[PATCH] Kprobes/IA64: arch specific handling
Anil S Keshavamurthy [Thu, 23 Jun 2005 07:09:28 +0000 (00:09 -0700)]
This is an IA64 arch specific handling of Kprobes

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Rusty Lynch <Rusty.lynch@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ia64/Kconfig.debug
arch/ia64/kernel/Makefile
arch/ia64/kernel/kprobes.c [new file with mode: 0644]
include/asm-ia64/kprobes.h [new file with mode: 0644]

index de9d507..fda67ac 100644 (file)
@@ -2,6 +2,17 @@ menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
+config KPROBES
+        bool "Kprobes"
+        depends on DEBUG_KERNEL
+        help
+          Kprobes allows you to trap at almost any kernel address and
+          execute a callback function.  register_kprobe() establishes
+          a probepoint and specifies the callback.  Kprobes is useful
+          for kernel debugging, non-intrusive instrumentation and testing.
+          If in doubt, say "N".
+
+
 choice
        prompt "Physical memory granularity"
        default IA64_GRANULE_64MB
index 4c73d8b..5290fa4 100644 (file)
@@ -20,6 +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_IA64_UNCACHED_ALLOCATOR)  += uncached.o
 mca_recovery-y                 += mca_drv.o mca_drv_asm.o
 
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
new file mode 100644 (file)
index 0000000..81a53f9
--- /dev/null
@@ -0,0 +1,332 @@
+/*
+ *  Kernel Probes (KProbes)
+ *  arch/ia64/kernel/kprobes.c
+ *
+ * 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) IBM Corporation, 2002, 2004
+ * Copyright (C) Intel Corporation, 2005
+ *
+ * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
+ *              <anil.s.keshavamurthy@intel.com> adapted from i386
+ */
+
+#include <linux/config.h>
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/preempt.h>
+#include <linux/moduleloader.h>
+
+#include <asm/pgtable.h>
+#include <asm/kdebug.h>
+
+/* kprobe_status settings */
+#define KPROBE_HIT_ACTIVE      0x00000001
+#define KPROBE_HIT_SS          0x00000002
+
+static struct kprobe *current_kprobe;
+static unsigned long kprobe_status;
+
+enum instruction_type {A, I, M, F, B, L, X, u};
+static enum instruction_type bundle_encoding[32][3] = {
+  { M, I, I },                         /* 00 */
+  { M, I, I },                         /* 01 */
+  { M, I, I },                         /* 02 */
+  { M, I, I },                         /* 03 */
+  { M, L, X },                         /* 04 */
+  { M, L, X },                         /* 05 */
+  { u, u, u },                         /* 06 */
+  { u, u, u },                         /* 07 */
+  { M, M, I },                         /* 08 */
+  { M, M, I },                         /* 09 */
+  { M, M, I },                         /* 0A */
+  { M, M, I },                         /* 0B */
+  { M, F, I },                         /* 0C */
+  { M, F, I },                         /* 0D */
+  { M, M, F },                         /* 0E */
+  { M, M, F },                         /* 0F */
+  { M, I, B },                         /* 10 */
+  { M, I, B },                         /* 11 */
+  { M, B, B },                         /* 12 */
+  { M, B, B },                         /* 13 */
+  { u, u, u },                         /* 14 */
+  { u, u, u },                         /* 15 */
+  { B, B, B },                         /* 16 */
+  { B, B, B },                         /* 17 */
+  { M, M, B },                         /* 18 */
+  { M, M, B },                         /* 19 */
+  { u, u, u },                         /* 1A */
+  { u, u, u },                         /* 1B */
+  { M, F, B },                         /* 1C */
+  { M, F, B },                         /* 1D */
+  { u, u, u },                         /* 1E */
+  { u, u, u },                         /* 1F */
+};
+
+int arch_prepare_kprobe(struct kprobe *p)
+{
+       unsigned long addr = (unsigned long) p->addr;
+       unsigned long bundle_addr = addr & ~0xFULL;
+       unsigned long slot = addr & 0xf;
+       bundle_t bundle;
+       unsigned long template;
+
+       /*
+        * TODO: Verify that a probe is not being inserted
+        *       in sensitive regions of code
+        * TODO: Verify that the memory holding the probe is rwx
+        * TODO: verify this is a kernel address
+        */
+       memcpy(&bundle, (unsigned long *)bundle_addr, sizeof(bundle_t));
+       template = bundle.quad0.template;
+       if (((bundle_encoding[template][1] == L) && slot > 1) || (slot > 2)) {
+               printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n", addr);
+               return -EINVAL;
+       }
+       return 0;
+}
+
+void arch_copy_kprobe(struct kprobe *p)
+{
+       unsigned long addr = (unsigned long)p->addr;
+       unsigned long bundle_addr = addr & ~0xFULL;
