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| author | Alexander Lobakin <alobakin@dlink.ru> | 2020-01-22 13:58:50 +0300 |
|---|---|---|
| committer | Paul Burton <paulburton@kernel.org> | 2020-01-22 10:16:47 -0800 |
| commit | 18d84e2e55b6abe1e5b8a658ad078796122899fb (patch) | |
| tree | e31bb34a5203c09d6aa16a06f4d2c25ff6ba6039 /arch/mips/lib/memcpy.S | |
| parent | 7de86604bbe4ecb3da0c8c40d4e4b1549e879f92 (diff) | |
| download | lwn-18d84e2e55b6abe1e5b8a658ad078796122899fb.tar.gz lwn-18d84e2e55b6abe1e5b8a658ad078796122899fb.zip | |
MIPS: make CPU_HAS_LOAD_STORE_LR opt-out
CPU_HAS_LOAD_STORE_LR was introduced in 932afdeec18b ("MIPS: Add Kconfig
variable for CPUs with unaligned load/store instructions") to make code
in kernel/unaligned.c and lib/mem{cpy,set}.S more intuitive and give a
possibility to easily add new CPUs without these instruction sets in
future.
Hovewer, this variant is not optimal for mainly two reasons:
* For now, we have 20+ CPUs with such instructions and only two (MIPS R6)
without. It will obviously be more effective and straightforward to
have an option for these two rather than for the rest.
* You can easily miss the fact that you need to select this option when
adding a new CPU, while all processors lacking these sets are
well-known, so the probability of missing something is way much lower.
We can address both points by turning CPU_HAS_LOAD_STORE_LR into opt-out
CPU_NO_LOAD_STORE_LR. This also makes MIPS root Kconfig more clear and
understandable.
Signed-off-by: Alexander Lobakin <alobakin@dlink.ru>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
Cc: Will Deacon <will@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'arch/mips/lib/memcpy.S')
| -rw-r--r-- | arch/mips/lib/memcpy.S | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/mips/lib/memcpy.S b/arch/mips/lib/memcpy.S index cdd19d8561e8..f7994d936505 100644 --- a/arch/mips/lib/memcpy.S +++ b/arch/mips/lib/memcpy.S @@ -301,14 +301,14 @@ and t0, src, ADDRMASK PREFS( 0, 2*32(src) ) PREFD( 1, 2*32(dst) ) -#ifdef CONFIG_CPU_HAS_LOAD_STORE_LR +#ifndef CONFIG_CPU_NO_LOAD_STORE_LR bnez t1, .Ldst_unaligned\@ nop bnez t0, .Lsrc_unaligned_dst_aligned\@ -#else +#else /* CONFIG_CPU_NO_LOAD_STORE_LR */ or t0, t0, t1 bnez t0, .Lcopy_unaligned_bytes\@ -#endif +#endif /* CONFIG_CPU_NO_LOAD_STORE_LR */ /* * use delay slot for fall-through * src and dst are aligned; need to compute rem @@ -389,7 +389,7 @@ bne rem, len, 1b .set noreorder -#ifdef CONFIG_CPU_HAS_LOAD_STORE_LR +#ifndef CONFIG_CPU_NO_LOAD_STORE_LR /* * src and dst are aligned, need to copy rem bytes (rem < NBYTES) * A loop would do only a byte at a time with possible branch @@ -491,7 +491,7 @@ bne len, rem, 1b .set noreorder -#endif /* CONFIG_CPU_HAS_LOAD_STORE_LR */ +#endif /* !CONFIG_CPU_NO_LOAD_STORE_LR */ .Lcopy_bytes_checklen\@: beqz len, .Ldone\@ nop @@ -520,7 +520,7 @@ jr ra nop -#ifndef CONFIG_CPU_HAS_LOAD_STORE_LR +#ifdef CONFIG_CPU_NO_LOAD_STORE_LR .Lcopy_unaligned_bytes\@: 1: COPY_BYTE(0) @@ -534,7 +534,7 @@ ADD src, src, 8 b 1b ADD dst, dst, 8 -#endif /* !CONFIG_CPU_HAS_LOAD_STORE_LR */ +#endif /* CONFIG_CPU_NO_LOAD_STORE_LR */ .if __memcpy == 1 END(memcpy) .set __memcpy, 0 |