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Commit 80006dbe authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
Browse files

kprobes/x86: Remove jprobe implementation 



Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/x86.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/lkml/152942433578.15209.14034551799624757792.stgit@devbox


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5a6cf77f

arch/x86/include/asm/kprobes.h

+0 −3
Original line number Original line Diff line number Diff line
@@ -111,9 +111,6 @@ struct kprobe_ctlblk { 
	unsigned long kprobe_status;

	unsigned long kprobe_status;

	unsigned long kprobe_old_flags;

	unsigned long kprobe_old_flags;

	unsigned long kprobe_saved_flags;

	unsigned long kprobe_saved_flags;

	unsigned long *jprobe_saved_sp;

	struct pt_regs jprobe_saved_regs;

	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];

	struct prev_kprobe prev_kprobe;

	struct prev_kprobe prev_kprobe;

};

};

arch/x86/kernel/kprobes/core.c

+3 −93
Original line number Original line Diff line number Diff line
@@ -66,8 +66,6 @@ 




#include "common.h"

#include "common.h"





void jprobe_return_end(void);



DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;

DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;

DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -690,10 +688,9 @@ int kprobe_int3_handler(struct pt_regs *regs) 
			/*

			/*

			 * If we have no pre-handler or it returned 0, we

			 * If we have no pre-handler or it returned 0, we

			 * continue with normal processing.  If we have a

			 * continue with normal processing.  If we have a

			 * pre-handler and it returned non-zero, it prepped

			 * pre-handler and it returned non-zero, that means

			 * for calling the break_handler below on re-entry

			 * user handler setup registers to exit to another

			 * for jprobe processing, so get out doing nothing

			 * instruction, we must skip the single stepping.

			 * more here.

			 */

			 */

			if (!p->pre_handler || !p->pre_handler(p, regs))

			if (!p->pre_handler || !p->pre_handler(p, regs))

				setup_singlestep(p, regs, kcb, 0);

				setup_singlestep(p, regs, kcb, 0);
@@ -1083,93 +1080,6 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, 
}

}

NOKPROBE_SYMBOL(kprobe_exceptions_notify);

NOKPROBE_SYMBOL(kprobe_exceptions_notify);





int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)

{

	struct jprobe *jp = container_of(p, struct jprobe, kp);

	unsigned long addr;

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	kcb->jprobe_saved_regs = *regs;

	kcb->jprobe_saved_sp = stack_addr(regs);

	addr = (unsigned long)(kcb->jprobe_saved_sp);



	/*

	 * As Linus pointed out, gcc assumes that the callee

	 * owns the argument space and could overwrite it, e.g.

	 * tailcall optimization. So, to be absolutely safe

	 * we also save and restore enough stack bytes to cover

	 * the argument area.

	 * Use __memcpy() to avoid KASAN stack out-of-bounds reports as we copy

	 * raw stack chunk with redzones:

	 */

	__memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, MIN_STACK_SIZE(addr));

	regs->ip = (unsigned long)(jp->entry);



	/*

	 * jprobes use jprobe_return() which skips the normal return

	 * path of the function, and this messes up the accounting of the

	 * function graph tracer to get messed up.

	 *

	 * Pause function graph tracing while performing the jprobe function.

	 */

	pause_graph_tracing();

	return 1;

}

NOKPROBE_SYMBOL(setjmp_pre_handler);



void jprobe_return(void)

{

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	/* Unpoison stack redzones in the frames we are going to jump over. */

	kasan_unpoison_stack_above_sp_to(kcb->jprobe_saved_sp);



	asm volatile (

#ifdef CONFIG_X86_64

			"       xchg   %%rbx,%%rsp	\n"

#else

			"       xchgl   %%ebx,%%esp	\n"

#endif

			"       int3			\n"

			"       .globl jprobe_return_end\n"

			"       jprobe_return_end:	\n"

			"       nop			\n"::"b"

			(kcb->jprobe_saved_sp):"memory");

}

NOKPROBE_SYMBOL(jprobe_return);

NOKPROBE_SYMBOL(jprobe_return_end);



int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)

{

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

	u8 *addr = (u8 *) (regs->ip - 1);

	struct jprobe *jp = container_of(p, struct jprobe, kp);

	void *saved_sp = kcb->jprobe_saved_sp;



	if ((addr > (u8 *) jprobe_return) &&

	    (addr < (u8 *) jprobe_return_end)) {

		if (stack_addr(regs) != saved_sp) {

			struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;

			printk(KERN_ERR

			       "current sp %p does not match saved sp %p\n",

			       stack_addr(regs), saved_sp);

			printk(KERN_ERR "Saved registers for jprobe %p\n", jp);

			show_regs(saved_regs);

			printk(KERN_ERR "Current registers\n");

			show_regs(regs);

			BUG();

		}

		/* It's OK to start function graph tracing again */

		unpause_graph_tracing();

		*regs = kcb->jprobe_saved_regs;

		__memcpy(saved_sp, kcb->jprobes_stack, MIN_STACK_SIZE(saved_sp));

		preempt_enable_no_resched();

		return 1;

	}

	return 0;

}

NOKPROBE_SYMBOL(longjmp_break_handler);



bool arch_within_kprobe_blacklist(unsigned long addr)

bool arch_within_kprobe_blacklist(unsigned long addr)

{

{

	bool is_in_entry_trampoline_section = false;

	bool is_in_entry_trampoline_section = false;