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![Colin Ian King](/assets/img/avatar_default.png)
pr_info message spans two lines and the literal string is missing a white space between words. Add the white space. Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
763 lines
19 KiB
C
763 lines
19 KiB
C
#include <trace/syscall.h>
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#include <trace/events/syscalls.h>
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#include <linux/syscalls.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/module.h> /* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
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#include <linux/ftrace.h>
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#include <linux/perf_event.h>
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#include <asm/syscall.h>
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#include "trace_output.h"
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#include "trace.h"
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static DEFINE_MUTEX(syscall_trace_lock);
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static int syscall_enter_register(struct trace_event_call *event,
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enum trace_reg type, void *data);
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static int syscall_exit_register(struct trace_event_call *event,
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enum trace_reg type, void *data);
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static struct list_head *
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syscall_get_enter_fields(struct trace_event_call *call)
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{
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struct syscall_metadata *entry = call->data;
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return &entry->enter_fields;
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}
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extern struct syscall_metadata *__start_syscalls_metadata[];
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extern struct syscall_metadata *__stop_syscalls_metadata[];
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static struct syscall_metadata **syscalls_metadata;
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#ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
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static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
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{
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/*
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* Only compare after the "sys" prefix. Archs that use
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* syscall wrappers may have syscalls symbols aliases prefixed
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* with ".SyS" or ".sys" instead of "sys", leading to an unwanted
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* mismatch.
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*/
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return !strcmp(sym + 3, name + 3);
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}
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#endif
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#ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
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/*
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* Some architectures that allow for 32bit applications
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* to run on a 64bit kernel, do not map the syscalls for
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* the 32bit tasks the same as they do for 64bit tasks.
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*
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* *cough*x86*cough*
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*
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* In such a case, instead of reporting the wrong syscalls,
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* simply ignore them.
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*
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* For an arch to ignore the compat syscalls it needs to
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* define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS as well as
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* define the function arch_trace_is_compat_syscall() to let
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* the tracing system know that it should ignore it.
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*/
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static int
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trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
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{
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if (unlikely(arch_trace_is_compat_syscall(regs)))
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return -1;
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return syscall_get_nr(task, regs);
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}
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#else
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static inline int
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trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
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{
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return syscall_get_nr(task, regs);
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}
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#endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */
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static __init struct syscall_metadata *
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find_syscall_meta(unsigned long syscall)
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{
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struct syscall_metadata **start;
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struct syscall_metadata **stop;
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char str[KSYM_SYMBOL_LEN];
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start = __start_syscalls_metadata;
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stop = __stop_syscalls_metadata;
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kallsyms_lookup(syscall, NULL, NULL, NULL, str);
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if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
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return NULL;
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for ( ; start < stop; start++) {
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if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
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return *start;
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}
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return NULL;
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}
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static struct syscall_metadata *syscall_nr_to_meta(int nr)
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{
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if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
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return NULL;
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return syscalls_metadata[nr];
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}
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const char *get_syscall_name(int syscall)
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{
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struct syscall_metadata *entry;
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entry = syscall_nr_to_meta(syscall);
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if (!entry)
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return NULL;
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return entry->name;
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}
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static enum print_line_t
