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![Sebastian Andrzej Siewior](/assets/img/avatar_default.png)
The state of the interrupts (irqflags) and the preemption counter are both passed down to tracing_generic_entry_update(). Only one bit of irqflags is actually required: The on/off state. The complete 32bit of the preemption counter isn't needed. Just whether of the upper bits (softirq, hardirq and NMI) are set and the preemption depth is needed. The irqflags and the preemption counter could be evaluated early and the information stored in an integer `trace_ctx'. tracing_generic_entry_update() would use the upper bits as the TRACE_FLAG_* and the lower 8bit as the disabled-preemption depth (considering that one must be substracted from the counter in one special cases). The actual preemption value is not used except for the tracing record. The `irqflags' variable is mostly used only for the tracing record. An exception here is for instance wakeup_tracer_call() or probe_wakeup_sched_switch() which explicilty disable interrupts and use that `irqflags' to save (and restore) the IRQ state and to record the state. Struct trace_event_buffer has also the `pc' and flags' members which can be replaced with `trace_ctx' since their actual value is not used outside of trace recording. This will reduce tracing_generic_entry_update() to simply assign values to struct trace_entry. The evaluation of the TRACE_FLAG_* bits is moved to _tracing_gen_ctx_flags() which replaces preempt_count() and local_save_flags() invocations. As an example, ftrace_syscall_enter() may invoke: - trace_buffer_lock_reserve() -> … -> tracing_generic_entry_update() - event_trigger_unlock_commit() -> ftrace_trace_stack() -> … -> tracing_generic_entry_update() -> ftrace_trace_userstack() -> … -> tracing_generic_entry_update() In this case the TRACE_FLAG_* bits were evaluated three times. By using the `trace_ctx' they are evaluated once and assigned three times. A build with all tracers enabled on x86-64 with and without the patch: text data bss dec hex filename 21970669 17084168 7639260 46694097 2c87ed1 vmlinux.old 21970293 17084168 7639260 46693721 2c87d59 vmlinux.new text shrank by 379 bytes, data remained constant. Link: https://lkml.kernel.org/r/20210125194511.3924915-2-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
825 lines
20 KiB
C
825 lines
20 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#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 <linux/xarray.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 DEFINE_XARRAY(syscalls_metadata_sparse);
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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 (IS_ENABLED(CONFIG_HAVE_SPARSE_SYSCALL_NR))
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return xa_load(&syscalls_metadata_sparse, (unsigned long)nr);
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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, _name) { \
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.type = #_type, .name = #_name, \
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.size = sizeof(_type), .align = __alignof__(_type), \
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.is_signed = is_signed_type(_type), .filter_type = FILTER_OTHER }
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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 offset = offsetof(typeof(trace), args);
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int ret = 0;
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int i;
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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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if (ret)
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break;
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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 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 trace_buffer *buffer;
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unsigned int trace_ctx;
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unsigned long args[6];
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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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trace_ctx = tracing_gen_ctx();
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buffer = tr->array_buffer.buffer;
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event = trace_buffer_lock_reserve(buffer,
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sys_data->enter_event->event.type, size, trace_ctx);
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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, args);
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memcpy(entry->args, args, sizeof(unsigned long) * sys_data->nb_args);
