x86, libnvdimm/test: Remove COPY_MC_TEST

The COPY_MC_TEST facility has served its purpose for validating the
early termination conditions of the copy_mc_fragile() implementation.
Remove it and the EXPORT_SYMBOL_GPL of copy_mc_fragile().
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/160316688322.3374697.8648308115165836243.stgit@dwillia2-desk3.amr.corp.intel.com

arch/x86/Kconfig.debug

@@ -62,9 +62,6 @@ 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 COPY_MC_TEST
-	def_bool n
-
 config EFI_PGT_DUMP
 	bool "Dump the EFI pagetable"
 	depends on EFI

arch/x86/include/asm/copy_mc_test.h

-/* 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_ */

arch/x86/lib/copy_mc.c

@@ -10,10 +10,6 @@
 #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)

arch/x86/lib/copy_mc_64.S

@@ -2,14 +2,11 @@
 /* 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
@@ -38,8 +35,6 @@ SYM_FUNC_START(copy_mc_fragile)
 	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
@@ -55,8 +50,6 @@ SYM_FUNC_START(copy_mc_fragile)
 
 .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
@@ -73,8 +66,6 @@ SYM_FUNC_START(copy_mc_fragile)
 	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
@@ -88,7 +79,6 @@ SYM_FUNC_START(copy_mc_fragile)
 .L_done:
 	ret
 SYM_FUNC_END(copy_mc_fragile)
-EXPORT_SYMBOL_GPL(copy_mc_fragile)
 
 	.section .fixup, "ax"
 	/*

tools/testing/nvdimm/test/nfit.c

@@ -23,7 +23,6 @@
 #include "nfit_test.h"
 #include "../watermark.h"
 
-#include <asm/copy_mc_test.h>
 #include <asm/mce.h>
 
 /*
@@ -3284,107 +3283,6 @@ static struct platform_driver nfit_test_driver = {
 	.id_table = nfit_test_id,
 };
 
-static char copy_mc_buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
-
-enum INJECT {
-	INJECT_NONE,
-	INJECT_SRC,
-	INJECT_DST,
-};
-
-static void copy_mc_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 copy_mc_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 copy_mc_test(void)
-{
-	char *inject_desc[] = { "none", "source", "destination" };
-	enum INJECT inj;
-
-	if (IS_ENABLED(CONFIG_COPY_MC_TEST)) {
-		pr_info("%s: run...\n", __func__);
-	} else {
-		pr_info("%s: disabled, skip.\n", __func__);
-		return;
-	}
-
-	for (inj = INJECT_NONE; inj <= INJECT_DST; inj++) {
-		int i;
-
-		pr_info("%s: inject: %s\n", __func__, inject_desc[inj]);
-		for (i = 0; i < 512; i++) {
-			unsigned long expect, rem;
-			void *src, *dst;
-			bool valid;
-
-			switch (inj) {
-			case INJECT_NONE:
-				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:
-				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:
-				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;
-			}
-
-			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",
-					__func__,
-					((unsigned long) dst) & ~PAGE_MASK,
-					((unsigned long ) src) & ~PAGE_MASK,
-					512, i, rem, valid ? "valid" : "bad",
-					expect);
-		}
-	}
-
-	copy_mc_inject_src(NULL);
-	copy_mc_inject_dst(NULL);
-}
-
 static __init int nfit_test_init(void)
 {
 	int rc, i;
@@ -3393,7 +3291,6 @@ static __init int nfit_test_init(void)
 	libnvdimm_test();
 	acpi_nfit_test();
 	device_dax_test();
-	copy_mc_test();
 	dax_pmem_test();
 	dax_pmem_core_test();
 #ifdef CONFIG_DEV_DAX_PMEM_COMPAT