powerpc: use switch frame for ret_from_kernel_thread parameters

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The kernel thread path in copy_thread creates a user interrupt frame on
stack and stores the function and arg parameters there, and
ret_from_kernel_thread loads them. This is a slightly confusing way to
overload that frame. Non-volatile registers are loaded from the switch
frame, so the parameters can be stored there. The user interrupt frame
is now only used by user threads when they return to user.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230325122904.2375060-4-npiggin@gmail.com

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Nicholas Piggin 2023-03-25 22:28:59 +10:00 • committed by Michael Ellerman

parent 959791e45f

commit af5ca9d5c8

3 changed files with 9 additions and 6 deletions

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1

arch/powerpc/kernel/entry_32.S

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1

arch/powerpc/kernel/interrupt_64.S

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13

arch/powerpc/kernel/process.c

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