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print_syscall_enter(struct trace_iterator *iter, int flags,
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struct trace_event *event)
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{
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struct trace_array *tr = iter->tr;
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struct trace_seq *s = &iter->seq;
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struct trace_entry *ent = iter->ent;
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struct syscall_trace_enter *trace;
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struct syscall_metadata *entry;
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int i, syscall;
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trace = (typeof(trace))ent;
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syscall = trace->nr;
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entry = syscall_nr_to_meta(syscall);
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if (!entry)
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goto end;
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if (entry->enter_event->event.type != ent->type) {
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WARN_ON_ONCE(1);
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goto end;
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}
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trace_seq_printf(s, "%s(", entry->name);
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for (i = 0; i < entry->nb_args; i++) {
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if (trace_seq_has_overflowed(s))
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goto end;
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/* parameter types */
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if (tr->trace_flags & TRACE_ITER_VERBOSE)
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trace_seq_printf(s, "%s ", entry->types[i]);
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/* parameter values */
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trace_seq_printf(s, "%s: %lx%s", entry->args[i],
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trace->args[i],
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i == entry->nb_args - 1 ? "" : ", ");
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}
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trace_seq_putc(s, ')');
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end:
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trace_seq_putc(s, '\n');
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return trace_handle_return(s);
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}
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static enum print_line_t
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print_syscall_exit(struct trace_iterator *iter, int flags,
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struct trace_event *event)
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{
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struct trace_seq *s = &iter->seq;
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struct trace_entry *ent = iter->ent;
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struct syscall_trace_exit *trace;
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int syscall;
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struct syscall_metadata *entry;
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trace = (typeof(trace))ent;
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syscall = trace->nr;
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entry = syscall_nr_to_meta(syscall);
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if (!entry) {
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trace_seq_putc(s, '\n');
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goto out;
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}
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if (entry->exit_event->event.type != ent->type) {
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WARN_ON_ONCE(1);
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return TRACE_TYPE_UNHANDLED;
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}
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trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
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trace->ret);
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out:
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return trace_handle_return(s);
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}
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extern char *__bad_type_size(void);
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#define SYSCALL_FIELD(type, field, name) \
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sizeof(type) != sizeof(trace.field) ? \
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__bad_type_size() : \
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#type, #name, offsetof(typeof(trace), field), \
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sizeof(trace.field), is_signed_type(type)
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static int __init
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__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
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{
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int i;
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int pos = 0;
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/* When len=0, we just calculate the needed length */
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#define LEN_OR_ZERO (len ? len - pos : 0)
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pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
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for (i = 0; i < entry->nb_args; i++) {
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pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
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entry->args[i], sizeof(unsigned long),
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i == entry->nb_args - 1 ? "" : ", ");
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}
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pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
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for (i = 0; i < entry->nb_args; i++) {
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pos += snprintf(buf + pos, LEN_OR_ZERO,
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", ((unsigned long)(REC->%s))", entry->args[i]);
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}
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#undef LEN_OR_ZERO
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/* return the length of print_fmt */
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return pos;
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}
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static int __init set_syscall_print_fmt(struct trace_event_call *call)
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{
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char *print_fmt;
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int len;
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struct syscall_metadata *entry = call->data;
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if (entry->enter_event != call) {
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call->print_fmt = "\"0x%lx\", REC->ret";
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return 0;
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}
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/* First: called with 0 length to calculate the needed length */
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len = __set_enter_print_fmt(entry, NULL, 0);
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print_fmt = kmalloc(len + 1, GFP_KERNEL);
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if (!print_fmt)
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return -ENOMEM;
