x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()
authorDan Williams <dan.j.williams@intel.com>
Tue, 6 Oct 2020 03:40:16 +0000 (20:40 -0700)
committerBorislav Petkov <bp@suse.de>
Tue, 6 Oct 2020 09:18:04 +0000 (11:18 +0200)
In reaction to a proposal to introduce a memcpy_mcsafe_fast()
implementation Linus points out that memcpy_mcsafe() is poorly named
relative to communicating the scope of the interface. Specifically what
addresses are valid to pass as source, destination, and what faults /
exceptions are handled.

Of particular concern is that even though x86 might be able to handle
the semantics of copy_mc_to_user() with its common copy_user_generic()
implementation other archs likely need / want an explicit path for this
case:

  On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote:
  >
  > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote:
  > >
  > > However now I see that copy_user_generic() works for the wrong reason.
  > > It works because the exception on the source address due to poison
  > > looks no different than a write fault on the user address to the
  > > caller, it's still just a short copy. So it makes copy_to_user() work
  > > for the wrong reason relative to the name.
  >
  > Right.
  >
  > And it won't work that way on other architectures. On x86, we have a
  > generic function that can take faults on either side, and we use it
  > for both cases (and for the "in_user" case too), but that's an
  > artifact of the architecture oddity.
  >
  > In fact, it's probably wrong even on x86 - because it can hide bugs -
  > but writing those things is painful enough that everybody prefers
  > having just one function.

Replace a single top-level memcpy_mcsafe() with either
copy_mc_to_user(), or copy_mc_to_kernel().

Introduce an x86 copy_mc_fragile() name as the rename for the
low-level x86 implementation formerly named memcpy_mcsafe(). It is used
as the slow / careful backend that is supplanted by a fast
copy_mc_generic() in a follow-on patch.

One side-effect of this reorganization is that separating copy_mc_64.S
to its own file means that perf no longer needs to track dependencies
for its memcpy_64.S benchmarks.

 [ bp: Massage a bit. ]

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com
Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
38 files changed:
arch/powerpc/Kconfig
arch/powerpc/include/asm/string.h
arch/powerpc/include/asm/uaccess.h
arch/powerpc/lib/Makefile
arch/powerpc/lib/copy_mc_64.S [moved from arch/powerpc/lib/memcpy_mcsafe_64.S with 98% similarity]
arch/x86/Kconfig
arch/x86/Kconfig.debug
arch/x86/include/asm/copy_mc_test.h [new file with mode: 0644]
arch/x86/include/asm/mce.h
arch/x86/include/asm/mcsafe_test.h [deleted file]
arch/x86/include/asm/string_64.h
arch/x86/include/asm/uaccess.h
arch/x86/include/asm/uaccess_64.h
arch/x86/kernel/cpu/mce/core.c
arch/x86/kernel/quirks.c
arch/x86/lib/Makefile
arch/x86/lib/copy_mc.c [new file with mode: 0644]
arch/x86/lib/copy_mc_64.S [new file with mode: 0644]
arch/x86/lib/memcpy_64.S
arch/x86/lib/usercopy_64.c
drivers/md/dm-writecache.c
drivers/nvdimm/claim.c
drivers/nvdimm/pmem.c
include/linux/string.h
include/linux/uaccess.h
include/linux/uio.h
lib/Kconfig
lib/iov_iter.c
tools/arch/x86/include/asm/mcsafe_test.h [deleted file]
tools/arch/x86/lib/memcpy_64.S
tools/objtool/check.c
tools/perf/bench/Build
tools/perf/bench/mem-memcpy-x86-64-lib.c [deleted file]
tools/testing/nvdimm/test/nfit.c
tools/testing/selftests/powerpc/copyloops/.gitignore
tools/testing/selftests/powerpc/copyloops/Makefile
tools/testing/selftests/powerpc/copyloops/copy_mc_64.S [new symlink]
tools/testing/selftests/powerpc/copyloops/memcpy_mcsafe_64.S [deleted symlink]

index 1f48bbf..76473ed 100644 (file)
@@ -136,7 +136,7 @@ config PPC
        select ARCH_HAS_STRICT_KERNEL_RWX       if (PPC32 && !HIBERNATION)
        select ARCH_HAS_TICK_BROADCAST          if GENERIC_CLOCKEVENTS_BROADCAST
        select ARCH_HAS_UACCESS_FLUSHCACHE
-       select ARCH_HAS_UACCESS_MCSAFE          if PPC64
+       select ARCH_HAS_COPY_MC                 if PPC64
        select ARCH_HAS_UBSAN_SANITIZE_ALL
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select ARCH_KEEP_MEMBLOCK
index 283552c..2aa0e31 100644 (file)
@@ -53,9 +53,7 @@ void *__memmove(void *to, const void *from, __kernel_size_t n);
 #ifndef CONFIG_KASAN
 #define __HAVE_ARCH_MEMSET32
 #define __HAVE_ARCH_MEMSET64
-#define __HAVE_ARCH_MEMCPY_MCSAFE
 
-extern int memcpy_mcsafe(void *dst, const void *src, __kernel_size_t sz);
 extern void *__memset16(uint16_t *, uint16_t v, __kernel_size_t);
 extern void *__memset32(uint32_t *, uint32_t v, __kernel_size_t);
 extern void *__memset64(uint64_t *, uint64_t v, __kernel_size_t);
index 0069990..20a3537 100644 (file)
@@ -435,6 +435,32 @@ do {                                                               \
 extern unsigned long __copy_tofrom_user(void __user *to,
                const void __user *from, unsigned long size);
 
+#ifdef CONFIG_ARCH_HAS_COPY_MC
+unsigned long __must_check
+copy_mc_generic(void *to, const void *from, unsigned long size);
+
+static inline unsigned long __must_check
+copy_mc_to_kernel(void *to, const void *from, unsigned long size)
+{
+       return copy_mc_generic(to, from, size);
+}
+#define copy_mc_to_kernel copy_mc_to_kernel
+
+static inline unsigned long __must_check
+copy_mc_to_user(void __user *to, const void *from, unsigned long n)
+{
+       if (likely(check_copy_size(from, n, true))) {
+               if (access_ok(to, n)) {
+                       allow_write_to_user(to, n);
+                       n = copy_mc_generic((void *)to, from, n);
+                       prevent_write_to_user(to, n);
+               }
+       }
+
+       return n;
+}
+#endif
+
 #ifdef __powerpc64__
 static inline unsigned long
 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
@@ -523,20 +549,6 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
        return ret;
 }
 
