arm64: Implement __lshrti3 library function
Commit fb8722735f50 ("arm64: support __int128 on gcc 5+") added support
for the __int128 data type, but this breaks the build in some configurations
where GCC ends up emitting calls to the __lshrti3 helper in libgcc, which
results in a link error:
kernel/sched/fair.o: In function `__calc_delta':
fair.c:(.text+0xca0): undefined reference to `__lshrti3'
kernel/time/timekeeping.o: In function `timekeeping_resume':
timekeeping.c:(.text+0x3f60): undefined reference to `__lshrti3'
make: *** [vmlinux] Error 1
Fix the build by providing an implementation of __lshrti3, like we do
already for __ashlti3 and __ashrti3.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/lib/tishift.S b/arch/arm64/lib/tishift.S
index 7236776..0179a43 100644
--- a/arch/arm64/lib/tishift.S
+++ b/arch/arm64/lib/tishift.S
@@ -57,3 +57,24 @@
mov x1, x2
ret
ENDPROC(__ashrti3)
+
+ENTRY(__lshrti3)
+ cbz x2, 1f
+ mov x3, #64
+ sub x3, x3, x2
+ cmp x3, #0
+ b.le 2f
+ lsr x0, x0, x2
+ lsl x3, x1, x3
+ lsr x2, x1, x2
+ orr x0, x0, x3
+ mov x1, x2
+1:
+ ret
+2:
+ neg w0, w3
+ mov x2, #0
+ lsr x0, x1, x0
+ mov x1, x2
+ ret
+ENDPROC(__lshrti3)