Merge tag 'x86_asm_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 asm updates from Borislav Petkov:

 - Move the 32-bit memmove() asm implementation out-of-line in order to
   fix a 32-bit full LTO build failure with clang where it would fail at
   register allocation.

   Move it to an asm file and clean it up while at it, similar to what
   has been already done on 64-bit

* tag 'x86_asm_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mem: Move memmove to out of line assembler

4 files changed, 223 insertions, 187 deletions

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 7ba5f61d7273..4f1a40a86534 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -60,6 +60,7 @@ ifeq ($(CONFIG_X86_32),y)
         lib-y += checksum_32.o
         lib-y += strstr_32.o
         lib-y += string_32.o
+        lib-y += memmove_32.o
 ifneq ($(CONFIG_X86_CMPXCHG64),y)
         lib-y += cmpxchg8b_emu.o atomic64_386_32.o
 endif
diff --git a/arch/x86/lib/memcpy_32.c b/arch/x86/lib/memcpy_32.c
index ef3af7ff2c8a..a29b64befb93 100644
--- a/arch/x86/lib/memcpy_32.c
+++ b/arch/x86/lib/memcpy_32.c
@@ -17,190 +17,3 @@ __visible void *memset(void *s, int c, size_t count)
 	return __memset(s, c, count);
 }
 EXPORT_SYMBOL(memset);
-
-__visible void *memmove(void *dest, const void *src, size_t n)
-{
-	int d0,d1,d2,d3,d4,d5;
-	char *ret = dest;
-
-	__asm__ __volatile__(
-		/* Handle more 16 bytes in loop */
-		"cmp $0x10, %0\n\t"
-		"jb	1f\n\t"
-
-		/* Decide forward/backward copy mode */
-		"cmp %2, %1\n\t"
-		"jb	2f\n\t"
-
-		/*
-		 * movs instruction have many startup latency
-		 * so we handle small size by general register.
-		 */
-		"cmp  $680, %0\n\t"
-		"jb 3f\n\t"
-		/*
-		 * movs instruction is only good for aligned case.
-		 */
-		"mov %1, %3\n\t"
-		"xor %2, %3\n\t"
-		"and $0xff, %3\n\t"
-		"jz 4f\n\t"
-		"3:\n\t"
-		"sub $0x10, %0\n\t"
-
-		/*
-		 * We gobble 16 bytes forward in each loop.
-		 */
-		"3:\n\t"
-		"sub $0x10, %0\n\t"
-		"mov 0*4(%1), %3\n\t"
-		"mov 1*4(%1), %4\n\t"
-		"mov  %3, 0*4(%2)\n\t"
-		"mov  %4, 1*4(%2)\n\t"
-		"mov 2*4(%1), %3\n\t"
-		"mov 3*4(%1), %4\n\t"
-		"mov  %3, 2*4(%2)\n\t"
-		"mov  %4, 3*4(%2)\n\t"
-		"lea  0x10(%1), %1\n\t"
-		"lea  0x10(%2), %2\n\t"
-		"jae 3b\n\t"
-		"add $0x10, %0\n\t"
-		"jmp 1f\n\t"
-
-		/*
-		 * Handle data forward by movs.
-		 */
-		".p2align 4\n\t"
-		"4:\n\t"
-		"mov -4(%1, %0), %3\n\t"
-		"lea -4(%2, %0), %4\n\t"
-		"shr $2, %0\n\t"
-		"rep movsl\n\t"
-		"mov %3, (%4)\n\t"
-		"jmp 11f\n\t"
-		/*
-		 * Handle data backward by movs.
-		 */
-		".p2align 4\n\t"
-		"6:\n\t"
-		"mov (%1), %3\n\t"
-		"mov %2, %4\n\t"
-		"lea -4(%1, %0), %1\n\t"
-		"lea -4(%2, %0), %2\n\t"
-		"shr $2, %0\n\t"
-		"std\n\t"
-		"rep movsl\n\t"
-		"mov %3,(%4)\n\t"
-		"cld\n\t"
-		"jmp 11f\n\t"
-
-		/*
-		 * Start to prepare for backward copy.