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/* Second: actually write the @print_fmt */
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__set_enter_print_fmt(entry, print_fmt, len + 1);
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call->print_fmt = print_fmt;
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return 0;
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}
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static void __init free_syscall_print_fmt(struct trace_event_call *call)
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{
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struct syscall_metadata *entry = call->data;
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if (entry->enter_event == call)
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kfree(call->print_fmt);
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}
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static int __init syscall_enter_define_fields(struct trace_event_call *call)
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{
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struct syscall_trace_enter trace;
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struct syscall_metadata *meta = call->data;
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int ret;
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int i;
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int offset = offsetof(typeof(trace), args);
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ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
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FILTER_OTHER);
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if (ret)
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return ret;
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for (i = 0; i < meta->nb_args; i++) {
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ret = trace_define_field(call, meta->types[i],
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meta->args[i], offset,
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sizeof(unsigned long), 0,
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FILTER_OTHER);
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offset += sizeof(unsigned long);
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}
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return ret;
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}
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static int __init syscall_exit_define_fields(struct trace_event_call *call)
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{
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struct syscall_trace_exit trace;
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int ret;
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ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
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FILTER_OTHER);
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if (ret)
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return ret;
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ret = trace_define_field(call, SYSCALL_FIELD(long, ret, ret),
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FILTER_OTHER);
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return ret;
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}
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static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
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{
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struct trace_array *tr = data;
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struct trace_event_file *trace_file;
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struct syscall_trace_enter *entry;
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struct syscall_metadata *sys_data;
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struct ring_buffer_event *event;
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struct ring_buffer *buffer;
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unsigned long irq_flags;
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int pc;
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int syscall_nr;
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int size;
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syscall_nr = trace_get_syscall_nr(current, regs);
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if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
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return;
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/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
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trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
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if (!trace_file)
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return;
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if (trace_trigger_soft_disabled(trace_file))
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return;
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sys_data = syscall_nr_to_meta(syscall_nr);
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if (!sys_data)
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return;
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size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
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local_save_flags(irq_flags);
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pc = preempt_count();
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buffer = tr->trace_buffer.buffer;
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event = trace_buffer_lock_reserve(buffer,
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sys_data->enter_event->event.type, size, irq_flags, pc);
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if (!event)
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return;
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entry = ring_buffer_event_data(event);
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entry->nr = syscall_nr;
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syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
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event_trigger_unlock_commit(trace_file, buffer, event, entry,
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irq_flags, pc);
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}
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static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
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{
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struct trace_array *tr = data;
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struct trace_event_file *trace_file;
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struct syscall_trace_exit *entry;
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struct syscall_metadata *sys_data;
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struct ring_buffer_event *event;
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struct ring_buffer *buffer;
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unsigned long irq_flags;
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int pc;
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int syscall_nr;
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syscall_nr = trace_get_syscall_nr(current, regs);
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if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
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return;
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/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
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trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
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if (!trace_file)
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return;
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if (trace_trigger_soft_disabled(trace_file))
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return;
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sys_data = syscall_nr_to_meta(syscall_nr);
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if (!sys_data)
