powerpc/kprobes: Add support for KPROBES_ON_FTRACE (ead514d5) · Commits · 戴 / test

Documentation/features/debug/kprobes-on-ftrace/arch-support.txt

+1 −1

Original line number	Diff line number	Diff line
		@@ -27,7 +27,7 @@
		\| nios2: \| TODO \|
		\| openrisc: \| TODO \|
		\| parisc: \| TODO \|
		\| powerpc: \| TODO \|
		\| powerpc: \| ok \|
		\| s390: \| TODO \|
		\| score: \| TODO \|
		\| sh: \| TODO \|

arch/powerpc/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -142,6 +142,7 @@ config PPC
		select HAVE_IRQ_EXIT_ON_IRQ_STACK
		select HAVE_KERNEL_GZIP
		select HAVE_KPROBES
		select HAVE_KPROBES_ON_FTRACE
		select HAVE_KRETPROBES
		select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
		select HAVE_MEMBLOCK

arch/powerpc/include/asm/kprobes.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -103,6 +103,16 @@ extern int kprobe_exceptions_notify(struct notifier_block *self,
		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 skip_singlestep(struct kprobe p, struct pt_regs regs,
		struct kprobe_ctlblk *kcb);
		#else
		static inline int skip_singlestep(struct kprobe p, struct pt_regs regs,
		struct kprobe_ctlblk *kcb)
		{
		return 0;
		}
		#endif
		#else
		static inline int kprobe_handler(struct pt_regs *regs) { return 0; }
		static inline int kprobe_post_handler(struct pt_regs *regs) { return 0; }

arch/powerpc/kernel/Makefile

+3 −0

Original line number	Diff line number	Diff line
		@@ -97,6 +97,7 @@ obj-$(CONFIG_BOOTX_TEXT) += btext.o
		obj-$(CONFIG_SMP) += smp.o
		obj-$(CONFIG_KPROBES) += kprobes.o
		obj-$(CONFIG_OPTPROBES) += optprobes.o optprobes_head.o
		obj-$(CONFIG_KPROBES_ON_FTRACE) += kprobes-ftrace.o
		obj-$(CONFIG_UPROBES) += uprobes.o
		obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o
		obj-$(CONFIG_STACKTRACE) += stacktrace.o
		@@ -150,6 +151,8 @@ GCOV_PROFILE_machine_kexec_32.o := n
		UBSAN_SANITIZE_machine_kexec_32.o := n
		GCOV_PROFILE_kprobes.o := n
		UBSAN_SANITIZE_kprobes.o := n
		GCOV_PROFILE_kprobes-ftrace.o := n
		UBSAN_SANITIZE_kprobes-ftrace.o := n
		UBSAN_SANITIZE_vdso.o := n

		extra-$(CONFIG_PPC_FPU) += fpu.o

arch/powerpc/kernel/kprobes-ftrace.c

0 → 100644

+104 −0

Original line number	Diff line number	Diff line
		/*
		* Dynamic Ftrace based Kprobes Optimization
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
		*
		* Copyright (C) Hitachi Ltd., 2012
		* Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
		* IBM Corporation
		*/
		#include <linux/kprobes.h>
		#include <linux/ptrace.h>
		#include <linux/hardirq.h>
		#include <linux/preempt.h>
		#include <linux/ftrace.h>

		static nokprobe_inline
		int __skip_singlestep(struct kprobe p, struct pt_regs regs,
		struct kprobe_ctlblk *kcb, unsigned long orig_nip)
		{
		/*
		* Emulate singlestep (and also recover regs->nip)
		* as if there is a nop
		*/
		regs->nip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
		if (unlikely(p->post_handler)) {
		kcb->kprobe_status = KPROBE_HIT_SSDONE;
		p->post_handler(p, regs, 0);
		}
		__this_cpu_write(current_kprobe, NULL);
		if (orig_nip)
		regs->nip = orig_nip;
		return 1;
		}

		int skip_singlestep(struct kprobe p, struct pt_regs regs,
		struct kprobe_ctlblk *kcb)
		{
		if (kprobe_ftrace(p))
		return __skip_singlestep(p, regs, kcb, 0);
		else
		return 0;
		}
		NOKPROBE_SYMBOL(skip_singlestep);

		/* Ftrace callback handler for kprobes */
		void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
		struct ftrace_ops ops, struct pt_regs regs)
		{
		struct kprobe *p;
		struct kprobe_ctlblk *kcb;
		unsigned long flags;

		/* Disable irq for emulating a breakpoint and avoiding preempt */
		local_irq_save(flags);
		hard_irq_disable();

		p = get_kprobe((kprobe_opcode_t *)nip);
		if (unlikely(!p) \|\| kprobe_disabled(p))
		goto end;

		kcb = get_kprobe_ctlblk();
		if (kprobe_running()) {
		kprobes_inc_nmissed_count(p);
		} else {
		unsigned long orig_nip = regs->nip;

		/*
		* On powerpc, NIP is before this instruction for the
		* pre handler
		*/
		regs->nip -= MCOUNT_INSN_SIZE;

		__this_cpu_write(current_kprobe, p);
		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
		if (!p->pre_handler \|\| !p->pre_handler(p, regs))
		__skip_singlestep(p, regs, kcb, orig_nip);
		/*
		* If pre_handler returns !0, it sets regs->nip and
		* resets current kprobe.
		*/
		}
		end:
		local_irq_restore(flags);
		}
		NOKPROBE_SYMBOL(kprobe_ftrace_handler);

		int arch_prepare_kprobe_ftrace(struct kprobe *p)
		{
		p->ainsn.insn = NULL;
		p->ainsn.boostable = -1;
		return 0;
		}

Original line number	Diff line number	Diff line
		@@ -27,7 +27,7 @@
		\| nios2: \| TODO \|
		\| openrisc: \| TODO \|
		\| parisc: \| TODO \|
		\| powerpc: \| TODO \|
		\| powerpc: \| ok \|
		\| s390: \| TODO \|
		\| score: \| TODO \|
		\| sh: \| TODO \|

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