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Diffstat (limited to 'arch/x86/mm/kmemcheck/kmemcheck.c')
-rw-r--r--arch/x86/mm/kmemcheck/kmemcheck.c658
1 files changed, 0 insertions, 658 deletions
diff --git a/arch/x86/mm/kmemcheck/kmemcheck.c b/arch/x86/mm/kmemcheck/kmemcheck.c
deleted file mode 100644
index 4515bae36bbe..000000000000
--- a/arch/x86/mm/kmemcheck/kmemcheck.c
+++ /dev/null
@@ -1,658 +0,0 @@
-/**
- * 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;
-}
generated by cgit (git 2.34.1) at 2024-05-03 17:06:54 +0000