-static __always_inline unsigned long __must_check
-copy_to_user_mcsafe(void __user *to, const void *from, unsigned long n)
-{
-       if (likely(check_copy_size(from, n, true))) {
-               if (access_ok(to, n)) {
-                       allow_write_to_user(to, n);
-                       n = memcpy_mcsafe((void *)to, from, n);
-                       prevent_write_to_user(to, n);
-               }
-       }
-
-       return n;
-}
-
 unsigned long __arch_clear_user(void __user *addr, unsigned long size);
 
 static inline unsigned long clear_user(void __user *addr, unsigned long size)
index d66a645..69a91b5 100644 (file)
@@ -39,7 +39,7 @@ obj-$(CONFIG_PPC_BOOK3S_64) += copyuser_power7.o copypage_power7.o \
                               memcpy_power7.o
 
 obj64-y        += copypage_64.o copyuser_64.o mem_64.o hweight_64.o \
-          memcpy_64.o memcpy_mcsafe_64.o
+          memcpy_64.o copy_mc_64.o
 
 ifndef CONFIG_PPC_QUEUED_SPINLOCKS
 obj64-$(CONFIG_SMP)    += locks.o
similarity index 98%
rename from arch/powerpc/lib/memcpy_mcsafe_64.S
rename to arch/powerpc/lib/copy_mc_64.S
index cb882d9..88d46c4 100644 (file)
@@ -50,7 +50,7 @@ err3; stb     r0,0(r3)
        blr
 
 
-_GLOBAL(memcpy_mcsafe)
+_GLOBAL(copy_mc_generic)
        mr      r7,r5
        cmpldi  r5,16
        blt     .Lshort_copy
@@ -239,4 +239,4 @@ err1;       stb     r0,0(r3)
 15:    li      r3,0
        blr
 
-EXPORT_SYMBOL_GPL(memcpy_mcsafe);
+EXPORT_SYMBOL_GPL(copy_mc_generic);
index 7101ac6..e876b3a 100644 (file)
@@ -75,7 +75,7 @@ config X86
        select ARCH_HAS_PTE_DEVMAP              if X86_64
        select ARCH_HAS_PTE_SPECIAL
        select ARCH_HAS_UACCESS_FLUSHCACHE      if X86_64
-       select ARCH_HAS_UACCESS_MCSAFE          if X86_64 && X86_MCE
+       select ARCH_HAS_COPY_MC                 if X86_64
        select ARCH_HAS_SET_MEMORY
        select ARCH_HAS_SET_DIRECT_MAP
        select ARCH_HAS_STRICT_KERNEL_RWX
index ee1d3c5..27b5e2b 100644 (file)
@@ -62,7 +62,7 @@ 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
+config COPY_MC_TEST
        def_bool n
 
 config EFI_PGT_DUMP
diff --git a/arch/x86/include/asm/copy_mc_test.h b/arch/x86/include/asm/copy_mc_test.h
new file mode 100644 (file)
index 0000000..e4991ba
--- /dev/null
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _COPY_MC_TEST_H_
+#define _COPY_MC_TEST_H_
+
+#ifndef __ASSEMBLY__
+#ifdef CONFIG_COPY_MC_TEST
+extern unsigned long copy_mc_test_src;
+extern unsigned long copy_mc_test_dst;
+
+static inline void copy_mc_inject_src(void *addr)
+{
+       if (addr)
+               copy_mc_test_src = (unsigned long) addr;
+       else
+               copy_mc_test_src = ~0UL;
+}
+
+static inline void copy_mc_inject_dst(void *addr)
+{
+       if (addr)
+               copy_mc_test_dst = (unsigned long) addr;
+       else
+               copy_mc_test_dst = ~0UL;
+}
+#else /* CONFIG_COPY_MC_TEST */
+static inline void copy_mc_inject_src(void *addr)
+{
+}
+
+static inline void copy_mc_inject_dst(void *addr)
+{
+}
+#endif /* CONFIG_COPY_MC_TEST */
+
+#else /* __ASSEMBLY__ */
+#include <asm/export.h>
+
+#ifdef CONFIG_COPY_MC_TEST
+.macro COPY_MC_TEST_CTL
+       .pushsection .data
+       .align 8
+       .globl copy_mc_test_src
+       copy_mc_test_src:
+               .quad 0
+       EXPORT_SYMBOL_GPL(copy_mc_test_src)
+       .globl copy_mc_test_dst
+       copy_mc_test_dst:
+               .quad 0
+       EXPORT_SYMBOL_GPL(copy_mc_test_dst)
+       .popsection
+.endm
+
+.macro COPY_MC_TEST_SRC reg count target
+       leaq \count(\reg), %r9
+       cmp copy_mc_test_src, %r9
+       ja \target
+.endm
+
+.macro COPY_MC_TEST_DST reg count target
+       leaq \count(\reg), %r9
+       cmp copy_mc_test_dst, %r9
+       ja \target
+.endm
+#else
+.macro COPY_MC_TEST_CTL
+.endm
+
+.macro COPY_MC_TEST_SRC reg count target
+.endm
+
+.macro COPY_MC_TEST_DST reg count target
+.endm
+#endif /* CONFIG_COPY_MC_TEST */
+#endif /* __ASSEMBLY__ */
+#endif /* _COPY_MC_TEST_H_ */
index 109af5c..ba2062d 100644 (file)
@@ -174,6 +174,15 @@ extern void mce_unregister_decode_chain(struct notifier_block *nb);
 
 extern int mce_p5_enabled;
 
+#ifdef CONFIG_ARCH_HAS_COPY_MC
+extern void enable_copy_mc_fragile(void);
+unsigned long __must_check copy_mc_fragile(void *dst, const void *src, unsigned cnt);
+#else
+static inline void enable_copy_mc_fragile(void)
+{
+}
+#endif
+
 #ifdef CONFIG_X86_MCE
 int mcheck_init(void);
 void mcheck_cpu_init(struct cpuinfo_x86 *c);
diff --git a/arch/x86/include/asm/mcsafe_test.h b/arch/x86/include/asm/mcsafe_test.h
deleted file mode 100644 (file)
index eb59804..0000000
+++ /dev/null
@@ -1,75 +0,0 @@
-/* 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_ */
index 75314c3..6e45082 100644 (file)
@@ -82,38 +82,6 @@ int strcmp(const char *cs, const char *ct);
 
