kmemcheck: rip it out

Fix up makefiles, remove references, and git rm kmemcheck.

Link: http://lkml.kernel.org/r/20171007030159.22241-4-alexander.levin@verizon.com


Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Tim Hansen <devtimhansen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/admin-guide/kernel-parameters.txt

@@ -1864,13 +1864,6 @@
 			Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
 			the default is off.
 
-	kmemcheck=	[X86] Boot-time kmemcheck enable/disable/one-shot mode
-			Valid arguments: 0, 1, 2
-			kmemcheck=0 (disabled)
-			kmemcheck=1 (enabled)
-			kmemcheck=2 (one-shot mode)
-			Default: 2 (one-shot mode)
-
 	kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
 			Default is 0 (don't ignore, but inject #GP)
 

Documentation/dev-tools/index.rst

@@ -21,7 +21,6 @@ whole; patches welcome!
    kasan
    ubsan
    kmemleak
-   kmemcheck
    gdb-kernel-debugging
    kgdb
    kselftest

MAINTAINERS

@@ -7688,16 +7688,6 @@ F:	include/linux/kdb.h
 F:	include/linux/kgdb.h
 F:	kernel/debug/
 
-KMEMCHECK
-M:	Vegard Nossum <vegardno@ifi.uio.no>
-M:	Pekka Enberg <penberg@kernel.org>
-S:	Maintained
-F:	Documentation/dev-tools/kmemcheck.rst
-F:	arch/x86/include/asm/kmemcheck.h
-F:	arch/x86/mm/kmemcheck/
-F:	include/linux/kmemcheck.h
-F:	mm/kmemcheck.c
-
 KMEMLEAK
 M:	Catalin Marinas <catalin.marinas@arm.com>
 S:	Maintained

arch/x86/Kconfig

@@ -112,7 +112,6 @@ config X86
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_KASAN			if X86_64 && SPARSEMEM_VMEMMAP
 	select HAVE_ARCH_KGDB
-	select HAVE_ARCH_KMEMCHECK
 	select HAVE_ARCH_MMAP_RND_BITS		if MMU
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
 	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
@@ -1430,7 +1429,7 @@ config ARCH_DMA_ADDR_T_64BIT
 
 config X86_DIRECT_GBPAGES
 	def_bool y
-	depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
+	depends on X86_64 && !DEBUG_PAGEALLOC
 	---help---
 	  Certain kernel features effectively disable kernel
 	  linear 1 GB mappings (even if the CPU otherwise

arch/x86/include/asm/kmemcheck.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ASM_X86_KMEMCHECK_H
-#define ASM_X86_KMEMCHECK_H
-
-#include <linux/types.h>
-#include <asm/ptrace.h>
-
-#ifdef CONFIG_KMEMCHECK
-bool kmemcheck_active(struct pt_regs *regs);
-
-void kmemcheck_show(struct pt_regs *regs);
-void kmemcheck_hide(struct pt_regs *regs);
-
-bool kmemcheck_fault(struct pt_regs *regs,
-	unsigned long address, unsigned long error_code);
-bool kmemcheck_trap(struct pt_regs *regs);
-#else
-static inline bool kmemcheck_active(struct pt_regs *regs)
-{
-	return false;
-}
-
-static inline void kmemcheck_show(struct pt_regs *regs)
-{
-}
-
-static inline void kmemcheck_hide(struct pt_regs *regs)
-{
-}
-
-static inline bool kmemcheck_fault(struct pt_regs *regs,
-	unsigned long address, unsigned long error_code)
-{
-	return false;
-}
-
-static inline bool kmemcheck_trap(struct pt_regs *regs)
-{
-	return false;
-}
-#endif /* CONFIG_KMEMCHECK */
-
-#endif

arch/x86/include/asm/string_32.h

@@ -179,8 +179,6 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len)
  *	No 3D Now!
  */
 
-#ifndef CONFIG_KMEMCHECK
-
 #if (__GNUC__ >= 4)
 #define memcpy(t, f, n) __builtin_memcpy(t, f, n)
 #else
@@ -189,13 +187,6 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len)
 	 ? __constant_memcpy((t), (f), (n))	\
 	 : __memcpy((t), (f), (n)))
 #endif
-#else
-/*
- * kmemcheck becomes very happy if we use the REP instructions unconditionally,
- * because it means that we know both memory operands in advance.
- */
-#define memcpy(t, f, n) __memcpy((t), (f), (n))
-#endif
 
 #endif
 #endif /* !CONFIG_FORTIFY_SOURCE */

arch/x86/include/asm/string_64.h

@@ -33,7 +33,6 @@ extern void *memcpy(void *to, const void *from, size_t len);
 extern void *__memcpy(void *to, const void *from, size_t len);
 
