Reads and writes to unsigned int 32 bit numbers must be address aligned or the l2 cache can return junk in the high order 16 bits on reads.
This patch activates the original work done for alignment in ltt for the UST code. The config.ac changes will isolate the use of alignment to the known arch type with the problem. Signed-off-by: Jason Wessel <[email protected]> --- configure.ac | 26 ++++++++++++++++++++++++++ include/ust/core.h | 6 +++--- 2 files changed, 29 insertions(+), 3 deletions(-) diff --git a/configure.ac b/configure.ac index 8ca32ff..d05b18c 100644 --- a/configure.ac +++ b/configure.ac @@ -10,6 +10,7 @@ AM_INIT_AUTOMAKE([foreign]) m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])]) AC_CONFIG_SRCDIR([ustctl/ustctl.c]) AC_CONFIG_HEADERS([config.h]) +AH_TEMPLATE([HAVE_EFFICIENT_UNALIGNED_ACCESS], [Use efficient unaligned access.]) # Checks for programs. AC_PROG_CC @@ -108,6 +109,7 @@ changequote([,])dnl ppc64) LIBFORMAT="elf64-powerpc" ;; s390) LIBFORMAT="elf32-s390" ;; s390x) LIBFORMAT="elf64-s390" ;; + armv5) LIBFORMAT="elf32-littlearm"; NO_UNALIGNED_ACCESS=1 ;; arm) LIBFORMAT="elf32-littlearm" ;; mips*) LIBFORMAT="" ;; *) AC_MSG_ERROR([unable to detect library format (unsupported architecture ($host_cpu)?)]) ;; @@ -115,6 +117,30 @@ esac AC_SUBST(LIBFORMAT) AC_MSG_RESULT($LIBFORMAT) +if test "x$host_cpu" = "xarm" ; then +AC_MSG_CHECKING([checking for armv5]) +AC_TRY_COMPILE( +[ +], +[ +#ifndef __ARM_ARCH_5TEJ__ +#error "no arm5 here" +#endif +], +[ + AC_MSG_RESULT([yes]) + NO_UNALIGNED_ACCESS=1 +] +, +[ + AC_MSG_RESULT([no]) +] +) +fi +if test x$NO_UNALIGNED_ACCESS = x ; then +AC_DEFINE([HAVE_EFFICIENT_UNALIGNED_ACCESS], [1]) +fi + AC_CONFIG_FILES([ Makefile doc/Makefile diff --git a/include/ust/core.h b/include/ust/core.h index e781a3a..4a2c6e5 100644 --- a/include/ust/core.h +++ b/include/ust/core.h @@ -23,7 +23,7 @@ #define likely(x) __builtin_expect(!!(x), 1) #define unlikely(x) __builtin_expect(!!(x), 0) -#if defined(CONFIG_LTT) && defined(CONFIG_LTT_ALIGNMENT) +#ifndef HAVE_EFFICIENT_UNALIGNED_ACCESS /* * Calculate the offset needed to align the type. @@ -42,7 +42,7 @@ static inline int ltt_get_alignment(void) return sizeof(void *); } -#else +#else /* HAVE_EFFICIENT_UNALIGNED_ACCESS */ static inline unsigned int ltt_align(size_t align_drift, size_t size_of_type) @@ -56,7 +56,7 @@ static inline int ltt_get_alignment(void) { return 0; } -#endif /* defined(CONFIG_LTT) && defined(CONFIG_LTT_ALIGNMENT) */ +#endif /* HAVE_EFFICIENT_UNALIGNED_ACCESS */ /* ARRAYS */ -- 1.7.1 _______________________________________________ ltt-dev mailing list [email protected] http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