 #endif
 
-#define __HAVE_ARCH_MEMCPY_MCSAFE 1
-__must_check unsigned long __memcpy_mcsafe(void *dst, const void *src,
-               size_t cnt);
-DECLARE_STATIC_KEY_FALSE(mcsafe_key);
-
-/**
- * memcpy_mcsafe - copy memory with indication if a machine check happened
- *
- * @dst:       destination address
- * @src:       source address
- * @cnt:       number of bytes to copy
- *
- * Low level memory copy function that catches machine checks
- * We only call into the "safe" function on systems that can
- * actually do machine check recovery. Everyone else can just
- * use memcpy().
- *
- * Return 0 for success, or number of bytes not copied if there was an
- * exception.
- */
-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(dst, src, cnt);
-       else
-#endif
-               memcpy(dst, src, cnt);
-       return 0;
-}
-
 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
 #define __HAVE_ARCH_MEMCPY_FLUSHCACHE 1
 void __memcpy_flushcache(void *dst, const void *src, size_t cnt);
index ecefaff..eff7fb8 100644 (file)
@@ -455,6 +455,15 @@ extern __must_check long strnlen_user(const char __user *str, long n);
 unsigned long __must_check clear_user(void __user *mem, unsigned long len);
 unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
 
+#ifdef CONFIG_ARCH_HAS_COPY_MC
+unsigned long __must_check
+copy_mc_to_kernel(void *to, const void *from, unsigned len);
+#define copy_mc_to_kernel copy_mc_to_kernel
+
+unsigned long __must_check
+copy_mc_to_user(void *to, const void *from, unsigned len);
+#endif
+
 /*
  * movsl can be slow when source and dest are not both 8-byte aligned
  */
index bc10e3d..e7265a5 100644 (file)
@@ -47,22 +47,6 @@ 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();
-       /*
-        * Note, __memcpy_mcsafe() is explicitly used since it can
-        * handle exceptions / faults.  memcpy_mcsafe() may fall back to
-        * memcpy() which lacks this handling.
-        */
-       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)
 {
        return copy_user_generic(dst, (__force void *)src, size);
@@ -102,8 +86,4 @@ __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
        kasan_check_write(dst, size);
        return __copy_user_flushcache(dst, src, size);
 }
-
-unsigned long
-mcsafe_handle_tail(char *to, char *from, unsigned len);
-
 #endif /* _ASM_X86_UACCESS_64_H */
index 11b6697..b5b70f4 100644 (file)
@@ -40,7 +40,6 @@
 #include <linux/debugfs.h>
 #include <linux/irq_work.h>
 #include <linux/export.h>
-#include <linux/jump_label.h>
 #include <linux/set_memory.h>
 #include <linux/sync_core.h>
 #include <linux/task_work.h>
@@ -2124,7 +2123,7 @@ void mce_disable_bank(int bank)
        and older.
  * mce=nobootlog Don't log MCEs from before booting.
  * mce=bios_cmci_threshold Don't program the CMCI threshold
- * mce=recovery force enable memcpy_mcsafe()
+ * mce=recovery force enable copy_mc_fragile()
  */
 static int __init mcheck_enable(char *str)
 {
@@ -2732,13 +2731,10 @@ static void __init mcheck_debugfs_init(void)
 static void __init mcheck_debugfs_init(void) { }
 #endif
 
-DEFINE_STATIC_KEY_FALSE(mcsafe_key);
-EXPORT_SYMBOL_GPL(mcsafe_key);
-
 static int __init mcheck_late_init(void)
 {
        if (mca_cfg.recovery)
-               static_branch_inc(&mcsafe_key);
+               enable_copy_mc_fragile();
 
        mcheck_debugfs_init();
 
index 1b10717..6d0df6a 100644 (file)
@@ -8,6 +8,7 @@
 
 #include <asm/hpet.h>
 #include <asm/setup.h>
+#include <asm/mce.h>
 
 #if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
 
@@ -624,10 +625,6 @@ static void amd_disable_seq_and_redirect_scrub(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3,
                        amd_disable_seq_and_redirect_scrub);
 
-#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
-#include <linux/jump_label.h>
-#include <asm/string_64.h>
-
 /* Ivy Bridge, Haswell, Broadwell */
 static void quirk_intel_brickland_xeon_ras_cap(struct pci_dev *pdev)
 {
@@ -636,7 +633,7 @@ static void quirk_intel_brickland_xeon_ras_cap(struct pci_dev *pdev)
        pci_read_config_dword(pdev, 0x84, &capid0);
 
        if (capid0 & 0x10)
-               static_branch_inc(&mcsafe_key);
+               enable_copy_mc_fragile();
 }
 
 /* Skylake */
@@ -653,7 +650,7 @@ static void quirk_intel_purley_xeon_ras_cap(struct pci_dev *pdev)
         * enabled, so memory machine check recovery is also enabled.
         */
        if ((capid0 & 0xc0) == 0xc0 || (capid5 & 0x1e0))
-               static_branch_inc(&mcsafe_key);
+               enable_copy_mc_fragile();
 
