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Commit f58ba100 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

tracing/syscalls: support for syscalls tracing on x86 



Extend x86 architecture syscall tracing support with syscall
metadata table details.

(The upcoming core syscall tracing modifications rely on this.)

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236955332-10133-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1b3fa2ce

arch/x86/include/asm/ftrace.h

+7 −0
Original line number Diff line number Diff line
@@ -28,6 +28,13 @@ 


#endif



/* FIXME: I don't want to stay hardcoded */

#ifdef CONFIG_X86_64

# define FTRACE_SYSCALL_MAX     296

#else

# define FTRACE_SYSCALL_MAX     333

#endif



#ifdef CONFIG_FUNCTION_TRACER

#define MCOUNT_ADDR		((long)(mcount))

#define MCOUNT_INSN_SIZE	5 /* sizeof mcount call */

arch/x86/kernel/ftrace.c

+63 −0
Original line number Diff line number Diff line
@@ -453,3 +453,66 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) 
	}

}

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */



#ifdef CONFIG_FTRACE_SYSCALLS



extern unsigned long __start_syscalls_metadata[];

extern unsigned long __stop_syscalls_metadata[];

extern unsigned long *sys_call_table;



static struct syscall_metadata **syscalls_metadata;



static struct syscall_metadata *find_syscall_meta(unsigned long *syscall)

{

	struct syscall_metadata *start;

	struct syscall_metadata *stop;

	char str[KSYM_SYMBOL_LEN];





	start = (struct syscall_metadata *)__start_syscalls_metadata;

	stop = (struct syscall_metadata *)__stop_syscalls_metadata;

	kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str);



	for ( ; start < stop; start++) {

		if (start->name && !strcmp(start->name, str))

			return start;

	}

	return NULL;

}



struct syscall_metadata *syscall_nr_to_meta(int nr)

{

	if (!syscalls_metadata || nr >= FTRACE_SYSCALL_MAX || nr < 0)

		return NULL;



	return syscalls_metadata[nr];

}



void arch_init_ftrace_syscalls(void)

{

	int i;

	struct syscall_metadata *meta;

	unsigned long **psys_syscall_table = &sys_call_table;

	static atomic_t refs;



	if (atomic_inc_return(&refs) != 1)

		goto end;



	syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *

					FTRACE_SYSCALL_MAX, GFP_KERNEL);

	if (!syscalls_metadata) {

		WARN_ON(1);

		return;

	}



	for (i = 0; i < FTRACE_SYSCALL_MAX; i++) {

		meta = find_syscall_meta(psys_syscall_table[i]);

		syscalls_metadata[i] = meta;

	}

	return;



	/* Paranoid: avoid overflow */

end:

	atomic_dec(&refs);

}

#endif