 #ifndef CONFIG_FORTIFY_SOURCE
-#ifndef CONFIG_KMEMCHECK
 #if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
 #define memcpy(dst, src, len)					\
 ({								\
@@ -46,13 +45,6 @@ extern void *__memcpy(void *to, const void *from, size_t len);
 	__ret;							\
 })
 #endif
-#else
-/*
- * kmemcheck becomes very happy if we use the REP instructions unconditionally,
- * because it means that we know both memory operands in advance.
- */
-#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
-#endif
 #endif /* !CONFIG_FORTIFY_SOURCE */
 
 #define __HAVE_ARCH_MEMSET

arch/x86/kernel/cpu/intel.c

@@ -187,21 +187,6 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 	if (c->x86 == 6 && c->x86_model < 15)
 		clear_cpu_cap(c, X86_FEATURE_PAT);
 
-#ifdef CONFIG_KMEMCHECK
-	/*
-	 * P4s have a "fast strings" feature which causes single-
-	 * stepping REP instructions to only generate a #DB on
-	 * cache-line boundaries.
-	 *
-	 * Ingo Molnar reported a Pentium D (model 6) and a Xeon
-	 * (model 2) with the same problem.
-	 */
-	if (c->x86 == 15)
-		if (msr_clear_bit(MSR_IA32_MISC_ENABLE,
-				  MSR_IA32_MISC_ENABLE_FAST_STRING_BIT) > 0)
-			pr_info("kmemcheck: Disabling fast string operations\n");
-#endif
-
 	/*
 	 * If fast string is not enabled in IA32_MISC_ENABLE for any reason,
 	 * clear the fast string and enhanced fast string CPU capabilities.

arch/x86/mm/Makefile

@@ -29,8 +29,6 @@ obj-$(CONFIG_X86_PTDUMP)	+= debug_pagetables.o
 
 obj-$(CONFIG_HIGHMEM)		+= highmem_32.o
 
-obj-$(CONFIG_KMEMCHECK)		+= kmemcheck/
-
 KASAN_SANITIZE_kasan_init_$(BITS).o := n
 obj-$(CONFIG_KASAN)		+= kasan_init_$(BITS).o
 

arch/x86/mm/init.c

@@ -163,12 +163,11 @@ static int page_size_mask;
 static void __init probe_page_size_mask(void)
 {
 	/*
-	 * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will
-	 * use small pages.
+	 * For pagealloc debugging, identity mapping will use small pages.
 	 * This will simplify cpa(), which otherwise needs to support splitting
 	 * large pages into small in interrupt context, etc.
 	 */
-	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled() && !IS_ENABLED(CONFIG_KMEMCHECK))
+	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
 		page_size_mask |= 1 << PG_LEVEL_2M;
 	else
 		direct_gbpages = 0;

