kernel/git/stable/linux.git/tools/perf/tests/bpf-script-test-prologue.c, branch master

perf parse-events: Remove BPF event support

2023-08-15T19:41:48+00:00

New features like the BPF --filter support in perf record have made the BPF event functionality somewhat redundant. As shown by commit fcb027c1a4f6 ("perf tools: Revert enable indices setting syntax for BPF map") and commit 14e4b9f4289a ("perf trace: Raw augmented syscalls fix libbpf 1.0+ compatibility") the BPF event support hasn't been well maintained and it adds considerable complexity in areas like event parsing, not least as '/' is a separator for event modifiers as well as in paths. This patch removes support in the event parser for BPF events and then the associated functions are removed. This leads to the removal of whole source files like bpf-loader.c. Removing support means that augmented syscalls in perf trace is broken, this will be fixed in a later commit adding support using BPF skeletons. The removal of BPF events causes an unused label warning from flex generated code, so update build to ignore it: ``` util/parse-events-flex.c:2704:1: error: label ‘find_rule’ defined but not used [-Werror=unused-label] 2704 | find_rule: /* we branch to this label when backing up */ ``` Committer notes: Extracted from a larger patch that was also removing the support for linking with libllvm and libclang, that were an alternative to using an external clang execution to compile the .c event source code into BPF bytecode. Testing it: # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c' \___ Bad event or PMU Unabled to find PMU or event on a PMU of 'home' Initial error: event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c' \___ Cannot find PMU `home'. Missing kernel support? Run 'perf list' for a list of valid events Usage: perf trace [] [] or: perf trace [] -- [] or: perf trace record [] [] or: perf trace record [] -- [] -e, --event event/syscall selector. use 'perf list' to list available events # Signed-off-by: Ian Rogers Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Andrii Nakryiko Cc: Anshuman Khandual Cc: Athira Rajeev Cc: Brendan Gregg Cc: Carsten Haitzler Cc: Eduard Zingerman Cc: Fangrui Song Cc: He Kuang Cc: Ingo Molnar Cc: James Clark Cc: Kan Liang Cc: Leo Yan Cc: Madhavan Srinivasan Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Naveen N. Rao Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Rob Herring Cc: Tiezhu Yang Cc: Tom Rix Cc: Wang Nan Cc: Wang ShaoBo Cc: Yang Jihong Cc: Yonghong Song Cc: YueHaibing Cc: bpf@vger.kernel.org Cc: llvm@lists.linux.dev Link: https://lore.kernel.org/r/20230810184853.2860737-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Arnaldo Carvalho de Melo

perf tests bpf prologue: Fix bpf-script-test-prologue test compile issue with clang

2023-01-09T14:57:47+00:00

While running 'perf test' for bpf, observed that "BPF prologue generation" test case fails to compile with clang. Logs below from powerpc: :33:2: error: use of undeclared identifier 'fmode_t' fmode_t f_mode = (fmode_t)_f_mode; ^ :37:6: error: use of undeclared identifier 'f_mode'; did you mean '_f_mode'? if (f_mode & FMODE_WRITE) ^~~~~~ _f_mode :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//build" that comes from kernel devel [ soft link to /usr/src/ ]. Clang picks this header file from "-working-directory" build option that specifies this build folder. But the commit 14e4b9f4289aed2c ("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//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//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: 14e4b9f4289aed2c ("perf trace: Raw augmented syscalls fix libbpf 1.0+ compatibility") Signed-off-by: Athira Jajeev Tested-by: Arnaldo Carvalho de Melo Cc: Andi Kleen Cc: Disha Goel Cc: Ian Rogers Cc: James Clark Cc: Jiri Olsa Cc: Kajol Jain Cc: linuxppc-dev@lists.ozlabs.org Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Nageswara R Sastry Cc: Namhyung Kim Link: https://lore.kernel.org/linux-perf-users/20230105120436.92051-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf tests: Add missing SPDX headers

2019-06-17T18:57:19+00:00

Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-p0kg493z2m8qizjbdefzip1i@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Fix endianness problem when loading parameters in prologue