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return;
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local_save_flags(irq_flags);
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pc = preempt_count();
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buffer = tr->trace_buffer.buffer;
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event = trace_buffer_lock_reserve(buffer,
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sys_data->exit_event->event.type, sizeof(*entry),
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irq_flags, pc);
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if (!event)
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return;
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entry = ring_buffer_event_data(event);
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entry->nr = syscall_nr;
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entry->ret = syscall_get_return_value(current, regs);
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event_trigger_unlock_commit(trace_file, buffer, event, entry,
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irq_flags, pc);
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}
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static int reg_event_syscall_enter(struct trace_event_file *file,
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struct trace_event_call *call)
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{
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struct trace_array *tr = file->tr;
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int ret = 0;
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int num;
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num = ((struct syscall_metadata *)call->data)->syscall_nr;
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if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
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return -ENOSYS;
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mutex_lock(&syscall_trace_lock);
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if (!tr->sys_refcount_enter)
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ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
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if (!ret) {
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rcu_assign_pointer(tr->enter_syscall_files[num], file);
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tr->sys_refcount_enter++;
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}
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mutex_unlock(&syscall_trace_lock);
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return ret;
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}
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static void unreg_event_syscall_enter(struct trace_event_file *file,
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struct trace_event_call *call)
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{
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struct trace_array *tr = file->tr;
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int num;
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num = ((struct syscall_metadata *)call->data)->syscall_nr;
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if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
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return;
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mutex_lock(&syscall_trace_lock);
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tr->sys_refcount_enter--;
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RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
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if (!tr->sys_refcount_enter)
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unregister_trace_sys_enter(ftrace_syscall_enter, tr);
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mutex_unlock(&syscall_trace_lock);
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}
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static int reg_event_syscall_exit(struct trace_event_file *file,
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struct trace_event_call *call)
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{
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struct trace_array *tr = file->tr;
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int ret = 0;
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int num;
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num = ((struct syscall_metadata *)call->data)->syscall_nr;
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if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
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return -ENOSYS;
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mutex_lock(&syscall_trace_lock);
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if (!tr->sys_refcount_exit)
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ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
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if (!ret) {
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rcu_assign_pointer(tr->exit_syscall_files[num], file);
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tr->sys_refcount_exit++;
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}
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mutex_unlock(&syscall_trace_lock);
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return ret;
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}
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static void unreg_event_syscall_exit(struct trace_event_file *file,
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struct trace_event_call *call)
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{
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struct trace_array *tr = file->tr;
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int num;
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num = ((struct syscall_metadata *)call->data)->syscall_nr;
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if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
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return;
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mutex_lock(&syscall_trace_lock);
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tr->sys_refcount_exit--;
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RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
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if (!tr->sys_refcount_exit)
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unregister_trace_sys_exit(ftrace_syscall_exit, tr);
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mutex_unlock(&syscall_trace_lock);
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}
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static int __init init_syscall_trace(struct trace_event_call *call)
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{
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int id;
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int num;
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num = ((struct syscall_metadata *)call->data)->syscall_nr;
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if (num < 0 || num >= NR_syscalls) {
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pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
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((struct syscall_metadata *)call->data)->name);
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return -ENOSYS;
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}
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if (set_syscall_print_fmt(call) < 0)
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return -ENOMEM;
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id = trace_event_raw_init(call);
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if (id < 0) {
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free_syscall_print_fmt(call);
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return id;
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}
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return id;
