kernel-ark/arch/sparc64/mm/fault.c
Will Schmidt dcca2bde4f During VM oom condition, kill all threads in process group
We have had complaints where a threaded application is left in a bad state
after one of it's threads is killed when we hit a VM: out_of_memory
condition.

Killing just one of the process threads can leave the application in a bad
state, whereas killing the entire process group would allow for the
application to restart, or be otherwise handled, and makes it very obvious
that something has gone wrong.

This change allows the entire process group to be taken down, rather
than just the one thread.

Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:42:52 -07:00

487 lines
13 KiB
C

/* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $
* arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
*
* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz)
*/
#include <asm/head.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kprobes.h>
#include <linux/kallsyms.h>
#include <linux/kdebug.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/uaccess.h>
#include <asm/asi.h>
#include <asm/lsu.h>
#include <asm/sections.h>
#include <asm/mmu_context.h>
#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs)
{
int ret = 0;
/* kprobe_running() needs smp_processor_id() */
if (!user_mode(regs)) {
preempt_disable();
if (kprobe_running() && kprobe_fault_handler(regs, 0))
ret = 1;
preempt_enable();
}
return ret;
}
#else
static inline int notify_page_fault(struct pt_regs *regs)
{
return 0;
}
#endif
/*
* To debug kernel to catch accesses to certain virtual/physical addresses.
* Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
* flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
* Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
* watched. This is only useful on a single cpu machine for now. After the watchpoint
* is detected, the process causing it will be killed, thus preventing an infinite loop.
*/
void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode)
{
unsigned long lsubits;
__asm__ __volatile__("ldxa [%%g0] %1, %0"
: "=r" (lsubits)
: "i" (ASI_LSU_CONTROL));
lsubits &= ~(LSU_CONTROL_PM | LSU_CONTROL_VM |
LSU_CONTROL_PR | LSU_CONTROL_VR |
LSU_CONTROL_PW | LSU_CONTROL_VW);
__asm__ __volatile__("stxa %0, [%1] %2\n\t"
"membar #Sync"
: /* no outputs */
: "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT),
"i" (ASI_DMMU));
lsubits |= ((unsigned long)mask << (mode ? 25 : 33));
if (flags & VM_READ)
lsubits |= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR);
if (flags & VM_WRITE)
lsubits |= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW);
__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
"membar #Sync"
: /* no outputs */
: "r" (lsubits), "i" (ASI_LSU_CONTROL)
: "memory");
}
static void __kprobes unhandled_fault(unsigned long address,
struct task_struct *tsk,
struct pt_regs *regs)
{
if ((unsigned long) address < PAGE_SIZE) {
printk(KERN_ALERT "Unable to handle kernel NULL "
"pointer dereference\n");
} else {
printk(KERN_ALERT "Unable to handle kernel paging request "
"at virtual address %016lx\n", (unsigned long)address);
}
printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
(tsk->mm ?
CTX_HWBITS(tsk->mm->context) :
CTX_HWBITS(tsk->active_mm->context)));
printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
(tsk->mm ? (unsigned long) tsk->mm->pgd :
(unsigned long) tsk->active_mm->pgd));
die_if_kernel("Oops", regs);
}
static void bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
{
printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
regs->tpc);
printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
print_symbol("RPC: <%s>\n", regs->u_regs[15]);
printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
dump_stack();
unhandled_fault(regs->tpc, current, regs);
}
/*
* We now make sure that mmap_sem is held in all paths that call
* this. Additionally, to prevent kswapd from ripping ptes from
* under us, raise interrupts around the time that we look at the