 }
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0ec3, quirk_intel_brickland_xeon_ras_cap);
@@ -661,7 +658,6 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2fc0, quirk_intel_brickland_xeon_
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, quirk_intel_brickland_xeon_ras_cap);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2083, quirk_intel_purley_xeon_ras_cap);
 #endif
-#endif
 
 bool x86_apple_machine;
 EXPORT_SYMBOL(x86_apple_machine);
index d46fff1..f7d23c9 100644 (file)
@@ -44,6 +44,7 @@ obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
 lib-y := delay.o misc.o cmdline.o cpu.o
 lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o
+lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc.o copy_mc_64.o
 lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
 lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
 lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/x86/lib/copy_mc.c b/arch/x86/lib/copy_mc.c
new file mode 100644 (file)
index 0000000..2633635
--- /dev/null
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2016-2020 Intel Corporation. All rights reserved. */
+
+#include <linux/jump_label.h>
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include <asm/mce.h>
+
+#ifdef CONFIG_X86_MCE
+/*
+ * See COPY_MC_TEST for self-test of the copy_mc_fragile()
+ * implementation.
+ */
+static DEFINE_STATIC_KEY_FALSE(copy_mc_fragile_key);
+
+void enable_copy_mc_fragile(void)
+{
+       static_branch_inc(&copy_mc_fragile_key);
+}
+#define copy_mc_fragile_enabled (static_branch_unlikely(&copy_mc_fragile_key))
+
+/*
+ * Similar to copy_user_handle_tail, probe for the write fault point, or
+ * source exception point.
+ */
+__visible notrace unsigned long
+copy_mc_fragile_handle_tail(char *to, char *from, unsigned len)
+{
+       for (; len; --len, to++, from++)
+               if (copy_mc_fragile(to, from, 1))
+                       break;
+       return len;
+}
+#else
+/*
+ * No point in doing careful copying, or consulting a static key when
+ * there is no #MC handler in the CONFIG_X86_MCE=n case.
+ */
+void enable_copy_mc_fragile(void)
+{
+}
+#define copy_mc_fragile_enabled (0)
+#endif
+
+/**
+ * copy_mc_to_kernel - memory copy that handles source exceptions
+ *
+ * @dst:       destination address
+ * @src:       source address
+ * @len:       number of bytes to copy
+ *
+ * Call into the 'fragile' version on systems that have trouble
+ * actually do machine check recovery. Everyone else can just
+ * use memcpy().
+ *
+ * Return 0 for success, or number of bytes not copied if there was an
+ * exception.
+ */
+unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len)
+{
+       if (copy_mc_fragile_enabled)
+               return copy_mc_fragile(dst, src, len);
+       memcpy(dst, src, len);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(copy_mc_to_kernel);
+
+unsigned long __must_check copy_mc_to_user(void *dst, const void *src, unsigned len)
+{
+       unsigned long ret;
+
+       if (!copy_mc_fragile_enabled)
+               return copy_user_generic(dst, src, len);
+
+       __uaccess_begin();
+       ret = copy_mc_fragile(dst, src, len);
+       __uaccess_end();
+       return ret;
+}
diff --git a/arch/x86/lib/copy_mc_64.S b/arch/x86/lib/copy_mc_64.S
new file mode 100644 (file)
index 0000000..c3b613c
--- /dev/null
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2016-2020 Intel Corporation. All rights reserved. */
+
+#include <linux/linkage.h>
+#include <asm/copy_mc_test.h>
+#include <asm/export.h>
+#include <asm/asm.h>
+
+#ifndef CONFIG_UML
+
+#ifdef CONFIG_X86_MCE
+COPY_MC_TEST_CTL
+
+/*
+ * copy_mc_fragile - copy memory with indication if an exception / fault happened
+ *
+ * The 'fragile' version is opted into by platform quirks and takes
+ * pains to avoid unrecoverable corner cases like 'fast-string'
+ * instruction sequences, and consuming poison across a cacheline
+ * boundary. The non-fragile version is equivalent to memcpy()
+ * regardless of CPU machine-check-recovery capability.
+ */
+SYM_FUNC_START(copy_mc_fragile)
+       cmpl $8, %edx
+       /* Less than 8 bytes? Go to byte copy loop */
+       jb .L_no_whole_words
+
+       /* Check for bad alignment of source */
+       testl $7, %esi
+       /* Already aligned */
+       jz .L_8byte_aligned
+
+       /* Copy one byte at a time until source is 8-byte aligned */
+       movl %esi, %ecx
+       andl $7, %ecx
+       subl $8, %ecx
+       negl %ecx
+       subl %ecx, %edx
+.L_read_leading_bytes:
+       movb (%rsi), %al
+       COPY_MC_TEST_SRC %rsi 1 .E_leading_bytes
+       COPY_MC_TEST_DST %rdi 1 .E_leading_bytes
+.L_write_leading_bytes:
+       movb %al, (%rdi)
+       incq %rsi
+       incq %rdi
+       decl %ecx
+       jnz .L_read_leading_bytes
+
+.L_8byte_aligned:
+       movl %edx, %ecx
+       andl $7, %edx
+       shrl $3, %ecx
+       jz .L_no_whole_words
+
+.L_read_words:
+       movq (%rsi), %r8
+       COPY_MC_TEST_SRC %rsi 8 .E_read_words
+       COPY_MC_TEST_DST %rdi 8 .E_write_words
+.L_write_words:
+       movq %r8, (%rdi)
+       addq $8, %rsi
+       addq $8, %rdi
+       decl %ecx
+       jnz .L_read_words
+
+       /* Any trailing bytes? */
+.L_no_whole_words:
+       andl %edx, %edx
+       jz .L_done_memcpy_trap
+
+       /* Copy trailing bytes */
+       movl %edx, %ecx
+.L_read_trailing_bytes:
+       movb (%rsi), %al
+       COPY_MC_TEST_SRC %rsi 1 .E_trailing_bytes
+       COPY_MC_TEST_DST %rdi 1 .E_trailing_bytes
+.L_write_trailing_bytes:
+       movb %al, (%rdi)
+       incq %rsi
+       incq %rdi
+       decl %ecx
+       jnz .L_read_trailing_bytes
+
+       /* Copy successful. Return zero */
+.L_done_memcpy_trap:
+       xorl %eax, %eax
+.L_done:
+       ret
+SYM_FUNC_END(copy_mc_fragile)
+EXPORT_SYMBOL_GPL(copy_mc_fragile)
+
+       .section .fixup, "ax"
+       /*
+        * 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
+       jmp     .L_done
+
+       /*
+        * 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 copy_mc_fragile_handle_tail
+
+       .previous
+
+       _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 /* CONFIG_X86_MCE */
+#endif /* !CONFIG_UML */
index bbcc05b..037faac 100644 (file)
@@ -4,7 +4,6 @@
 #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>
 
@@ -187,117 +186,3 @@ SYM_FUNC_START_LOCAL(memcpy_orig)
 SYM_FUNC_END(memcpy_orig)
 