-		 */
-		".p2align 4\n\t"
-		"2:\n\t"
-		"cmp  $680, %0\n\t"
-		"jb 5f\n\t"
-		"mov %1, %3\n\t"
-		"xor %2, %3\n\t"
-		"and $0xff, %3\n\t"
-		"jz 6b\n\t"
-
-		/*
-		 * Calculate copy position to tail.
-		 */
-		"5:\n\t"
-		"add %0, %1\n\t"
-		"add %0, %2\n\t"
-		"sub $0x10, %0\n\t"
-
-		/*
-		 * We gobble 16 bytes backward in each loop.
-		 */
-		"7:\n\t"
-		"sub $0x10, %0\n\t"
-
-		"mov -1*4(%1), %3\n\t"
-		"mov -2*4(%1), %4\n\t"
-		"mov  %3, -1*4(%2)\n\t"
-		"mov  %4, -2*4(%2)\n\t"
-		"mov -3*4(%1), %3\n\t"
-		"mov -4*4(%1), %4\n\t"
-		"mov  %3, -3*4(%2)\n\t"
-		"mov  %4, -4*4(%2)\n\t"
-		"lea  -0x10(%1), %1\n\t"
-		"lea  -0x10(%2), %2\n\t"
-		"jae 7b\n\t"
-		/*
-		 * Calculate copy position to head.
-		 */
-		"add $0x10, %0\n\t"
-		"sub %0, %1\n\t"
-		"sub %0, %2\n\t"
-
-		/*
-		 * Move data from 8 bytes to 15 bytes.
-		 */
-		".p2align 4\n\t"
-		"1:\n\t"
-		"cmp $8, %0\n\t"
-		"jb 8f\n\t"
-		"mov 0*4(%1), %3\n\t"
-		"mov 1*4(%1), %4\n\t"
-		"mov -2*4(%1, %0), %5\n\t"
-		"mov -1*4(%1, %0), %1\n\t"
-
-		"mov  %3, 0*4(%2)\n\t"
-		"mov  %4, 1*4(%2)\n\t"
-		"mov  %5, -2*4(%2, %0)\n\t"
-		"mov  %1, -1*4(%2, %0)\n\t"
-		"jmp 11f\n\t"
-
-		/*
-		 * Move data from 4 bytes to 7 bytes.
-		 */
-		".p2align 4\n\t"
-		"8:\n\t"
-		"cmp $4, %0\n\t"
-		"jb 9f\n\t"
-		"mov 0*4(%1), %3\n\t"
-		"mov -1*4(%1, %0), %4\n\t"
-		"mov  %3, 0*4(%2)\n\t"
-		"mov  %4, -1*4(%2, %0)\n\t"
-		"jmp 11f\n\t"
-
-		/*
-		 * Move data from 2 bytes to 3 bytes.
-		 */
-		".p2align 4\n\t"
-		"9:\n\t"
-		"cmp $2, %0\n\t"
-		"jb 10f\n\t"
-		"movw 0*2(%1), %%dx\n\t"
-		"movw -1*2(%1, %0), %%bx\n\t"
-		"movw %%dx, 0*2(%2)\n\t"
-		"movw %%bx, -1*2(%2, %0)\n\t"
-		"jmp 11f\n\t"
-
-		/*
-		 * Move data for 1 byte.
-		 */
-		".p2align 4\n\t"
-		"10:\n\t"
-		"cmp $1, %0\n\t"
-		"jb 11f\n\t"
-		"movb (%1), %%cl\n\t"
-		"movb %%cl, (%2)\n\t"
-		".p2align 4\n\t"
-		"11:"
-		: "=&c" (d0), "=&S" (d1), "=&D" (d2),
-		  "=r" (d3),"=r" (d4), "=r"(d5)
-		:"0" (n),
-		 "1" (src),
-		 "2" (dest)
-		:"memory");
-
-	return ret;
-
-}
-EXPORT_SYMBOL(memmove);
diff --git a/arch/x86/lib/memmove_32.S b/arch/x86/lib/memmove_32.S
new file mode 100644
index 000000000000..0588b2c0fc95
--- /dev/null
+++ b/arch/x86/lib/memmove_32.S
@@ -0,0 +1,200 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+#include <asm/export.h>
+
+SYM_FUNC_START(memmove)
+/*
+ * void *memmove(void *dest_in, const void *src_in, size_t n)
+ * -mregparm=3 passes these in registers:
+ * dest_in: %eax
+ * src_in: %edx
+ * n: %ecx
+ * See also: arch/x86/entry/calling.h for description of the calling convention.
