Hi,
This patch is the i386 architecture dependent codes of djprobe.
I heard that we need to synchronize caches of each processor if we
execute self modifying on i386.
So, this patch synchronize caches by using CPUID and smp_call_function.
---
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: [email protected]
Signed-off-by: Masami Hiramatsu <[email protected]>
arch/i386/Kconfig | 8 +
arch/i386/kernel/Makefile | 1
arch/i386/kernel/djprobe.c | 172 ++++++++++++++++++++++++++++++++++++++++
arch/i386/kernel/stub_djprobe.S | 77 +++++++++++++++++
include/asm-i386/djprobe.h | 56 +++++++++++++
5 files changed, 314 insertions(+)
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/Kconfig linux-2.6.14-rc5-mm1.djp.3/arch/i386/Kconfig
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/Kconfig 2005-10-25 11:28:49.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/Kconfig 2005-10-27 11:26:55.000000000 +0900
@@ -1317,6 +1317,14 @@ config KPROBES
a probepoint and specifies the callback. Kprobes is useful
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
+
+config DJPROBE
+ bool "Direct Jump probe"
+ depends on KPROBES && !PREEMPT
+ help
+ Djprobe allows you to dynamically hook at any kernel function
+ entry points and collect the debugging or performance analysis
+ information non-disruptively.
endmenu
source "arch/i386/Kconfig.debug"
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/Makefile linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/Makefile
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/Makefile 2005-10-25 11:28:49.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/Makefile 2005-10-25 14:39:12.000000000 +0900
@@ -29,6 +29,7 @@ obj-$(CONFIG_KEXEC) += machine_kexec.o
obj-$(CONFIG_X86_NUMAQ) += numaq.o
obj-$(CONFIG_X86_SUMMIT_NUMA) += summit.o
obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_DJPROBE) += stub_djprobe.o djprobe.o
obj-$(CONFIG_MODULES) += module.o
obj-y += sysenter.o vsyscall.o
obj-$(CONFIG_ACPI_SRAT) += srat.o
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/djprobe.c linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/djprobe.c
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/djprobe.c 1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/djprobe.c 2005-10-28 17:52:29.000000000 +0900
@@ -0,0 +1,172 @@
+/*
+ * Kernel Direct Jump Probe (Djprobes)
+ * arch/i386/kernel/djprobe.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) Hitachi, Ltd. 2005
+ *
+ * 2005-Aug Created by Masami HIRAMATSU <[email protected]>
+ * Initial implementation of Direct jump probe (djprobe)
+ * to reduce overhead.
+ */
+
+#include <linux/config.h>
+#include <linux/djprobe.h>
+#include <linux/ptrace.h>
+#include <linux/spinlock.h>
+#include <linux/preempt.h>
+#include <asm/cacheflush.h>
+#include <asm/kdebug.h>
+#include <asm/desc.h>
+#include <asm/processor.h>
+
+
+/*
+ * When kernel full preemption is enabled, we can't ensure that no threads
+ * are executing the modified code. It may be stored in the stack of the
+ * threads. In this case, the djprobe interfaces are emulated by using
+ * kprobe.
+ * When kernel full preemption is disabled, threads are scheduled
+ * from only limited addresses. So it is easy to check whether the
+ * preemption can occur in the modified code.
+ */
+
+/*
+ * On pentium series, Unsynchronized cross-modifying code
+ * operations can cause unexpected instruction execution results.
+ * So after code modified, we should synchronize it on each processor.