arch/x86/mm/kmemcheck/Makefile

-obj-y := error.o kmemcheck.o opcode.o pte.o selftest.o shadow.o

arch/x86/mm/kmemcheck/error.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/interrupt.h>
-#include <linux/kdebug.h>
-#include <linux/kmemcheck.h>
-#include <linux/kernel.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/stacktrace.h>
-#include <linux/string.h>
-
-#include "error.h"
-#include "shadow.h"
-
-enum kmemcheck_error_type {
-	KMEMCHECK_ERROR_INVALID_ACCESS,
-	KMEMCHECK_ERROR_BUG,
-};
-
-#define SHADOW_COPY_SIZE (1 << CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT)
-
-struct kmemcheck_error {
-	enum kmemcheck_error_type type;
-
-	union {
-		/* KMEMCHECK_ERROR_INVALID_ACCESS */
-		struct {
-			/* Kind of access that caused the error */
-			enum kmemcheck_shadow state;
-			/* Address and size of the erroneous read */
-			unsigned long	address;
-			unsigned int	size;
-		};
-	};
-
-	struct pt_regs		regs;
-	struct stack_trace	trace;
-	unsigned long		trace_entries[32];
-
-	/* We compress it to a char. */
-	unsigned char		shadow_copy[SHADOW_COPY_SIZE];
-	unsigned char		memory_copy[SHADOW_COPY_SIZE];
-};
-
-/*
- * Create a ring queue of errors to output. We can't call printk() directly
- * from the kmemcheck traps, since this may call the console drivers and
- * result in a recursive fault.
- */
-static struct kmemcheck_error error_fifo[CONFIG_KMEMCHECK_QUEUE_SIZE];
-static unsigned int error_count;
-static unsigned int error_rd;
-static unsigned int error_wr;
-static unsigned int error_missed_count;
-
-static struct kmemcheck_error *error_next_wr(void)
-{
-	struct kmemcheck_error *e;
-
-	if (error_count == ARRAY_SIZE(error_fifo)) {
-		++error_missed_count;
-		return NULL;
-	}
-
-	e = &error_fifo[error_wr];
-	if (++error_wr == ARRAY_SIZE(error_fifo))
-		error_wr = 0;
-	++error_count;
-	return e;
-}
-
-static struct kmemcheck_error *error_next_rd(void)
-{
-	struct kmemcheck_error *e;
-
-	if (error_count == 0)
-		return NULL;
-
-	e = &error_fifo[error_rd];
-	if (++error_rd == ARRAY_SIZE(error_fifo))
-		error_rd = 0;
-	--error_count;
-	return e;
-}
-
-void kmemcheck_error_recall(void)
-{
-	static const char *desc[] = {
-		[KMEMCHECK_SHADOW_UNALLOCATED]		= "unallocated",
-		[KMEMCHECK_SHADOW_UNINITIALIZED]	= "uninitialized",
-		[KMEMCHECK_SHADOW_INITIALIZED]		= "initialized",
-		[KMEMCHECK_SHADOW_FREED]		= "freed",
-	};
-
-	static const char short_desc[] = {
-		[KMEMCHECK_SHADOW_UNALLOCATED]		= 'a',
-		[KMEMCHECK_SHADOW_UNINITIALIZED]	= 'u',
-		[KMEMCHECK_SHADOW_INITIALIZED]		= 'i',
-		[KMEMCHECK_SHADOW_FREED]		= 'f',
-	};
-
-	struct kmemcheck_error *e;
-	unsigned int i;
-
-	e = error_next_rd();
-	if (!e)
-		return;
-
-	switch (e->type) {
-	case KMEMCHECK_ERROR_INVALID_ACCESS:
-		printk(KERN_WARNING "WARNING: kmemcheck: Caught %d-bit read from %s memory (%p)\n",
-			8 * e->size, e->state < ARRAY_SIZE(desc) ?
-				desc[e->state] : "(invalid shadow state)",
-			(void *) e->address);
-
-		printk(KERN_WARNING);
-		for (i = 0; i < SHADOW_COPY_SIZE; ++i)
-			printk(KERN_CONT "%02x", e->memory_copy[i]);
-		printk(KERN_CONT "\n");
-
-		printk(KERN_WARNING);
-		for (i = 0; i < SHADOW_COPY_SIZE; ++i) {
-			if (e->shadow_copy[i] < ARRAY_SIZE(short_desc))
-				printk(KERN_CONT " %c", short_desc[e->shadow_copy[i]]);
-			else
-				printk(KERN_CONT " ?");
-		}
-		printk(KERN_CONT "\n");
-		printk(KERN_WARNING "%*c\n", 2 + 2
-			* (int) (e->address & (SHADOW_COPY_SIZE - 1)), '^');
-		break;
-	case KMEMCHECK_ERROR_BUG:
-		printk(KERN_EMERG "ERROR: kmemcheck: Fatal error\n");
-		break;
-	}
-
-	__show_regs(&e->regs, 1);
-	print_stack_trace(&e->trace, 0);
-}
-
-static void do_wakeup(unsigned long data)
-{
-	while (error_count > 0)
-		kmemcheck_error_recall();
-
-	if (error_missed_count > 0) {
-		printk(KERN_WARNING "kmemcheck: Lost %d error reports because "
-			"the queue was too small\n", error_missed_count);
-		error_missed_count = 0;
-	}
-}
-
-static DECLARE_TASKLET(kmemcheck_tasklet, &do_wakeup, 0);
-
-/*
- * Save the context of an error report.
- */
-void kmemcheck_error_save(enum kmemcheck_shadow state,
-	unsigned long address, unsigned int size, struct pt_regs *regs)
-{
-	static unsigned long prev_ip;
-
-	struct kmemcheck_error *e;
-	void *shadow_copy;
-	void *memory_copy;
-
-	/* Don't report several adjacent errors from the same EIP. */
-	if (regs->ip == prev_ip)
-		return;
-	prev_ip = regs->ip;
-
-	e = error_next_wr();
-	if (!e)
-		return;
-
-	e->type = KMEMCHECK_ERROR_INVALID_ACCESS;
-
-	e->state = state;
-	e->address = address;
-	e->size = size;
-
-	/* Save regs */
-	memcpy(&e->regs, regs, sizeof(*regs));
-
-	/* Save stack trace */
-	e->trace.nr_entries = 0;
-	e->trace.entries = e->trace_entries;
-	e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
-	e->trace.skip = 0;
-	save_stack_trace_regs(regs, &e->trace);
-
-	/* Round address down to nearest 16 bytes */
-	shadow_copy = kmemcheck_shadow_lookup(address
-		& ~(SHADOW_COPY_SIZE - 1));
-	BUG_ON(!shadow_copy);
-
-	memcpy(e->shadow_copy, shadow_copy, SHADOW_COPY_SIZE);
-
-	kmemcheck_show_addr(address);
-	memory_copy = (void *) (address & ~(SHADOW_COPY_SIZE - 1));
-	memcpy(e->memory_copy, memory_copy, SHADOW_COPY_SIZE);
-	kmemcheck_hide_addr(address);
-
-	tasklet_hi_schedule_first(&kmemcheck_tasklet);
-}
-
-/*
- * Save the context of a kmemcheck bug.
- */
-void kmemcheck_error_save_bug(struct pt_regs *regs)
-{
-	struct kmemcheck_error *e;
-
-	e = error_next_wr();
-	if (!e)
-		return;
-
-	e->type = KMEMCHECK_ERROR_BUG;
-
-	memcpy(&e->regs, regs, sizeof(*regs));
-
-	e->trace.nr_entries = 0;
-	e->trace.entries = e->trace_entries;
-	e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
-	e->trace.skip = 1;
-	save_stack_trace(&e->trace);
-
-	tasklet_hi_schedule_first(&kmemcheck_tasklet);
-}