 .popsection
-
-#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.
- * Writes to target are posted and don't generate machine checks.
- */
-SYM_FUNC_START(__memcpy_mcsafe)
-       cmpl $8, %edx
-       /* Less than 8 bytes? Go to byte copy loop */
-       jb .L_no_whole_words
-
-       /* Check for bad alignment of source */
-       testl $7, %esi
-       /* Already aligned */
-       jz .L_8byte_aligned
-
-       /* Copy one byte at a time until source is 8-byte aligned */
-       movl %esi, %ecx
-       andl $7, %ecx
-       subl $8, %ecx
-       negl %ecx
-       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
-       incq %rdi
-       decl %ecx
-       jnz .L_read_leading_bytes
-
-.L_8byte_aligned:
-       movl %edx, %ecx
-       andl $7, %edx
-       shrl $3, %ecx
-       jz .L_no_whole_words
-
-.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
-       addq $8, %rdi
-       decl %ecx
-       jnz .L_read_words
-
-       /* Any trailing bytes? */
-.L_no_whole_words:
-       andl %edx, %edx
-       jz .L_done_memcpy_trap
-
-       /* Copy trailing bytes */
-       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
-       incq %rdi
-       decl %ecx
-       jnz .L_read_trailing_bytes
-
-       /* Copy successful. Return zero */
-.L_done_memcpy_trap:
-       xorl %eax, %eax
-.L_done:
-       ret
-SYM_FUNC_END(__memcpy_mcsafe)
-EXPORT_SYMBOL_GPL(__memcpy_mcsafe)
-
-       .section .fixup, "ax"
-       /*
-        * 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
-       jmp     .L_done
-
-       /*
-        * 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_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
index b0dfac3..5f1d4a9 100644 (file)
@@ -56,27 +56,6 @@ unsigned long clear_user(void __user *to, unsigned long n)
 }
 EXPORT_SYMBOL(clear_user);
 
-/*
- * 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 notrace 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
index 86dbe0c..9fc18fa 100644 (file)
@@ -49,7 +49,7 @@ do {                                                          \
 #define pmem_assign(dest, src) ((dest) = (src))
 #endif
 
-#if defined(__HAVE_ARCH_MEMCPY_MCSAFE) && defined(DM_WRITECACHE_HAS_PMEM)
+#if IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC) && defined(DM_WRITECACHE_HAS_PMEM)
 #define DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
 #endif
 
@@ -984,7 +984,8 @@ static void writecache_resume(struct dm_target *ti)
        }
        wc->freelist_size = 0;
 
-       r = memcpy_mcsafe(&sb_seq_count, &sb(wc)->seq_count, sizeof(uint64_t));
+       r = copy_mc_to_kernel(&sb_seq_count, &sb(wc)->seq_count,
+                             sizeof(uint64_t));
        if (r) {
                writecache_error(wc, r, "hardware memory error when reading superblock: %d", r);
                sb_seq_count = cpu_to_le64(0);
@@ -1000,7 +1001,8 @@ static void writecache_resume(struct dm_target *ti)
                        e->seq_count = -1;
                        continue;
                }
-               r = memcpy_mcsafe(&wme, memory_entry(wc, e), sizeof(struct wc_memory_entry));
+               r = copy_mc_to_kernel(&wme, memory_entry(wc, e),
+                                     sizeof(struct wc_memory_entry));
                if (r) {
                        writecache_error(wc, r, "hardware memory error when reading metadata entry %lu: %d",
                                         (unsigned long)b, r);
@@ -1198,7 +1200,7 @@ static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data
 
                if (rw == READ) {
                        int r;
-                       r = memcpy_mcsafe(buf, data, size);
+                       r = copy_mc_to_kernel(buf, data, size);
                        flush_dcache_page(bio_page(bio));
                        if (unlikely(r)) {
                                writecache_error(wc, r, "hardware memory error when reading data: %d", r);
@@ -2341,7 +2343,7 @@ invalid_optional:
                }
        }
 
-       r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
+       r = copy_mc_to_kernel(&s, sb(wc), sizeof(struct wc_memory_superblock));
        if (r) {
                ti->error = "Hardware memory error when reading superblock";
                goto bad;
@@ -2352,7 +2354,8 @@ invalid_optional:
                        ti->error = "Unable to initialize device";
                        goto bad;
                }
-               r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
+               r = copy_mc_to_kernel(&s, sb(wc),
+                                     sizeof(struct wc_memory_superblock));
                if (r) {
                        ti->error = "Hardware memory error when reading superblock";
                        goto bad;
index 45964ac..22d865b 100644 (file)
@@ -268,7 +268,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
        if (rw == READ) {
                if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align)))
                        return -EIO;
-               if (memcpy_mcsafe(buf, nsio->addr + offset, size) != 0)
+               if (copy_mc_to_kernel(buf, nsio->addr + offset, size) != 0)
                        return -EIO;
                return 0;
        }
index fab29b5..5c6939e 100644 (file)
@@ -125,7 +125,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
        while (len) {
                mem = kmap_atomic(page);
                chunk = min_t(unsigned int, len, PAGE_SIZE - off);
-               rem = memcpy_mcsafe(mem + off, pmem_addr, chunk);
+               rem = copy_mc_to_kernel(mem + off, pmem_addr, chunk);
                kunmap_atomic(mem);
                if (rem)
                        return BLK_STS_IOERR;
@@ -304,7 +304,7 @@ static long pmem_dax_direct_access(struct dax_device *dax_dev,
 
 /*
  * Use the 'no check' versions of copy_from_iter_flushcache() and
- * copy_to_iter_mcsafe() to bypass HARDENED_USERCOPY overhead. Bounds
+ * copy_mc_to_iter() to bypass HARDENED_USERCOPY overhead. Bounds
  * checking, both file offset and device offset, is handled by
  * dax_iomap_actor()
  */
@@ -317,7 +317,7 @@ static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,
                void *addr, size_t bytes, struct iov_iter *i)
 {
-       return _copy_to_iter_mcsafe(addr, bytes, i);
+       return _copy_mc_to_iter(addr, bytes, i);
 }
 
 static const struct dax_operations pmem_dax_ops = {
index 9b7a063..b1f3894 100644 (file)
@@ -161,20 +161,13 @@ extern int bcmp(const void *,const void *,__kernel_size_t);
 #ifndef __HAVE_ARCH_MEMCHR
 extern void * memchr(const void *,int,__kernel_size_t);
 #endif
-#ifndef __HAVE_ARCH_MEMCPY_MCSAFE
-static inline __must_check unsigned long memcpy_mcsafe(void *dst,
-               const void *src, size_t cnt)
-{
-       memcpy(dst, src, cnt);
-       return 0;
-}
-#endif
 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
 {
        memcpy(dst, src, cnt);
 }
 #endif
+
 void *memchr_inv(const void *s, int c, size_t n);
 char *strreplace(char *s, char old, char new);
 
index 94b2854..1ae36bc 100644 (file)
@@ -179,6 +179,19 @@ copy_in_user(void __user *to, const void __user *from, unsigned long n)
 }
 #endif
 
