Commit 4c25f0ff authored by Heiko Carstens's avatar Heiko Carstens
Browse files

s390/entry: workaround llvm's IAS limitations 



llvm's integrated assembler cannot handle immediate values which are
calculated with two local labels:

<instantiation>:3:13: error: invalid operand for instruction
 clgfi %r14,.Lsie_done - .Lsie_gmap

Workaround this by adding clang specific code which reads the specific
value from memory. Since this code is within the hot paths of the kernel
and adds an additional memory reference, keep the original code, and add
ifdef'ed code.

Acked-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/r/20220511120532.2228616-5-hca@linux.ibm.com


Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent e6ed91fd

arch/s390/kernel/entry.S

+12 −2
Original line number Diff line number Diff line
@@ -172,9 +172,19 @@ _LPP_OFFSET = __LC_LPP 
	lgr	%r14,\reg

	larl	%r13,\start

	slgr	%r14,%r13

	lghi	%r13,\end - \start

	clgr	%r14,%r13

#ifdef CONFIG_AS_IS_LLVM

	clgfrl	%r14,.Lrange_size\@

#else

	clgfi	%r14,\end - \start

#endif

	jhe	\outside_label

#ifdef CONFIG_AS_IS_LLVM

	.section .rodata, "a"

	.align 4

.Lrange_size\@:

	.long	\end - \start

	.previous

#endif

	.endm



	.macro SIEEXIT