+
+       memcpy(&p->ainsn.insn.bundle, (unsigned long *)bundle_addr,
+                               sizeof(bundle_t));
+       memcpy(&p->opcode.bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));
+}
+
+void arch_arm_kprobe(struct kprobe *p)
+{
+       unsigned long addr = (unsigned long)p->addr;
+       unsigned long arm_addr = addr & ~0xFULL;
+       unsigned long slot = addr & 0xf;
+       unsigned long template;
+       bundle_t bundle;
+
+       memcpy(&bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));
+
+       template = bundle.quad0.template;
+       if (slot == 1 && bundle_encoding[template][1] == L)
+               slot = 2;
+       switch (slot) {
+       case 0:
+               bundle.quad0.slot0 = BREAK_INST;
+               break;
+       case 1:
+               bundle.quad0.slot1_p0 = BREAK_INST;
+               bundle.quad1.slot1_p1 = (BREAK_INST >> (64-46));
+               break;
+       case 2:
+               bundle.quad1.slot2 = BREAK_INST;
+               break;
+       }
+
+       /* Flush icache for the instruction at the emulated address */
+       flush_icache_range((unsigned long)&p->ainsn.insn.bundle,
+                       (unsigned long)&p->ainsn.insn.bundle +
+                       sizeof(bundle_t));
+       /*
+        * Patch the original instruction with the probe instruction
+        * and flush the instruction cache
+        */
+       memcpy((char *) arm_addr, (char *) &bundle, sizeof(bundle_t));
+       flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
+}
+
+void arch_disarm_kprobe(struct kprobe *p)
+{
+       unsigned long addr = (unsigned long)p->addr;
+       unsigned long arm_addr = addr & ~0xFULL;
+
+       /* p->opcode contains the original unaltered bundle */
+       memcpy((char *) arm_addr, (char *) &p->opcode.bundle, sizeof(bundle_t));
+       flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
+}
+
+void arch_remove_kprobe(struct kprobe *p)
+{
+}
+
+/*
+ * We are resuming execution after a single step fault, so the pt_regs
+ * structure reflects the register state after we executed the instruction
+ * located in the kprobe (p->ainsn.insn.bundle).  We still need to adjust
+ * the ip to point back to the original stack address, and if we see that
+ * the slot has incremented back to zero, then we need to point to the next
+ * slot location.
+ */
+static void resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+       unsigned long bundle = (unsigned long)p->addr & ~0xFULL;
+
+       /*
+        * TODO: Handle cases where kprobe was inserted on a branch instruction
+        */
+
+       if (!ia64_psr(regs)->ri)
+               regs->cr_iip = bundle + 0x10;
+       else
+               regs->cr_iip = bundle;
+
+       ia64_psr(regs)->ss = 0;
+}
+
+static void prepare_ss(struct kprobe *p, struct pt_regs *regs)
+{
+       unsigned long bundle_addr = (unsigned long) &p->ainsn.insn.bundle;
+       unsigned long slot = (unsigned long)p->addr & 0xf;
+
+       /* Update instruction pointer (IIP) and slot number (IPSR.ri) */
+       regs->cr_iip = bundle_addr & ~0xFULL;
+
+       if (slot > 2)
+               slot = 0;
+
+       ia64_psr(regs)->ri = slot;
+
+       /* turn on single stepping */
+       ia64_psr(regs)->ss = 1;
+}
+
+static int pre_kprobes_handler(struct pt_regs *regs)
+{
+       struct kprobe *p;
+       int ret = 0;
+       kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
+
+       preempt_disable();
+
+       /* Handle recursion cases */
+       if (kprobe_running()) {
+               p = get_kprobe(addr);
+               if (p) {
+                       if (kprobe_status == KPROBE_HIT_SS) {
+                               unlock_kprobes();
+                               goto no_kprobe;
+                       }
+                       arch_disarm_kprobe(p);
+                       ret = 1;
+               } else {
+                       /*
+                        * jprobe instrumented function just completed
+                        */
+                       p = current_kprobe;
+                       if (p->break_handler && p->break_handler(p, regs)) {
+                               goto ss_probe;
+                       }
+               }
+       }
+
+       lock_kprobes();
+       p = get_kprobe(addr);
+       if (!p) {
+               unlock_kprobes();
+               goto no_kprobe;
+       }
+
+       kprobe_status = KPROBE_HIT_ACTIVE;
+       current_kprobe = p;
+
+       if (p->pre_handler && p->pre_handler(p, regs))
+               /*
+                * Our pre-handler is specifically requesting that we just
+                * do a return.  This is handling the case where the
+                * pre-handler is really our special jprobe pre-handler.
