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Commit 82090035 authored by Kumar Gala's avatar Kumar Gala
Browse files

[POWERPC] Added kprobes support to ppc32 



Added kprobes to ppc32 platforms that have use single_step_exception.  This
excludes 4xx and anything Book-E since their debug mechanisms for single stepping
are completely different.

Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
parent 84232005

arch/powerpc/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -1206,7 +1206,7 @@ source "arch/powerpc/oprofile/Kconfig" 


config KPROBES

	bool "Kprobes (EXPERIMENTAL)"

	depends on PPC64 && KALLSYMS && EXPERIMENTAL && MODULES

	depends on !BOOKE && !4xx && KALLSYMS && EXPERIMENTAL && MODULES

	help

	  Kprobes allows you to trap at almost any kernel address and

	  execute a callback function.  register_kprobe() establishes

arch/powerpc/kernel/kprobes.c

+6 −2
Original line number Diff line number Diff line
@@ -46,8 +46,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) 
	if ((unsigned long)p->addr & 0x03) {

		printk("Attempt to register kprobe at an unaligned address\n");

		ret = -EINVAL;

	} else if (IS_MTMSRD(insn) || IS_RFID(insn)) {

		printk("Cannot register a kprobe on rfid or mtmsrd\n");

	} else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {

		printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");

		ret = -EINVAL;

	}
@@ -483,8 +483,12 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) 
	memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));



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

#ifdef CONFIG_PPC64

	regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry);

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

#else

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

#endif



	return 1;

}

arch/powerpc/lib/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -16,11 +16,11 @@ obj-$(CONFIG_PPC64) += checksum_64.o copypage_64.o copyuser_64.o \ 
			   strcase.o

obj-$(CONFIG_QUICC_ENGINE) += rheap.o

obj-$(CONFIG_XMON)	+= sstep.o

obj-$(CONFIG_KPROBES)	+= sstep.o

obj-$(CONFIG_NOT_COHERENT_CACHE)	+= dma-noncoherent.o



ifeq ($(CONFIG_PPC64),y)

obj-$(CONFIG_SMP)	+= locks.o

obj-$(CONFIG_DEBUG_KERNEL) += sstep.o

endif



# Temporary hack until we have migrated to asm-powerpc

include/asm-powerpc/kprobes.h

+6 −1
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ typedef unsigned int kprobe_opcode_t; 
#define IS_TDI(instr)		(((instr) & 0xfc000000) == 0x08000000)

#define IS_TWI(instr)		(((instr) & 0xfc000000) == 0x0c000000)



#ifdef CONFIG_PPC64

/*

 * 64bit powerpc uses function descriptors.

 * Handle cases where:
@@ -67,9 +68,13 @@ typedef unsigned int kprobe_opcode_t; 
}



#define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)((func_descr_t *)pentry)



#define is_trap(instr)	(IS_TW(instr) || IS_TD(instr) || \

			IS_TWI(instr) || IS_TDI(instr))

#else

/* Use stock kprobe_lookup_name since ppc32 doesn't use function descriptors */

#define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)(pentry)

#define is_trap(instr)	(IS_TW(instr) || IS_TWI(instr))

#endif



#define ARCH_SUPPORTS_KRETPROBES

#define  ARCH_INACTIVE_KPROBE_COUNT 1

include/asm-powerpc/sstep.h

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ struct pt_regs; 
 */

#define IS_MTMSRD(instr)	(((instr) & 0xfc0007be) == 0x7c000124)

#define IS_RFID(instr)		(((instr) & 0xfc0007fe) == 0x4c000024)

#define IS_RFI(instr)		(((instr) & 0xfc0007fe) == 0x4c000064)



/* Emulate instructions that cause a transfer of control. */

extern int emulate_step(struct pt_regs *regs, unsigned int instr);