Remove eBPF interfaces within user_events to ensure they are fully reviewed. Link: https://lore.kernel.org/all/20220329165718.GA10381@kbox/ Signed-off-by: Beau Belgrave <beaub@xxxxxxxxxxxxxxxxxxx> --- Documentation/trace/user_events.rst | 14 ++---- include/uapi/linux/user_events.h | 53 --------------------- kernel/trace/trace_events_user.c | 73 +---------------------------- 3 files changed, 4 insertions(+), 136 deletions(-) diff --git a/Documentation/trace/user_events.rst b/Documentation/trace/user_events.rst index bddedabaca80..c180936f49fc 100644 --- a/Documentation/trace/user_events.rst +++ b/Documentation/trace/user_events.rst @@ -7,7 +7,7 @@ user_events: User-based Event Tracing Overview -------- User based trace events allow user processes to create events and trace data -that can be viewed via existing tools, such as ftrace, perf and eBPF. +that can be viewed via existing tools, such as ftrace and perf. To enable this feature, build your kernel with CONFIG_USER_EVENTS=y. Programs can view status of the events via @@ -67,8 +67,7 @@ The command string format is as follows:: Supported Flags ^^^^^^^^^^^^^^^ -**BPF_ITER** - EBPF programs attached to this event will get the raw iovec -struct instead of any data copies for max performance. +None yet Field Format ^^^^^^^^^^^^ @@ -160,7 +159,7 @@ The following values are defined to aid in checking what has been attached: **EVENT_STATUS_FTRACE** - Bit set if ftrace has been attached (Bit 0). -**EVENT_STATUS_PERF** - Bit set if perf/eBPF has been attached (Bit 1). +**EVENT_STATUS_PERF** - Bit set if perf has been attached (Bit 1). Writing Data ------------ @@ -204,13 +203,6 @@ It's advised for user programs to do the following:: **NOTE:** *The write_index is not emitted out into the trace being recorded.* -EBPF ----- -EBPF programs that attach to a user-based event tracepoint are given a pointer -to a struct user_bpf_context. The bpf context contains the data type (which can -be a user or kernel buffer, or can be a pointer to the iovec) and the data -length that was emitted (minus the write_index). - Example Code ------------ See sample code in samples/user_events. diff --git a/include/uapi/linux/user_events.h b/include/uapi/linux/user_events.h index e570840571e1..736e05603463 100644 --- a/include/uapi/linux/user_events.h +++ b/include/uapi/linux/user_events.h @@ -32,9 +32,6 @@ /* Create dynamic location entry within a 32-bit value */ #define DYN_LOC(offset, size) ((size) << 16 | (offset)) -/* Use raw iterator for attached BPF program(s), no affect on ftrace/perf */ -#define FLAG_BPF_ITER (1 << 0) - /* * Describes an event registration and stores the results of the registration. * This structure is passed to the DIAG_IOCSREG ioctl, callers at a minimum @@ -63,54 +60,4 @@ struct user_reg { /* Requests to delete a user_event */ #define DIAG_IOCSDEL _IOW(DIAG_IOC_MAGIC, 1, char*) -/* Data type that was passed to the BPF program */ -enum { - /* Data resides in kernel space */ - USER_BPF_DATA_KERNEL, - - /* Data resides in user space */ - USER_BPF_DATA_USER, - - /* Data is a pointer to a user_bpf_iter structure */ - USER_BPF_DATA_ITER, -}; - -/* - * Describes an iovec iterator that BPF programs can use to access data for - * a given user_event write() / writev() call. - */ -struct user_bpf_iter { - - /* Offset of the data within the first iovec */ - __u32 iov_offset; - - /* Number of iovec structures */ - __u32 nr_segs; - - /* Pointer to iovec structures */ - const struct iovec *iov; -}; - -/* Context that BPF programs receive when attached