Messages in this thread Patch in this message | | | Date | Mon, 7 Aug 2006 17:25:37 +0530 | From | Ananth N Mavinakayanahalli <> | Subject | [PATCH 1/3] Kprobes: Make kprobe modules more portable |
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From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
This patch introduces KPROBE_ADDR, a macro that abstracts out the architecture-specific artefacts of getting the correct text address given a symbol. While we are at it, also introduce the symbol_name field in struct kprobe to allow for users to just specify the address to be probed in terms of the kernel symbol. In-kernel kprobes infrastructure decodes the actual text address to probe. The symbol resolution happens only if the kprobe.addr isn't explicitly specified.
--- Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Prasanna S.P <prasanna@in.ibm.com>
--- include/asm-powerpc/kprobes.h | 2 ++ include/linux/kprobes.h | 8 ++++++++ kernel/kprobes.c | 4 ++++ 3 files changed, 14 insertions(+)
Index: linux-2.6.18-rc3/include/asm-powerpc/kprobes.h =================================================================== --- linux-2.6.18-rc3.orig/include/asm-powerpc/kprobes.h +++ linux-2.6.18-rc3/include/asm-powerpc/kprobes.h @@ -44,6 +44,8 @@ typedef unsigned int kprobe_opcode_t; #define IS_TDI(instr) (((instr) & 0xfc000000) == 0x08000000) #define IS_TWI(instr) (((instr) & 0xfc000000) == 0x0c000000) +#define KPROBE_ADDR(name) *((kprobe_opcode_t **)(kallsyms_lookup_name(name))) + #define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)((func_descr_t *)pentry) #define is_trap(instr) (IS_TW(instr) || IS_TD(instr) || \ Index: linux-2.6.18-rc3/include/linux/kprobes.h =================================================================== --- linux-2.6.18-rc3.orig/include/linux/kprobes.h +++ linux-2.6.18-rc3/include/linux/kprobes.h @@ -36,6 +36,7 @@ #include <linux/spinlock.h> #include <linux/rcupdate.h> #include <linux/mutex.h> +#include <linux/kallsyms.h> #ifdef CONFIG_KPROBES #include <asm/kprobes.h> @@ -49,6 +50,10 @@ /* Attach to insert probes on any functions which should be ignored*/ #define __kprobes __attribute__((__section__(".kprobes.text"))) +#ifndef KPROBE_ADDR /* powerpc has its own definition */ +#define KPROBE_ADDR(name) (kprobe_opcode_t *)(kallsyms_lookup_name(name)) +#endif /* KPROBE_ADDR */ + struct kprobe; struct pt_regs; struct kretprobe; @@ -77,6 +82,9 @@ struct kprobe { /* location of the probe point */ kprobe_opcode_t *addr; + /* Allow user to indicate symbol name of the probe point */ + char *symbol_name; + /* Called before addr is executed. */ kprobe_pre_handler_t pre_handler; Index: linux-2.6.18-rc3/kernel/kprobes.c =================================================================== --- linux-2.6.18-rc3.orig/kernel/kprobes.c +++ linux-2.6.18-rc3/kernel/kprobes.c @@ -446,6 +446,10 @@ static int __kprobes __register_kprobe(s struct kprobe *old_p; struct module *probed_mod; + /* Do the kallsyms lookup only if p->addr == NULL */ + if (!p->addr && (p->symbol_name)) + p->addr = KPROBE_ADDR(p->symbol_name); + if ((!kernel_text_address((unsigned long) p->addr)) || in_kprobes_functions((unsigned long) p->addr)) return -EINVAL; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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