arch/x86/mm/kmemcheck/error.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__ERROR_H
-#define ARCH__X86__MM__KMEMCHECK__ERROR_H
-
-#include <linux/ptrace.h>
-
-#include "shadow.h"
-
-void kmemcheck_error_save(enum kmemcheck_shadow state,
-	unsigned long address, unsigned int size, struct pt_regs *regs);
-
-void kmemcheck_error_save_bug(struct pt_regs *regs);
-
-void kmemcheck_error_recall(void);
-
-#endif

arch/x86/mm/kmemcheck/kmemcheck.c

-/**
- * kmemcheck - a heavyweight memory checker for the linux kernel
- * Copyright (C) 2007, 2008  Vegard Nossum <vegardno@ifi.uio.no>
- * (With a lot of help from Ingo Molnar and Pekka Enberg.)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License (version 2) as
- * published by the Free Software Foundation.
- */
-
-#include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/kallsyms.h>
-#include <linux/kernel.h>
-#include <linux/kmemcheck.h>
-#include <linux/mm.h>
-#include <linux/page-flags.h>
-#include <linux/percpu.h>
-#include <linux/ptrace.h>
-#include <linux/string.h>
-#include <linux/types.h>
-
-#include <asm/cacheflush.h>
-#include <asm/kmemcheck.h>
-#include <asm/pgtable.h>
-#include <asm/tlbflush.h>
-
-#include "error.h"
-#include "opcode.h"
-#include "pte.h"
-#include "selftest.h"
-#include "shadow.h"
-
-
-#ifdef CONFIG_KMEMCHECK_DISABLED_BY_DEFAULT
-#  define KMEMCHECK_ENABLED 0
-#endif
-
-#ifdef CONFIG_KMEMCHECK_ENABLED_BY_DEFAULT
-#  define KMEMCHECK_ENABLED 1
-#endif
-
-#ifdef CONFIG_KMEMCHECK_ONESHOT_BY_DEFAULT
-#  define KMEMCHECK_ENABLED 2
-#endif
-
-int kmemcheck_enabled = KMEMCHECK_ENABLED;
-
-int __init kmemcheck_init(void)
-{
-#ifdef CONFIG_SMP
-	/*
-	 * Limit SMP to use a single CPU. We rely on the fact that this code
-	 * runs before SMP is set up.
-	 */
-	if (setup_max_cpus > 1) {
-		printk(KERN_INFO
-			"kmemcheck: Limiting number of CPUs to 1.\n");
-		setup_max_cpus = 1;
-	}
-#endif
-
-	if (!kmemcheck_selftest()) {
-		printk(KERN_INFO "kmemcheck: self-tests failed; disabling\n");
-		kmemcheck_enabled = 0;
-		return -EINVAL;
-	}
-
-	printk(KERN_INFO "kmemcheck: Initialized\n");
-	return 0;
-}
-
-early_initcall(kmemcheck_init);
-
-/*
- * We need to parse the kmemcheck= option before any memory is allocated.
- */
-static int __init param_kmemcheck(char *str)
-{
-	int val;
-	int ret;
-
-	if (!str)
-		return -EINVAL;
-
-	ret = kstrtoint(str, 0, &val);
-	if (ret)
-		return ret;
-	kmemcheck_enabled = val;
-	return 0;
-}
-
-early_param("kmemcheck", param_kmemcheck);
-
-int kmemcheck_show_addr(unsigned long address)
-{
-	pte_t *pte;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return 0;
-
-	set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
-	__flush_tlb_one(address);
-	return 1;
-}
-
-int kmemcheck_hide_addr(unsigned long address)
-{
-	pte_t *pte;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return 0;
-
-	set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
-	__flush_tlb_one(address);
-	return 1;
-}
-
-struct kmemcheck_context {
-	bool busy;
-	int balance;
-
-	/*
-	 * There can be at most two memory operands to an instruction, but
-	 * each address can cross a page boundary -- so we may need up to
-	 * four addresses that must be hidden/revealed for each fault.
-	 */
-	unsigned long addr[4];
-	unsigned long n_addrs;
-	unsigned long flags;
-
-	/* Data size of the instruction that caused a fault. */
-	unsigned int size;
-};
-
-static DEFINE_PER_CPU(struct kmemcheck_context, kmemcheck_context);
-
-bool kmemcheck_active(struct pt_regs *regs)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	return data->balance > 0;
-}
-
-/* Save an address that needs to be shown/hidden */
-static void kmemcheck_save_addr(unsigned long addr)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	BUG_ON(data->n_addrs >= ARRAY_SIZE(data->addr));
-	data->addr[data->n_addrs++] = addr;
-}
-
-static unsigned int kmemcheck_show_all(void)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-	unsigned int i;
-	unsigned int n;
-
-	n = 0;
-	for (i = 0; i < data->n_addrs; ++i)
-		n += kmemcheck_show_addr(data->addr[i]);
-
-	return n;
-}
-
-static unsigned int kmemcheck_hide_all(void)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-	unsigned int i;
-	unsigned int n;
-
-	n = 0;
-	for (i = 0; i < data->n_addrs; ++i)
-		n += kmemcheck_hide_addr(data->addr[i]);
-
-	return n;
-}
-
-/*
- * Called from the #PF handler.
- */
-void kmemcheck_show(struct pt_regs *regs)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	BUG_ON(!irqs_disabled());
-
-	if (unlikely(data->balance != 0)) {
-		kmemcheck_show_all();
-		kmemcheck_error_save_bug(regs);
-		data->balance = 0;
-		return;
-	}
-
-	/*
-	 * None of the addresses actually belonged to kmemcheck. Note that
-	 * this is not an error.
-	 */
-	if (kmemcheck_show_all() == 0)
-		return;
-
-	++data->balance;
-
-	/*
-	 * The IF needs to be cleared as well, so that the faulting
-	 * instruction can run "uninterrupted". Otherwise, we might take
-	 * an interrupt and start executing that before we've had a chance
-	 * to hide the page again.
-	 *
-	 * NOTE: In the rare case of multiple faults, we must not override
