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authorDan Williams <dan.j.williams@intel.com>2018-06-08 15:16:44 -0700
committerDan Williams <dan.j.williams@intel.com>2018-06-08 15:16:44 -0700
commit930218affeadd1325ea17e053f0dcecf218f5a4f (patch)
tree203c293668a88e03b9f292cf4d5a294ca8a4275a /arch/x86
parentb56845794e1e93121acb74ca325db965035d5545 (diff)
parent5d8beee20d89e34ff1dcb0da84adf7607858c59d (diff)
downloadlinux-930218affeadd1325ea17e053f0dcecf218f5a4f.tar.gz
Merge branch 'for-4.18/mcsafe' into libnvdimm-for-next
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/Kconfig.debug3
-rw-r--r--arch/x86/include/asm/mcsafe_test.h75
-rw-r--r--arch/x86/include/asm/string_64.h10
-rw-r--r--arch/x86/include/asm/uaccess_64.h14
-rw-r--r--arch/x86/lib/memcpy_64.S112
-rw-r--r--arch/x86/lib/usercopy_64.c21
7 files changed, 174 insertions, 62 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c07f492b871a..6ca22706cd64 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -60,6 +60,7 @@ config X86
select ARCH_HAS_PMEM_API if X86_64
select ARCH_HAS_REFCOUNT
select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
+ select ARCH_HAS_UACCESS_MCSAFE if X86_64
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_STRICT_KERNEL_RWX
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/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index 533f74c300c2..d33f92b9fa22 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -116,7 +116,8 @@ int strcmp(const char *cs, const char *ct);
#endif
#define __HAVE_ARCH_MEMCPY_MCSAFE 1
-__must_check int memcpy_mcsafe_unrolled(void *dst, const void *src, size_t cnt);
+__must_check unsigned long __memcpy_mcsafe(void *dst, const void *src,
+ size_t cnt);
DECLARE_STATIC_KEY_FALSE(mcsafe_key);
/**
@@ -131,14 +132,15 @@ DECLARE_STATIC_KEY_FALSE(mcsafe_key);
* actually do machine check recovery. Everyone else can just
* use memcpy().
*
- * Return 0 for success, -EFAULT for fail
+ * Return 0 for success, or number of bytes not copied if there was an
+ * exception.
*/
-static __always_inline __must_check int
+static __always_inline __must_check unsigned long
memcpy_mcsafe(void *dst, const void *src, size_t cnt)
{
#ifdef CONFIG_X86_MCE
if (static_branch_unlikely(&mcsafe_key))
- return memcpy_mcsafe_unrolled(dst, src, cnt);
+ return __memcpy_mcsafe(dst, src, cnt);
else
#endif
memcpy(dst, src, cnt);
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index 62546b3a398e..62acb613114b 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -47,6 +47,17 @@ copy_user_generic(void *to, const void *from, unsigned len)
}
static __always_inline __must_check unsigned long
+copy_to_user_mcsafe(void *to, const void *from, unsigned len)
+{
+ unsigned long ret;
+
+ __uaccess_begin();
+ ret = memcpy_mcsafe(to, from, len);
+ __uaccess_end();
+ return ret;
+}
+
+static __always_inline __must_check unsigned long
raw_copy_from_user(void *dst, const void __user *src, unsigned long size)
{
int ret = 0;
@@ -194,4 +205,7 @@ __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
unsigned long
copy_user_handle_tail(char *to, char *from, unsigned len);
+unsigned long
+mcsafe_handle_tail(char *to, char *from, unsigned len);
+
#endif /* _ASM_X86_UACCESS_64_H */
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index 9a53a06e5a3e..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>
@@ -183,12 +184,15 @@ ENTRY(memcpy_orig)
ENDPROC(memcpy_orig)
#ifndef CONFIG_UML
+
+MCSAFE_TEST_CTL
+
/*
- * memcpy_mcsafe_unrolled - memory copy with machine check exception handling
+ * __memcpy_mcsafe - memory copy with machine check exception handling
* Note that we only catch machine checks when reading the source addresses.
* Writes to target are posted and don't generate machine checks.