+#ifndef copy_mc_to_kernel
+/*
+ * Without arch opt-in this generic copy_mc_to_kernel() will not handle
+ * #MC (or arch equivalent) during source read.
+ */
+static inline unsigned long __must_check
+copy_mc_to_kernel(void *dst, const void *src, size_t cnt)
+{
+       memcpy(dst, src, cnt);
+       return 0;
+}
+#endif
+
 static __always_inline void pagefault_disabled_inc(void)
 {
        current->pagefault_disabled++;
index 3835a8a..f14410c 100644 (file)
@@ -185,10 +185,10 @@ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
 #define _copy_from_iter_flushcache _copy_from_iter_nocache
 #endif
 
-#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
-size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i);
+#ifdef CONFIG_ARCH_HAS_COPY_MC
+size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
 #else
-#define _copy_to_iter_mcsafe _copy_to_iter
+#define _copy_mc_to_iter _copy_to_iter
 #endif
 
 static __always_inline __must_check
@@ -201,12 +201,12 @@ size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
 }
 
 static __always_inline __must_check
-size_t copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i)
+size_t copy_mc_to_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
        if (unlikely(!check_copy_size(addr, bytes, true)))
                return 0;
        else
-               return _copy_to_iter_mcsafe(addr, bytes, i);
+               return _copy_mc_to_iter(addr, bytes, i);
 }
 
 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
index b4b98a0..b46a9fd 100644 (file)
@@ -635,7 +635,12 @@ config UACCESS_MEMCPY
 config ARCH_HAS_UACCESS_FLUSHCACHE
        bool
 
-config ARCH_HAS_UACCESS_MCSAFE
+# arch has a concept of a recoverable synchronous exception due to a
+# memory-read error like x86 machine-check or ARM data-abort, and
+# implements copy_mc_to_{user,kernel} to abort and report
+# 'bytes-transferred' if that exception fires when accessing the source
+# buffer.
+config ARCH_HAS_COPY_MC
        bool
 
 # Temporary. Goes away when all archs are cleaned up
index 5e40786..d13304a 100644 (file)
@@ -637,30 +637,30 @@ size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 }
 EXPORT_SYMBOL(_copy_to_iter);
 
-#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
-static int copyout_mcsafe(void __user *to, const void *from, size_t n)
+#ifdef CONFIG_ARCH_HAS_COPY_MC
+static int copyout_mc(void __user *to, const void *from, size_t n)
 {
        if (access_ok(to, n)) {
                instrument_copy_to_user(to, from, n);
-               n = copy_to_user_mcsafe((__force void *) to, from, n);
+               n = copy_mc_to_user((__force void *) to, from, n);
        }
        return n;
 }
 
-static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset,
+static unsigned long copy_mc_to_page(struct page *page, size_t offset,
                const char *from, size_t len)
 {
        unsigned long ret;
        char *to;
 
        to = kmap_atomic(page);
-       ret = memcpy_mcsafe(to + offset, from, len);
+       ret = copy_mc_to_kernel(to + offset, from, len);
        kunmap_atomic(to);
 
        return ret;
 }
 
-static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes,
+static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes,
                                struct iov_iter *i)
 {
        struct pipe_inode_info *pipe = i->pipe;
@@ -678,7 +678,7 @@ static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes,
                size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
                unsigned long rem;
 
-               rem = memcpy_mcsafe_to_page(pipe->bufs[i_head & p_mask].page,
+               rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page,
                                            off, addr, chunk);
                i->head = i_head;
                i->iov_offset = off + chunk - rem;
@@ -695,18 +695,17 @@ static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes,
 }
 
 /**
- * _copy_to_iter_mcsafe - copy to user with source-read error exception handling
+ * _copy_mc_to_iter - copy to iter with source memory error exception handling
  * @addr: source kernel address
  * @bytes: total transfer length
  * @iter: destination iterator
  *
- * The pmem driver arranges for filesystem-dax to use this facility via
- * dax_copy_to_iter() for protecting read/write to persistent memory.
- * Unless / until an architecture can guarantee identical performance
- * between _copy_to_iter_mcsafe() and _copy_to_iter() it would be a
- * performance regression to switch more users to the mcsafe version.
+ * The pmem driver deploys this for the dax operation
+ * (dax_copy_to_iter()) for dax reads (bypass page-cache and the
+ * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes
+ * successfully copied.
  *
- * Otherwise, the main differences between this and typical _copy_to_iter().
+ * The main differences between this and typical _copy_to_iter().
  *
  * * Typical tail/residue handling after a fault retries the copy
  *   byte-by-byte until the fault happens again. Re-triggering machine
@@ -717,23 +716,22 @@ static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes,
  * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies.
  *   Compare to copy_to_iter() where only ITER_IOVEC attempts might return
  *   a short copy.
- *
- * See MCSAFE_TEST for self-test.
  */
-size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
+size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 {
        const char *from = addr;
        unsigned long rem, curr_addr, s_addr = (unsigned long) addr;
 