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event_trigger_unlock_commit(trace_file, buffer, event, entry,
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trace_ctx);
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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 trace_buffer *buffer;
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unsigned int trace_ctx;
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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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trace_ctx = tracing_gen_ctx();
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buffer = tr->array_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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trace_ctx);
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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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trace_ctx);
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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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static struct trace_event_fields __refdata syscall_enter_fields_array[] = {
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|
SYSCALL_FIELD(int, __syscall_nr),
|
|
{ .type = TRACE_FUNCTION_TYPE,
|
|
.define_fields = syscall_enter_define_fields },
|
|
{}
|
|
};
|
|
|
|
struct trace_event_functions enter_syscall_print_funcs = {
|
|
.trace = print_syscall_enter,
|
|
};
|
|
|
|
struct trace_event_functions exit_syscall_print_funcs = {
|
|
.trace = print_syscall_exit,
|
|
};
|
|
|
|
struct trace_event_class __refdata event_class_syscall_enter = {
|
|
.system = "syscalls",
|
|
.reg = syscall_enter_register,
|
|
.fields_array = syscall_enter_fields_array,
|
|
.get_fields = syscall_get_enter_fields,
|
|
.raw_init = init_syscall_trace,
|
|
};
|
|
|
|
struct trace_event_class __refdata event_class_syscall_exit = {
|
|
.system = "syscalls",
|
|
.reg = syscall_exit_register,
|
|
.fields_array = (struct trace_event_fields[]){
|
|
SYSCALL_FIELD(int, __syscall_nr),
|
|
SYSCALL_FIELD(long, ret),
|
|
{}
|
|
},
|
|
.fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
|
|
.raw_init = init_syscall_trace,
|
|
};
|
|
|
|
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;
|
|
void *ret;
|
|
|
|
if (!IS_ENABLED(CONFIG_HAVE_SPARSE_SYSCALL_NR)) {
|
|
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;
|
|
|
|
if (!IS_ENABLED(CONFIG_HAVE_SPARSE_SYSCALL_NR)) {
|
|
syscalls_metadata[i] = meta;
|
|
} else {
|
|
ret = xa_store(&syscalls_metadata_sparse, i, meta,
|
|
GFP_KERNEL);
|
|
WARN(xa_is_err(ret),
|
|
"Syscall memory allocation failed\n");
|
|
}
|
|
|
|
}
|
|
}
|
|
|
|
#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 int perf_call_bpf_enter(struct trace_event_call *call, struct pt_regs *regs,
|
|
struct syscall_metadata *sys_data,
|
|
struct syscall_trace_enter *rec)
|
|
{
|
|
struct syscall_tp_t {
|
|
unsigned long long regs;
|
|
unsigned long syscall_nr;
|
|
unsigned long args[SYSCALL_DEFINE_MAXARGS];
|
|
} param;
|
|
int i;
|
|
|
|
*(struct pt_regs **)¶m = regs;
|
|
param.syscall_nr = rec->nr;
|
|
for (i = 0; i < sys_data->nb_args; i++)
|
|
param.args[i] = rec->args[i];
|
|
return trace_call_bpf(call, ¶m);
|
|
}
|
|
|
|
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;
|
|
unsigned long args[6];
|
|
bool valid_prog_array;
|
|
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);
|
|
valid_prog_array = bpf_prog_array_valid(sys_data->enter_event);
|
|
if (!valid_prog_array && 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, args);
|
|
memcpy(&rec->args, args, sizeof(unsigned long) * sys_data->nb_args);
|
|
|
|
if ((valid_prog_array &&
|
|
!perf_call_bpf_enter(sys_data->enter_event, regs, sys_data, rec)) ||
|
|
hlist_empty(head)) {
|
|
perf_swevent_put_recursion_context(rctx);
|
|
return;
|
|
}
|
|
|
|
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 int perf_call_bpf_exit(struct trace_event_call *call, struct pt_regs *regs,
|
|
struct syscall_trace_exit *rec)
|
|
{
|
|
struct syscall_tp_t {
|
|
unsigned long long regs;
|
|
unsigned long syscall_nr;
|
|
unsigned long ret;
|
|
} param;
|
|
|
|
*(struct pt_regs **)¶m = regs;
|
|
param.syscall_nr = rec->nr;
|
|
param.ret = rec->ret;
|
|
return trace_call_bpf(call, ¶m);
|
|
}
|
|
|
|
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;
|
|
bool valid_prog_array;
|
|
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);
|
|
valid_prog_array = bpf_prog_array_valid(sys_data->exit_event);
|
|
if (!valid_prog_array && 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);
|
|
|
|
if ((valid_prog_array &&
|
|
!perf_call_bpf_exit(sys_data->exit_event, regs, rec)) ||
|
|
hlist_empty(head)) {
|
|
perf_swevent_put_recursion_context(rctx);
|
|
return;
|
|
}
|
|
|
|
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;
|
|
}
|