From 3a872d89baae821a0f6e2c1055d4b47650661137 Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Mon, 2 Oct 2006 02:17:30 -0700 Subject: [PATCH] Kprobes: Make kprobe modules more portable In an effort to make kprobe modules more portable, here is a patch that: o Introduces the "symbol_name" field to struct kprobe. The symbol->address resolution now happens in the kernel in an architecture agnostic manner. 64-bit powerpc users no longer have to specify the ".symbols" o Introduces the "offset" field to struct kprobe to allow a user to specify an offset into a symbol. o The legacy mechanism of specifying the kprobe.addr is still supported. However, if both the kprobe.addr and kprobe.symbol_name are specified, probe registration fails with an -EINVAL. o The symbol resolution code uses kallsyms_lookup_name(). So CONFIG_KPROBES now depends on CONFIG_KALLSYMS o Apparantly kprobe modules were the only legitimate out-of-tree user of the kallsyms_lookup_name() EXPORT. Now that the symbol resolution happens in-kernel, remove the EXPORT as suggested by Christoph Hellwig o Modify tcp_probe.c that uses the kprobe interface so as to make it work on multiple platforms (in its earlier form, the code wouldn't work, say, on powerpc) Signed-off-by: Ananth N Mavinakayanahalli Signed-off-by: Prasanna S Panchamukhi Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-powerpc/kprobes.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/asm-powerpc/kprobes.h') diff --git a/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h index 34e1f89a5fa..1ef54be6abf 100644 --- a/include/asm-powerpc/kprobes.h +++ b/include/asm-powerpc/kprobes.h @@ -44,6 +44,21 @@ typedef unsigned int kprobe_opcode_t; #define IS_TDI(instr) (((instr) & 0xfc000000) == 0x08000000) #define IS_TWI(instr) (((instr) & 0xfc000000) == 0x0c000000) +/* + * 64bit powerpc uses function descriptors. + * Handle cases where: + * - User passes a <.symbol> + * - User passes a + * - User passes a non-existant symbol, kallsyms_lookup_name + * returns 0. Don't deref the NULL pointer in that case + */ +#define kprobe_lookup_name(name, addr) \ +{ \ + addr = (kprobe_opcode_t *)kallsyms_lookup_name(name); \ + if (!(name[0] == '.') && addr) \ + addr = *(kprobe_opcode_t **)addr; \ +} + #define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)((func_descr_t *)pentry) #define is_trap(instr) (IS_TW(instr) || IS_TD(instr) || \ -- cgit v1.2.3