Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit c530e2f0 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
Browse files

powerpc/kprobes: Remove jprobe powerpc implementation 



Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/powerpc. This also reverts commits
related __is_active_jprobe() function.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arch@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/lkml/152942445234.15209.12868722778364739753.stgit@devbox


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2efb75cd

arch/powerpc/include/asm/kprobes.h

+0 −2
Original line number Diff line number Diff line
@@ -88,7 +88,6 @@ struct prev_kprobe { 
struct kprobe_ctlblk {

	unsigned long kprobe_status;

	unsigned long kprobe_saved_msr;

	struct pt_regs jprobe_saved_regs;

	struct prev_kprobe prev_kprobe;

};
@@ -104,7 +103,6 @@ extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr); 
extern int kprobe_handler(struct pt_regs *regs);

extern int kprobe_post_handler(struct pt_regs *regs);

#ifdef CONFIG_KPROBES_ON_FTRACE

extern int __is_active_jprobe(unsigned long addr);

extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,

			   struct kprobe_ctlblk *kcb);

#else

arch/powerpc/kernel/kprobes-ftrace.c

+0 −15
Original line number Diff line number Diff line
@@ -25,21 +25,6 @@ 
#include <linux/preempt.h>

#include <linux/ftrace.h>



/*

 * This is called from ftrace code after invoking registered handlers to

 * disambiguate regs->nip changes done by jprobes and livepatch. We check if

 * there is an active jprobe at the provided address (mcount location).

 */

int __is_active_jprobe(unsigned long addr)

{

	if (!preemptible()) {

		struct kprobe *p = raw_cpu_read(current_kprobe);

		return (p && (unsigned long)p->addr == addr) ? 1 : 0;

	}



	return 0;

}



static nokprobe_inline

int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,

		      struct kprobe_ctlblk *kcb, unsigned long orig_nip)

arch/powerpc/kernel/kprobes.c

+0 −54
Original line number Diff line number Diff line
@@ -611,60 +611,6 @@ unsigned long arch_deref_entry_point(void *entry) 
}

NOKPROBE_SYMBOL(arch_deref_entry_point);



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

{

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

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));



	/* setup return addr to the jprobe handler routine */

	regs->nip = arch_deref_entry_point(jp->entry);

#ifdef PPC64_ELF_ABI_v2

	regs->gpr[12] = (unsigned long)jp->entry;

#elif defined(PPC64_ELF_ABI_v1)

	regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);

#endif



	/*

	 * jprobes use jprobe_return() which skips the normal return

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

	 * function graph tracer.

	 *

	 * Pause function graph tracing while performing the jprobe function.

	 */

	pause_graph_tracing();



	return 1;

}

NOKPROBE_SYMBOL(setjmp_pre_handler);



void __used jprobe_return(void)

{

	asm volatile("jprobe_return_trap:\n"

		     "trap\n"

		     ::: "memory");

}

NOKPROBE_SYMBOL(jprobe_return);



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

{

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	if (regs->nip != ppc_kallsyms_lookup_name("jprobe_return_trap")) {

		pr_debug("longjmp_break_handler NIP (0x%lx) does not match jprobe_return_trap (0x%lx)\n",

				regs->nip, ppc_kallsyms_lookup_name("jprobe_return_trap"));

		return 0;

	}



	memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));

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

	unpause_graph_tracing();

	preempt_enable_no_resched();

	return 1;

}

NOKPROBE_SYMBOL(longjmp_break_handler);



static struct kprobe trampoline_p = {

	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,

	.pre_handler = trampoline_probe_handler

arch/powerpc/kernel/trace/ftrace_64_mprofile.S

+5 −34
Original line number Diff line number Diff line
@@ -104,39 +104,13 @@ ftrace_regs_call: 
	bl	ftrace_stub

	nop



	/* Load the possibly modified NIP */

	ld	r15, _NIP(r1)



	/* Load ctr with the possibly modified NIP */

	ld	r3, _NIP(r1)

	mtctr	r3

#ifdef CONFIG_LIVEPATCH

	cmpd	r14, r15	/* has NIP been altered? */

#endif



#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_KPROBES_ON_FTRACE)

	/* NIP has not been altered, skip over further checks */

	beq	1f



	/* Check if there is an active jprobe on us */

	subi	r3, r14, 4

	bl	__is_active_jprobe

	nop



	/*

	 * If r3 == 1, then this is a kprobe/jprobe.

	 * else, this is livepatched function.

	 *

	 * The conditional branch for livepatch_handler below will use the

	 * result of this comparison. For kprobe/jprobe, we just need to branch to

	 * the new NIP, not call livepatch_handler. The branch below is bne, so we

	 * want CR0[EQ] to be true if this is a kprobe/jprobe. Which means we want

	 * CR0[EQ] = (r3 == 1).

	 */

	cmpdi	r3, 1

1:

	cmpd	r14, r3		/* has NIP been altered? */

#endif



	/* Load CTR with the possibly modified NIP */

	mtctr	r15



	/* Restore gprs */

	REST_GPR(0,r1)

	REST_10GPRS(2,r1)
@@ -154,10 +128,7 @@ ftrace_regs_call: 
	addi r1, r1, SWITCH_FRAME_SIZE



#ifdef CONFIG_LIVEPATCH

        /*

	 * Based on the cmpd or cmpdi above, if the NIP was altered and we're

	 * not on a kprobe/jprobe, then handle livepatch.

	 */

        /* Based on the cmpd above, if the NIP was altered handle livepatch */

	bne-	livepatch_handler

#endif