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sh: Tidy up and generalize page fault error paths.

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This follows the x86 changes for tidying up the page fault error paths.
We'll build on top of this for _32/_64 unification.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2012-05-14 10:27:34 +09:00
parent c4f10e5cd7
commit dbdb4e9f3f
2 changed files with 222 additions and 105 deletions
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2
arch/sh/include/asm/kdebug.h
View File

@ -10,4 +10,6 @@ enum die_val {
DIE_SSTEP,
};
extern void printk_address(unsigned long address, int reliable);
#endif /* __ASM_SH_KDEBUG_H */

325
arch/sh/mm/fault_32.c
View File

@ -2,7 +2,7 @@
* Page fault handler for SH with an MMU.
*
* Copyright (C) 1999 Niibe Yutaka
* Copyright (C) 2003 - 2009 Paul Mundt
* Copyright (C) 2003 - 2012 Paul Mundt
*
* Based on linux/arch/i386/mm/fault.c:
* Copyright (C) 1995 Linus Torvalds
@ -16,6 +16,7 @@
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/perf_event.h>
#include <linux/kdebug.h>
#include <asm/io_trapped.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
@ -35,6 +36,20 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap)
return ret;
}
static void
force_sig_info_fault(int si_signo, int si_code, unsigned long address,
struct task_struct *tsk)
{
siginfo_t info;
info.si_signo = si_signo;
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = (void __user *)address;
force_sig_info(si_signo, &info, tsk);
}
/*
* This is useful to dump out the page tables associated with
* 'addr' in mm 'mm'.
@ -176,6 +191,185 @@ static noinline int vmalloc_fault(unsigned long address)
return 0;
}
static void
show_fault_oops(struct pt_regs *regs, unsigned long address)
{
if (!oops_may_print())
return;
printk(KERN_ALERT "BUG: unable to handle kernel ");
if (address < PAGE_SIZE)
printk(KERN_CONT "NULL pointer dereference");
else
printk(KERN_CONT "paging request");
printk(KERN_CONT " at %08lx\n", address);
printk(KERN_ALERT "PC:");
printk_address(regs->pc, 1);
show_pte(NULL, address);
}
static noinline void
no_context(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address)
{
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
return;
if (handle_trapped_io(regs, address))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
bust_spinlocks(1);
show_fault_oops(regs, address);
die("Oops", regs, writeaccess);
bust_spinlocks(0);
do_exit(SIGKILL);
}
static void
__bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address, int si_code)
{
struct task_struct *tsk = current;
/* User mode accesses just cause a SIGSEGV */
if (user_mode(regs)) {
/*
* It's possible to have interrupts off here:
*/
local_irq_enable();
force_sig_info_fault(SIGSEGV, si_code, address, tsk);
return;
}
no_context(regs, writeaccess, address);
}
static noinline void
bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address)
{
__bad_area_nosemaphore(regs, writeaccess, address, SEGV_MAPERR);
}
static void
__bad_area(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address, int si_code)
{
struct mm_struct *mm = current->mm;
/*
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
up_read(&mm->mmap_sem);
__bad_area_nosemaphore(regs, writeaccess, address, si_code);
}
static noinline void
bad_area(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)
{
__bad_area(regs, writeaccess, address, SEGV_MAPERR);
}
static noinline void
bad_area_access_error(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address)
{
__bad_area(regs, writeaccess, address, SEGV_ACCERR);
}
static void out_of_memory(void)
{
/*
* We ran out of memory, call the OOM killer, and return the userspace
* (which will retry the fault, or kill us if we got oom-killed):
*/
up_read(&current->mm->mmap_sem);
pagefault_out_of_memory();
}
static void
do_sigbus(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)
{
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
up_read(&mm->mmap_sem);
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs))
no_context(regs, writeaccess, address);
force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
}
static noinline int
mm_fault_error(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address, unsigned int fault)
