summaryrefslogtreecommitdiff
path: root/tools
diff options
context:
space:
mode:
authorDan Williams <dan.j.williams@intel.com>2020-10-06 06:40:16 +0300
committerBorislav Petkov <bp@suse.de>2020-10-06 12:18:04 +0300
commitec6347bb43395cb92126788a1a5b25302543f815 (patch)
tree98a65bc27c57de7d21fdf657e0e94a95bb50935f /tools
parented9705e4ad1c19ae51ed0cb4c112f9eb6dfc69fc (diff)
downloadlinux-ec6347bb43395cb92126788a1a5b25302543f815.tar.xz
x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()
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
Diffstat (limited to 'tools')
-rw-r--r--tools/arch/x86/include/asm/mcsafe_test.h13
-rw-r--r--tools/arch/x86/lib/memcpy_64.S115
-rw-r--r--tools/objtool/check.c4
-rw-r--r--tools/perf/bench/Build1
-rw-r--r--tools/perf/bench/mem-memcpy-x86-64-lib.c24
-rw-r--r--tools/testing/nvdimm/test/nfit.c49
-rw-r--r--tools/testing/selftests/powerpc/copyloops/.gitignore2
-rw-r--r--tools/testing/selftests/powerpc/copyloops/Makefile6
l---------tools/testing/selftests/powerpc/copyloops/copy_mc_64.S1
l---------tools/testing/selftests/powerpc/copyloops/memcpy_mcsafe_64.S1
10 files changed, 32 insertions, 184 deletions
diff --git a/tools/arch/x86/include/asm/mcsafe_test.h b/tools/arch/x86/include/asm/mcsafe_test.h
deleted file mode 100644
index 2ccd588fbad4..000000000000
--- a/tools/arch/x86/include/asm/mcsafe_test.h
+++ /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_ */
diff --git a/tools/arch/x86/lib/memcpy_64.S b/tools/arch/x86/lib/memcpy_64.S
index 45f8e1b02241..0b5b8ae56bd9 100644
--- a/tools/arch/x86/lib/memcpy_64.S
+++ b/tools/arch/x86/lib/memcpy_64.S
@@ -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 $3, %ecx
- addl %edx, %ecx
- movl %ecx, %edx
- jmp mcsafe_handle_tail
-
- .previous
-
- _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .E_leading_bytes)
- _ASM_EXTABLE_FAULT(.L_read_words, .E_read_words)
- _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .E_trailing_bytes)
- _ASM_EXTABLE(.L_write_leading_bytes, .E_leading_bytes)
- _ASM_EXTABLE(.L_write_words, .E_write_words)
- _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes)
-#endif
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e034a8f24f46..893f021fec63 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -548,8 +548,8 @@ static const char *uaccess_safe_builtin[] = {
"__ubsan_handle_shift_out_of_bounds",
/* misc */
"csum_partial_copy_generic",
- "__memcpy_mcsafe",
- "mcsafe_handle_tail",
+ "copy_mc_fragile",
+ "copy_mc_fragile_handle_tail",
"ftrace_likely_update", /* CONFIG_TRACE_BRANCH_PROFILING */
NULL
};
diff --git a/tools/perf/bench/Build b/tools/perf/bench/Build
index dd68a40a790c..878db6a59a41 100644
--- a/tools/perf/bench/Build
+++ b/tools/perf/bench/Build
@@ -13,7 +13,6 @@ perf-y += synthesize.o
perf-y += kallsyms-parse.o
perf-y += find-bit-bench.o
-perf-$(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
index 4130734dde84..000000000000
--- a/tools/perf/bench/mem-memcpy-x86-64-lib.c
+++ /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;
-}
diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index a1a5dc645b40..2ac0fff6dad8 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/tools/testing/nvdimm/test/nfit.c
@@ -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
diff --git a/tools/testing/selftests/powerpc/copyloops/.gitignore b/tools/testing/selftests/powerpc/copyloops/.gitignore
index ddaf140b8255..994b11af765c 100644
--- a/tools/testing/selftests/powerpc/copyloops/.gitignore
+++ b/tools/testing/selftests/powerpc/copyloops/.gitignore
@@ -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
diff --git a/tools/testing/selftests/powerpc/copyloops/Makefile b/tools/testing/selftests/powerpc/copyloops/Makefile
index 0917983a1c78..3095b1f1c02b 100644
--- a/tools/testing/selftests/powerpc/copyloops/Makefile
+++ b/tools/testing/selftests/powerpc/copyloops/Makefile
@@ -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
index 000000000000..dcbe06d500fb
--- /dev/null
+++ b/tools/testing/selftests/powerpc/copyloops/copy_mc_64.S
@@ -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
index f0feef3062f6..000000000000
--- a/tools/testing/selftests/powerpc/copyloops/memcpy_mcsafe_64.S
+++ /dev/null
@@ -1 +0,0 @@
-../../../../../arch/powerpc/lib/memcpy_mcsafe_64.S \ No newline at end of file