in liburcu master, thanks!
Mathieu
----- On Dec 15, 2020, at 11:28 AM, Michael Jeanson mjean...@efficios.com wrote:
> Remove the configure time CONFIG_RCU_ARM_HAVE_DMB option and replace it
> by compile time detection based on the ARM ISA version. This makes sure
> we unconditionnaly use the DMB instruction only on ARMv7 where it's part
> of the baseline ISA.
>
> This will change the behavior on ARMv6 platform that possibly have this
> instruction but it was probably already broken since we use the 'ISH'
> option which doesn't seem to be valid on this ISA.
>
> This will also allow sharing headers in a multi-arch environment and
> reduce the build system complexity.
>
> Signed-off-by: Michael Jeanson <mjean...@efficios.com>
> Cc: Jason Wessel <jason.wes...@windriver.com>
> Change-Id: I8e56ada55148d8e0f198c3d2e741ea414de5fef2
> ---
> configure.ac | 19 -------------------
> include/urcu/arch.h | 7 +++++++
> include/urcu/arch/arm.h | 13 +++++++++++--
> include/urcu/config.h.in | 3 ---
> 4 files changed, 18 insertions(+), 24 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index d1d43e6..daa967a 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -21,7 +21,6 @@ m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
> AC_REQUIRE_AUX_FILE([tap-driver.sh])
>
> AH_TEMPLATE([CONFIG_RCU_SMP], [Enable SMP support. With SMP support enabled,
> uniprocessors are also supported. With SMP support disabled, UP systems work
> fine, but the behavior of SMP systems is undefined.])
> -AH_TEMPLATE([CONFIG_RCU_ARM_HAVE_DMB], [Use the dmb instruction if available
> for use on ARM.])
> AH_TEMPLATE([CONFIG_RCU_TLS], [TLS provided by the compiler.])
> AH_TEMPLATE([CONFIG_RCU_HAVE_CLOCK_GETTIME], [clock_gettime() is detected.])
> AH_TEMPLATE([CONFIG_RCU_FORCE_SYS_MEMBARRIER], [Require the operating system
> to
> support the membarrier system call for default and bulletproof flavors.])
> @@ -124,24 +123,6 @@ AS_IF([test "$host_cpu" = "armv7l"],[
> AM_CFLAGS="$AM_CFLAGS -mcpu=cortex-a9 -mtune=cortex-a9 -O1"
> ])
>
> -# ARM-specific checks
> -AS_CASE([$host_cpu], [arm*], [
> - AC_MSG_CHECKING([for dmb instruction])
> - AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
> - int main()
> - {
> - asm volatile("dmb":::"memory");
> - return 0;
> - }
> - ]])
> - ],[
> - AC_MSG_RESULT([yes])
> - AC_DEFINE([CONFIG_RCU_ARM_HAVE_DMB], [1])
> - ],[
> - AC_MSG_RESULT([no])
> - ])
> -])
> -
> # Search for clock_gettime
> AC_SEARCH_LIBS([clock_gettime], [rt], [
> AC_DEFINE([CONFIG_RCU_HAVE_CLOCK_GETTIME], [1])
> diff --git a/include/urcu/arch.h b/include/urcu/arch.h
> index c4b8bc2..620743c 100644
> --- a/include/urcu/arch.h
> +++ b/include/urcu/arch.h
> @@ -41,6 +41,7 @@
> * URCU_ARCH_ALPHA : All DEC Alpha variants
> * URCU_ARCH_IA64 : All Intel Itanium variants
> * URCU_ARCH_ARM : All ARM 32 bits variants
> + * URCU_ARCH_ARMV7 : All ARMv7 ISA variants
> * URCU_ARCH_AARCH64 : All ARM 64 bits variants
> * URCU_ARCH_MIPS : All MIPS variants
> * URCU_ARCH_NIOS2 : All Intel / Altera NIOS II variants
> @@ -105,6 +106,12 @@
> #define URCU_ARCH_IA64 1
> #include <urcu/arch/ia64.h>
>
> +#elif (defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7__))
> +
> +#define URCU_ARCH_ARMV7 1
> +#define URCU_ARCH_ARM 1
> +#include <urcu/arch/arm.h>
> +
> #elif (defined(__arm__) || defined(__arm))
>
> #define URCU_ARCH_ARM 1
> diff --git a/include/urcu/arch/arm.h b/include/urcu/arch/arm.h
> index e904b06..54ca4fa 100644
> --- a/include/urcu/arch/arm.h
> +++ b/include/urcu/arch/arm.h
> @@ -30,7 +30,15 @@
> extern "C" {
> #endif
>
> -#ifdef CONFIG_RCU_ARM_HAVE_DMB
> +/*
> + * Using DMB is faster than the builtin __sync_synchronize and this
> instruction
> is
> + * part of the baseline ARMv7 ISA.
> + */
> +#ifdef URCU_ARCH_ARMV7
> +
> +/* For backwards compat. */
> +#define CONFIG_RCU_ARM_HAVE_DMB 1
> +
> /*
> * Issues full system DMB operation.
> */
> @@ -44,7 +52,8 @@ extern "C" {
> #define cmm_smp_mb() __asm__ __volatile__ ("dmb ish":::"memory")
> #define cmm_smp_rmb() __asm__ __volatile__ ("dmb ish":::"memory")
> #define cmm_smp_wmb() __asm__ __volatile__ ("dmb ish":::"memory")
> -#endif /* CONFIG_RCU_ARM_HAVE_DMB */
> +
> +#endif /* URCU_ARCH_ARMV7 */
>
> #include <stdlib.h>
> #include <sys/time.h>
> diff --git a/include/urcu/config.h.in b/include/urcu/config.h.in
> index faf7817..99d763a 100644
> --- a/include/urcu/config.h.in
> +++ b/include/urcu/config.h.in
> @@ -5,9 +5,6 @@
> behavior of SMP systems is undefined. */
> #undef CONFIG_RCU_SMP
>
> -/* Use the dmb instruction is available for use on ARM. */
> -#undef CONFIG_RCU_ARM_HAVE_DMB
> -
> /* TLS provided by the compiler. */
> #undef CONFIG_RCU_TLS
>
> --
> 2.29.2
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
_______________________________________________
lttng-dev mailing list
lttng-dev@lists.lttng.org
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
