Commit 768ae440 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

x86/ftrace: Use text_poke() 



Move ftrace over to using the generic x86 text_poke functions; this
avoids having a second/different copy of that code around.

This also avoids ftrace violating the (new) W^X rule and avoids
fragmenting the kernel text page-tables, due to no longer having to
toggle them RW.

Tested-by: default avatarAlexei Starovoitov <ast@kernel.org>
Tested-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.761255803@infradead.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 63f62add

arch/x86/include/asm/ftrace.h

+0 −2
Original line number Diff line number Diff line
@@ -34,8 +34,6 @@ struct dyn_arch_ftrace { 
	/* No extra data needed for x86 */

};



int ftrace_int3_handler(struct pt_regs *regs);



#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR



#endif /*  CONFIG_DYNAMIC_FTRACE */

arch/x86/kernel/alternative.c

+14 −4
Original line number Diff line number Diff line
@@ -949,7 +949,7 @@ static struct bp_patching_desc { 
	int nr_entries;

} bp_patching;



static int patch_cmp(const void *key, const void *elt)

static int notrace patch_cmp(const void *key, const void *elt)

{

	struct text_poke_loc *tp = (struct text_poke_loc *) elt;
@@ -961,7 +961,7 @@ static int patch_cmp(const void *key, const void *elt) 
}

NOKPROBE_SYMBOL(patch_cmp);



int poke_int3_handler(struct pt_regs *regs)

int notrace poke_int3_handler(struct pt_regs *regs)

{

	struct text_poke_loc *tp;

	void *ip;
@@ -1209,10 +1209,15 @@ void text_poke_finish(void) 
	text_poke_flush(NULL);

}



void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate)

void __ref text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate)

{

	struct text_poke_loc *tp;



	if (unlikely(system_state == SYSTEM_BOOTING)) {

		text_poke_early(addr, opcode, len);

		return;

	}



	text_poke_flush(addr);



	tp = &tp_vec[tp_vec_nr++];
@@ -1230,10 +1235,15 @@ void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emu 
 * dynamically allocated memory. This function should be used when it is

 * not possible to allocate memory.

 */

void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate)

void __ref text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate)

{

	struct text_poke_loc tp;



	if (unlikely(system_state == SYSTEM_BOOTING)) {

		text_poke_early(addr, opcode, len);

		return;

	}



	text_poke_loc_init(&tp, addr, opcode, len, emulate);

	text_poke_bp_batch(&tp, 1);

}

arch/x86/kernel/ftrace.c

+120 −543

File changed.

Preview size limit exceeded, changes collapsed.

arch/x86/kernel/traps.c

+0 −9
Original line number Diff line number Diff line
@@ -563,15 +563,6 @@ NOKPROBE_SYMBOL(do_general_protection); 


dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)

{

#ifdef CONFIG_DYNAMIC_FTRACE

	/*

	 * ftrace must be first, everything else may cause a recursive crash.

	 * See note by declaration of modifying_ftrace_code in ftrace.c

	 */

	if (unlikely(atomic_read(&modifying_ftrace_code)) &&

	    ftrace_int3_handler(regs))

		return;

#endif

	if (poke_int3_handler(regs))

		return;

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