{
/*
* Pagefault was interrupted by SIGKILL. We have no reason to
* continue pagefault.
*/
if (fatal_signal_pending(current)) {
if (!(fault & VM_FAULT_RETRY))
up_read(&current->mm->mmap_sem);
if (!user_mode(regs))
no_context(regs, writeaccess, address);
return 1;
}
if (!(fault & VM_FAULT_ERROR))
return 0;
if (fault & VM_FAULT_OOM) {
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs)) {
up_read(&current->mm->mmap_sem);
no_context(regs, writeaccess, address);
return 1;
}
out_of_memory();
} else {
if (fault & VM_FAULT_SIGBUS)
do_sigbus(regs, writeaccess, address);
else
BUG();
}
return 1;
}
static inline int access_error(int write, struct vm_area_struct *vma)
{
if (write) {
/* write, present and write, not present: */
if (unlikely(!(vma->vm_flags & VM_WRITE)))
return 1;
return 0;
}
/* read, not present: */
if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
return 1;
return 0;
}
static int fault_in_kernel_space(unsigned long address)
{
return address >= TASK_SIZE;
@ -194,15 +388,12 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
int si_code;
int fault;
siginfo_t info;
unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(writeaccess ? FAULT_FLAG_WRITE : 0));
tsk = current;
mm = tsk->mm;
si_code = SEGV_MAPERR;
vec = lookup_exception_vector();
/*
@ -220,7 +411,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
if (notify_page_fault(regs, vec))
return;
goto bad_area_nosemaphore;
bad_area_nosemaphore(regs, writeaccess, address);
return;
}
if (unlikely(notify_page_fault(regs, vec)))
@ -236,34 +428,38 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
* If we're in an interrupt, have no user context or are running
* in an atomic region then we must not take the fault:
*/
if (in_atomic() || !mm)
goto no_context;
if (unlikely(in_atomic() || !mm)) {
bad_area_nosemaphore(regs, writeaccess, address);
return;
}
retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
if (unlikely(!vma)) {
bad_area(regs, writeaccess, address);
return;
}
if (likely(vma->vm_start <= address))
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
bad_area(regs, writeaccess, address);
return;
}
if (unlikely(expand_stack(vma, address))) {
bad_area(regs, writeaccess, address);
return;
}
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
si_code = SEGV_ACCERR;
if (writeaccess) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
if (unlikely(access_error(writeaccess, vma))) {
bad_area_access_error(regs, writeaccess, address);
return;
}
/*
@ -273,16 +469,9 @@ good_area:
*/
fault = handle_mm_fault(mm, vma, address, flags);
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return;
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
else if (fault & VM_FAULT_SIGBUS)
goto do_sigbus;
BUG();
}
if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
if (mm_fault_error(regs, writeaccess, address, fault))
return;
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR) {
@ -307,80 +496,6 @@ good_area:
}
up_read(&mm->mmap_sem);
return;
/*
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
bad_area:
up_read(&mm->mmap_sem);
bad_area_nosemaphore:
if (user_mode(regs)) {
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = (void *) address;
force_sig_info(SIGSEGV, &info, tsk);
return;
}
no_context:
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
return;
if (handle_trapped_io(regs, address))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*
*/
bust_spinlocks(1);
if (oops_may_print()) {
printk(KERN_ALERT
"Unable to handle kernel %s at virtual address %08lx\n",
(address < PAGE_SIZE) ? "NULL pointer dereference" :
"paging request", address);
show_pte(mm, address);
}
die("Oops", regs, writeaccess);
bust_spinlocks(0);
do_exit(SIGKILL);
/*
* We ran out of memory, or some other thing happened to us that made
* us unable to handle the page fault gracefully.
*/
out_of_memory:
up_read(&mm->mmap_sem);
if (!user_mode(regs))
goto no_context;
pagefault_out_of_memory();
return;
do_sigbus:
up_read(&mm->mmap_sem);
/*
* Send a sigbus, regardless of whether we were in kernel
* or user mode.
*/
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRERR;
info.si_addr = (void *)address;
force_sig_info(SIGBUS, &info, tsk);
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
goto no_context;
}
/*