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MIPS: Use Kconfig to select CPU_NO_EFFICIENT_FFS 

Select CONFIG_CPU_NO_EFFICIENT_FFS via Kconfig when the kernel is
configured for a pre-MIPS32r1 CPU, rather than defining its equivalent
in asm/cpu-features.h based upon overrides of cpu_has_mips* macros.

The latter only works if a platform has an cpu-feature-overrides.h
header which defines cpu_has_mips* macros, which are not generally
needed. There are many cases where we know that the target ISA for a
kernel build is MIPS32r1 or later & thus includes the CLZ instruction,
without requiring any overrides from the platform. Using Kconfig allows
us to take those into account, and more naturally make a decision about
instruction support using information about the target ISA.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21045/
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
hifive-unleashed-5.1
Paul Burton 2018-11-08 23:44:55 +00:00
parent 47bf2b0317
commit 57eeacede4
No known key found for this signature in database
GPG Key ID: 3EA79FACB57500DD
2 changed files with 12 additions and 11 deletions
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13
arch/mips/Kconfig
View File

@ -15,6 +15,7 @@ config MIPS
select ARCH_WANT_IPC_PARSE_VERSION
select BUILDTIME_EXTABLE_SORT
select CLONE_BACKWARDS
select CPU_NO_EFFICIENT_FFS if (TARGET_ISA_REV < 1)
select CPU_PM if CPU_IDLE
select DMA_DIRECT_OPS
select GENERIC_ATOMIC64 if !64BIT
@ -2031,7 +2032,7 @@ config CPU_MIPS64
default y if CPU_MIPS64_R1 || CPU_MIPS64_R2 || CPU_MIPS64_R6
#
# These two indicate the revision of the architecture, either Release 1 or Release 2
# These indicate the revision of the architecture
#
config CPU_MIPSR1
bool
@ -2052,6 +2053,16 @@ config CPU_MIPSR6
select MIPS_CRC_SUPPORT
select MIPS_SPRAM
config TARGET_ISA_REV
int
default 1 if CPU_MIPSR1
default 2 if CPU_MIPSR2
default 6 if CPU_MIPSR6
default 0
help
Reflects the ISA revision being targeted by the kernel build. This
is effectively the Kconfig equivalent of MIPS_ISA_REV.
config EVA
bool

10
arch/mips/include/asm/cpu-features.h
View File

@ -253,16 +253,6 @@
#endif
#endif
/* __builtin_constant_p(cpu_has_mips_r) && cpu_has_mips_r */
#if !((defined(cpu_has_mips32r1) && cpu_has_mips32r1) || \
(defined(cpu_has_mips32r2) && cpu_has_mips32r2) || \
(defined(cpu_has_mips32r6) && cpu_has_mips32r6) || \
(defined(cpu_has_mips64r1) && cpu_has_mips64r1) || \
(defined(cpu_has_mips64r2) && cpu_has_mips64r2) || \
(defined(cpu_has_mips64r6) && cpu_has_mips64r6))
#define CPU_NO_EFFICIENT_FFS 1
#endif
#ifndef cpu_has_mips_1
# define cpu_has_mips_1 (!cpu_has_mips_r6)
#endif