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}
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struct trace_event_functions enter_syscall_print_funcs = {
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.trace = print_syscall_enter,
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};
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struct trace_event_functions exit_syscall_print_funcs = {
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.trace = print_syscall_exit,
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};
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struct trace_event_class __refdata event_class_syscall_enter = {
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.system = "syscalls",
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.reg = syscall_enter_register,
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.define_fields = syscall_enter_define_fields,
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.get_fields = syscall_get_enter_fields,
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.raw_init = init_syscall_trace,
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};
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struct trace_event_class __refdata event_class_syscall_exit = {
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.system = "syscalls",
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.reg = syscall_exit_register,
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.define_fields = syscall_exit_define_fields,
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.fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
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.raw_init = init_syscall_trace,
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};
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|
|
|
unsigned long __init __weak arch_syscall_addr(int nr)
|
|
{
|
|
return (unsigned long)sys_call_table[nr];
|
|
}
|
|
|
|
void __init init_ftrace_syscalls(void)
|
|
{
|
|
struct syscall_metadata *meta;
|
|
unsigned long addr;
|
|
int i;
|
|
|
|
syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata),
|
|
GFP_KERNEL);
|
|
if (!syscalls_metadata) {
|
|
WARN_ON(1);
|
|
return;
|
|
}
|
|
|
|
for (i = 0; i < NR_syscalls; i++) {
|
|
addr = arch_syscall_addr(i);
|
|
meta = find_syscall_meta(addr);
|
|
if (!meta)
|
|
continue;
|
|
|
|
meta->syscall_nr = i;
|
|
syscalls_metadata[i] = meta;
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
|
|
static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
|
|
static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
|
|
static int sys_perf_refcount_enter;
|
|
static int sys_perf_refcount_exit;
|
|
|
|
static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
|
|
{
|
|
struct syscall_metadata *sys_data;
|
|
struct syscall_trace_enter *rec;
|
|
struct hlist_head *head;
|
|
int syscall_nr;
|
|
int rctx;
|
|
int size;
|
|
|
|
syscall_nr = trace_get_syscall_nr(current, regs);
|
|
if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
|
|
return;
|
|
if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
|
|
return;
|
|
|
|
sys_data = syscall_nr_to_meta(syscall_nr);
|
|
if (!sys_data)
|
|
return;
|
|
|
|
head = this_cpu_ptr(sys_data->enter_event->perf_events);
|
|
if (hlist_empty(head))
|
|
return;
|
|
|
|
/* get the size after alignment with the u32 buffer size field */
|
|
size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
|
|
size = ALIGN(size + sizeof(u32), sizeof(u64));
|
|
size -= sizeof(u32);
|
|
|
|
rec = perf_trace_buf_alloc(size, NULL, &rctx);
|
|
if (!rec)
|
|
return;
|
|
|
|
rec->nr = syscall_nr;
|
|
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
|
|
(unsigned long *)&rec->args);
|
|
perf_trace_buf_submit(rec, size, rctx,
|
|
sys_data->enter_event->event.type, 1, regs,
|
|
head, NULL);
|
|
}
|
|
|
|
static int perf_sysenter_enable(struct trace_event_call *call)
|
|
{
|
|
int ret = 0;
|
|
int num;
|
|
|
|
num = ((struct syscall_metadata *)call->data)->syscall_nr;
|
|
|
|
mutex_lock(&syscall_trace_lock);
|
|
if (!sys_perf_refcount_enter)
|
|
ret = register_trace_sys_enter(perf_syscall_enter, NULL);
|
|
if (ret) {
|
|
pr_info("event trace: Could not activate syscall entry trace point");
|
|
} else {
|
|
set_bit(num, enabled_perf_enter_syscalls);
|
|
sys_perf_refcount_enter++;
|
|
}
|
|
mutex_unlock(&syscall_trace_lock);
|
|
return ret;
|
|
}
|
|
|
|
static void perf_sysenter_disable(struct trace_event_call *call)
|
|
{
|
|
int num;
|
|
|
|
num = ((struct syscall_metadata *)call->data)->syscall_nr;
|
|
|
|
mutex_lock(&syscall_trace_lock);
|
|
sys_perf_refcount_enter--;
|
|
clear_bit(num, enabled_perf_enter_syscalls);
|
|
if (!sys_perf_refcount_enter)
|
|
unregister_trace_sys_enter(perf_syscall_enter, NULL);
|
|
mutex_unlock(&syscall_trace_lock);
|
|
}
|
|
|
|
static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
|
|
{
|
|
struct syscall_metadata *sys_data;
|
|
struct syscall_trace_exit *rec;
|
|
struct hlist_head *head;
|
|
int syscall_nr;
|
|
int rctx;
|
|
int size;
|
|
|
|
syscall_nr = trace_get_syscall_nr(current, regs);
|
|
if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
|
|
return;
|
|
if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
|
|
return;
|
|
|
|
sys_data = syscall_nr_to_meta(syscall_nr);
|
|
if (!sys_data)
|
|
return;
|
|
|
|
head = this_cpu_ptr(sys_data->exit_event->perf_events);
|
|
if (hlist_empty(head))
|
|
return;
|
|
|
|
/* We can probably do that at build time */
|
|
size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
|
|
size -= sizeof(u32);
|
|
|
|
rec = perf_trace_buf_alloc(size, NULL, &rctx);
|
|
if (!rec)
|
|
return;
|
|
|
|
rec->nr = syscall_nr;
|
|
rec->ret = syscall_get_return_value(current, regs);
|
|
perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
|
|
1, regs, head, NULL);
|
|
}
|
|
|
|
static int perf_sysexit_enable(struct trace_event_call *call)
|
|
{
|
|
int ret = 0;
|
|
int num;
|
|
|
|
num = ((struct syscall_metadata *)call->data)->syscall_nr;
|
|
|
|
mutex_lock(&syscall_trace_lock);
|
|
if (!sys_perf_refcount_exit)
|
|
ret = register_trace_sys_exit(perf_syscall_exit, NULL);
|
|
if (ret) {
|
|
pr_info("event trace: Could not activate syscall exit trace point");
|
|
} else {
|
|
set_bit(num, enabled_perf_exit_syscalls);
|
|
sys_perf_refcount_exit++;
|
|
}
|
|
mutex_unlock(&syscall_trace_lock);
|
|
return ret;
|
|
}
|
|
|
|
static void perf_sysexit_disable(struct trace_event_call *call)
|
|
{
|
|
int num;
|
|
|
|
num = ((struct syscall_metadata *)call->data)->syscall_nr;
|
|
|
|
mutex_lock(&syscall_trace_lock);
|
|
sys_perf_refcount_exit--;
|
|
clear_bit(num, enabled_perf_exit_syscalls);
|
|
if (!sys_perf_refcount_exit)
|
|
unregister_trace_sys_exit(perf_syscall_exit, NULL);
|
|
mutex_unlock(&syscall_trace_lock);
|
|
}
|
|
|
|
#endif /* CONFIG_PERF_EVENTS */
|
|
|
|
static int syscall_enter_register(struct trace_event_call *event,
|
|
enum trace_reg type, void *data)
|
|
{
|
|
struct trace_event_file *file = data;
|
|
|
|
switch (type) {
|
|
case TRACE_REG_REGISTER:
|
|
return reg_event_syscall_enter(file, event);
|
|
case TRACE_REG_UNREGISTER:
|
|
unreg_event_syscall_enter(file, event);
|
|
return 0;
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
case TRACE_REG_PERF_REGISTER:
|
|
return perf_sysenter_enable(event);
|
|
case TRACE_REG_PERF_UNREGISTER:
|
|
perf_sysenter_disable(event);
|
|
return 0;
|
|
case TRACE_REG_PERF_OPEN:
|
|
case TRACE_REG_PERF_CLOSE:
|
|
case TRACE_REG_PERF_ADD:
|
|
case TRACE_REG_PERF_DEL:
|
|
return 0;
|
|
#endif
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int syscall_exit_register(struct trace_event_call *event,
|
|
enum trace_reg type, void *data)
|
|
{
|
|
struct trace_event_file *file = data;
|
|
|
|
switch (type) {
|
|
case TRACE_REG_REGISTER:
|
|
return reg_event_syscall_exit(file, event);
|
|
case TRACE_REG_UNREGISTER:
|
|
unreg_event_syscall_exit(file, event);
|
|
return 0;
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
case TRACE_REG_PERF_REGISTER:
|
|
return perf_sysexit_enable(event);
|
|
case TRACE_REG_PERF_UNREGISTER:
|
|
perf_sysexit_disable(event);
|
|
return 0;
|
|
case TRACE_REG_PERF_OPEN:
|
|
case TRACE_REG_PERF_CLOSE:
|
|
case TRACE_REG_PERF_ADD:
|
|
case TRACE_REG_PERF_DEL:
|
|
return 0;
|
|
#endif
|
|
}
|
|
return 0;
|
|
}
|