+ */
+static void __local_serialize_cpu(void * info)
+{
+ serialize_cpu();
+}
+
+static inline void smp_serialize_cpus(void)
+{
+ on_each_cpu(__local_serialize_cpu, NULL, 1,1);
+}
+
+/* jmp code manipulators */
+struct __arch_jmp_op {
+ char op;
+ long raddr;
+} __attribute__((packed));
+/* insert jmp code */
+static inline void __set_jmp_op(void *from, void *to, int sync)
+{
+ struct __arch_jmp_op *jop;
+ jop = (struct __arch_jmp_op *)from;
+ jop->raddr=(long)(to) - ((long)(from) + 5);
+ mb();
+ if (sync) smp_serialize_cpus();
+ jop->op = RELATIVEJUMP_INSTRUCTION;
+}
+/* switch back to the kprobe */
+static inline void __set_breakpoint_op(void *dest, void *orig)
+{
+ struct __arch_jmp_op *jop = (struct __arch_jmp_op *)dest,
+ *jop2 = (struct __arch_jmp_op *)orig;
+
+ jop->op = BREAKPOINT_INSTRUCTION;
+ jop->raddr = jop2->raddr;
+ mb();
+ smp_serialize_cpus();
+}
+
+/* djprobe call back function: called from stub code */
+static void asmlinkage djprobe_callback(struct djprobe_instance * djpi,
+ struct pt_regs *regs)
+{
+ struct djprobe *djp;
+ rcu_read_lock();
+ list_for_each_entry_rcu(djp, &djpi->plist, plist) {
+ if (djp->handler)
+ djp->handler(djp, regs);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Copy post processing instructions
+ * Target instructions MUST be relocatable.
+ */
+int __kprobes arch_prepare_djprobe_instance(struct djprobe_instance *djpi,
+ unsigned long size)
+{
+ kprobe_opcode_t *stub;
+ stub = djpi->stub.insn;
+ djpi->stub.size = size;
+
+ /* copy arch-dep-instance from template */
+ memcpy((void*)stub, (void*)&arch_tmpl_stub_entry, ARCH_STUB_SIZE);
+
+ /* set probe information */
+ *((long*)(stub + ARCH_STUB_VAL_IDX)) = (long)djpi;
+ /* set probe function */
+ *((long*)(stub + ARCH_STUB_CALL_IDX)) = (long)djprobe_callback;
+
+ /* copy instructions into the middle of djporbe instance */
+ memcpy((void*)(stub + ARCH_STUB_INST_IDX),
+ (void*)djpi->kp.addr, size);
+
+ /* set returning jmp instruction at the tail of djporbe instance*/
+ __set_jmp_op(stub + ARCH_STUB_INST_IDX + size,
+ (void*)((long)djpi->kp.addr + size), 0);
+
+ return 0;
+}
+
+/* Insert "jmp" instruction into the probing point. */
+void __kprobes arch_install_djprobe_instance(struct djprobe_instance *djpi)
+{
+ __set_jmp_op((void*)djpi->kp.addr, (void*)djpi->stub.insn, 1);
+}
+
+/* Write back original instructions & kprobe */
+void __kprobes arch_uninstall_djprobe_instance(struct djprobe_instance *djpi)
+{
+ kprobe_opcode_t *stub;
+ stub = &djpi->stub.insn[ARCH_STUB_INST_IDX];
+ __set_breakpoint_op((void*)djpi->kp.addr, (void*)stub);
+}
+
+static DEFINE_SPINLOCK(djprobe_handler_lock);
+
+/* djprobe handler : switch to a bypass code */
+int __kprobes djprobe_pre_handler(struct kprobe * kp, struct pt_regs * regs)
+{
+ struct djprobe_instance *djpi =
+ container_of(kp,struct djprobe_instance, kp);
+ kprobe_opcode_t *stub = djpi->stub.insn;
+
+ spin_lock(&djprobe_handler_lock);
+ if (DJPI_EMPTY(djpi)) {
+ kp->ainsn.insn[0] = kp->opcode;
+ return 0;
+ } else {
+ regs->eip = (unsigned long)stub;
+ regs->eflags |= TF_MASK;
+ regs->eflags &= ~IF_MASK;
+ kp->ainsn.insn[0] = RETURN_INSTRUCTION;
+ return 1; /* already prepared */
+ }
+}
+
+void __kprobes djprobe_post_handler(struct kprobe * kp, struct pt_regs * regs,
+ unsigned long flags)
+{
+ spin_unlock(&djprobe_handler_lock);
+}
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/stub_djprobe.S linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/stub_djprobe.S
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/stub_djprobe.S 1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/stub_djprobe.S 2005-10-25 14:39:12.000000000 +0900
@@ -0,0 +1,77 @@
+/*
+ * linux/arch/i386/stub_djprobe.S
+ *
+ * Copyright (C) HITACHI,LTD. 2005
+ * Created by Masami Hiramatsu <[email protected]>
+ */
+
+#include <linux/config.h>
+
+# jmp into this function from other functions.
