7 files changed, 24 insertions, 72 deletions
diff --git a/tools/arch/x86/lib/memcpy_64.S b/tools/arch/x86/lib/memcpy_64.S
index a91ac666f758..d055b82d22cc 100644
--- a/tools/arch/x86/lib/memcpy_64.S
+++ b/tools/arch/x86/lib/memcpy_64.S
@@ -10,13 +10,6 @@
 .section .noinstr.text, "ax"
 
 /*
- * We build a jump to memcpy_orig by default which gets NOPped out on
- * the majority of x86 CPUs which set REP_GOOD. In addition, CPUs which
- * have the enhanced REP MOVSB/STOSB feature (ERMS), change those NOPs
- * to a jmp to memcpy_erms which does the REP; MOVSB mem copy.
- */
-
-/*
  * memcpy - Copy a memory block.
  *
  * Input:
@@ -26,17 +19,21 @@
  *
  * Output:
  * rax original destination
+ *
+ * The FSRM alternative should be done inline (avoiding the call and
+ * the disgusting return handling), but that would require some help
+ * from the compiler for better calling conventions.
+ *
+ * The 'rep movsb' itself is small enough to replace the call, but the
+ * two register moves blow up the code. And one of them is "needed"
+ * only for the return value that is the same as the source input,
+ * which the compiler could/should do much better anyway.
  */
 SYM_TYPED_FUNC_START(__memcpy)
-	ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \
-		      "jmp memcpy_erms", X86_FEATURE_ERMS
+	ALTERNATIVE "jmp memcpy_orig", "", X86_FEATURE_FSRM
 
 	movq %rdi, %rax
 	movq %rdx, %rcx
-	shrq $3, %rcx
-	andl $7, %edx
-	rep movsq
-	movl %edx, %ecx
 	rep movsb
 	RET
 SYM_FUNC_END(__memcpy)
@@ -45,17 +42,6 @@ EXPORT_SYMBOL(__memcpy)
 SYM_FUNC_ALIAS(memcpy, __memcpy)
 EXPORT_SYMBOL(memcpy)
 
-/*
- * memcpy_erms() - enhanced fast string memcpy. This is faster and
- * simpler than memcpy. Use memcpy_erms when possible.
- */
-SYM_FUNC_START_LOCAL(memcpy_erms)
-	movq %rdi, %rax
-	movq %rdx, %rcx
-	rep movsb
-	RET
-SYM_FUNC_END(memcpy_erms)
-
 SYM_FUNC_START_LOCAL(memcpy_orig)
 	movq %rdi, %rax
 
diff --git a/tools/arch/x86/lib/memset_64.S b/tools/arch/x86/lib/memset_64.S
index 6143b1a6fa2c..7c59a704c458 100644
--- a/tools/arch/x86/lib/memset_64.S
+++ b/tools/arch/x86/lib/memset_64.S
@@ -18,27 +18,22 @@
  * rdx   count (bytes)
  *
  * rax   original destination
+ *
+ * The FSRS alternative should be done inline (avoiding the call and
+ * the disgusting return handling), but that would require some help
+ * from the compiler for better calling conventions.
+ *
+ * The 'rep stosb' itself is small enough to replace the call, but all
+ * the register moves blow up the code. And two of them are "needed"
+ * only for the return value that is the same as the source input,
+ * which the compiler could/should do much better anyway.
  */
 SYM_FUNC_START(__memset)
-	/*
-	 * Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended
-	 * to use it when possible. If not available, use fast string instructions.
-	 *
-	 * Otherwise, use original memset function.
-	 */
-	ALTERNATIVE_2 "jmp memset_orig", "", X86_FEATURE_REP_GOOD, \
-		      "jmp memset_erms", X86_FEATURE_ERMS
+	ALTERNATIVE "jmp memset_orig", "", X86_FEATURE_FSRS
 
 	movq %rdi,%r9
+	movb %sil,%al
 	movq %rdx,%rcx
-	andl $7,%edx
-	shrq $3,%rcx
-	/* expand byte value  */
-	movzbl %sil,%esi
-	movabs $0x0101010101010101,%rax
-	imulq %rsi,%rax
-	rep stosq
-	movl %edx,%ecx
 	rep stosb
 	movq %r9,%rax
 	RET
@@ -48,26 +43,6 @@ EXPORT_SYMBOL(__memset)
 SYM_FUNC_ALIAS(memset, __memset)
 EXPORT_SYMBOL(memset)
 