+ *
+ * n can remain in %ecx, but for `rep movsl`, we'll need dest in %edi and src
+ * in %esi.
+ */
+.set dest_in, %eax
+.set dest, %edi
+.set src_in, %edx
+.set src, %esi
+.set n, %ecx
+.set tmp0, %edx
+.set tmp0w, %dx
+.set tmp1, %ebx
+.set tmp1w, %bx
+.set tmp2, %eax
+.set tmp3b, %cl
+
+/*
+ * Save all callee-saved registers, because this function is going to clobber
+ * all of them:
+ */
+	pushl	%ebp
+	movl	%esp, %ebp	// set standard frame pointer
+
+	pushl	%ebx
+	pushl	%edi
+	pushl	%esi
+	pushl	%eax		// save 'dest_in' parameter [eax] as the return value
+
+	movl src_in, src
+	movl dest_in, dest
+
+	/* Handle more 16 bytes in loop */
+	cmpl	$0x10, n
+	jb	.Lmove_16B
+
+	/* Decide forward/backward copy mode */
+	cmpl	dest, src
+	jb	.Lbackwards_header
+
+	/*
+	 * movs instruction have many startup latency
+	 * so we handle small size by general register.
+	 */
+	cmpl	$680, n
+	jb	.Ltoo_small_forwards
+	/* movs instruction is only good for aligned case. */
+	movl	src, tmp0
+	xorl	dest, tmp0
+	andl	$0xff, tmp0
+	jz	.Lforward_movs
+.Ltoo_small_forwards:
+	subl	$0x10, n
+
+	/* We gobble 16 bytes forward in each loop. */
+.Lmove_16B_forwards_loop:
+	subl	$0x10, n
+	movl	0*4(src), tmp0
+	movl	1*4(src), tmp1
+	movl	tmp0, 0*4(dest)
+	movl	tmp1, 1*4(dest)
+	movl	2*4(src), tmp0
+	movl	3*4(src), tmp1
+	movl	tmp0, 2*4(dest)
+	movl	tmp1, 3*4(dest)
+	leal	0x10(src), src
+	leal	0x10(dest), dest
+	jae	.Lmove_16B_forwards_loop
+	addl	$0x10, n
+	jmp	.Lmove_16B
+
+	/* Handle data forward by movs. */
+.p2align 4
+.Lforward_movs:
+	movl	-4(src, n), tmp0
+	leal	-4(dest, n), tmp1
+	shrl	$2, n
+	rep	movsl
+	movl	tmp0, (tmp1)
+	jmp	.Ldone
+
+	/* Handle data backward by movs. */
+.p2align 4
+.Lbackwards_movs:
+	movl	(src), tmp0
+	movl	dest, tmp1
+	leal	-4(src, n), src
+	leal	-4(dest, n), dest
+	shrl	$2, n
+	std
+	rep	movsl
+	movl	tmp0,(tmp1)
+	cld
+	jmp	.Ldone
+
+	/* Start to prepare for backward copy. */
+.p2align 4
+.Lbackwards_header:
+	cmpl	$680, n
+	jb	.Ltoo_small_backwards
+	movl	src, tmp0
+	xorl	dest, tmp0
+	andl	$0xff, tmp0
+	jz	.Lbackwards_movs
+
+	/* Calculate copy position to tail. */
+.Ltoo_small_backwards:
+	addl	n, src
+	addl	n, dest
+	subl	$0x10, n
+
+	/* We gobble 16 bytes backward in each loop. */
+.Lmove_16B_backwards_loop:
+	subl	$0x10, n
+
+	movl	-1*4(src), tmp0
+	movl	-2*4(src), tmp1
+	movl	tmp0, -1*4(dest)
+	movl	tmp1, -2*4(dest)
+	movl	-3*4(src), tmp0
+	movl	-4*4(src), tmp1
+	movl	tmp0, -3*4(dest)
+	movl	tmp1, -4*4(dest)
+	leal	-0x10(src), src
+	leal	-0x10(dest), dest
+	jae	.Lmove_16B_backwards_loop
