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arch/tile: update some comments to clarify register usage.

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Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
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Chris Metcalf
2010-10-14 14:42:58 -04:00
parent 5592840ba8
commit d6f0f22c3c
2 changed files with 6 additions and 3 deletions
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7
arch/tile/kernel/process.c
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@@ -214,9 +214,10 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
/*
* Copy the callee-saved registers from the passed pt_regs struct
* into the context-switch callee-saved registers area.
* We have to restore the callee-saved registers since we may
* be cloning a userspace task with userspace register state,
* and we won't be unwinding the same kernel frames to restore them.
* This way when we start the interrupt-return sequence, the
* callee-save registers will be correctly in registers, which
* is how we assume the compiler leaves them as we start doing
* the normal return-from-interrupt path after calling C code.
* Zero out the C ABI save area to mark the top of the stack.
*/
ksp = (unsigned long) childregs;