-/*
- * ISO C memset - set a memory block to a byte value. This function uses
- * enhanced rep stosb to override the fast string function.
- * The code is simpler and shorter than the fast string function as well.
- *
- * rdi   destination
- * rsi   value (char)
- * rdx   count (bytes)
- *
- * rax   original destination
- */
-SYM_FUNC_START_LOCAL(memset_erms)
-	movq %rdi,%r9
-	movb %sil,%al
-	movq %rdx,%rcx
-	rep stosb
-	movq %r9,%rax
-	RET
-SYM_FUNC_END(memset_erms)
-
 SYM_FUNC_START_LOCAL(memset_orig)
 	movq %rdi,%r10
 
diff --git a/tools/include/asm/alternative.h b/tools/include/asm/alternative.h
index b54bd860dff6..7ce02a223732 100644
--- a/tools/include/asm/alternative.h
+++ b/tools/include/asm/alternative.h
@@ -4,7 +4,6 @@
 
 /* Just disable it so we can build arch/x86/lib/memcpy_64.S for perf bench: */
 
-#define altinstruction_entry #
-#define ALTERNATIVE_2 #
+#define ALTERNATIVE #
 
 #endif
diff --git a/tools/perf/bench/mem-memcpy-x86-64-asm-def.h b/tools/perf/bench/mem-memcpy-x86-64-asm-def.h
index 50ae8bd58296..6188e19d3129 100644
--- a/tools/perf/bench/mem-memcpy-x86-64-asm-def.h
+++ b/tools/perf/bench/mem-memcpy-x86-64-asm-def.h
@@ -7,7 +7,3 @@ MEMCPY_FN(memcpy_orig,
 MEMCPY_FN(__memcpy,
 	"x86-64-movsq",
 	"movsq-based memcpy() in arch/x86/lib/memcpy_64.S")
-
-MEMCPY_FN(memcpy_erms,
-	"x86-64-movsb",
-	"movsb-based memcpy() in arch/x86/lib/memcpy_64.S")
diff --git a/tools/perf/bench/mem-memcpy-x86-64-asm.S b/tools/perf/bench/mem-memcpy-x86-64-asm.S
index 6eb45a2aa8db..1b9fef7efcdc 100644
--- a/tools/perf/bench/mem-memcpy-x86-64-asm.S
+++ b/tools/perf/bench/mem-memcpy-x86-64-asm.S
@@ -2,7 +2,7 @@
 
 /* Various wrappers to make the kernel .S file build in user-space: */
 
-// memcpy_orig and memcpy_erms are being defined as SYM_L_LOCAL but we need it
+// memcpy_orig is being defined as SYM_L_LOCAL but we need it
 #define SYM_FUNC_START_LOCAL(name)                      \
         SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
 #define memcpy MEMCPY /* don't hide glibc's memcpy() */
diff --git a/tools/perf/bench/mem-memset-x86-64-asm-def.h b/tools/perf/bench/mem-memset-x86-64-asm-def.h
index dac6d2b7c39b..247c72fdfb9d 100644
--- a/tools/perf/bench/mem-memset-x86-64-asm-def.h
+++ b/tools/perf/bench/mem-memset-x86-64-asm-def.h
@@ -7,7 +7,3 @@ MEMSET_FN(memset_orig,
 MEMSET_FN(__memset,
 	"x86-64-stosq",
 	"movsq-based memset() in arch/x86/lib/memset_64.S")
-
-MEMSET_FN(memset_erms,
-	"x86-64-stosb",
-	"movsb-based memset() in arch/x86/lib/memset_64.S")
diff --git a/tools/perf/bench/mem-memset-x86-64-asm.S b/tools/perf/bench/mem-memset-x86-64-asm.S
index 6f093c483842..abd26c95f1aa 100644
--- a/tools/perf/bench/mem-memset-x86-64-asm.S
+++ b/tools/perf/bench/mem-memset-x86-64-asm.S
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-// memset_orig and memset_erms are being defined as SYM_L_LOCAL but we need it
+// memset_orig is being defined as SYM_L_LOCAL but we need it
 #define SYM_FUNC_START_LOCAL(name)                      \
         SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
 #define memset MEMSET /* don't hide glibc's memset() */