2017-08-16T13:31:11+00:00

Perf's BPF prologue generator unconditionally fetches 8 bytes for function parameters, which causes problems on big endian machines. Thomas gives a detailed analysis for this problem: http://lkml.kernel.org/r/968ebda5-abe4-8830-8d69-49f62529d151@linux.vnet.ibm.com ---- 8< ---- I investigated perf test BPF for s390x and have a question regarding the 38.3 subtest (bpf-prologue test) which fails on s390x. When I turn on trace_printk in tests/bpf-script-test-prologue.c I see this output in /sys/kernel/debug/tracing/trace: [root@s8360047 perf]# cat /sys/kernel/debug/tracing/trace perf-30229 [000] d..2 170161.535791: : f_mode 2001d00000000 offset:0 orig:0 perf-30229 [000] d..2 170161.535809: : f_mode 6001f00000000 offset:0 orig:0 perf-30229 [000] d..2 170161.535815: : f_mode 6001f00000000 offset:1 orig:0 perf-30229 [000] d..2 170161.535819: : f_mode 2001d00000000 offset:1 orig:0 perf-30229 [000] d..2 170161.535822: : f_mode 2001d00000000 offset:2 orig:1 perf-30229 [000] d..2 170161.535825: : f_mode 6001f00000000 offset:2 orig:1 perf-30229 [000] d..2 170161.535828: : f_mode 6001f00000000 offset:3 orig:1 perf-30229 [000] d..2 170161.535832: : f_mode 2001d00000000 offset:3 orig:1 perf-30229 [000] d..2 170161.535835: : f_mode 2001d00000000 offset:4 orig:0 perf-30229 [000] d..2 170161.535841: : f_mode 6001f00000000 offset:4 orig:0 [...] There are 3 parameters the eBPF program tests/bpf-script-test-prologue.c accesses: f_mode (member of struct file at offset 140) offset and orig. They are parameters of the lseek() system call triggered in this test case in function llseek_loop(). What is really strange is the value of f_mode. It is an 8 byte value, whereas in the probe event it is defined as a 4 byte value. The lower 4 bytes are all zero and do not belong to member f_mode. The correct value should be 2001d for read-only and 6001f for read-write open mode. Here is the output of the 'perf test -vv bpf' trace: Try to find probe point from debuginfo. Matched function: null_lseek [2d9310d] Probe point found: null_lseek+0 Searching 'file' variable in context. Converting variable file into trace event. converting f_mode in file f_mode type is unsigned int. Opening /sys/kernel/debug/tracing//README write=0 Searching 'offset' variable in context. Converting variable offset into trace event. offset type is long long int. Searching 'orig' variable in context. Converting variable orig into trace event. orig type is int. Found 1 probe_trace_events. Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: p:perf_bpf_probe/func _text+8794224 f_mode=+140(%r2):x32 ---- 8< ---- This patch parses the type of each argument and converts data from memory to expected type. Now the test runs successfully on 4.13.0-rc5: [root@s8360046 perf]# ./perf test bpf 38: BPF filter : 38.1: Basic BPF filtering : Ok 38.2: BPF pinning : Ok 38.3: BPF prologue generation : Ok 38.4: BPF relocation checker : Ok [root@s8360046 perf]# Signed-off-by: Wang Nan Cc: Hendrik Brueckner Link: http://lkml.kernel.org/r/20170815092159.31912-1-tmricht@linux.vnet.ibm.com Signed-off-by: Thomas-Mich Richter Signed-off-by: Arnaldo Carvalho de Melo

perf test llvm: Avoid error when PROFILE_ALL_BRANCHES is set

2017-06-19T19:11:26+00:00

The 'if' keyword is a define that expands to complex code when CONFIG_PROFILE_ALL_BRANCHES is selected, which causes a 'perf test LLVM' failure like: $ ./perf test LLVM 35: LLVM search and compile : 35.1: Basic BPF llvm compile : Ok 35.2: kbuild searching : Ok 35.3: Compile source for BPF prologue generation: FAILED! 35.4: Compile source for BPF relocation : Skip The only affected test case is bpf-script-test-prologue.c because it uses kernel headers and has 'if' inside. This patch undefines 'if' to make it passes perf test. More detailed analysis from a message in this thread, also by Wang: The problem is caused by following relocation information: $ readelf -a ./llvmsubtest3 ... [ 5] _ftrace_branch PROGBITS 0000000000000000 00000260 00000000000000a0 0000000000000000 WA 0 0 4 ... Relocation section '.relfunc=null_lseek file->f_mode offset orig' at offset 0x490 contains 4 entries: Offset Info Type Sym. Value Sym. Name 000000000038 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch 0000000000b0 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch 000000000128 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch 0000000001c0 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch Relocation section '.rel_ftrace_branch' at offset 0x4d0 contains 8 entries: Offset Info Type Sym. Value Sym. Name 000000000000 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n 000000000008 000100000001 unrecognized: 1 0000000000000015 .L.str 000000000028 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n 000000000030 000100000001 unrecognized: 1 0000000000000015 .L.str 000000000050 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n 000000000058 000100000001 unrecognized: 1 0000000000000015 .L.str 000000000078 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n 000000000080 000100000001 unrecognized: 1 0000000000000015 .L.str ... So I think the failure is because you enabled CONFIG_PROFILE_ALL_BRANCHES. I can reproduce your buggy result by selecting CONFIG_PROFILE_ALL_BRANCHES in my kbuild: $ ./perf test LLVM 35: LLVM search and compile : 35.1: Basic BPF llvm compile : Ok 35.2: kbuild searching : Ok 35.3: Compile source for BPF prologue generation: FAILED! 35.4: Compile source for BPF relocation : Skip Simply undef CONFIG_PROFILE_ALL_BRANCHES in clang opts not working because it is introduced by "#include ", which override cmdline options. So I think the best way is to undefine 'if' inside BPF script. Reported-and-Tested-by: Thomas-Mich Richter Signed-off-by: Wang Nan Cc: Alexei Starovoitov Cc: Hendrik Brueckner Cc: Zefan Li Link: http://lkml.kernel.org/r/20170620183203.2517-1-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf test: Test the BPF prologue adding infrastructure

