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authorAnanth N Mavinakayanahalli <ananth@in.ibm.com>2006-10-02 02:17:30 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-02 07:57:16 -0700
commit3a872d89baae821a0f6e2c1055d4b47650661137 (patch)
tree5ac6aa55e04960e02f25ff5079078f975957b1b3 /include
parent782237a2418e2561a87c86a4832726931adce737 (diff)
[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 <ananth@in.ibm.com> Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
-rw-r--r--include/asm-powerpc/kprobes.h15
-rw-r--r--include/linux/kprobes.h6
2 files changed, 21 insertions, 0 deletions
diff --git a/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h
index 34e1f89a5fa0..1ef54be6abfa 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 <symbol>
+ * - 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) || \
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 8bf6702da2a0..a5c5a0cb0d5c 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -77,6 +77,12 @@ struct kprobe {
/* location of the probe point */
kprobe_opcode_t *addr;
+ /* Allow user to indicate symbol name of the probe point */
+ char *symbol_name;
+
+ /* Offset into the symbol */
+ unsigned int offset;
+
/* Called before addr is executed. */
kprobe_pre_handler_t pre_handler;