Currently exec-target.c file is linked as static and this post a requirement to install libc dev package to build. Without it, build-break when compiling selftest/powerpc/benchmark.
CC exec_target /usr/bin/ld: cannot find -lc: No such file or directory collect2: error: ld returned 1 exit status
exec_target.c is using "syscall" library function which could be replaced with a inline assembly and the same is proposed as a fix here.
Suggested-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Madhavan Srinivasan maddy@linux.ibm.com --- Chnagelog v1: - Add comment for clobber register and proper list of clobber registers as suggested by Michael Ellerman and Christophe Leroy
.../selftests/powerpc/benchmarks/Makefile | 2 +- .../selftests/powerpc/benchmarks/exec_target.c | 16 ++++++++++++++-- 2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/powerpc/benchmarks/Makefile b/tools/testing/selftests/powerpc/benchmarks/Makefile index 1321922038d0..ca4483c238b9 100644 --- a/tools/testing/selftests/powerpc/benchmarks/Makefile +++ b/tools/testing/selftests/powerpc/benchmarks/Makefile @@ -18,4 +18,4 @@ $(OUTPUT)/context_switch: LDLIBS += -lpthread
$(OUTPUT)/fork: LDLIBS += -lpthread
-$(OUTPUT)/exec_target: CFLAGS += -static -nostartfiles +$(OUTPUT)/exec_target: CFLAGS += -nostartfiles diff --git a/tools/testing/selftests/powerpc/benchmarks/exec_target.c b/tools/testing/selftests/powerpc/benchmarks/exec_target.c index c14b0fc1edde..a6408d3f26cd 100644 --- a/tools/testing/selftests/powerpc/benchmarks/exec_target.c +++ b/tools/testing/selftests/powerpc/benchmarks/exec_target.c @@ -7,10 +7,22 @@ */
#define _GNU_SOURCE -#include <unistd.h> #include <sys/syscall.h>
void _start(void) { - syscall(SYS_exit, 0); + asm volatile ( + "li %%r0, %[sys_exit];" + "li %%r3, 0;" + "sc;" + : + : [sys_exit] "i" (SYS_exit) + /* + * "sc" will clobber r0, r3-r13, cr0, ctr, xer and memory. + * Even though sys_exit never returns, handle clobber + * registers. + */ + : "r0", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", + "r11", "r12", "r13", "cr0", "ctr", "xer", "memory" + ); }