-	 * the original flags:
-	 */
-	if (!(regs->flags & X86_EFLAGS_TF))
-		data->flags = regs->flags;
-
-	regs->flags |= X86_EFLAGS_TF;
-	regs->flags &= ~X86_EFLAGS_IF;
-}
-
-/*
- * Called from the #DB handler.
- */
-void kmemcheck_hide(struct pt_regs *regs)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-	int n;
-
-	BUG_ON(!irqs_disabled());
-
-	if (unlikely(data->balance != 1)) {
-		kmemcheck_show_all();
-		kmemcheck_error_save_bug(regs);
-		data->n_addrs = 0;
-		data->balance = 0;
-
-		if (!(data->flags & X86_EFLAGS_TF))
-			regs->flags &= ~X86_EFLAGS_TF;
-		if (data->flags & X86_EFLAGS_IF)
-			regs->flags |= X86_EFLAGS_IF;
-		return;
-	}
-
-	if (kmemcheck_enabled)
-		n = kmemcheck_hide_all();
-	else
-		n = kmemcheck_show_all();
-
-	if (n == 0)
-		return;
-
-	--data->balance;
-
-	data->n_addrs = 0;
-
-	if (!(data->flags & X86_EFLAGS_TF))
-		regs->flags &= ~X86_EFLAGS_TF;
-	if (data->flags & X86_EFLAGS_IF)
-		regs->flags |= X86_EFLAGS_IF;
-}
-
-void kmemcheck_show_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i) {
-		unsigned long address;
-		pte_t *pte;
-		unsigned int level;
-
-		address = (unsigned long) page_address(&p[i]);
-		pte = lookup_address(address, &level);
-		BUG_ON(!pte);
-		BUG_ON(level != PG_LEVEL_4K);
-
-		set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
-		set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_HIDDEN));
-		__flush_tlb_one(address);
-	}
-}
-
-bool kmemcheck_page_is_tracked(struct page *p)
-{
-	/* This will also check the "hidden" flag of the PTE. */
-	return kmemcheck_pte_lookup((unsigned long) page_address(p));
-}
-
-void kmemcheck_hide_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i) {
-		unsigned long address;
-		pte_t *pte;
-		unsigned int level;
-
-		address = (unsigned long) page_address(&p[i]);
-		pte = lookup_address(address, &level);
-		BUG_ON(!pte);
-		BUG_ON(level != PG_LEVEL_4K);
-
-		set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
-		set_pte(pte, __pte(pte_val(*pte) | _PAGE_HIDDEN));
-		__flush_tlb_one(address);
-	}
-}
-
-/* Access may NOT cross page boundary */
-static void kmemcheck_read_strict(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	void *shadow;
-	enum kmemcheck_shadow status;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (!shadow)
-		return;
-
-	kmemcheck_save_addr(addr);
-	status = kmemcheck_shadow_test(shadow, size);
-	if (status == KMEMCHECK_SHADOW_INITIALIZED)
-		return;
-
-	if (kmemcheck_enabled)
-		kmemcheck_error_save(status, addr, size, regs);
-
-	if (kmemcheck_enabled == 2)
-		kmemcheck_enabled = 0;
-
-	/* Don't warn about it again. */
-	kmemcheck_shadow_set(shadow, size);
-}
-
-bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size)
-{
-	enum kmemcheck_shadow status;
-	void *shadow;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (!shadow)
-		return true;
-
-	status = kmemcheck_shadow_test_all(shadow, size);
-
-	return status == KMEMCHECK_SHADOW_INITIALIZED;
-}
-
-/* Access may cross page boundary */
-static void kmemcheck_read(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	unsigned long page = addr & PAGE_MASK;
-	unsigned long next_addr = addr + size - 1;
-	unsigned long next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		kmemcheck_read_strict(regs, addr, size);
-		return;
-	}
-
-	/*
-	 * What we do is basically to split the access across the
-	 * two pages and handle each part separately. Yes, this means
-	 * that we may now see reads that are 3 + 5 bytes, for
-	 * example (and if both are uninitialized, there will be two
-	 * reports), but it makes the code a lot simpler.
-	 */
-	kmemcheck_read_strict(regs, addr, next_page - addr);
-	kmemcheck_read_strict(regs, next_page, next_addr - next_page);
-}
-
-static void kmemcheck_write_strict(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	void *shadow;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (!shadow)
-		return;
-
-	kmemcheck_save_addr(addr);
-	kmemcheck_shadow_set(shadow, size);
-}
-
-static void kmemcheck_write(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	unsigned long page = addr & PAGE_MASK;
-	unsigned long next_addr = addr + size - 1;
-	unsigned long next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		kmemcheck_write_strict(regs, addr, size);
-		return;
-	}
-
-	/* See comment in kmemcheck_read(). */
-	kmemcheck_write_strict(regs, addr, next_page - addr);
-	kmemcheck_write_strict(regs, next_page, next_addr - next_page);
-}
-
-/*
- * Copying is hard. We have two addresses, each of which may be split across
- * a page (and each page will have different shadow addresses).
- */
-static void kmemcheck_copy(struct pt_regs *regs,
-	unsigned long src_addr, unsigned long dst_addr, unsigned int size)
-{
-	uint8_t shadow[8];
-	enum kmemcheck_shadow status;
-
-	unsigned long page;
-	unsigned long next_addr;
-	unsigned long next_page;
-
-	uint8_t *x;
-	unsigned int i;
-	unsigned int n;
-
-	BUG_ON(size > sizeof(shadow));
-
-	page = src_addr & PAGE_MASK;
-	next_addr = src_addr + size - 1;
-	next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		/* Same page */
