WSL2-Linux-Kernel/arch/mips/lib
James Hogan ebabcf17bc MIPS: Implement __multi3 for GCC7 MIPS64r6 builds
GCC7 is a bit too eager to generate suboptimal __multi3 calls (128bit
multiply with 128bit result) for MIPS64r6 builds, even in code which
doesn't explicitly use 128bit types, such as the following:

unsigned long func(unsigned long a, unsigned long b)
{
	return a > (~0UL) / b;
}

Which GCC rearanges to:

return (unsigned __int128)a * (unsigned __int128)b > 0xffffffffffffffff;

Therefore implement __multi3, but only for MIPS64r6 with GCC7 as under
normal circumstances we wouldn't expect any calls to __multi3 to be
generated from kernel code.

Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: James Hogan <jhogan@kernel.org>
Tested-by: Waldemar Brodkorb <wbx@openadk.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Maciej W. Rozycki <macro@mips.com>
Cc: Matthew Fortune <matthew.fortune@mips.com>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17890/
2018-01-11 14:40:31 +01:00
..
Makefile MIPS: Implement __multi3 for GCC7 MIPS64r6 builds 2018-01-11 14:40:31 +01:00
ashldi3.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ashrdi3.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bitops.c MIPS: Remove unneeded volatile from arch/mips/lib/bitops.c 2013-05-08 01:19:06 +02:00
bswapdi.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bswapsi.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cmpdi2.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
csum_partial.S MIPS: Export csum functions alongside their definitions 2017-01-03 16:34:50 +01:00
delay.c MIPS: Include asm/delay.h for __{,n,u}delay() 2017-08-29 15:21:54 +02:00
dump_tlb.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iomap-pci.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iomap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iomap_copy.c MIPS: Add __ioread64_copy 2017-09-04 13:53:14 +02:00
libgcc.h MIPS: Implement __multi3 for GCC7 MIPS64r6 builds 2018-01-11 14:40:31 +01:00
lshrdi3.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
memcpy.S MIPS: R6: Fix PREF instruction usage by memcpy for MIPS R6 2017-06-29 02:42:24 +02:00
memset.S MIPS: Export memcpy & memset functions alongside their definitions 2017-01-03 16:34:50 +01:00
mips-atomic.c MIPS: Cleanup the unused __arch_local_irq_restore() function 2016-01-22 01:58:49 +01:00
multi3.c MIPS: Implement __multi3 for GCC7 MIPS64r6 builds 2018-01-11 14:40:31 +01:00
r3k_dump_tlb.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
strncpy_user.S get rid of unused __strncpy_from_user() instances 2017-05-15 23:40:28 -04:00
strnlen_user.S mips: get rid of unused __strnlen_user() 2017-05-15 23:40:32 -04:00
ucmpdi2.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
uncached.c mips: delete non-required instances of include <linux/init.h> 2014-01-24 22:39:56 +01:00