[PATCH] uml: remove spinlock wrapper functions

[safe/jmp/linux-2.6] / arch / um / kernel / trap_kern.c

diff --git a/arch/um/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c
index b5fc89f..02f6d4d 100644 (file)
--- a/arch/um/kernel/trap_kern.c
+++ b/arch/um/kernel/trap_kern.c
@@ -1,4 +1,4 @@
-/* 
+/*
  * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
  * Licensed under the GPL
  */
@@ -18,6 +18,7 @@
 #include "asm/a.out.h"
 #include "asm/current.h"
 #include "asm/irq.h"
+#include "sysdep/sigcontext.h"
 #include "user_util.h"
 #include "kern_util.h"
 #include "kern.h"
@@ -25,6 +26,13 @@
 #include "mconsole_kern.h"
 #include "mem.h"
 #include "mem_kern.h"
+#include "sysdep/sigcontext.h"
+#include "sysdep/ptrace.h"
+#include "os.h"
+#ifdef CONFIG_MODE_SKAS
+#include "skas.h"
+#endif
+#include "os.h"
 
 /* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by segv(). */
 int handle_page_fault(unsigned long address, unsigned long ip, 
@@ -39,6 +47,12 @@ int handle_page_fault(unsigned long address, unsigned long ip,
        int err = -EFAULT;
 
        *code_out = SEGV_MAPERR;
+
+       /* If the fault was during atomic operation, don't take the fault, just
+        * fail. */
+       if (in_atomic())
+               goto out_nosemaphore;
+
        down_read(&mm->mmap_sem);
        vma = find_vma(mm, address);
        if(!vma) 
@@ -57,7 +71,8 @@ good_area:
        if(is_write && !(vma->vm_flags & VM_WRITE)) 
                goto out;
 
-        if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
+       /* Don't require VM_READ|VM_EXEC for write faults! */
+        if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC)))
                 goto out;
 
        do {
@@ -84,11 +99,20 @@ survive:
                pte = pte_offset_kernel(pmd, address);
        } while(!pte_present(*pte));
        err = 0;
-       *pte = pte_mkyoung(*pte);
-       if(pte_write(*pte)) *pte = pte_mkdirty(*pte);
+       /* The below warning was added in place of
+        *      pte_mkyoung(); if (is_write) pte_mkdirty();
+        * If it's triggered, we'd see normally a hang here (a clean pte is
+        * marked read-only to emulate the dirty bit).
+        * However, the generic code can mark a PTE writable but clean on a
+        * concurrent read fault, triggering this harmlessly. So comment it out.
+        */
+#if 0
+       WARN_ON(!pte_young(*pte) || (is_write && !pte_dirty(*pte)));
+#endif
        flush_tlb_page(vma, address);
 out:
        up_read(&mm->mmap_sem);
+out_nosemaphore:
        return(err);
 
 /*
@@ -105,6 +129,25 @@ out_of_memory:
        goto out;
 }
 
+void segv_handler(int sig, union uml_pt_regs *regs)
+{
+       struct faultinfo * fi = UPT_FAULTINFO(regs);
+
+       if(UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)){
+               bad_segv(*fi, UPT_IP(regs));
+               return;
+       }
+       segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
+}
+
+struct kern_handlers handlinfo_kern = {
+       .relay_signal = relay_signal,
+       .winch = winch,
+       .bus_handler = relay_signal,
+       .page_fault = segv_handler,
+       .sigio_handler = sigio_handler,
+       .timer_handler = timer_handler
+};
 /*
  * We give a *copy* of the faultinfo in the regs to segv.
  * This must be done, since nesting SEGVs could overwrite
@@ -125,7 +168,15 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
         }
        else if(current->mm == NULL)
                panic("Segfault with no mm");
-       err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
+
+       if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi))
+               err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
+       else {
+               err = -EFAULT;
+               /* A thread accessed NULL, we get a fault, but CR2 is invalid.
+                * This code is used in __do_copy_from_user() of TT mode. */
+               address = 0;
+       }
 
        catcher = current->thread.fault_catcher;
        if(!err)
@@ -147,7 +198,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
                si.si_signo = SIGBUS;
                si.si_errno = 0;
                si.si_code = BUS_ADRERR;
-               si.si_addr = (void *)address;
+               si.si_addr = (void __user *)address;
                 current->thread.arch.faultinfo = fi;
                force_sig_info(SIGBUS, &si, current);
        } else if (err == -ENOMEM) {
@@ -156,7 +207,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
        } else {
                BUG_ON(err != -EFAULT);
                si.si_signo = SIGSEGV;
-               si.si_addr = (void *) address;
+               si.si_addr = (void __user *) address;
                 current->thread.arch.faultinfo = fi;
                force_sig_info(SIGSEGV, &si, current);
        }
@@ -169,8 +220,8 @@ void bad_segv(struct faultinfo fi, unsigned long ip)
 
        si.si_signo = SIGSEGV;
        si.si_code = SEGV_ACCERR;
-        si.si_addr = (void *) FAULT_ADDRESS(fi);
-        current->thread.arch.faultinfo = fi;
+       si.si_addr = (void __user *) FAULT_ADDRESS(fi);
+       current->thread.arch.faultinfo = fi;
        force_sig_info(SIGSEGV, &si, current);
 }