-		x = kmemcheck_shadow_lookup(src_addr);
-		if (x) {
-			kmemcheck_save_addr(src_addr);
-			for (i = 0; i < size; ++i)
-				shadow[i] = x[i];
-		} else {
-			for (i = 0; i < size; ++i)
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-		}
-	} else {
-		n = next_page - src_addr;
-		BUG_ON(n > sizeof(shadow));
-
-		/* First page */
-		x = kmemcheck_shadow_lookup(src_addr);
-		if (x) {
-			kmemcheck_save_addr(src_addr);
-			for (i = 0; i < n; ++i)
-				shadow[i] = x[i];
-		} else {
-			/* Not tracked */
-			for (i = 0; i < n; ++i)
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-		}
-
-		/* Second page */
-		x = kmemcheck_shadow_lookup(next_page);
-		if (x) {
-			kmemcheck_save_addr(next_page);
-			for (i = n; i < size; ++i)
-				shadow[i] = x[i - n];
-		} else {
-			/* Not tracked */
-			for (i = n; i < size; ++i)
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-		}
-	}
-
-	page = dst_addr & PAGE_MASK;
-	next_addr = dst_addr + size - 1;
-	next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		/* Same page */
-		x = kmemcheck_shadow_lookup(dst_addr);
-		if (x) {
-			kmemcheck_save_addr(dst_addr);
-			for (i = 0; i < size; ++i) {
-				x[i] = shadow[i];
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-			}
-		}
-	} else {
-		n = next_page - dst_addr;
-		BUG_ON(n > sizeof(shadow));
-
-		/* First page */
-		x = kmemcheck_shadow_lookup(dst_addr);
-		if (x) {
-			kmemcheck_save_addr(dst_addr);
-			for (i = 0; i < n; ++i) {
-				x[i] = shadow[i];
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-			}
-		}
-
-		/* Second page */
-		x = kmemcheck_shadow_lookup(next_page);
-		if (x) {
-			kmemcheck_save_addr(next_page);
-			for (i = n; i < size; ++i) {
-				x[i - n] = shadow[i];
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-			}
-		}
-	}
-
-	status = kmemcheck_shadow_test(shadow, size);
-	if (status == KMEMCHECK_SHADOW_INITIALIZED)
-		return;
-
-	if (kmemcheck_enabled)
-		kmemcheck_error_save(status, src_addr, size, regs);
-
-	if (kmemcheck_enabled == 2)
-		kmemcheck_enabled = 0;
-}
-
-enum kmemcheck_method {
-	KMEMCHECK_READ,
-	KMEMCHECK_WRITE,
-};
-
-static void kmemcheck_access(struct pt_regs *regs,
-	unsigned long fallback_address, enum kmemcheck_method fallback_method)
-{
-	const uint8_t *insn;
-	const uint8_t *insn_primary;
-	unsigned int size;
-
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	/* Recursive fault -- ouch. */
-	if (data->busy) {
-		kmemcheck_show_addr(fallback_address);
-		kmemcheck_error_save_bug(regs);
-		return;
-	}
-
-	data->busy = true;
-
-	insn = (const uint8_t *) regs->ip;
-	insn_primary = kmemcheck_opcode_get_primary(insn);
-
-	kmemcheck_opcode_decode(insn, &size);
-
-	switch (insn_primary[0]) {
-#ifdef CONFIG_KMEMCHECK_BITOPS_OK
-		/* AND, OR, XOR */
-		/*
-		 * Unfortunately, these instructions have to be excluded from
-		 * our regular checking since they access only some (and not
-		 * all) bits. This clears out "bogus" bitfield-access warnings.
-		 */
-	case 0x80:
-	case 0x81:
-	case 0x82:
-	case 0x83:
-		switch ((insn_primary[1] >> 3) & 7) {
-			/* OR */
-		case 1:
-			/* AND */
-		case 4:
-			/* XOR */
-		case 6:
-			kmemcheck_write(regs, fallback_address, size);
-			goto out;
-
-			/* ADD */
-		case 0:
-			/* ADC */
-		case 2:
-			/* SBB */
-		case 3:
-			/* SUB */
-		case 5:
-			/* CMP */
-		case 7:
-			break;
-		}
-		break;
-#endif
-
-		/* MOVS, MOVSB, MOVSW, MOVSD */
-	case 0xa4:
-	case 0xa5:
-		/*
-		 * These instructions are special because they take two
-		 * addresses, but we only get one page fault.
-		 */
-		kmemcheck_copy(regs, regs->si, regs->di, size);
-		goto out;
-
-		/* CMPS, CMPSB, CMPSW, CMPSD */
-	case 0xa6:
-	case 0xa7:
-		kmemcheck_read(regs, regs->si, size);
-		kmemcheck_read(regs, regs->di, size);
-		goto out;
-	}
-
-	/*
-	 * If the opcode isn't special in any way, we use the data from the
-	 * page fault handler to determine the address and type of memory
-	 * access.
-	 */
-	switch (fallback_method) {
-	case KMEMCHECK_READ:
-		kmemcheck_read(regs, fallback_address, size);
-		goto out;
-	case KMEMCHECK_WRITE:
-		kmemcheck_write(regs, fallback_address, size);
-		goto out;
-	}
-
-out:
-	data->busy = false;
-}
-
-bool kmemcheck_fault(struct pt_regs *regs, unsigned long address,
-	unsigned long error_code)
-{
-	pte_t *pte;
-
-	/*
-	 * XXX: Is it safe to assume that memory accesses from virtual 86
-	 * mode or non-kernel code segments will _never_ access kernel
-	 * memory (e.g. tracked pages)? For now, we need this to avoid
-	 * invoking kmemcheck for PnP BIOS calls.
-	 */
-	if (regs->flags & X86_VM_MASK)
-		return false;
-	if (regs->cs != __KERNEL_CS)
-		return false;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return false;
-
-	WARN_ON_ONCE(in_nmi());
-
-	if (error_code & 2)
-		kmemcheck_access(regs, address, KMEMCHECK_WRITE);
-	else
-		kmemcheck_access(regs, address, KMEMCHECK_READ);
-
-	kmemcheck_show(regs);
-	return true;
-}
-
-bool kmemcheck_trap(struct pt_regs *regs)
-{
-	if (!kmemcheck_active(regs))
-		return false;
-
-	/* We're done. */
-	kmemcheck_hide(regs);
-	return true;
-}