        if (unlikely(iov_iter_is_pipe(i)))
-               return copy_pipe_to_iter_mcsafe(addr, bytes, i);
+               return copy_mc_pipe_to_iter(addr, bytes, i);
        if (iter_is_iovec(i))
                might_fault();
        iterate_and_advance(i, bytes, v,
-               copyout_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len),
+               copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len,
+                          v.iov_len),
                ({
-               rem = memcpy_mcsafe_to_page(v.bv_page, v.bv_offset,
-                               (from += v.bv_len) - v.bv_len, v.bv_len);
+               rem = copy_mc_to_page(v.bv_page, v.bv_offset,
+                                     (from += v.bv_len) - v.bv_len, v.bv_len);
                if (rem) {
                        curr_addr = (unsigned long) from;
                        bytes = curr_addr - s_addr - rem;
@@ -741,8 +739,8 @@ size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
                }
                }),
                ({
-               rem = memcpy_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len,
-                               v.iov_len);
+               rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len)
+                                       - v.iov_len, v.iov_len);
                if (rem) {
                        curr_addr = (unsigned long) from;
                        bytes = curr_addr - s_addr - rem;
@@ -753,8 +751,8 @@ size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
 
        return bytes;
 }
-EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe);
-#endif /* CONFIG_ARCH_HAS_UACCESS_MCSAFE */
+EXPORT_SYMBOL_GPL(_copy_mc_to_iter);
+#endif /* CONFIG_ARCH_HAS_COPY_MC */
 
 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
diff --git a/tools/arch/x86/include/asm/mcsafe_test.h b/tools/arch/x86/include/asm/mcsafe_test.h
deleted file mode 100644 (file)
index 2ccd588..0000000
+++ /dev/null
@@ -1,13 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _MCSAFE_TEST_H_
-#define _MCSAFE_TEST_H_
-
-.macro MCSAFE_TEST_CTL
-.endm
-
-.macro MCSAFE_TEST_SRC reg count target
-.endm
-
-.macro MCSAFE_TEST_DST reg count target
-.endm
-#endif /* _MCSAFE_TEST_H_ */
index 45f8e1b..0b5b8ae 100644 (file)
@@ -4,7 +4,6 @@
 #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>
 
@@ -187,117 +186,3 @@ SYM_FUNC_START(memcpy_orig)
 SYM_FUNC_END(memcpy_orig)
 
 .popsection
-
-#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.
- * Writes to target are posted and don't generate machine checks.
- */
-SYM_FUNC_START(__memcpy_mcsafe)
-       cmpl $8, %edx
-       /* Less than 8 bytes? Go to byte copy loop */
-       jb .L_no_whole_words
-
-       /* Check for bad alignment of source */
-       testl $7, %esi
-       /* Already aligned */
-       jz .L_8byte_aligned
-
-       /* Copy one byte at a time until source is 8-byte aligned */
-       movl %esi, %ecx
-       andl $7, %ecx
-       subl $8, %ecx
-       negl %ecx
-       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
-       incq %rdi
-       decl %ecx
-       jnz .L_read_leading_bytes
-
-.L_8byte_aligned:
-       movl %edx, %ecx
-       andl $7, %edx
-       shrl $3, %ecx
-       jz .L_no_whole_words
-
-.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
-       addq $8, %rdi
-       decl %ecx
-       jnz .L_read_words
-
-       /* Any trailing bytes? */
-.L_no_whole_words:
-       andl %edx, %edx
-       jz .L_done_memcpy_trap
-
-       /* Copy trailing bytes */
-       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
-       incq %rdi
-       decl %ecx
-       jnz .L_read_trailing_bytes
-
-       /* Copy successful. Return zero */
-.L_done_memcpy_trap:
-       xorl %eax, %eax
-.L_done:
-       ret
-SYM_FUNC_END(__memcpy_mcsafe)
-EXPORT_SYMBOL_GPL(__memcpy_mcsafe)
-
-       .section .fixup, "ax"
-       /*
-        * 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
-       jmp     .L_done
-
-       /*
-        * 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_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
index e034a8f..893f021 100644 (file)
@@ -548,8 +548,8 @@ static const char *uaccess_safe_builtin[] = {
        "__ubsan_handle_shift_out_of_bounds",
        /* misc */
        "csum_partial_copy_generic",
-       "__memcpy_mcsafe",
-       "mcsafe_handle_tail",
+       "copy_mc_fragile",
+       "copy_mc_fragile_handle_tail",
        "ftrace_likely_update", /* CONFIG_TRACE_BRANCH_PROFILING */
        NULL
 };
index dd68a40..878db6a 100644 (file)
@@ -13,7 +13,6 @@ perf-y += synthesize.o
 perf-y += kallsyms-parse.o
 perf-y += find-bit-bench.o
 
-perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-lib.o
 perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-asm.o
 perf-$(CONFIG_X86_64) += mem-memset-x86-64-asm.o
 
diff --git a/tools/perf/bench/mem-memcpy-x86-64-lib.c b/tools/perf/bench/mem-memcpy-x86-64-lib.c
deleted file mode 100644 (file)
index 4130734..0000000
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * From code in arch/x86/lib/usercopy_64.c, copied to keep tools/ copy
- * of the kernel's arch/x86/lib/memcpy_64.s used in 'perf bench mem memcpy'
- * happy.
- */
-#include <linux/types.h>
-
-unsigned long __memcpy_mcsafe(void *dst, const void *src, size_t cnt);
-unsigned long mcsafe_handle_tail(char *to, char *from, unsigned len);
-
-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;
-}
index a1a5dc6..2ac0fff 100644 (file)
@@ -23,7 +23,8 @@
 #include "nfit_test.h"
 #include "../watermark.h"
 
-#include <asm/mcsafe_test.h>
+#include <asm/copy_mc_test.h>
+#include <asm/mce.h>
 
 /*
  * Generate an NFIT table to describe the following topology:
@@ -3283,7 +3284,7 @@ static struct platform_driver nfit_test_driver = {
        .id_table = nfit_test_id,
 };
 
-static char mcsafe_buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
+static char copy_mc_buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
 
 enum INJECT {
        INJECT_NONE,
@@ -3291,7 +3292,7 @@ enum INJECT {
        INJECT_DST,
 };
 
-static void mcsafe_test_init(char *dst, char *src, size_t size)
+static void copy_mc_test_init(char *dst, char *src, size_t size)
 {
        size_t i;
 
@@ -3300,7 +3301,7 @@ static void mcsafe_test_init(char *dst, char *src, size_t size)
                src[i] = (char) i;
 }
 
