From c265784de7adff9e07934b712204556fb0b3ba43 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Fri, 23 Aug 2019 15:45:54 -0300 Subject: [PATCH] perf augmented_raw_syscalls: Introduce helper to get the scratch space We need more than the BPF stack can give us to format the raw_syscalls:sys_enter augmented tracepoint, so we use a PERCPU_ARRAY map for that, use a helper to shorten the sequence to access that area. Signed-off-by: Arnaldo Carvalho de Melo --- .../examples/bpf/augmented_raw_syscalls.c | 32 +++++++++---------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c index 0a8d217d65c7..8fd5ea059903 100644 --- a/tools/perf/examples/bpf/augmented_raw_syscalls.c +++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c @@ -78,8 +78,15 @@ struct augmented_args_payload { }; }; +// We need more tmp space than the BPF stack can give us bpf_map(augmented_args_tmp, PERCPU_ARRAY, int, struct augmented_args_payload, 1); +static inline struct augmented_args_payload *augmented_args_payload(void) +{ + int key = 0; + return bpf_map_lookup_elem(&augmented_args_tmp, &key); +} + static inline unsigned int augmented_arg__read_str(struct augmented_arg *augmented_arg, const void *arg, unsigned int arg_len) { @@ -122,8 +129,7 @@ int syscall_unaugmented(struct syscall_enter_args *args) SEC("!syscalls:sys_enter_connect") int sys_enter_connect(struct syscall_enter_args *args) { - int key = 0; - struct augmented_args_payload *augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key); + struct augmented_args_payload *augmented_args = augmented_args_payload(); const void *sockaddr_arg = (const void *)args->args[1]; unsigned int socklen = args->args[2]; unsigned int len = sizeof(augmented_args->args); @@ -143,8 +149,7 @@ int sys_enter_connect(struct syscall_enter_args *args) SEC("!syscalls:sys_enter_sendto") int sys_enter_sendto(struct syscall_enter_args *args) { - int key = 0; - struct augmented_args_payload *augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key); + struct augmented_args_payload *augmented_args = augmented_args_payload(); const void *sockaddr_arg = (const void *)args->args[4]; unsigned int socklen = args->args[5]; unsigned int len = sizeof(augmented_args->args); @@ -164,8 +169,7 @@ int sys_enter_sendto(struct syscall_enter_args *args) SEC("!syscalls:sys_enter_open") int sys_enter_open(struct syscall_enter_args *args) { - int key = 0; - struct augmented_args_payload *augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key); + struct augmented_args_payload *augmented_args = augmented_args_payload(); const void *filename_arg = (const void *)args->args[0]; unsigned int len = sizeof(augmented_args->args); @@ -181,8 +185,7 @@ int sys_enter_open(struct syscall_enter_args *args) SEC("!syscalls:sys_enter_openat") int sys_enter_openat(struct syscall_enter_args *args) { - int key = 0; - struct augmented_args_payload *augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key); + struct augmented_args_payload *augmented_args = augmented_args_payload(); const void *filename_arg = (const void *)args->args[1]; unsigned int len = sizeof(augmented_args->args); @@ -198,8 +201,7 @@ int sys_enter_openat(struct syscall_enter_args *args) SEC("!syscalls:sys_enter_rename") int sys_enter_rename(struct syscall_enter_args *args) { - int key = 0; - struct augmented_args_payload *augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key); + struct augmented_args_payload *augmented_args = augmented_args_payload(); const void *oldpath_arg = (const void *)args->args[0], *newpath_arg = (const void *)args->args[1]; unsigned int len = sizeof(augmented_args->args), oldpath_len; @@ -217,8 +219,7 @@ int sys_enter_rename(struct syscall_enter_args *args) SEC("!syscalls:sys_enter_renameat") int sys_enter_renameat(struct syscall_enter_args *args) { - int key = 0; - struct augmented_args_payload *augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key); + struct augmented_args_payload *augmented_args = augmented_args_payload(); const void *oldpath_arg = (const void *)args->args[1], *newpath_arg = (const void *)args->args[3]; unsigned int len = sizeof(augmented_args->args), oldpath_len; @@ -248,14 +249,13 @@ int sys_enter(struct syscall_enter_args *args) */ unsigned int len = sizeof(augmented_args->args); struct syscall *syscall; - int key = 0; if (pid_filter__has(&pids_filtered, getpid())) return 0; - augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key); - if (augmented_args == NULL) - return 1; + augmented_args = augmented_args_payload(); + if (augmented_args == NULL) + return 1; probe_read(&augmented_args->args, sizeof(augmented_args->args), args);