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[S390] cleanup lowcore access from program checks

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Read all required fields for program checks from the lowcore in the
first level interrupt handler in entry[64].S. If the context that
caused the fault was enabled for interrupts we can now re-enable the
irqs in entry[64].S.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2010-10-25 16:10:37 +02:00
committed by Martin Schwidefsky
parent 84afdcee62
commit 1e54622e04
6 changed files with 109 additions and 171 deletions
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36
arch/s390/mm/fault.c
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@@ -333,12 +333,6 @@ static inline int do_exception(struct pt_regs *regs, int access,
goto out;
address = trans_exc_code & __FAIL_ADDR_MASK;
/*
* When we get here, the fault happened in the current
* task's user address space, so we can switch on the
* interrupts again and then search the VMAs
*/
local_irq_enable();
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
down_read(&mm->mmap_sem);
@@ -397,20 +391,20 @@ out:
return fault;
}
void __kprobes do_protection_exception(struct pt_regs *regs, long int_code)
void __kprobes do_protection_exception(struct pt_regs *regs, long pgm_int_code,
unsigned long trans_exc_code)
{
unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
int fault;
/* Protection exception is supressing, decrement psw address. */
regs->psw.addr -= (int_code >> 16);
regs->psw.addr -= (pgm_int_code >> 16);
/*
* Check for low-address protection. This needs to be treated
* as a special case because the translation exception code
* field is not guaranteed to contain valid data in this case.
*/
if (unlikely(!(trans_exc_code & 4))) {
do_low_address(regs, int_code, trans_exc_code);
do_low_address(regs, pgm_int_code, trans_exc_code);
return;
}
fault = do_exception(regs, VM_WRITE, trans_exc_code);
@@ -418,9 +412,9 @@ void __kprobes do_protection_exception(struct pt_regs *regs, long int_code)
do_fault_error(regs, 4, trans_exc_code, fault);
}
void __kprobes do_dat_exception(struct pt_regs *regs, long int_code)
void __kprobes do_dat_exception(struct pt_regs *regs, long pgm_int_code,
unsigned long trans_exc_code)
{
unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
int access, fault;
access = VM_READ | VM_EXEC | VM_WRITE;
@@ -431,21 +425,19 @@ void __kprobes do_dat_exception(struct pt_regs *regs, long int_code)
#endif
fault = do_exception(regs, access, trans_exc_code);
if (unlikely(fault))
do_fault_error(regs, int_code & 255, trans_exc_code, fault);
do_fault_error(regs, pgm_int_code & 255, trans_exc_code, fault);
}
#ifdef CONFIG_64BIT
void __kprobes do_asce_exception(struct pt_regs *regs, long int_code)
void __kprobes do_asce_exception(struct pt_regs *regs, long pgm_int_code,
unsigned long trans_exc_code)
{
unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
goto no_context;
local_irq_enable();
down_read(&mm->mmap_sem);
vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK);
up_read(&mm->mmap_sem);
@@ -457,16 +449,16 @@ void __kprobes do_asce_exception(struct pt_regs *regs, long int_code)
/* User mode accesses just cause a SIGSEGV */
if (regs->psw.mask & PSW_MASK_PSTATE) {
do_sigsegv(regs, int_code, SEGV_MAPERR, trans_exc_code);
do_sigsegv(regs, pgm_int_code, SEGV_MAPERR, trans_exc_code);
return;
}
no_context:
do_no_context(regs, int_code, trans_exc_code);
do_no_context(regs, pgm_int_code, trans_exc_code);
}
#endif
int __handle_fault(unsigned long uaddr, unsigned long int_code, int write_user)
int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write)
{
struct pt_regs regs;
int access, fault;
@@ -477,14 +469,14 @@ int __handle_fault(unsigned long uaddr, unsigned long int_code, int write_user)
regs.psw.addr = (unsigned long) __builtin_return_address(0);
regs.psw.addr |= PSW_ADDR_AMODE;
uaddr &= PAGE_MASK;
access = write_user ? VM_WRITE : VM_READ;
access = write ? VM_WRITE : VM_READ;
fault = do_exception(&regs, access, uaddr | 2);
if (unlikely(fault)) {
if (fault & VM_FAULT_OOM) {
pagefault_out_of_memory();
fault = 0;
} else if (fault & VM_FAULT_SIGBUS)
do_sigbus(&regs, int_code, uaddr);
do_sigbus(&regs, pgm_int_code, uaddr);
}
return fault ? -EFAULT : 0;
}