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@xxxxxxxxxxxxxx>
Signed-off-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
---
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"
+ );
}
--
2.45.2