arch/x86/mm/kmemcheck/opcode.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/types.h>
-
-#include "opcode.h"
-
-static bool opcode_is_prefix(uint8_t b)
-{
-	return
-		/* Group 1 */
-		b == 0xf0 || b == 0xf2 || b == 0xf3
-		/* Group 2 */
-		|| b == 0x2e || b == 0x36 || b == 0x3e || b == 0x26
-		|| b == 0x64 || b == 0x65
-		/* Group 3 */
-		|| b == 0x66
-		/* Group 4 */
-		|| b == 0x67;
-}
-
-#ifdef CONFIG_X86_64
-static bool opcode_is_rex_prefix(uint8_t b)
-{
-	return (b & 0xf0) == 0x40;
-}
-#else
-static bool opcode_is_rex_prefix(uint8_t b)
-{
-	return false;
-}
-#endif
-
-#define REX_W (1 << 3)
-
-/*
- * This is a VERY crude opcode decoder. We only need to find the size of the
- * load/store that caused our #PF and this should work for all the opcodes
- * that we care about. Moreover, the ones who invented this instruction set
- * should be shot.
- */
-void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size)
-{
-	/* Default operand size */
-	int operand_size_override = 4;
-
-	/* prefixes */
-	for (; opcode_is_prefix(*op); ++op) {
-		if (*op == 0x66)
-			operand_size_override = 2;
-	}
-
-	/* REX prefix */
-	if (opcode_is_rex_prefix(*op)) {
-		uint8_t rex = *op;
-
-		++op;
-		if (rex & REX_W) {
-			switch (*op) {
-			case 0x63:
-				*size = 4;
-				return;
-			case 0x0f:
-				++op;
-
-				switch (*op) {
-				case 0xb6:
-				case 0xbe:
-					*size = 1;
-					return;
-				case 0xb7:
-				case 0xbf:
-					*size = 2;
-					return;
-				}
-
-				break;
-			}
-
-			*size = 8;
-			return;
-		}
-	}
-
-	/* escape opcode */
-	if (*op == 0x0f) {
-		++op;
-
-		/*
-		 * This is move with zero-extend and sign-extend, respectively;
-		 * we don't have to think about 0xb6/0xbe, because this is
-		 * already handled in the conditional below.
-		 */
-		if (*op == 0xb7 || *op == 0xbf)
-			operand_size_override = 2;
-	}
-
-	*size = (*op & 1) ? operand_size_override : 1;
-}
-
-const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op)
-{
-	/* skip prefixes */
-	while (opcode_is_prefix(*op))
-		++op;
-	if (opcode_is_rex_prefix(*op))
-		++op;
-	return op;
-}