-static bool mcsafe_test_validate(unsigned char *dst, unsigned char *src,
+static bool copy_mc_test_validate(unsigned char *dst, unsigned char *src,
                size_t size, unsigned long rem)
 {
        size_t i;
@@ -3321,12 +3322,12 @@ static bool mcsafe_test_validate(unsigned char *dst, unsigned char *src,
        return true;
 }
 
-void mcsafe_test(void)
+void copy_mc_test(void)
 {
        char *inject_desc[] = { "none", "source", "destination" };
        enum INJECT inj;
 
-       if (IS_ENABLED(CONFIG_MCSAFE_TEST)) {
+       if (IS_ENABLED(CONFIG_COPY_MC_TEST)) {
                pr_info("%s: run...\n", __func__);
        } else {
                pr_info("%s: disabled, skip.\n", __func__);
@@ -3344,31 +3345,31 @@ void mcsafe_test(void)
 
                        switch (inj) {
                        case INJECT_NONE:
-                               mcsafe_inject_src(NULL);
-                               mcsafe_inject_dst(NULL);
-                               dst = &mcsafe_buf[2048];
-                               src = &mcsafe_buf[1024 - i];
+                               copy_mc_inject_src(NULL);
+                               copy_mc_inject_dst(NULL);
+                               dst = &copy_mc_buf[2048];
+                               src = &copy_mc_buf[1024 - i];
                                expect = 0;
                                break;
                        case INJECT_SRC:
-                               mcsafe_inject_src(&mcsafe_buf[1024]);
-                               mcsafe_inject_dst(NULL);
-                               dst = &mcsafe_buf[2048];
-                               src = &mcsafe_buf[1024 - i];
+                               copy_mc_inject_src(&copy_mc_buf[1024]);
+                               copy_mc_inject_dst(NULL);
+                               dst = &copy_mc_buf[2048];
+                               src = &copy_mc_buf[1024 - i];
                                expect = 512 - i;
                                break;
                        case INJECT_DST:
-                               mcsafe_inject_src(NULL);
-                               mcsafe_inject_dst(&mcsafe_buf[2048]);
-                               dst = &mcsafe_buf[2048 - i];
-                               src = &mcsafe_buf[1024];
+                               copy_mc_inject_src(NULL);
+                               copy_mc_inject_dst(&copy_mc_buf[2048]);
+                               dst = &copy_mc_buf[2048 - i];
+                               src = &copy_mc_buf[1024];
                                expect = 512 - i;
                                break;
                        }
 
-                       mcsafe_test_init(dst, src, 512);
-                       rem = __memcpy_mcsafe(dst, src, 512);
-                       valid = mcsafe_test_validate(dst, src, 512, expect);
+                       copy_mc_test_init(dst, src, 512);
+                       rem = copy_mc_fragile(dst, src, 512);
+                       valid = copy_mc_test_validate(dst, src, 512, expect);
                        if (rem == expect && valid)
                                continue;
                        pr_info("%s: copy(%#lx, %#lx, %d) off: %d rem: %ld %s expect: %ld\n",
@@ -3380,8 +3381,8 @@ void mcsafe_test(void)
                }
        }
 
-       mcsafe_inject_src(NULL);
-       mcsafe_inject_dst(NULL);
+       copy_mc_inject_src(NULL);
+       copy_mc_inject_dst(NULL);
 }
 
 static __init int nfit_test_init(void)
@@ -3392,7 +3393,7 @@ static __init int nfit_test_init(void)
        libnvdimm_test();
        acpi_nfit_test();
        device_dax_test();
-       mcsafe_test();
+       copy_mc_test();
        dax_pmem_test();
        dax_pmem_core_test();
 #ifdef CONFIG_DEV_DAX_PMEM_COMPAT
index ddaf140..994b11a 100644 (file)
@@ -12,4 +12,4 @@ memcpy_p7_t1
 copyuser_64_exc_t0
 copyuser_64_exc_t1
 copyuser_64_exc_t2
-memcpy_mcsafe_64
+copy_mc_64
index 0917983..3095b1f 100644 (file)
@@ -12,7 +12,7 @@ ASFLAGS = $(CFLAGS) -Wa,-mpower4
 TEST_GEN_PROGS := copyuser_64_t0 copyuser_64_t1 copyuser_64_t2 \
                copyuser_p7_t0 copyuser_p7_t1 \
                memcpy_64_t0 memcpy_64_t1 memcpy_64_t2 \
-               memcpy_p7_t0 memcpy_p7_t1 memcpy_mcsafe_64 \
+               memcpy_p7_t0 memcpy_p7_t1 copy_mc_64 \
                copyuser_64_exc_t0 copyuser_64_exc_t1 copyuser_64_exc_t2
 
 EXTRA_SOURCES := validate.c ../harness.c stubs.S
@@ -45,9 +45,9 @@ $(OUTPUT)/memcpy_p7_t%:       memcpy_power7.S $(EXTRA_SOURCES)
                -D SELFTEST_CASE=$(subst memcpy_p7_t,,$(notdir $@)) \
                -o $@ $^
 
-$(OUTPUT)/memcpy_mcsafe_64: memcpy_mcsafe_64.S $(EXTRA_SOURCES)
+$(OUTPUT)/copy_mc_64: copy_mc_64.S $(EXTRA_SOURCES)
        $(CC) $(CPPFLAGS) $(CFLAGS) \
-               -D COPY_LOOP=test_memcpy_mcsafe \
+               -D COPY_LOOP=test_copy_mc_generic \
                -o $@ $^
 
 $(OUTPUT)/copyuser_64_exc_t%: copyuser_64.S exc_validate.c ../harness.c \
diff --git a/tools/testing/selftests/powerpc/copyloops/copy_mc_64.S b/tools/testing/selftests/powerpc/copyloops/copy_mc_64.S
new file mode 120000 (symlink)
index 0000000..dcbe06d
--- /dev/null
@@ -0,0 +1 @@
+../../../../../arch/powerpc/lib/copy_mc_64.S
\ No newline at end of file
diff --git a/tools/testing/selftests/powerpc/copyloops/memcpy_mcsafe_64.S b/tools/testing/selftests/powerpc/copyloops/memcpy_mcsafe_64.S
deleted file mode 120000 (symlink)
index f0feef3..0000000
+++ /dev/null
@@ -1 +0,0 @@
-../../../../../arch/powerpc/lib/memcpy_mcsafe_64.S
\ No newline at end of file