#include <linux/module.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
+#include <linux/uaccess.h>
#include <asm/system.h>
-#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/kdebug.h>
#include <asm/s390_ext.h>
return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb);
}
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
+static int __kprobes __notify_page_fault(struct pt_regs *regs, long err)
{
- struct die_args args = {
- .regs = regs,
- .str = str,
- .err = err,
- .trapnr = trap,
- .signr = sig
- };
- return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args);
+ struct die_args args = { .str = "page fault",
+ .trapnr = 14,
+ .signr = SIGSEGV };
+ args.regs = regs;
+ args.err = err;
+ return atomic_notifier_call_chain(¬ify_page_fault_chain,
+ DIE_PAGE_FAULT, &args);
+}
+
+static inline int notify_page_fault(struct pt_regs *regs, long err)
+{
+ if (unlikely(kprobe_running()))
+ return __notify_page_fault(regs, err);
+ return NOTIFY_DONE;
}
#else
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
+static inline int notify_page_fault(struct pt_regs *regs, long err)
{
return NOTIFY_DONE;
}
}
/*
- * Check which address space is addressed by the access
- * register in S390_lowcore.exc_access_id.
- * Returns 1 for user space and 0 for kernel space.
- */
-static int __check_access_register(struct pt_regs *regs, int error_code)
-{
- int areg = S390_lowcore.exc_access_id;
-
- if (areg == 0)
- /* Access via access register 0 -> kernel address */
- return 0;
- save_access_regs(current->thread.acrs);
- if (regs && areg < NUM_ACRS && current->thread.acrs[areg] <= 1)
- /*
- * access register contains 0 -> kernel address,
- * access register contains 1 -> user space address
- */
- return current->thread.acrs[areg];
-
- /* Something unhealthy was done with the access registers... */
- die("page fault via unknown access register", regs, error_code);
- do_exit(SIGKILL);
- return 0;
-}
-
-/*
- * Check which address space the address belongs to.
- * May return 1 or 2 for user space and 0 for kernel space.
- * Returns 2 for user space in primary addressing mode with
- * CONFIG_S390_EXEC_PROTECT on and kernel parameter noexec=on.
+ * Returns the address space associated with the fault.
+ * Returns 0 for kernel space, 1 for user space and
+ * 2 for code execution in user space with noexec=on.
*/
-static inline int check_user_space(struct pt_regs *regs, int error_code)
+static inline int check_space(struct task_struct *tsk)
{
/*
- * The lowest two bits of S390_lowcore.trans_exc_code indicate
- * which paging table was used:
- * 0: Primary Segment Table Descriptor
- * 1: STD determined via access register
- * 2: Secondary Segment Table Descriptor
- * 3: Home Segment Table Descriptor
+ * The lowest two bits of S390_lowcore.trans_exc_code
+ * indicate which paging table was used.
*/
- int descriptor = S390_lowcore.trans_exc_code & 3;
- if (unlikely(descriptor == 1))
- return __check_access_register(regs, error_code);
- if (descriptor == 2)
- return current->thread.mm_segment.ar4;
- return ((descriptor != 0) ^ (switch_amode)) << s390_noexec;
+ int desc = S390_lowcore.trans_exc_code & 3;
+
+ if (desc == 3) /* Home Segment Table Descriptor */
+ return switch_amode == 0;
+ if (desc == 2) /* Secondary Segment Table Descriptor */
+ return tsk->thread.mm_segment.ar4;
+#ifdef CONFIG_S390_SWITCH_AMODE
+ if (unlikely(desc == 1)) { /* STD determined via access register */
+ /* %a0 always indicates primary space. */
+ if (S390_lowcore.exc_access_id != 0) {
+ save_access_regs(tsk->thread.acrs);
+ /*
+ * An alet of 0 indicates primary space.
+ * An alet of 1 indicates secondary space.
+ * Any other alet values generate an
+ * alen-translation exception.