*/
-ENTRY(memcpy_mcsafe_unrolled)
+ENTRY(__memcpy_mcsafe)
cmpl $8, %edx
/* Less than 8 bytes? Go to byte copy loop */
jb .L_no_whole_words
@@ -204,58 +208,33 @@ ENTRY(memcpy_mcsafe_unrolled)
subl $8, %ecx
negl %ecx
subl %ecx, %edx
-.L_copy_leading_bytes:
+.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
incq %rdi
decl %ecx
- jnz .L_copy_leading_bytes
+ jnz .L_read_leading_bytes
.L_8byte_aligned:
- /* Figure out how many whole cache lines (64-bytes) to copy */
- movl %edx, %ecx
- andl $63, %edx
- shrl $6, %ecx
- jz .L_no_whole_cache_lines
-
- /* Loop copying whole cache lines */
-.L_cache_w0: movq (%rsi), %r8
-.L_cache_w1: movq 1*8(%rsi), %r9
-.L_cache_w2: movq 2*8(%rsi), %r10
-.L_cache_w3: movq 3*8(%rsi), %r11
- movq %r8, (%rdi)
- movq %r9, 1*8(%rdi)
- movq %r10, 2*8(%rdi)
- movq %r11, 3*8(%rdi)
-.L_cache_w4: movq 4*8(%rsi), %r8
-.L_cache_w5: movq 5*8(%rsi), %r9
-.L_cache_w6: movq 6*8(%rsi), %r10
-.L_cache_w7: movq 7*8(%rsi), %r11
- movq %r8, 4*8(%rdi)
- movq %r9, 5*8(%rdi)
- movq %r10, 6*8(%rdi)
- movq %r11, 7*8(%rdi)
- leaq 64(%rsi), %rsi
- leaq 64(%rdi), %rdi
- decl %ecx
- jnz .L_cache_w0
-
- /* Are there any trailing 8-byte words? */
-.L_no_whole_cache_lines:
movl %edx, %ecx
andl $7, %edx
shrl $3, %ecx
jz .L_no_whole_words
- /* Copy trailing words */
-.L_copy_trailing_words:
+.L_read_words:
movq (%rsi), %r8
- mov %r8, (%rdi)
- leaq 8(%rsi), %rsi
- leaq 8(%rdi), %rdi
+ 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
+ addq $8, %rdi
decl %ecx
- jnz .L_copy_trailing_words
+ jnz .L_read_words
/* Any trailing bytes? */
.L_no_whole_words:
@@ -264,38 +243,55 @@ ENTRY(memcpy_mcsafe_unrolled)
/* Copy trailing bytes */
movl %edx, %ecx
-.L_copy_trailing_bytes:
+.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
incq %rdi
decl %ecx
- jnz .L_copy_trailing_bytes
+ jnz .L_read_trailing_bytes
/* Copy successful. Return zero */
.L_done_memcpy_trap:
xorq %rax, %rax
ret
-ENDPROC(memcpy_mcsafe_unrolled)
-EXPORT_SYMBOL_GPL(memcpy_mcsafe_unrolled)
+ENDPROC(__memcpy_mcsafe)
+EXPORT_SYMBOL_GPL(__memcpy_mcsafe)
.section .fixup, "ax"
- /* Return -EFAULT for any failure */
-.L_memcpy_mcsafe_fail:
- mov $-EFAULT, %rax
+ /*
+ * Return number of bytes not copied for any failure. Note that
+ * there is no "tail" handling since the source buffer is 8-byte
+ * aligned and poison is cacheline aligned.
+ */
+.E_read_words:
+ shll $3, %ecx
+.E_leading_bytes:
+ addl %edx, %ecx
+.E_trailing_bytes:
+ mov %ecx, %eax
ret
+ /*
+ * For write fault handling, given the destination is unaligned,
+ * we handle faults on multi-byte writes with a byte-by-byte
+ * copy up to the write-protected page.
+ */
+.E_write_words:
+ shll $3, %ecx
+ addl %edx, %ecx
+ movl %ecx, %edx
+ jmp mcsafe_handle_tail
+
.previous
- _ASM_EXTABLE_FAULT(.L_copy_leading_bytes, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w0, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w1, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w2, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w3, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w4, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w5, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w6, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_cache_w7, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_copy_trailing_words, .L_memcpy_mcsafe_fail)
- _ASM_EXTABLE_FAULT(.L_copy_trailing_bytes, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .E_leading_bytes)
+ _ASM_EXTABLE_FAULT(.L_read_words, .E_read_words)
+ _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .E_trailing_bytes)
+ _ASM_EXTABLE(.L_write_leading_bytes, .E_leading_bytes)
+ _ASM_EXTABLE(.L_write_words, .E_write_words)
+ _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes)
#endif
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index 75d3776123cc..7ebc9901dd05 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -75,6 +75,27 @@ copy_user_handle_tail(char *to, char *from, unsigned len)
return len;
}
+/*
+ * Similar to copy_user_handle_tail, probe for the write fault point,
+ * but reuse __memcpy_mcsafe in case a new read error is encountered.
+ * clac() is handled in _copy_to_iter_mcsafe().
+ */
+__visible unsigned long
+mcsafe_handle_tail(char *to, char *from, unsigned len)
+{
+ for (; len; --len, to++, from++) {
+ /*
+ * Call the assembly routine back directly since
+ * memcpy_mcsafe() may silently fallback to memcpy.
+ */
+ unsigned long rem = __memcpy_mcsafe(to, from, 1);
+
+ if (rem)
+ break;
+ }
+ return len;
+}
+
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
/**
* clean_cache_range - write back a cache range with CLWB