ARC: Always use SWAPE instructions for __arch_swab32()

Since commit 67a697e7576 ("ARC: retire ARC750 support") all supported
CPUs have the 'swape' instruction.

Always use the implementation of __arch_swabe() which uses 'swape'.
ARCH_USE_BUILTIN_BSWAP can not be used as that results on libcalls on
-mcpu=arc700.

As as side-effect, remove a leak of an internal kconfig symbol through
the UAPI headers.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/lkml/0ae2688a-5a22-405b-adaf-9b5ad712b245@app.fastmail.com/
Suggested-by: Vineet Gupta <vgupta@kernel.org>
Link: https://lore.kernel.org/lkml/a033a402-e3c5-4982-9fff-b6a4c55817ae@kernel.org/
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index f27e6b90428e450214fa77c7c77b52659b50852d..2ed7186c81c5730f254d96e4f963933930e5f6e1 100644 (file)
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -121,7 +121,6 @@ choice
 config ARC_CPU_770
        bool "ARC770"
        depends on ISA_ARCOMPACT
-       select ARC_HAS_SWAPE
        help
          Support for ARC770 core introduced with Rel 4.10 (Summer 2011)
          This core has a bunch of cool new features:
@@ -340,10 +339,6 @@ config ARC_HAS_LLSC
        default y
        depends on !ARC_CANT_LLSC
 
-config ARC_HAS_SWAPE
-       bool "Insn: SWAPE (endian-swap)"
-       default y
-
 if ISA_ARCV2
 
 config ARC_USE_UNALIGNED_MEM_ACCESS

diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 0c5e6e6314f2987edb21b035bd1b3ade6e9109b2..868805ffcfeab7cba17c6df79617b051aa7cfbb3 100644 (file)
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -9,7 +9,7 @@ ifeq ($(CROSS_COMPILE),)
 CROSS_COMPILE := $(call cc-cross-prefix, arc-linux- arceb-linux- arc-linux-gnu-)
 endif
 
-cflags-y       += -fno-common -pipe -fno-builtin -mmedium-calls -D__linux__
+cflags-y       += -fno-common -pipe -fno-builtin -mmedium-calls -mswape -D__linux__
 
 tune-mcpu-def-$(CONFIG_ISA_ARCOMPACT)  := -mcpu=arc700
 tune-mcpu-def-$(CONFIG_ISA_ARCV2)      := -mcpu=hs38
@@ -41,7 +41,6 @@ endif
 cflags-y                               += -fsection-anchors
 
 cflags-$(CONFIG_ARC_HAS_LLSC)          += -mlock
-cflags-$(CONFIG_ARC_HAS_SWAPE)         += -mswape
 
 ifdef CONFIG_ISA_ARCV2
 

diff --git a/arch/arc/include/uapi/asm/swab.h b/arch/arc/include/uapi/asm/swab.h
index 8d1f1ef44ba75078cdd5339dd6dff7cb2825e3c6..417ea30f29f5925b4606f7d86632bdcd8589a7d9 100644 (file)
--- a/arch/arc/include/uapi/asm/swab.h
+++ b/arch/arc/include/uapi/asm/swab.h
@@ -19,9 +19,6 @@
 
 #include <linux/types.h>
 
-/* Native single cycle endian swap insn */
-#ifdef CONFIG_ARC_HAS_SWAPE
-
 #define __arch_swab32(x)               \
 ({                                     \
        unsigned int tmp = x;           \
@@ -32,66 +29,6 @@
        tmp;                            \
 })
 
-#else
-
-/* Several ways of Endian-Swap Emulation for ARC
- * 0: kernel generic
- * 1: ARC optimised "C"
- * 2: ARC Custom instruction
- */
-#define ARC_BSWAP_TYPE 1
-
-#if (ARC_BSWAP_TYPE == 1)              /******* Software only ********/
-
-/* The kernel default implementation of htonl is
- *             return  x<<24 | x>>24 |
- *              (x & (__u32)0x0000ff00UL)<<8 | (x & (__u32)0x00ff0000UL)>>8;
- *
- * This generates 9 instructions on ARC (excluding the ld/st)
- *
- * 8051fd8c:   ld     r3,[r7,20]       ; Mem op : Get the value to be swapped
- * 8051fd98:   asl    r5,r3,24         ; get  3rd Byte
- * 8051fd9c:   lsr    r2,r3,24         ; get  0th Byte
- * 8051fda0:   and    r4,r3,0xff00
- * 8051fda8:   asl    r4,r4,8          ; get 1st Byte
- * 8051fdac:   and    r3,r3,0x00ff0000
- * 8051fdb4:   or     r2,r2,r5         ; combine 0th and 3rd Bytes
- * 8051fdb8:   lsr    r3,r3,8          ; 2nd Byte at correct place in Dst Reg
- * 8051fdbc:   or     r2,r2,r4         ; combine 0,3 Bytes with 1st Byte
- * 8051fdc0:   or     r2,r2,r3         ; combine 0,3,1 Bytes with 2nd Byte
- * 8051fdc4:   st     r2,[r1,20]       ; Mem op : save result back to mem
- *
- * Joern suggested a better "C" algorithm which is great since
- * (1) It is portable to any architecture
- * (2) At the same time it takes advantage of ARC ISA (rotate intrns)
- */
-
-#define __arch_swab32(x)                                       \
-({     unsigned long __in = (x), __tmp;                        \
-       __tmp = __in << 8 | __in >> 24; /* ror tmp,in,24 */     \
-       __in = __in << 24 | __in >> 8; /* ror in,in,8 */        \
-       __tmp ^= __in;                                          \
-       __tmp &= 0xff00ff;                                      \
-       __tmp ^ __in;                                           \
-})
-
-#elif (ARC_BSWAP_TYPE == 2)    /* Custom single cycle bswap instruction */
-
-#define __arch_swab32(x)                                               \
-({                                                                     \
-       unsigned int tmp = x;                                           \
-       __asm__(                                                        \
-       "       .extInstruction bswap, 7, 0x00, SUFFIX_NONE, SYNTAX_2OP \n"\
-       "       bswap  %0, %1                                           \n"\
-       : "=r" (tmp)                                                    \
-       : "r" (tmp));                                                   \
-       tmp;                                                            \
-})
-
-#endif /* ARC_BSWAP_TYPE=zzz */
-
-#endif /* CONFIG_ARC_HAS_SWAPE */
-
 #if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
 #define __SWAB_64_THRU_32__
 #endif

diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
index 0e4e939efc9409274a52c3112dcd62e29588357d..727f7f82c2c72142ea872cd8983ffa96097456b8 100755 (executable)
--- a/scripts/headers_install.sh
+++ b/scripts/headers_install.sh
@@ -70,7 +70,6 @@ configs=$(sed -e '
 #
 # The format is <file-name>:<CONFIG-option> in each line.
 config_leak_ignores="
-arch/arc/include/uapi/asm/swab.h:CONFIG_ARC_HAS_SWAPE
 arch/arm/include/uapi/asm/ptrace.h:CONFIG_CPU_ENDIAN_BE8
 arch/nios2/include/uapi/asm/swab.h:CONFIG_NIOS2_CI_SWAB_NO
 arch/nios2/include/uapi/asm/swab.h:CONFIG_NIOS2_CI_SWAB_SUPPORT