arch/x86/mm/kmemcheck/opcode.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__OPCODE_H
-#define ARCH__X86__MM__KMEMCHECK__OPCODE_H
-
-#include <linux/types.h>
-
-void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size);
-const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op);
-
-#endif

arch/x86/mm/kmemcheck/pte.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/mm.h>
-
-#include <asm/pgtable.h>
-
-#include "pte.h"
-
-pte_t *kmemcheck_pte_lookup(unsigned long address)
-{
-	pte_t *pte;
-	unsigned int level;
-
-	pte = lookup_address(address, &level);
-	if (!pte)
-		return NULL;
-	if (level != PG_LEVEL_4K)
-		return NULL;
-	if (!pte_hidden(*pte))
-		return NULL;
-
-	return pte;
-}
-

arch/x86/mm/kmemcheck/pte.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__PTE_H
-#define ARCH__X86__MM__KMEMCHECK__PTE_H
-
-#include <linux/mm.h>
-
-#include <asm/pgtable.h>
-
-pte_t *kmemcheck_pte_lookup(unsigned long address);
-
-#endif

arch/x86/mm/kmemcheck/selftest.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/bug.h>
-#include <linux/kernel.h>
-
-#include "opcode.h"
-#include "selftest.h"
-
-struct selftest_opcode {
-	unsigned int expected_size;
-	const uint8_t *insn;
-	const char *desc;
-};
-
-static const struct selftest_opcode selftest_opcodes[] = {
-	/* REP MOVS */
-	{1, "\xf3\xa4", 		"rep movsb <mem8>, <mem8>"},
-	{4, "\xf3\xa5",			"rep movsl <mem32>, <mem32>"},
-
-	/* MOVZX / MOVZXD */
-	{1, "\x66\x0f\xb6\x51\xf8",	"movzwq <mem8>, <reg16>"},
-	{1, "\x0f\xb6\x51\xf8",		"movzwq <mem8>, <reg32>"},
-
-	/* MOVSX / MOVSXD */
-	{1, "\x66\x0f\xbe\x51\xf8",	"movswq <mem8>, <reg16>"},
-	{1, "\x0f\xbe\x51\xf8",		"movswq <mem8>, <reg32>"},
-
-#ifdef CONFIG_X86_64
-	/* MOVZX / MOVZXD */
-	{1, "\x49\x0f\xb6\x51\xf8",	"movzbq <mem8>, <reg64>"},
-	{2, "\x49\x0f\xb7\x51\xf8",	"movzbq <mem16>, <reg64>"},
-
-	/* MOVSX / MOVSXD */
-	{1, "\x49\x0f\xbe\x51\xf8",	"movsbq <mem8>, <reg64>"},
-	{2, "\x49\x0f\xbf\x51\xf8",	"movsbq <mem16>, <reg64>"},
-	{4, "\x49\x63\x51\xf8",		"movslq <mem32>, <reg64>"},
-#endif
-};
-
-static bool selftest_opcode_one(const struct selftest_opcode *op)
-{
-	unsigned size;
-
-	kmemcheck_opcode_decode(op->insn, &size);
-
-	if (size == op->expected_size)
-		return true;
-
-	printk(KERN_WARNING "kmemcheck: opcode %s: expected size %d, got %d\n",
-		op->desc, op->expected_size, size);
-	return false;
-}
-
-static bool selftest_opcodes_all(void)
-{
-	bool pass = true;
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(selftest_opcodes); ++i)
-		pass = pass && selftest_opcode_one(&selftest_opcodes[i]);
-
-	return pass;
-}
-
-bool kmemcheck_selftest(void)
-{
-	bool pass = true;
-
-	pass = pass && selftest_opcodes_all();
-
-	return pass;
-}