diff options
| author | Maciej W. Rozycki <macro@orcam.me.uk> | 2026-03-30 02:54:09 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-11 14:29:42 +0200 |
| commit | 37459f84cf22ff9f84c8589839ea1448e79295b5 (patch) | |
| tree | af6ea692928971df2e30981f4a334f0064c3e9eb /arch | |
| parent | 2e65996ad8aca332e5f694589f9be1265aa8bad0 (diff) | |
MIPS: Fix the GCC version check for `__multi3' workaround
commit ec8bf18814915460d9c617b556bf024efef26613 upstream.
It was only GCC 10 that fixed a MIPS64r6 code generation issue with a
`__multi3' libcall inefficiently produced to perform 64-bit widening
multiplication while suitable machine instructions exist to do such a
calculation. The fix went in with GCC commit 48b2123f6336 ("re PR
target/82981 (unnecessary __multi3 call for mips64r6 linux kernel)").
Adjust our code accordingly, removing build failures such as:
mips64-linux-ld: lib/math/div64.o: in function `mul_u64_add_u64_div_u64':
div64.c:(.text+0x84): undefined reference to `__multi3'
with the GCC versions affected.
Fixes: ebabcf17bcd7 ("MIPS: Implement __multi3 for GCC7 MIPS64r6 builds")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202601140146.hMLODc6v-lkp@intel.com/
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v4.15+
Reviewed-by: David Laight <david.laight.linux@gmail.com.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/lib/multi3.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/mips/lib/multi3.c b/arch/mips/lib/multi3.c index 4c2483f410c2..92b3778bb56f 100644 --- a/arch/mips/lib/multi3.c +++ b/arch/mips/lib/multi3.c @@ -4,12 +4,12 @@ #include "libgcc.h" /* - * GCC 7 & older can suboptimally generate __multi3 calls for mips64r6, so for + * GCC 9 & older can suboptimally generate __multi3 calls for mips64r6, so for * that specific case only we implement that intrinsic here. * * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981 */ -#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ < 8) +#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ < 10) /* multiply 64-bit values, low 64-bits returned */ static inline long long notrace dmulu(long long a, long long b) @@ -51,4 +51,4 @@ ti_type notrace __multi3(ti_type a, ti_type b) } EXPORT_SYMBOL(__multi3); -#endif /* 64BIT && CPU_MIPSR6 && GCC7 */ +#endif /* 64BIT && CPU_MIPSR6 && GCC9 */ |