+.global arch_tmpl_stub_entry
+arch_tmpl_stub_entry:
+ nop
+ subl $8, %esp #skip segment registers.
+ pushf
+ subl $20, %esp #skip segment registers.
+ pushl %eax
+ pushl %ebp
+ pushl %edi
+ pushl %esi
+ pushl %edx
+ pushl %ecx
+ pushl %ebx
+
+ movl %esp, %eax
+ pushl %eax
+ addl $60, %eax
+ movl %eax, 56(%esp)
+.global arch_tmpl_stub_val
+arch_tmpl_stub_val:
+ movl $0xffffffff, %eax
+ pushl %eax
+.global arch_tmpl_stub_call
+arch_tmpl_stub_call:
+ movl $0xffffffff, %eax
+ call *%eax
+ addl $8, %esp
+
+ popl %ebx
+ popl %ecx
+ popl %edx
+ popl %esi
+ popl %edi
+ popl %ebp
+ popl %eax
+ addl $20, %esp
+ popf
+ addl $8, %esp
+.global arch_tmpl_stub_inst
+arch_tmpl_stub_inst:
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+.global arch_tmpl_stub_end
+arch_tmpl_stub_end:
diff -Narup linux-2.6.14-rc5-mm1.djp.2/include/asm-i386/djprobe.h linux-2.6.14-rc5-mm1.djp.3/include/asm-i386/djprobe.h
--- linux-2.6.14-rc5-mm1.djp.2/include/asm-i386/djprobe.h 1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/include/asm-i386/djprobe.h 2005-10-25 14:39:12.000000000 +0900
@@ -0,0 +1,56 @@
+#ifndef _ASM_DJPROBE_H
+#define _ASM_DJPROBE_H
+/*
+ * Kernel Direct Jump Probe (Djprobe)
+ * include/asm-i386/djprobe.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) Hitachi, Ltd. 2005
+ *
+ * 2005-Aug Created by Masami HIRAMATSU <[email protected]>
+ * Initial implementation of Direct jump probe (djprobe)
+ * to reduce overhead.
+ */
+
+#define RELATIVEJUMP_INSTRUCTION 0xe9
+#define RETURN_INSTRUCTION 0xc3
+
+#ifndef CONFIG_PREEMPT
+#define ARCH_SUPPORTS_DJPROBES
+#endif /* CONFIG_PREEMPT */
+
+/* stub template code */
+extern kprobe_opcode_t arch_tmpl_stub_entry;
+extern kprobe_opcode_t arch_tmpl_stub_val;
+extern kprobe_opcode_t arch_tmpl_stub_call;
+extern kprobe_opcode_t arch_tmpl_stub_inst;
+extern kprobe_opcode_t arch_tmpl_stub_end;
+
+#define ARCH_STUB_VAL_IDX ((long)&arch_tmpl_stub_val - (long)&arch_tmpl_stub_entry + 1)
+#define ARCH_STUB_CALL_IDX ((long)&arch_tmpl_stub_call - (long)&arch_tmpl_stub_entry + 1)
+#define ARCH_STUB_INST_IDX ((long)&arch_tmpl_stub_inst - (long)&arch_tmpl_stub_entry)
+#define ARCH_STUB_SIZE ((long)&arch_tmpl_stub_end - (long)&arch_tmpl_stub_entry)
+
+#define ARCH_STUB_INSN_MAX 20
+#define ARCH_STUB_INSN_MIN 5
+
+struct arch_djprobe_stub {
+ kprobe_opcode_t *insn;
+ int size;
+};
+#define DJPI_ARCH_SIZE(djpi) (djpi->stub.size)
+
+#endif /* _ASM_DJPROBE_H */
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