Commit b2761dc2 authored by Anil S Keshavamurthy's avatar Anil S Keshavamurthy Committed by Linus Torvalds

[PATCH] Kprobes/IA64: architecture specific JProbes support

This patch adds IA64 architecture specific JProbes support on top of Kprobes
Signed-off-by: default avatarAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: default avatarRusty Lynch <Rusty.lynch@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fd7b231f
...@@ -20,7 +20,7 @@ obj-$(CONFIG_SMP) += smp.o smpboot.o domain.o ...@@ -20,7 +20,7 @@ obj-$(CONFIG_SMP) += smp.o smpboot.o domain.o
obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o
obj-$(CONFIG_IA64_CYCLONE) += cyclone.o obj-$(CONFIG_IA64_CYCLONE) += cyclone.o
obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o
obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_KPROBES) += kprobes.o jprobes.o
obj-$(CONFIG_IA64_UNCACHED_ALLOCATOR) += uncached.o obj-$(CONFIG_IA64_UNCACHED_ALLOCATOR) += uncached.o
mca_recovery-y += mca_drv.o mca_drv_asm.o mca_recovery-y += mca_drv.o mca_drv_asm.o
......
/*
* Jprobe specific operations
*
* 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) Intel Corporation, 2005
*
* 2005-May Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
* <anil.s.keshavamurthy@intel.com> initial implementation
*
* Jprobes (a.k.a. "jump probes" which is built on-top of kprobes) allow a
* probe to be inserted into the beginning of a function call. The fundamental
* difference between a jprobe and a kprobe is the jprobe handler is executed
* in the same context as the target function, while the kprobe handlers
* are executed in interrupt context.
*
* For jprobes we initially gain control by placing a break point in the
* first instruction of the targeted function. When we catch that specific
* break, we:
* * set the return address to our jprobe_inst_return() function
* * jump to the jprobe handler function
*
* Since we fixed up the return address, the jprobe handler will return to our
* jprobe_inst_return() function, giving us control again. At this point we
* are back in the parents frame marker, so we do yet another call to our
* jprobe_break() function to fix up the frame marker as it would normally
* exist in the target function.
*
* Our jprobe_return function then transfers control back to kprobes.c by
* executing a break instruction using one of our reserved numbers. When we
* catch that break in kprobes.c, we continue like we do for a normal kprobe
* by single stepping the emulated instruction, and then returning execution
* to the correct location.
*/
#include <asm/asmmacro.h>
/*
* void jprobe_break(void)
*/
ENTRY(jprobe_break)
break.m 0x80300
END(jprobe_break)
/*
* void jprobe_inst_return(void)
*/
GLOBAL_ENTRY(jprobe_inst_return)
br.call.sptk.many b0=jprobe_break
END(jprobe_inst_return)
...@@ -35,12 +35,15 @@ ...@@ -35,12 +35,15 @@
#include <asm/pgtable.h> #include <asm/pgtable.h>
#include <asm/kdebug.h> #include <asm/kdebug.h>
extern void jprobe_inst_return(void);
/* kprobe_status settings */ /* kprobe_status settings */
#define KPROBE_HIT_ACTIVE 0x00000001 #define KPROBE_HIT_ACTIVE 0x00000001
#define KPROBE_HIT_SS 0x00000002 #define KPROBE_HIT_SS 0x00000002
static struct kprobe *current_kprobe; static struct kprobe *current_kprobe;
static unsigned long kprobe_status; static unsigned long kprobe_status;
static struct pt_regs jprobe_saved_regs;
enum instruction_type {A, I, M, F, B, L, X, u}; enum instruction_type {A, I, M, F, B, L, X, u};
static enum instruction_type bundle_encoding[32][3] = { static enum instruction_type bundle_encoding[32][3] = {
...@@ -318,15 +321,28 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, ...@@ -318,15 +321,28 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{ {
printk(KERN_WARNING "Jprobes is not supported\n"); struct jprobe *jp = container_of(p, struct jprobe, kp);
return 0; unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
}
void jprobe_return(void) /* save architectural state */
{ jprobe_saved_regs = *regs;
/* after rfi, execute the jprobe instrumented function */
regs->cr_iip = addr & ~0xFULL;
ia64_psr(regs)->ri = addr & 0xf;
regs->r1 = ((struct fnptr *)(jp->entry))->gp;
/*
* fix the return address to our jprobe_inst_return() function
* in the jprobes.S file
*/
regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
return 1;
} }
int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{ {
return 0; *regs = jprobe_saved_regs;
return 1;
} }
...@@ -59,6 +59,11 @@ struct arch_specific_insn { ...@@ -59,6 +59,11 @@ struct arch_specific_insn {
kprobe_opcode_t insn; kprobe_opcode_t insn;
}; };
/* ia64 does not need this */
static inline void jprobe_return(void)
{
}
#ifdef CONFIG_KPROBES #ifdef CONFIG_KPROBES
extern int kprobe_exceptions_notify(struct notifier_block *self, extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data); unsigned long val, void *data);
......
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