+ */
+ if (tsk->thread.acrs[S390_lowcore.exc_access_id])
+ return tsk->thread.mm_segment.ar4;
+ }
+ }
+#endif
+ /* Primary Segment Table Descriptor */
+ return switch_amode << s390_noexec;
}
/*
force_sig_info(SIGSEGV, &si, current);
}
+static void do_no_context(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ const struct exception_table_entry *fixup;
+
+ /* Are we prepared to handle this kernel fault? */
+ fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK);
+ if (fixup) {
+ regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
+ return;
+ }
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+ if (check_space(current) == 0)
+ printk(KERN_ALERT "Unable to handle kernel pointer dereference"
+ " at virtual kernel address %p\n", (void *)address);
+ else
+ printk(KERN_ALERT "Unable to handle kernel paging request"
+ " at virtual user address %p\n", (void *)address);
+
+ die("Oops", regs, error_code);
+ do_exit(SIGKILL);
+}
+
+static void do_low_address(struct pt_regs *regs, unsigned long error_code)
+{
+ /* Low-address protection hit in kernel mode means
+ NULL pointer write access in kernel mode. */
+ if (regs->psw.mask & PSW_MASK_PSTATE) {
+ /* Low-address protection hit in user mode 'cannot happen'. */
+ die ("Low-address protection", regs, error_code);
+ do_exit(SIGKILL);
+ }
+
+ do_no_context(regs, error_code, 0);
+}
+
+/*
+ * We ran out of memory, or some other thing happened to us that made
+ * us unable to handle the page fault gracefully.
+ */
+static int do_out_of_memory(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+
+ up_read(&mm->mmap_sem);
+ if (is_init(tsk)) {
+ yield();
+ down_read(&mm->mmap_sem);
+ return 1;
+ }
+ printk("VM: killing process %s\n", tsk->comm);
+ if (regs->psw.mask & PSW_MASK_PSTATE)
+ do_exit(SIGKILL);
+ do_no_context(regs, error_code, address);
+ return 0;
+}
+
+static void do_sigbus(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+
+ up_read(&mm->mmap_sem);
+ /*
+ * Send a sigbus, regardless of whether we were in kernel
+ * or user mode.
+ */
+ tsk->thread.prot_addr = address;
+ tsk->thread.trap_no = error_code;
+ force_sig(SIGBUS, tsk);
+
+ /* Kernel mode? Handle exceptions or die */
+ if (!(regs->psw.mask & PSW_MASK_PSTATE))
+ do_no_context(regs, error_code, address);
+}
+
#ifdef CONFIG_S390_EXEC_PROTECT
extern long sys_sigreturn(struct pt_regs *regs);
extern long sys_rt_sigreturn(struct pt_regs *regs);
extern long sys32_sigreturn(struct pt_regs *regs);
extern long sys32_rt_sigreturn(struct pt_regs *regs);
-static inline void do_sigreturn(struct mm_struct *mm, struct pt_regs *regs,
- int rt)
+static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
+ unsigned long address, unsigned long error_code)
{
+ u16 instruction;
+ int rc, compat;
+
+ pagefault_disable();
+ rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
+ pagefault_enable();
+ if (rc)
+ return -EFAULT;
+
up_read(&mm->mmap_sem);
clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
#ifdef CONFIG_COMPAT
- if (test_tsk_thread_flag(current, TIF_31BIT)) {
- if (rt)
- sys32_rt_sigreturn(regs);
- else
- sys32_sigreturn(regs);
- return;
- }
-#endif /* CONFIG_COMPAT */
- if (rt)
- sys_rt_sigreturn(regs);
+ compat = test_tsk_thread_flag(current, TIF_31BIT);
+ if (compat && instruction == 0x0a77)
+ sys32_sigreturn(regs);