+                */
+               return 1;
+
+ss_probe:
+       prepare_ss(p, regs);
+       kprobe_status = KPROBE_HIT_SS;
+       return 1;
+
+no_kprobe:
+       preempt_enable_no_resched();
+       return ret;
+}
+
+static int post_kprobes_handler(struct pt_regs *regs)
+{
+       if (!kprobe_running())
+               return 0;
+
+       if (current_kprobe->post_handler)
+               current_kprobe->post_handler(current_kprobe, regs, 0);
+
+       resume_execution(current_kprobe, regs);
+
+       unlock_kprobes();
+       preempt_enable_no_resched();
+       return 1;
+}
+
+static int kprobes_fault_handler(struct pt_regs *regs, int trapnr)
+{
+       if (!kprobe_running())
+               return 0;
+
+       if (current_kprobe->fault_handler &&
+           current_kprobe->fault_handler(current_kprobe, regs, trapnr))
+               return 1;
+
+       if (kprobe_status & KPROBE_HIT_SS) {
+               resume_execution(current_kprobe, regs);
+               unlock_kprobes();
+               preempt_enable_no_resched();
+       }
+
+       return 0;
+}
+
+int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
+                            void *data)
+{
+       struct die_args *args = (struct die_args *)data;
+       switch(val) {
+       case DIE_BREAK:
+               if (pre_kprobes_handler(args->regs))
+                       return NOTIFY_STOP;
+               break;
+       case DIE_SS:
+               if (post_kprobes_handler(args->regs))
+                       return NOTIFY_STOP;
+               break;
+       case DIE_PAGE_FAULT:
+               if (kprobes_fault_handler(args->regs, args->trapnr))
+                       return NOTIFY_STOP;
+       default:
+               break;
+       }
+       return NOTIFY_DONE;
+}
+
+int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+       printk(KERN_WARNING "Jprobes is not supported\n");
+       return 0;
+}
+
+void jprobe_return(void)
+{
+}
+
+int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+       return 0;
+}
diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h
new file mode 100644 (file)
index 0000000..2a6f2a1
--- /dev/null
@@ -0,0 +1,72 @@
+#ifndef _ASM_KPROBES_H
+#define _ASM_KPROBES_H
+/*
+ *  Kernel Probes (KProbes)
+ *  include/asm-ia64/kprobes.h
+ *
+ * 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) IBM Corporation, 2002, 2004
+ * Copyright (C) Intel Corporation, 2005
+ *
+ * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
+ *              <anil.s.keshavamurthy@intel.com> adapted from i386
+ */
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <asm/break.h>
+
+#define BREAK_INST     (long)(__IA64_BREAK_KPROBE << 6)
+
+typedef struct _bundle {
+       struct {
+               unsigned long long template : 5;
+               unsigned long long slot0 : 41;
+               unsigned long long slot1_p0 : 64-46;
+       } quad0;
+       struct {
+               unsigned long long slot1_p1 : 41 - (64-46);
+               unsigned long long slot2 : 41;
+       } quad1;
+} __attribute__((__aligned__(16)))  bundle_t;
+
+#define JPROBE_ENTRY(pentry)   (kprobe_opcode_t *)pentry
+
+typedef struct kprobe_opcode {
+       bundle_t bundle;
+} kprobe_opcode_t;
+
+struct fnptr {
+       unsigned long ip;
+       unsigned long gp;
+};
+
+/* Architecture specific copy of original instruction*/
+struct arch_specific_insn {
+       /* copy of the original instruction */
+       kprobe_opcode_t insn;
+};
+
+#ifdef CONFIG_KPROBES
+extern int kprobe_exceptions_notify(struct notifier_block *self,
+                                   unsigned long val, void *data);
+#else                          /* !CONFIG_KPROBES */
+static inline int kprobe_exceptions_notify(struct notifier_block *self,
+                                          unsigned long val, void *data)
+{
+       return 0;
+}
+#endif
+#endif                         /* _ASM_KPROBES_H */