diff options
author | Masami Hiramatsu <mhiramat@kernel.org> | 2018-04-25 21:18:03 +0900 |
---|---|---|
committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-10-10 22:19:07 -0400 |
commit | 533059281ee594f9fbb9e58042aaec77083ef251 (patch) | |
tree | 92019727bc72f3253f5e9de7152ced000cc4f27b /kernel/trace/trace_probe_tmpl.h | |
parent | 7bfbc63eda08b8158c040d6882c807f62b0750bb (diff) | |
download | linux-533059281ee594f9fbb9e58042aaec77083ef251.tar.bz2 |
tracing: probeevent: Introduce new argument fetching code
Replace {k,u}probe event argument fetching framework with switch-case based.
Currently that is implemented with structures, macros and chain of
function-pointers, which is more complicated than necessary and may get a
performance penalty by retpoline.
This simplify that with an array of "fetch_insn" (opcode and oprands), and
make process_fetch_insn() just interprets it. No function pointers are used.
Link: http://lkml.kernel.org/r/152465868340.26224.2551120475197839464.stgit@devbox
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_probe_tmpl.h')
-rw-r--r-- | kernel/trace/trace_probe_tmpl.h | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h new file mode 100644 index 000000000000..c8a5272abf01 --- /dev/null +++ b/kernel/trace/trace_probe_tmpl.h @@ -0,0 +1,120 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Traceprobe fetch helper inlines + */ + +static nokprobe_inline void +fetch_store_raw(unsigned long val, struct fetch_insn *code, void *buf) +{ + switch (code->size) { + case 1: + *(u8 *)buf = (u8)val; + break; + case 2: + *(u16 *)buf = (u16)val; + break; + case 4: + *(u32 *)buf = (u32)val; + break; + case 8: + //TBD: 32bit signed + *(u64 *)buf = (u64)val; + break; + default: + *(unsigned long *)buf = val; + } +} + +static nokprobe_inline void +fetch_apply_bitfield(struct fetch_insn *code, void *buf) +{ + switch (code->basesize) { + case 1: + *(u8 *)buf <<= code->lshift; + *(u8 *)buf >>= code->rshift; + break; + case 2: + *(u16 *)buf <<= code->lshift; + *(u16 *)buf >>= code->rshift; + break; + case 4: + *(u32 *)buf <<= code->lshift; + *(u32 *)buf >>= code->rshift; + break; + case 8: + *(u64 *)buf <<= code->lshift; + *(u64 *)buf >>= code->rshift; + break; + } +} + +/* Define this for each callsite */ +static int +process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, + void *dest, bool pre); + +/* Sum up total data length for dynamic arraies (strings) */ +static nokprobe_inline int +__get_data_size(struct trace_probe *tp, struct pt_regs *regs) +{ + struct probe_arg *arg; + int i, ret = 0; + u32 len; + + for (i = 0; i < tp->nr_args; i++) { + arg = tp->args + i; + if (unlikely(arg->dynamic)) { + process_fetch_insn(arg->code, regs, &len, true); + ret += len; + } + } + + return ret; +} + +/* Store the value of each argument */ +static nokprobe_inline void +store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs, + u8 *data, int maxlen) +{ + struct probe_arg *arg; + u32 end = tp->size; + u32 *dl; /* Data (relative) location */ + int i; + + for (i = 0; i < tp->nr_args; i++) { + arg = tp->args + i; + if (unlikely(arg->dynamic)) { + /* + * First, we set the relative location and + * maximum data length to *dl + */ + dl = (u32 *)(data + arg->offset); + *dl = make_data_rloc(maxlen, end - arg->offset); + /* Then try to fetch string or dynamic array data */ + process_fetch_insn(arg->code, regs, dl, false); + /* Reduce maximum length */ + end += get_rloc_len(*dl); + maxlen -= get_rloc_len(*dl); + /* Trick here, convert data_rloc to data_loc */ + *dl = convert_rloc_to_loc(*dl, ent_size + arg->offset); + } else + /* Just fetching data normally */ + process_fetch_insn(arg->code, regs, data + arg->offset, + false); + } +} + +static inline int +print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args, + u8 *data, void *field) +{ + int i; + + for (i = 0; i < nr_args; i++) { + trace_seq_printf(s, " %s=", args[i].name); + if (!args[i].type->print(s, data + args[i].offset, field)) + return -ENOMEM; + } + return 0; +} |