[SPARC64]: Simplify user fault fixup handling.
Instead of doing byte-at-a-time user accesses to figure
out where the fault occurred, read the saved fault_address
from the current thread structure.
For the sake of defensive programming, if the fault_address
does not fall into the user buffer range, simply assume the
whole area faulted. This will cause the fixup for
copy_from_user() to clear the entire kernel side buffer.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/lib/user_fixup.c b/arch/sparc64/lib/user_fixup.c
index 0278e34..19d1fdb 100644
--- a/arch/sparc64/lib/user_fixup.c
+++ b/arch/sparc64/lib/user_fixup.c
@@ -11,61 +11,56 @@
/* Calculating the exact fault address when using
* block loads and stores can be very complicated.
+ *
* Instead of trying to be clever and handling all
* of the cases, just fix things up simply here.
*/
+static unsigned long compute_size(unsigned long start, unsigned long size, unsigned long *offset)
+{
+ unsigned long fault_addr = current_thread_info()->fault_address;
+ unsigned long end = start + size;
+
+ if (fault_addr < start || fault_addr >= end) {
+ *offset = 0;
+ } else {
+ *offset = start - fault_addr;
+ size = end - fault_addr;
+ }
+ return size;
+}
+
unsigned long copy_from_user_fixup(void *to, const void __user *from, unsigned long size)
{
- char *dst = to;
- const char __user *src = from;
+ unsigned long offset;
- while (size) {
- if (__get_user(*dst, src))
- break;
- dst++;
- src++;
- size--;
- }
-
- if (size)
- memset(dst, 0, size);
+ size = compute_size((unsigned long) from, size, &offset);
+ if (likely(size))
+ memset(to + offset, 0, size);
return size;
}
unsigned long copy_to_user_fixup(void __user *to, const void *from, unsigned long size)
{
- char __user *dst = to;
- const char *src = from;
+ unsigned long offset;
- while (size) {
- if (__put_user(*src, dst))
- break;
- dst++;
- src++;
- size--;
- }
-
- return size;
+ return compute_size((unsigned long) to, size, &offset);
}
unsigned long copy_in_user_fixup(void __user *to, void __user *from, unsigned long size)
{
- char __user *dst = to;
- char __user *src = from;
+ unsigned long fault_addr = current_thread_info()->fault_address;
+ unsigned long start = (unsigned long) to;
+ unsigned long end = start + size;
- while (size) {
- char tmp;
+ if (fault_addr >= start && fault_addr < end)
+ return end - fault_addr;
- if (__get_user(tmp, src))
- break;
- if (__put_user(tmp, dst))
- break;
- dst++;
- src++;
- size--;
- }
+ start = (unsigned long) from;
+ end = start + size;
+ if (fault_addr >= start && fault_addr < end)
+ return end - fault_addr;
return size;
}
diff --git a/arch/sparc64/mm/fault.c b/arch/sparc64/mm/fault.c
index 59dc9a2..4a52e79 100644
--- a/arch/sparc64/mm/fault.c
+++ b/arch/sparc64/mm/fault.c
@@ -457,7 +457,7 @@
}
up_read(&mm->mmap_sem);
- goto fault_done;
+ return;
/*
* Something tried to access memory that isn't in our memory map..
@@ -469,8 +469,7 @@
handle_kernel_fault:
do_kernel_fault(regs, si_code, fault_code, insn, address);
-
- goto fault_done;
+ return;
/*
* We ran out of memory, or some other thing happened to us that made
@@ -501,9 +500,4 @@
/* Kernel mode? Handle exceptions or die */
if (regs->tstate & TSTATE_PRIV)
goto handle_kernel_fault;
-
-fault_done:
- /* These values are no longer needed, clear them. */
- set_thread_fault_code(0);
- current_thread_info()->fault_address = 0;
}
diff --git a/include/asm-sparc64/uaccess.h b/include/asm-sparc64/uaccess.h
index bc8ddbb..203e8ee 100644
--- a/include/asm-sparc64/uaccess.h
+++ b/include/asm-sparc64/uaccess.h
@@ -251,7 +251,7 @@
{
unsigned long ret = ___copy_from_user(to, from, size);
- if (ret)
+ if (unlikely(ret))
ret = copy_from_user_fixup(to, from, size);
return ret;
}
@@ -267,7 +267,7 @@
{
unsigned long ret = ___copy_to_user(to, from, size);
- if (ret)
+ if (unlikely(ret))
ret = copy_to_user_fixup(to, from, size);
return ret;
}
@@ -283,7 +283,7 @@
{
unsigned long ret = ___copy_in_user(to, from, size);
- if (ret)
+ if (unlikely(ret))
ret = copy_in_user_fixup(to, from, size);
return ret;
}