s390/string: Convert memset(16|32|64)() to C

Convert memset(16|32|64)() from assembler to C, which should make it
easier to read and change, if required. And it allows the compiler to
optimize the code, and use different instructions, except for the used
inline assemblies.

Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile
index e1f82d118bc95b8ac05b1f931d702ba078df1330..10b75e053a6f6bb9083548e8f82796f0aa9a9958 100644 (file)
--- a/arch/s390/boot/Makefile
+++ b/arch/s390/boot/Makefile
@@ -31,7 +31,7 @@ CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 CFLAGS_string.o = -ffreestanding
 
 obj-y  := head.o als.o startup.o physmem_info.o ipl_parm.o ipl_report.o vmem.o
-obj-y  += string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o
+obj-y  += string.o ebcdic.o sclp_early_core.o ipl_vmparm.o cmdline.o
 obj-y  += version.o pgm_check.o ctype.o ipl_data.o relocs.o alternative.o
 obj-y  += uv.o printk.o trampoline.o
 obj-$(CONFIG_RANDOMIZE_BASE)   += kaslr.o

diff --git a/arch/s390/boot/mem.S b/arch/s390/boot/mem.S
deleted file mode 100644 (file)
index b334636..0000000
--- a/arch/s390/boot/mem.S
+++ /dev/null
@@ -1,2 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#include "../lib/mem.S"

diff --git a/arch/s390/boot/string.c b/arch/s390/boot/string.c
index bd68161434a602a0c73ce354ce743753cf3e68f0..e4ad196cb7200ff70ae52c601ec94acabfb76330 100644 (file)
--- a/arch/s390/boot/string.c
+++ b/arch/s390/boot/string.c
@@ -43,11 +43,7 @@ ssize_t sized_strscpy(char *dst, const char *src, size_t count)
 
 void *memset64(uint64_t *s, uint64_t v, size_t count)
 {
-       uint64_t *xs = s;
-
-       while (count--)
-               *xs++ = v;
-       return s;
+       return __memset64(s, v, count * sizeof(v));
 }
 
 char *skip_spaces(const char *str)

diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
index c82aedef027287fa33e3cd9273688f941fec83ac..aa6cc6a1fe88151ce84a23d07a4b420fed749e89 100644 (file)
--- a/arch/s390/lib/Makefile
+++ b/arch/s390/lib/Makefile
@@ -10,7 +10,6 @@ CFLAGS_string.o = -ffreestanding
 
 lib-y += delay.o string.o uaccess.o find.o spinlock.o tishift.o
 lib-y += csum-partial.o
-obj-y += mem.o
 lib-$(CONFIG_KPROBES) += probes.o
 lib-$(CONFIG_UPROBES) += probes.o
 obj-$(CONFIG_S390_KPROBES_SANITY_TEST) += test_kprobes_s390.o

diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S
deleted file mode 100644 (file)
index d2e1ca8..0000000
--- a/arch/s390/lib/mem.S
+++ /dev/null
@@ -1,57 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * String handling functions.
- *
- * Copyright IBM Corp. 2012
- */
-
-#include <linux/export.h>
-#include <linux/linkage.h>
-#include <asm/nospec-insn.h>
-
-       GEN_BR_THUNK %r14
-
-/*
- * __memset16/32/64
- *
- * void *__memset16(uint16_t *s, uint16_t v, size_t count)
- * void *__memset32(uint32_t *s, uint32_t v, size_t count)
- * void *__memset64(uint64_t *s, uint64_t v, size_t count)
- */
-.macro __MEMSET bits,bytes,insn
-SYM_FUNC_START(__memset\bits)
-       ltgr    %r4,%r4
-       jz      .L__memset_exit\bits
-       cghi    %r4,\bytes
-       je      .L__memset_store\bits
-       aghi    %r4,-(\bytes+1)
-       srlg    %r5,%r4,8
-       ltgr    %r5,%r5
-       lgr     %r1,%r2
-       jz      .L__memset_remainder\bits
-.L__memset_loop\bits:
-       \insn   %r3,0(%r1)
-       mvc     \bytes(256-\bytes,%r1),0(%r1)
-       la      %r1,256(%r1)
-       brctg   %r5,.L__memset_loop\bits
-.L__memset_remainder\bits:
-       \insn   %r3,0(%r1)
-       exrl    %r4,.L__memset_mvc\bits
-       BR_EX   %r14
-.L__memset_store\bits:
-       \insn   %r3,0(%r2)
-.L__memset_exit\bits:
-       BR_EX   %r14
-.L__memset_mvc\bits:
-       mvc     \bytes(1,%r1),0(%r1)
-SYM_FUNC_END(__memset\bits)
-.endm
-
-__MEMSET 16,2,sth
-EXPORT_SYMBOL(__memset16)
-
-__MEMSET 32,4,st
-EXPORT_SYMBOL(__memset32)
-
-__MEMSET 64,8,stg
-EXPORT_SYMBOL(__memset64)

