void kmemcheck_show(struct pt_regs *regs)
{
struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
BUG_ON(!irqs_disabled());
if (unlikely(data->balance != 0)) {
kmemcheck_show_all();
kmemcheck_error_save_bug(regs);
data->balance = 0;
return;
}
if (kmemcheck_show_all() == 0)
return;
++data->balance;
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 = &__get_cpu_var(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;
}
/*
* Called from the #PF handler.
*/
void kmemcheck_show(struct pt_regs *regs)
{
struct kmemcheck_context *data = &__get_cpu_var(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;
}
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 = &__get_cpu_var(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;
}
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 = &__get_cpu_var(kmemcheck_context);
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
case 0x80:
case 0x81:
case 0x82:
case 0x83:
switch ((insn_primary[1] >> 3) & 7) {
case 1:
case 4:
case 6:
kmemcheck_write(regs, fallback_address, size);
goto out;
case 0:
case 2:
case 3:
case 5:
case 7:
break;
}
break;
#endif
case 0xa4:
case 0xa5:
kmemcheck_copy(regs, regs->si, regs->di, size);
goto out;
case 0xa6:
case 0xa7:
kmemcheck_read(regs, regs->si, size);
kmemcheck_read(regs, regs->di, size);
goto out;
}
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;
}