+ else if (compat && instruction == 0x0aad)
+ sys32_rt_sigreturn(regs);
else
+#endif
+ if (instruction == 0x0a77)
sys_sigreturn(regs);
- return;
-}
-
-static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
- unsigned long address, unsigned long error_code)
-{
- pgd_t *pgd;
- pmd_t *pmd;
- pte_t *pte;
- u16 *instruction;
- unsigned long pfn, uaddr = regs->psw.addr;
-
- spin_lock(&mm->page_table_lock);
- pgd = pgd_offset(mm, uaddr);
- if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
- goto out_fault;
- pmd = pmd_offset(pgd, uaddr);
- if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
- goto out_fault;
- pte = pte_offset_map(pmd_offset(pgd_offset(mm, uaddr), uaddr), uaddr);
- if (!pte || !pte_present(*pte))
- goto out_fault;
- pfn = pte_pfn(*pte);
- if (!pfn_valid(pfn))
- goto out_fault;
- spin_unlock(&mm->page_table_lock);
-
- instruction = (u16 *) ((pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE-1)));
- if (*instruction == 0x0a77)
- do_sigreturn(mm, regs, 0);
- else if (*instruction == 0x0aad)
- do_sigreturn(mm, regs, 1);
+ else if (instruction == 0x0aad)
+ sys_rt_sigreturn(regs);
else {
- printk("- XXX - do_exception: task = %s, primary, NO EXEC "
- "-> SIGSEGV\n", current->comm);
- up_read(&mm->mmap_sem);
current->thread.prot_addr = address;
current->thread.trap_no = error_code;
do_sigsegv(regs, error_code, SEGV_MAPERR, address);
}
return 0;
-out_fault:
- spin_unlock(&mm->page_table_lock);
- return -EFAULT;
}
#endif /* CONFIG_S390_EXEC_PROTECT */
* 11 Page translation -> Not present (nullification)
* 3b Region third trans. -> Not present (nullification)
*/
-static inline void __kprobes
-do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection)
+static inline void
+do_exception(struct pt_regs *regs, unsigned long error_code, int write)
{
- struct task_struct *tsk;
- struct mm_struct *mm;
- struct vm_area_struct * vma;
- unsigned long address;
- int user_address;
- const struct exception_table_entry *fixup;
- int si_code = SEGV_MAPERR;
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ unsigned long address;
+ int space;
+ int si_code;
- tsk = current;
- mm = tsk->mm;
-
- if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
- SIGSEGV) == NOTIFY_STOP)
+ if (notify_page_fault(regs, error_code) == NOTIFY_STOP)
return;
- /*
- * 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 (is_protection && !(S390_lowcore.trans_exc_code & 4)) {
-
- /* Low-address protection hit in kernel mode means
- NULL pointer write access in kernel mode. */
- if (!(regs->psw.mask & PSW_MASK_PSTATE)) {
- address = 0;
- user_address = 0;
- goto no_context;
- }
+ tsk = current;
+ mm = tsk->mm;
- /* Low-address protection hit in user mode 'cannot happen'. */
- die ("Low-address protection", regs, error_code);
- do_exit(SIGKILL);
- }
-
- /*
- * get the failing address
- * more specific the segment and page table portion of
- * the address
- */
- address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
- user_address = check_user_space(regs, error_code);
+ /* get the failing address and the affected space */
+ address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
+ space = check_space(tsk);
/*
* Verify that the fault happened in user space, that
* we are not in an interrupt and that there is a
* user context.