2015-11-18T20:51:04+00:00

This patch introduces a new BPF script to test the BPF prologue adding routines. The new script probes at null_lseek, which is the function pointer used when we try to lseek on '/dev/null'. The null_lseek function is chosen because it is used by function pointers, so we don't need to consider inlining and LTO. By extracting file->f_mode, bpf-script-test-prologue.c should know whether the file is writable or readonly. According to llseek_loop() and bpf-script-test-prologue.c, one fourth of total lseeks should be collected. Committer note: Testing it: # perf test -v BPF Kernel build dir is set to /lib/modules/4.3.0+/build set env: KBUILD_DIR=/lib/modules/4.3.0+/build unset env: KBUILD_OPTS include option is set to -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h set env: NR_CPUS=4 set env: LINUX_VERSION_CODE=0x40300 set env: CLANG_EXEC=/usr/libexec/icecc/bin/clang set env: CLANG_OPTIONS=-xc set env: KERNEL_INC_OPTIONS= -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h set env: WORKING_DIR=/lib/modules/4.3.0+/build set env: CLANG_SOURCE=- llvm compiling command template: echo '/* * bpf-script-test-prologue.c * Test BPF prologue */ #ifndef LINUX_VERSION_CODE # error Need LINUX_VERSION_CODE # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig' #endif #define SEC(NAME) __attribute__((section(NAME), used)) #include #define FMODE_READ 0x1 #define FMODE_WRITE 0x2 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) = (void *) 6; SEC("func=null_lseek file->f_mode offset orig") int bpf_func__null_lseek(void *ctx, int err, unsigned long f_mode, unsigned long offset, unsigned long orig) { if (err) return 0; if (f_mode & FMODE_WRITE) return 0; if (offset & 1) return 0; if (orig == SEEK_CUR) return 0; return 1; } char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; ' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o - libbpf: loading object '[bpf_prologue_test]' from buffer libbpf: section .strtab, size 135, link 0, flags 0, type=3 libbpf: section .text, size 0, link 0, flags 6, type=1 libbpf: section .data, size 0, link 0, flags 3, type=1 libbpf: section .bss, size 0, link 0, flags 3, type=8 libbpf: section func=null_lseek file->f_mode offset orig, size 112, link 0, flags 6, type=1 libbpf: found program func=null_lseek file->f_mode offset orig libbpf: section license, size 4, link 0, flags 3, type=1 libbpf: license of [bpf_prologue_test] is GPL libbpf: section version, size 4, link 0, flags 3, type=1 libbpf: kernel version of [bpf_prologue_test] is 40300 libbpf: section .symtab, size 168, link 1, flags 0, type=2 bpf: config program 'func=null_lseek file->f_mode offset orig' symbol:null_lseek file:(null) line:0 offset:0 return:0 lazy:(null) parsing arg: file->f_mode into file, f_mode(1) parsing arg: offset into offset parsing arg: orig into orig bpf: config 'func=null_lseek file->f_mode offset orig' is ok Looking at the vmlinux_path (7 entries long) Using /lib/modules/4.3.0+/build/vmlinux for symbols Open Debuginfo file: /lib/modules/4.3.0+/build/vmlinux Try to find probe point from debuginfo. Matched function: null_lseek Probe point found: null_lseek+0 Searching 'file' variable in context. Converting variable file into trace event. converting f_mode in file f_mode type is unsigned int. Searching 'offset' variable in context. Converting variable offset into trace event. offset type is long long int. Searching 'orig' variable in context. Converting variable orig into trace event. orig type is int. Found 1 probe_trace_events. Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: p:perf_bpf_probe/func _text+4840528 f_mode=+68(%di):u32 offset=%si:s64 orig=%dx:s32 libbpf: don't need create maps for [bpf_prologue_test] prologue: pass validation prologue: slow path prologue: fetch arg 0, base reg is %di prologue: arg 0: offset 68 prologue: fetch arg 1, base reg is %si prologue: fetch arg 2, base reg is %dx add bpf event perf_bpf_probe:func and attach bpf program 3 adding perf_bpf_probe:func adding perf_bpf_probe:func to 0x51672c0 mmap size 1052672B Opening /sys/kernel/debug/tracing//kprobe_events write=1 Opening /sys/kernel/debug/tracing//uprobe_events write=1 Parsing probe_events: p:perf_bpf_probe/func _text+4840528 f_mode=+68(%di):u32 offset=%si:s64 orig=%dx:s32 Group:perf_bpf_probe Event:func probe:p Writing event: -:perf_bpf_probe/func test child finished with 0 ---- end ---- Test BPF filter: Ok # Signed-off-by: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Masami Hiramatsu Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-13-git-send-email-wangnan0@huawei.com [ Added tools/perf/tests/llvm-src-prologue.c to .gitignore ] Signed-off-by: Arnaldo Carvalho de Melo