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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>
This commit is contained in:
Steven Rostedt 2009-09-15 08:30:14 -07:00 committed by Steven Rostedt
parent 9135c3cc5a
commit be10ab1090
1 changed files with 1 additions and 2 deletions
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3
arch/powerpc/kernel/entry_64.S
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@ -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