While running perf test for bpf, observed that "BPF prologue generation" test case fails to compile with clang. Logs below from powerpc:
<stdin>:33:2: error: use of undeclared identifier 'fmode_t' fmode_t f_mode = (fmode_t)_f_mode; ^ <stdin>:37:6: error: use of undeclared identifier 'f_mode'; did you mean '_f_mode'? if (f_mode & FMODE_WRITE) ^~~~~~ _f_mode <stdin>:30:60: note: '_f_mode' declared here int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode, ^ 2 errors generated. The test code tests/bpf-script-test-prologue.c uses fmode_t. And the error above is for "fmode_t" which is defined in include/linux/types.h as part of kernel build directory: "/lib/modules/<kernel_version>/build" that comes from kernel devel [ soft link to /usr/src/<kernel_version> ]. Clang picks this header file from "-working-directory" build option that specifies this build folder. But the 'commit 14e4b9f4289a ("perf trace: Raw augmented syscalls fix libbpf 1.0+ compatibility")', changed the include directory to use: "/usr/include". Post this change, types.h from /usr/include/ is getting picked upwhich doesn’t contain definition of "fmode_t" and hence fails to compile. Compilation command before this commit: /usr/bin/clang -D__KERNEL__ -D__NR_CPUS__=72 -DLINUX_VERSION_CODE=0x50e00 -xc -I/root/lib/perf/include/bpf -nostdinc -I./arch/powerpc/include -I./arch/powerpc/include/generated -I./include -I./arch/powerpc/include/uapi -I./arch/powerpc/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -Wno-unused-value -Wno-pointer-sign -working-directory /lib/modules/<ver>/build -c - -target bpf -g -O2 -o - Compilation command after this commit: /usr/bin/clang -D__KERNEL__ -D__NR_CPUS__=72 -DLINUX_VERSION_CODE=0x50e00 -xc -I/usr/include/ -nostdinc -I./arch/powerpc/include -I./arch/powerpc/include/generated -I./include -I./arch/powerpc/include/uapi -I./arch/powerpc/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -Wno-unused-value -Wno-pointer-sign -working-directory /lib/modules/<ver>/build -c - -target bpf -g -O2 -o - The difference is addition of -I/usr/include/ in the first line which is causing the error. Fix this by adding typedef for "fmode_t" in the testcase to solve the compile issue. Fixes: 14e4b9f4289a ("perf trace: Raw augmented syscalls fix libbpf 1.0+ compatibility") Signed-off-by: Athira Rajeev <atraj...@linux.vnet.ibm.com> --- tools/perf/tests/bpf-script-test-prologue.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/perf/tests/bpf-script-test-prologue.c b/tools/perf/tests/bpf-script-test-prologue.c index bd83d364cf30..91778b5c6125 100644 --- a/tools/perf/tests/bpf-script-test-prologue.c +++ b/tools/perf/tests/bpf-script-test-prologue.c @@ -20,6 +20,8 @@ # undef if #endif +typedef unsigned int __bitwise fmode_t; + #define FMODE_READ 0x1 #define FMODE_WRITE 0x2 -- 2.31.1