*/
- if (user_address == 0 || in_atomic() || !mm)
- goto no_context;
+ if (unlikely(space == 0 || in_atomic() || !mm))
+ goto no_context;
/*
* When we get here, the fault happened in the current
*/
local_irq_enable();
- down_read(&mm->mmap_sem);
+ down_read(&mm->mmap_sem);
- vma = find_vma(mm, address);
- if (!vma)
- goto bad_area;
+ si_code = SEGV_MAPERR;
+ vma = find_vma(mm, address);
+ if (!vma)
+ goto bad_area;
#ifdef CONFIG_S390_EXEC_PROTECT
- if (unlikely((user_address == 2) && !(vma->vm_flags & VM_EXEC)))
+ if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC)))
if (!signal_return(mm, regs, address, error_code))
/*
* signal_return() has done an up_read(&mm->mmap_sem)
return;
#endif
- if (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 (vma->vm_start <= address)
+ goto good_area;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ 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 (!is_protection) {
+ if (!write) {
/* page not present, check vm flags */
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
- switch (handle_mm_fault(mm, vma, address, is_protection)) {
+ switch (handle_mm_fault(mm, vma, address, write)) {
case VM_FAULT_MINOR:
tsk->min_flt++;
break;
tsk->maj_flt++;
break;
case VM_FAULT_SIGBUS:
- goto do_sigbus;
+ do_sigbus(regs, error_code, address);
+ return;
case VM_FAULT_OOM:
- goto out_of_memory;
+ if (do_out_of_memory(regs, error_code, address))
+ goto survive;
+ return;
default:
BUG();
}
* The instruction that caused the program check will
* be repeated. Don't signal single step via SIGTRAP.
*/
- clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
+ clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
return;
/*
* Fix it, but check if it's kernel or user first..
*/
bad_area:
- up_read(&mm->mmap_sem);
+ up_read(&mm->mmap_sem);
- /* User mode accesses just cause a SIGSEGV */
- if (regs->psw.mask & PSW_MASK_PSTATE) {
- tsk->thread.prot_addr = address;
- tsk->thread.trap_no = error_code;
+ /* User mode accesses just cause a SIGSEGV */
+ if (regs->psw.mask & PSW_MASK_PSTATE) {
+ tsk->thread.prot_addr = address;
+ tsk->thread.trap_no = error_code;
do_sigsegv(regs, error_code, si_code, address);
- return;
+ return;
}
no_context:
- /* Are we prepared to handle this kernel fault? */
- fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK);
- if (fixup) {
- regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
- return;
- }
-
-/*
- * Oops. The kernel tried to access some bad page. We'll have to
- * terminate things with extreme prejudice.
- */
- if (user_address == 0)
- printk(KERN_ALERT "Unable to handle kernel pointer dereference"
- " at virtual kernel address %p\n", (void *)address);
- else
- printk(KERN_ALERT "Unable to handle kernel paging request"
- " at virtual user address %p\n", (void *)address);
-
- die("Oops", regs, error_code);
- 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 (is_init(tsk)) {
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- printk("VM: killing process %s\n", tsk->comm);
- if (regs->psw.mask & PSW_MASK_PSTATE)
- do_exit(SIGKILL);
- goto no_context;
-
-do_sigbus:
- up_read(&mm->mmap_sem);
-
- /*
- * Send a sigbus, regardless of whether we were in kernel
- * or user mode.
- */
- tsk->thread.prot_addr = address;
- tsk->thread.trap_no = error_code;
- force_sig(SIGBUS, tsk);
-
- /* Kernel mode? Handle exceptions or die */
- if (!(regs->psw.mask & PSW_MASK_PSTATE))
- goto no_context;
+ do_no_context(regs, error_code, address);
}
-void do_protection_exception(struct pt_regs *regs, unsigned long error_code)
+void __kprobes do_protection_exception(struct pt_regs *regs,
+ unsigned long error_code)
{
+ /* Protection exception is supressing, decrement psw address. */
regs->psw.addr -= (error_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(!(S390_lowcore.trans_exc_code & 4))) {
+ do_low_address(regs, error_code);
+ return;
+ }
do_exception(regs, 4, 1);
}
-void do_dat_exception(struct pt_regs *regs, unsigned long error_code)
+void __kprobes do_dat_exception(struct pt_regs *regs, unsigned long error_code)
{
do_exception(regs, error_code & 0xff, 0);
}
projects / linux-2.6-omap-h63xx.git / blobdiff