powerpc/modules: Create module_trampoline_target()
ftrace has way too much knowledge of our kernel module trampoline
layout hidden inside it. Create module_trampoline_target() that gives
the target address of a kernel module trampoline.
Signed-off-by: Anton Blanchard <anton@samba.org>
diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h
index f2711f0..dcfcad1 100644
--- a/arch/powerpc/include/asm/module.h
+++ b/arch/powerpc/include/asm/module.h
@@ -79,6 +79,8 @@
#endif
bool is_module_trampoline(u32 *insns);
+int module_trampoline_target(struct module *mod, u32 *trampoline,
+ unsigned long *target);
struct exception_table_entry;
void sort_ex_table(struct exception_table_entry *start,
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 4db5ecd..ef349d0 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -176,6 +176,35 @@
return true;
}
+int module_trampoline_target(struct module *mod, u32 *trampoline,
+ unsigned long *target)
+{
+ u32 buf[2];
+ u16 upper, lower;
+ long offset;
+ void *toc_entry;
+
+ if (probe_kernel_read(buf, trampoline, sizeof(buf)))
+ return -EFAULT;
+
+ upper = buf[0] & 0xffff;
+ lower = buf[1] & 0xffff;
+
+ /* perform the addis/addi, both signed */
+ offset = ((short)upper << 16) + (short)lower;
+
+ /*
+ * Now get the address this trampoline jumps to. This
+ * is always 32 bytes into our trampoline stub.
+ */
+ toc_entry = (void *)mod->arch.toc + offset + 32;
+
+ if (probe_kernel_read(target, toc_entry, sizeof(*target)))
+ return -EFAULT;
+
+ return 0;
+}
+
#endif
/* Count how many different 24-bit relocations (different symbol,