* pte, kswapd will have to wait to get his smp ipi response from
* us. vmtruncate likewise. This saves us having to get pte lock.
*/
static unsigned int get_user_insn(unsigned long tpc)
{
pgd_t *pgdp = pgd_offset(current->mm, tpc);
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep, pte;
unsigned long pa;
u32 insn = 0;
unsigned long pstate;
if (pgd_none(*pgdp))
goto outret;
pudp = pud_offset(pgdp, tpc);
if (pud_none(*pudp))
goto outret;
pmdp = pmd_offset(pudp, tpc);
if (pmd_none(*pmdp))
goto outret;
/* This disables preemption for us as well. */
__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
__asm__ __volatile__("wrpr %0, %1, %%pstate"
: : "r" (pstate), "i" (PSTATE_IE));
ptep = pte_offset_map(pmdp, tpc);
pte = *ptep;
if (!pte_present(pte))
goto out;
pa = (pte_pfn(pte) << PAGE_SHIFT);
pa += (tpc & ~PAGE_MASK);
/* Use phys bypass so we don't pollute dtlb/dcache. */
__asm__ __volatile__("lduwa [%1] %2, %0"
: "=r" (insn)
: "r" (pa), "i" (ASI_PHYS_USE_EC));
out:
pte_unmap(ptep);
__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
outret:
return insn;
}
extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
unsigned int insn, int fault_code)
{
siginfo_t info;
info.si_code = code;
info.si_signo = sig;
info.si_errno = 0;
if (fault_code & FAULT_CODE_ITLB)
info.si_addr = (void __user *) regs->tpc;
else
info.si_addr = (void __user *)
compute_effective_address(regs, insn, 0);
info.si_trapno = 0;
force_sig_info(sig, &info, current);
}
extern int handle_ldf_stq(u32, struct pt_regs *);
extern int handle_ld_nf(u32, struct pt_regs *);
static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
{
if (!insn) {
if (!regs->tpc || (regs->tpc & 0x3))
return 0;
if (regs->tstate & TSTATE_PRIV) {
insn = *(unsigned int *) regs->tpc;
} else {
insn = get_user_insn(regs->tpc);
}
}
return insn;
}
static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
unsigned int insn, unsigned long address)
{
unsigned char asi = ASI_P;
if ((!insn) && (regs->tstate & TSTATE_PRIV))
goto cannot_handle;
/* If user insn could be read (thus insn is zero), that
* is fine. We will just gun down the process with a signal
* in that case.
*/
if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
(insn & 0xc0800000) == 0xc0800000) {
if (insn & 0x2000)
asi = (regs->tstate >> 24);
else
asi = (insn >> 5);
if ((asi & 0xf2) == 0x82) {
if (insn & 0x1000000) {
handle_ldf_stq(insn, regs);
} else {
/* This was a non-faulting load. Just clear the
* destination register(s) and continue with the next
* instruction. -jj
*/
handle_ld_nf(insn, regs);
}
return;
}
}
/* Is this in ex_table? */
if (regs->tstate & TSTATE_PRIV) {
const struct exception_table_entry *entry;
if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) {
if (insn & 0x2000)
asi = (regs->tstate >> 24);
else
asi = (insn >> 5);
}
/* Look in asi.h: All _S asis have LS bit set */
if ((asi & 0x1) &&
(entry = search_exception_tables(regs->tpc))) {
regs->tpc = entry->fixup;
regs->tnpc = regs->tpc + 4;
return;
}
} else {
/* The si_code was set to make clear whether
* this was a SEGV_MAPERR or SEGV_ACCERR fault.
*/
do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
return;
}
cannot_handle:
unhandled_fault (address, current, regs);
}
asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned int insn = 0;
int si_code, fault_code, fault;
unsigned long address, mm_rss;
fault_code = get_thread_fault_code();
if (notify_page_fault(regs))
return;
si_code = SEGV_MAPERR;
address = current_thread_info()->fault_address;
if ((fault_code & FAULT_CODE_ITLB) &&
(fault_code & FAULT_CODE_DTLB))
BUG();
if (regs->tstate & TSTATE_PRIV) {
unsigned long tpc = regs->tpc;
/* Sanity check the PC. */
if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) ||
(tpc >= MODULES_VADDR && tpc < MODULES_END)) {
/* Valid, no problems... */
} else {
bad_kernel_pc(regs, address);
return;
}
}
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
*/
if (in_atomic() || !mm)
