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-rw-r--r--arch/x86/Kconfig.debug3
-rw-r--r--arch/x86/include/asm/mcsafe_test.h75
-rw-r--r--arch/x86/lib/memcpy_64.S10
3 files changed, 88 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 192e4d2f9efc..c6dd1d980081 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -72,6 +72,9 @@ config EARLY_PRINTK_USB_XDBC
You should normally say N here, unless you want to debug early
crashes or need a very simple printk logging facility.
+config MCSAFE_TEST
+ def_bool n
+
config X86_PTDUMP_CORE
def_bool n
diff --git a/arch/x86/include/asm/mcsafe_test.h b/arch/x86/include/asm/mcsafe_test.h
new file mode 100644
index 000000000000..eb59804b6201
--- /dev/null
+++ b/arch/x86/include/asm/mcsafe_test.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _MCSAFE_TEST_H_
+#define _MCSAFE_TEST_H_
+
+#ifndef __ASSEMBLY__
+#ifdef CONFIG_MCSAFE_TEST
+extern unsigned long mcsafe_test_src;
+extern unsigned long mcsafe_test_dst;
+
+static inline void mcsafe_inject_src(void *addr)
+{
+ if (addr)
+ mcsafe_test_src = (unsigned long) addr;
+ else
+ mcsafe_test_src = ~0UL;
+}
+
+static inline void mcsafe_inject_dst(void *addr)
+{
+ if (addr)
+ mcsafe_test_dst = (unsigned long) addr;
+ else
+ mcsafe_test_dst = ~0UL;
+}
+#else /* CONFIG_MCSAFE_TEST */
+static inline void mcsafe_inject_src(void *addr)
+{
+}
+
+static inline void mcsafe_inject_dst(void *addr)
+{
+}
+#endif /* CONFIG_MCSAFE_TEST */
+
+#else /* __ASSEMBLY__ */
+#include <asm/export.h>
+
+#ifdef CONFIG_MCSAFE_TEST
+.macro MCSAFE_TEST_CTL
+ .pushsection .data
+ .align 8
+ .globl mcsafe_test_src
+ mcsafe_test_src:
+ .quad 0
+ EXPORT_SYMBOL_GPL(mcsafe_test_src)
+ .globl mcsafe_test_dst
+ mcsafe_test_dst:
+ .quad 0
+ EXPORT_SYMBOL_GPL(mcsafe_test_dst)
+ .popsection
+.endm
+
+.macro MCSAFE_TEST_SRC reg count target
+ leaq \count(\reg), %r9
+ cmp mcsafe_test_src, %r9
+ ja \target
+.endm
+
+.macro MCSAFE_TEST_DST reg count target
+ leaq \count(\reg), %r9
+ cmp mcsafe_test_dst, %r9
+ ja \target
+.endm
+#else
+.macro MCSAFE_TEST_CTL
+.endm
+
+.macro MCSAFE_TEST_SRC reg count target
+.endm
+
+.macro MCSAFE_TEST_DST reg count target
+.endm
+#endif /* CONFIG_MCSAFE_TEST */
+#endif /* __ASSEMBLY__ */
+#endif /* _MCSAFE_TEST_H_ */
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index c3b527a9f95d..298ef1479240 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -3,6 +3,7 @@
#include <linux/linkage.h>
#include <asm/errno.h>
#include <asm/cpufeatures.h>
+#include <asm/mcsafe_test.h>
#include <asm/alternative-asm.h>
#include <asm/export.h>
@@ -183,6 +184,9 @@ ENTRY(memcpy_orig)
ENDPROC(memcpy_orig)
#ifndef CONFIG_UML
+
+MCSAFE_TEST_CTL
+
/*
* __memcpy_mcsafe - memory copy with machine check exception handling
* Note that we only catch machine checks when reading the source addresses.
@@ -206,6 +210,8 @@ ENTRY(__memcpy_mcsafe)
subl %ecx, %edx
.L_read_leading_bytes:
movb (%rsi), %al
+ MCSAFE_TEST_SRC %rsi 1 .E_leading_bytes
+ MCSAFE_TEST_DST %rdi 1 .E_leading_bytes
.L_write_leading_bytes:
movb %al, (%rdi)
incq %rsi
@@ -221,6 +227,8 @@ ENTRY(__memcpy_mcsafe)
.L_read_words:
movq (%rsi), %r8
+ MCSAFE_TEST_SRC %rsi 8 .E_read_words
+ MCSAFE_TEST_DST %rdi 8 .E_write_words
.L_write_words:
movq %r8, (%rdi)
addq $8, %rsi
@@ -237,6 +245,8 @@ ENTRY(__memcpy_mcsafe)
movl %edx, %ecx
.L_read_trailing_bytes:
movb (%rsi), %al
+ MCSAFE_TEST_SRC %rsi 1 .E_trailing_bytes
+ MCSAFE_TEST_DST %rdi 1 .E_trailing_bytes
.L_write_trailing_bytes:
movb %al, (%rdi)
incq %rsi