diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/ia64/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/ia64/kernel/jprobes.S | 61 | ||||
| -rw-r--r-- | arch/ia64/kernel/kprobes.c | 28 |
3 files changed, 84 insertions, 7 deletions
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile index 5290fa4..b2e2f65 100644 --- a/arch/ia64/kernel/Makefile +++ b/arch/ia64/kernel/Makefile @@ -20,7 +20,7 @@ obj-$(CONFIG_SMP) += smp.o smpboot.o domain.o obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o obj-$(CONFIG_IA64_CYCLONE) += cyclone.o obj-$(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 mca_recovery-y += mca_drv.o mca_drv_asm.o diff --git a/arch/ia64/kernel/jprobes.S b/arch/ia64/kernel/jprobes.S new file mode 100644 index 0000000..b7fa3cc --- /dev/null +++ b/arch/ia64/kernel/jprobes.S @@ -0,0 +1,61 @@ +/* + * 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) diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 81a53f9..6683a44 100644 --- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -35,12 +35,15 @@ #include <asm/pgtable.h> #include <asm/kdebug.h> +extern void jprobe_inst_return(void); + /* kprobe_status settings */ #define KPROBE_HIT_ACTIVE 0x00000001 #define KPROBE_HIT_SS 0x00000002 static struct kprobe *current_kprobe; static unsigned long kprobe_status; +static struct pt_regs jprobe_saved_regs; enum instruction_type {A, I, M, F, B, L, X, u}; static enum instruction_type bundle_encoding[32][3] = { @@ -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) { - printk(KERN_WARNING "Jprobes is not supported\n"); - return 0; -} + struct jprobe *jp = container_of(p, struct jprobe, kp); + 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) { - return 0; + *regs = jprobe_saved_regs; + return 1; } |