The following commit has been merged in the linux branch: commit be10ab109099f8bd8dd365677a9fe641584c1b5b Author: Steven Rostedt srostedt@redhat.com Date: Tue Sep 15 08:30:14 2009 -0700

powerpc64/ftrace: use PACA to retrieve TOC in mod_return_to_handler

The mod_return_to_handler needs to switch to the kernel TOC before jumping to a the kernel code. It currently does this by looking at the kernel function data and retrieves the TOC that way.

Not only is this inefficient, it also breaks with a relocatable kernel. The PACA contains the kernel TOC and we can easily retrieve it that way.

Reported-by: Sachin Sant sachinp@in.ibm.com Signed-off-by: Steven Rostedt rostedt@goodmis.org

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 900e0ee..f9fd54b 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -1038,8 +1038,7 @@ _GLOBAL(mod_return_to_handler) * We are in a module using the module's TOC. * Switch to our TOC to run inside the core kernel. */ - LOAD_REG_IMMEDIATE(r4,ftrace_return_to_handler) - ld r2, 8(r4) + ld r2, PACATOC(r13)

bl .ftrace_return_to_handler nop