goto intr_or_no_mm;
if (test_thread_flag(TIF_32BIT)) {
if (!(regs->tstate & TSTATE_PRIV))
regs->tpc &= 0xffffffff;
address &= 0xffffffff;
}
if (!down_read_trylock(&mm->mmap_sem)) {
if ((regs->tstate & TSTATE_PRIV) &&
!search_exception_tables(regs->tpc)) {
insn = get_fault_insn(regs, insn);
goto handle_kernel_fault;
}
down_read(&mm->mmap_sem);
}
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
/* Pure DTLB misses do not tell us whether the fault causing
* load/store/atomic was a write or not, it only says that there
* was no match. So in such a case we (carefully) read the
* instruction to try and figure this out. It's an optimization
* so it's ok if we can't do this.
*
* Special hack, window spill/fill knows the exact fault type.
*/
if (((fault_code &
(FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
(vma->vm_flags & VM_WRITE) != 0) {
insn = get_fault_insn(regs, 0);
if (!insn)
goto continue_fault;
/* All loads, stores and atomics have bits 30 and 31 both set
* in the instruction. Bit 21 is set in all stores, but we
* have to avoid prefetches which also have bit 21 set.
*/
if ((insn & 0xc0200000) == 0xc0200000 &&
(insn & 0x01780000) != 0x01680000) {
/* Don't bother updating thread struct value,
* because update_mmu_cache only cares which tlb
* the access came from.
*/
fault_code |= FAULT_CODE_WRITE;
}
}
continue_fault:
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (!(fault_code & FAULT_CODE_WRITE)) {
/* Non-faulting loads shouldn't expand stack. */
insn = get_fault_insn(regs, insn);
if ((insn & 0xc0800000) == 0xc0800000) {
unsigned char asi;
if (insn & 0x2000)
asi = (regs->tstate >> 24);
else
asi = (insn >> 5);
if ((asi & 0xf2) == 0x82)
goto bad_area;
}
}
if (expand_stack(vma, address))
goto bad_area;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
si_code = SEGV_ACCERR;
/* If we took a ITLB miss on a non-executable page, catch
* that here.
*/
if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
BUG_ON(address != regs->tpc);
BUG_ON(regs->tstate & TSTATE_PRIV);
goto bad_area;
}
if (fault_code & FAULT_CODE_WRITE) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
/* Spitfire has an icache which does not snoop
* processor stores. Later processors do...
*/
if (tlb_type == spitfire &&
(vma->vm_flags & VM_EXEC) != 0 &&
vma->vm_file != NULL)
set_thread_fault_code(fault_code |
FAULT_CODE_BLKCOMMIT);
} else {
/* Allow reads even for write-only mappings */
if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
goto bad_area;
}
fault = handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE));
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 (fault & VM_FAULT_MAJOR)
current->maj_flt++;
else
current->min_flt++;
up_read(&mm->mmap_sem);
mm_rss = get_mm_rss(mm);
#ifdef CONFIG_HUGETLB_PAGE
mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE));
#endif
if (unlikely(mm_rss >
mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
tsb_grow(mm, MM_TSB_BASE, mm_rss);
#ifdef CONFIG_HUGETLB_PAGE
mm_rss = mm->context.huge_pte_count;
if (unlikely(mm_rss >
mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit))
tsb_grow(mm, MM_TSB_HUGE, mm_rss);
#endif
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:
insn = get_fault_insn(regs, insn);
up_read(&mm->mmap_sem);
handle_kernel_fault:
do_kernel_fault(regs, si_code, fault_code, insn, address);
return;
/*
* 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:
insn = get_fault_insn(regs, insn);
up_read(&mm->mmap_sem);
printk("VM: killing process %s\n", current->comm);
if (!(regs->tstate & TSTATE_PRIV))
do_group_exit(SIGKILL);
goto handle_kernel_fault;
intr_or_no_mm:
insn = get_fault_insn(regs, 0);
goto handle_kernel_fault;
do_sigbus:
insn = get_fault_insn(regs, insn);
up_read(&mm->mmap_sem);
/*
* Send a sigbus, regardless of whether we were in kernel
* or user mode.
*/
do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
/* Kernel mode? Handle exceptions or die */
if (regs->tstate & TSTATE_PRIV)
goto handle_kernel_fault;
}