4 files changed, 192 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
diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index 4ea385be528f..a8fb63edcf89 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/tools/testing/nvdimm/test/nfit.c
@@ -29,6 +29,8 @@
 #include "nfit_test.h"
 #include "../watermark.h"
 
+#include <asm/mcsafe_test.h>
+
 /*
  * Generate an NFIT table to describe the following topology:
  *
@@ -2681,6 +2683,107 @@ static struct platform_driver nfit_test_driver = {
         .id_table = nfit_test_id,
 };
 
+static char mcsafe_buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
+
+enum INJECT {
+        INJECT_NONE,
+        INJECT_SRC,
+        INJECT_DST,
+};
+
+static void mcsafe_test_init(char *dst, char *src, size_t size)
+{
+        size_t i;
+
+        memset(dst, 0xff, size);
+        for (i = 0; i < size; i++)
+                src[i] = (char) i;
+}
+
+static bool mcsafe_test_validate(unsigned char *dst, unsigned char *src,
+                size_t size, unsigned long rem)
+{
+        size_t i;
+
+        for (i = 0; i < size - rem; i++)
+                if (dst[i] != (unsigned char) i) {
+                        pr_info_once("%s:%d: offset: %zd got: %#x expect: %#x\n",
+                                        __func__, __LINE__, i, dst[i],
+                                        (unsigned char) i);
+                        return false;
+                }
+        for (i = size - rem; i < size; i++)
+                if (dst[i] != 0xffU) {
+                        pr_info_once("%s:%d: offset: %zd got: %#x expect: 0xff\n",
+                                        __func__, __LINE__, i, dst[i]);
+                        return false;
+                }
+        return true;
+}
+
+void mcsafe_test(void)
+{
+        char *inject_desc[] = { "none", "source", "destination" };
+        enum INJECT inj;
+
+        if (IS_ENABLED(CONFIG_MCSAFE_TEST)) {
+                pr_info("%s: run...\n", __func__);
+        } else {
+                pr_info("%s: di