diff --git a/arch/s390/lib/string.c b/arch/s390/lib/string.c
index 056ea2027ddd2d435f0b93f1214c66beb3ce6ccd..cb65b8f5392a98f663500d837c76d25aa7c9bc3b 100644 (file)
--- a/arch/s390/lib/string.c
+++ b/arch/s390/lib/string.c
@@ -158,6 +158,53 @@ EXPORT_SYMBOL(__memcpy);
 EXPORT_SYMBOL(memcpy);
 #endif
 
+#define DEFINE_MEMSET(_bits, _bytes, _type)                                    \
+void *__memset##_bits(_type *s, _type v, size_t n)                             \
+{                                                                              \
+       _type *xs = s;                                                          \
+                                                                               \
+       if (!n)                                                                 \
+               return s;                                                       \
+       while (n >= 256) {                                                      \
+               *xs = v;                                                        \
+               asm volatile(                                                   \
+                       "       mvc     %[_b](256-%[_b],%[xs]),0(%[xs])\n"      \
+                       :                                                       \
+                       : [xs] "a" (xs), [_b] "i" (_bytes)                      \
+                       : "memory");                                            \
+               xs = (_type *)((char *)xs + 256);                               \
+               n -= 256;                                                       \
+       }                                                                       \
+       if (!n)                                                                 \
+               return s;                                                       \
+       *xs = v;                                                                \
+       if (n == _bytes)                                                        \
+               return s;                                                       \
+       n -= _bytes + 1;                                                        \
+       asm volatile(                                                           \
+               "       exrl     %[n],1f\n"                                     \
+               "       j        2f\n"                                          \
+               "1:     mvc      %[_b](1,%[xs]),0(%[xs])\n"                     \
+               "2:"                                                            \
+               :                                                               \
+               : [n] "a" (n), [xs] "a" (xs), [_b] "i" (_bytes)                 \
+               : "memory");                                                    \
+       return s;                                                               \
+}                                                                              \
+EXPORT_SYMBOL(__memset##_bits)
+
+#ifdef __HAVE_ARCH_MEMSET16
+DEFINE_MEMSET(16, 2, uint16_t);
+#endif
+
+#ifdef __HAVE_ARCH_MEMSET32
+DEFINE_MEMSET(32, 4, uint32_t);
+#endif
+
+#ifdef __HAVE_ARCH_MEMSET64
+DEFINE_MEMSET(64, 8, uint64_t);
+#endif
+
 /*
  * Helper functions to find the end of a string
  */

diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile
index f55764d0c49e4a7dc592444e3360660bad5eecd7..e74410bb1b8841472670117bde461425de8fde9b 100644 (file)
--- a/arch/s390/purgatory/Makefile
+++ b/arch/s390/purgatory/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-purgatory-y := head.o purgatory.o string.o sha256.o mem.o
+purgatory-y := head.o purgatory.o string.o sha256.o
 
 targets += $(purgatory-y) purgatory.lds purgatory purgatory.chk purgatory.ro
 PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
@@ -10,9 +10,6 @@ $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 
 CFLAGS_sha256.o := -D__NO_FORTIFY
 
-$(obj)/mem.o: $(srctree)/arch/s390/lib/mem.S FORCE
-       $(call if_changed_rule,as_o_S)
-
 CC_FLAGS_MARCH_MINIMUM := -march=z10
 
 KBUILD_CFLAGS := $(CC_FLAGS_DIALECT) -fno-strict-aliasing -Wall -Wstrict-prototypes