+	/* Calculate copy position to head. */
+	addl	$0x10, n
+	subl	n, src
+	subl	n, dest
+
+	/* Move data from 8 bytes to 15 bytes. */
+.p2align 4
+.Lmove_16B:
+	cmpl	$8, n
+	jb	.Lmove_8B
+	movl	0*4(src), tmp0
+	movl	1*4(src), tmp1
+	movl	-2*4(src, n), tmp2
+	movl	-1*4(src, n), src
+
+	movl	tmp0, 0*4(dest)
+	movl	tmp1, 1*4(dest)
+	movl	tmp2, -2*4(dest, n)
+	movl	src, -1*4(dest, n)
+	jmp	.Ldone
+
+	/* Move data from 4 bytes to 7 bytes. */
+.p2align 4
+.Lmove_8B:
+	cmpl	$4, n
+	jb	.Lmove_4B
+	movl	0*4(src), tmp0
+	movl	-1*4(src, n), tmp1
+	movl	tmp0, 0*4(dest)
+	movl	tmp1, -1*4(dest, n)
+	jmp	.Ldone
+
+	/* Move data from 2 bytes to 3 bytes. */
+.p2align 4
+.Lmove_4B:
+	cmpl	$2, n
+	jb	.Lmove_1B
+	movw	0*2(src), tmp0w
+	movw	-1*2(src, n), tmp1w
+	movw	tmp0w, 0*2(dest)
+	movw	tmp1w, -1*2(dest, n)
+	jmp	.Ldone
+
+	/* Move data for 1 byte. */
+.p2align 4
+.Lmove_1B:
+	cmpl	$1, n
+	jb	.Ldone
+	movb	(src), tmp3b
+	movb	tmp3b, (dest)
+.p2align 4
+.Ldone:
+	popl	dest_in	// restore 'dest_in' [eax] as the return value
+	/* Restore all callee-saved registers: */
+	popl	%esi
+	popl	%edi
+	popl	%ebx
+	popl	%ebp
+
+	RET
+SYM_FUNC_END(memmove)
+EXPORT_SYMBOL(memmove)
diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c
index 2b5cc70ac53f..7513e6d5dc90 100644
--- a/lib/memcpy_kunit.c
+++ b/lib/memcpy_kunit.c
@@ -105,6 +105,8 @@ static void memcpy_test(struct kunit *test)
 #undef TEST_OP
 }
 
+static unsigned char larger_array [2048];
+
 static void memmove_test(struct kunit *test)
 {
 #define TEST_OP "memmove"
@@ -179,6 +181,26 @@ static void memmove_test(struct kunit *test)
 	ptr = &overlap.data[2];
 	memmove(ptr, overlap.data, 5);
 	compare("overlapping write", overlap, overlap_expected);
+
+	/* Verify larger overlapping moves. */
+	larger_array[256] = 0xAAu;
+	/*
+	 * Test a backwards overlapping memmove first. 256 and 1024 are
+	 * important for i386 to use rep movsl.
+	 */
+	memmove(larger_array, larger_array + 256, 1024);
+	KUNIT_ASSERT_EQ(test, larger_array[0], 0xAAu);
+	KUNIT_ASSERT_EQ(test, larger_array[256], 0x00);
+	KUNIT_ASSERT_NULL(test,
+		memchr(larger_array + 1, 0xaa, ARRAY_SIZE(larger_array) - 1));
+	/* Test a forwards overlapping memmove. */
+	larger_array[0] = 0xBBu;
+	memmove(larger_array + 256, larger_array, 1024);
+	KUNIT_ASSERT_EQ(test, larger_array[0], 0xBBu);
+	KUNIT_ASSERT_EQ(test, larger_array[256], 0xBBu);
+	KUNIT_ASSERT_NULL(test, memchr(larger_array + 1, 0xBBu, 256 - 1));
+	KUNIT_ASSERT_NULL(test,
+		memchr(larger_array + 257, 0xBBu, ARRAY_SIZE(larger_array) - 257));
 #undef TEST_OP
 }