Commit 89bbe4c7 authored Jun 11, 2020 by Nicholas Piggin Committed by Michael Ellerman Jun 22, 2020

powerpc/64: indirect function call use bctrl rather than blrl in ret_from_kernel_thread



blrl is not recommended to use as an indirect function call, as it may
corrupt the link stack predictor.

This is not a performance critical path but this should be fixed for
consistency.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611121119.1015740-1-npiggin@gmail.com

parent 48778464

arch/powerpc/kernel/entry_64.S

+2 −2

Original line number	Diff line number	Diff line
		@@ -233,12 +233,12 @@ _GLOBAL(ret_from_fork)
		_GLOBAL(ret_from_kernel_thread)
		bl schedule_tail
		REST_NVGPRS(r1)
		mtlr r14
		mtctr r14
		mr r3,r15
		#ifdef PPC64_ELF_ABI_v2
		mr r12,r14
		#endif
		blrl
		bctrl
		li r3,0
		b .Lsyscall_exit