to a user_event */ -struct user_bpf_context { - - /* Data type being passed (see union below) */ - __u32 data_type; - - /* Length of the data */ - __u32 data_len; - - /* Pointer to data, varies by data type */ - union { - /* Kernel data (data_type == USER_BPF_DATA_KERNEL) */ - void *kdata; - - /* User data (data_type == USER_BPF_DATA_USER) */ - void *udata; - - /* Direct iovec (data_type == USER_BPF_DATA_ITER) */ - struct user_bpf_iter *iter; - }; -}; - #endif /* _UAPI_LINUX_USER_EVENTS_H */ diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 8b3d241a31c2..3bc97e44253f 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -42,9 +42,6 @@ #define MAX_FIELD_ARRAY_SIZE 1024 #define MAX_FIELD_ARG_NAME 256 -#define MAX_BPF_COPY_SIZE PAGE_SIZE -#define MAX_STACK_BPF_DATA 512 - static char *register_page_data; static DEFINE_MUTEX(reg_mutex); @@ -405,19 +402,6 @@ static int user_event_parse_field(char *field, struct user_event *user, type[0] != 'u', FILTER_OTHER); } -static void user_event_parse_flags(struct user_event *user, char *flags) -{ - char *flag; - - if (flags == NULL) - return; - - while ((flag = strsep(&flags, ",")) != NULL) { - if (strcmp(flag, "BPF_ITER") == 0) - user->flags |= FLAG_BPF_ITER; - } -} - static int user_event_parse_fields(struct user_event *user, char *args) { char *field; @@ -713,64 +697,14 @@ static void user_event_ftrace(struct user_event *user, struct iov_iter *i, } #ifdef CONFIG_PERF_EVENTS -static void user_event_bpf(struct user_event *user, struct iov_iter *i) -{ - struct user_bpf_context context; - struct user_bpf_iter bpf_i; - char fast_data[MAX_STACK_BPF_DATA]; - void *temp = NULL; - - if ((user->flags & FLAG_BPF_ITER) && iter_is_iovec(i)) { - /* Raw iterator */ - context.data_type = USER_BPF_DATA_ITER; - context.data_len = i->count; - context.iter = &bpf_i; - - bpf_i.iov_offset = i->iov_offset; - bpf_i.iov = i->iov; - bpf_i.nr_segs = i->nr_segs; - } else if (i->nr_segs == 1 && iter_is_iovec(i)) { - /* Single buffer from user */ - context.data_type = USER_BPF_DATA_USER; - context.data_len = i->count; - context.udata = i->iov->iov_base + i->iov_offset; - } else { - /* Multi buffer from user */ - struct iov_iter copy = *i; - size_t copy_size = min_t(size_t, i->count, MAX_BPF_COPY_SIZE); - - context.data_type = USER_BPF_DATA_KERNEL; - context.kdata = fast_data; - - if (unlikely(copy_size > sizeof(fast_data))) { - temp = kmalloc(copy_size, GFP_NOWAIT); - - if (temp) - context.kdata = temp; - else - copy_size = sizeof(fast_data); - } - - context.data_len = copy_nofault(context.kdata, - copy_size, ©); - } - - trace_call_bpf(&user->call, &context); - - kfree(temp); -} - /* - * Writes the user supplied payload out to perf ring buffer or eBPF program. + * Writes the user supplied payload out to perf ring buffer. */ static void user_event_perf(struct user_event *user, struct iov_iter *i, void *tpdata, bool *faulted) { struct hlist_head *perf_head; - if (bpf_prog_array_valid(&user->call)) - user_event_bpf(user, i); - perf_head = this_cpu_ptr(user->call.perf_events); if (perf_head && !hlist_empty(perf_head)) { @@ -1136,8 +1070,6 @@ static int user_event_parse(char *name, char *args, char *flags, user->tracepoint.name = name; - user_event_parse_flags(user, flags); - ret = user_event_parse_fields(user, args); if (ret) @@ -1575,9 +1507,6 @@ static int user_seq_show(struct seq_file *m, void *p) busy++; } - if (flags & FLAG_BPF_ITER) - seq_puts(m, " FLAG:BPF_ITER"); - seq_puts(m, "\n"); active++; } base-commit: 5efabdadcf4a5b9a37847ecc85ba71cf2eff0fcf -- 2.25.1
