[SPARC64]: Refine register window trap handling.
When saving and restoing trap state, do the window spill/fill
handling inline so that we never trap deeper than 2 trap levels.
This is important for chips like Niagara.
The window fixup code is massively simplified, and many more
improvements are now possible.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
index 26548fc..803eea4 100644
--- a/arch/sparc64/kernel/process.c
+++ b/arch/sparc64/kernel/process.c
@@ -541,6 +541,18 @@
}
}
+static void stack_unaligned(unsigned long sp)
+{
+ siginfo_t info;
+
+ info.si_signo = SIGBUS;
+ info.si_errno = 0;
+ info.si_code = BUS_ADRALN;
+ info.si_addr = (void __user *) sp;
+ info.si_trapno = 0;
+ force_sig_info(SIGBUS, &info, current);
+}
+
void fault_in_user_windows(void)
{
struct thread_info *t = current_thread_info();
@@ -556,13 +568,17 @@
flush_user_windows();
window = get_thread_wsaved();
- if (window != 0) {
+ if (likely(window != 0)) {
window -= 1;
do {
unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
struct reg_window *rwin = &t->reg_window[window];
- if (copy_to_user((char __user *)sp, rwin, winsize))
+ if (unlikely(sp & 0x7UL))
+ stack_unaligned(sp);
+
+ if (unlikely(copy_to_user((char __user *)sp,
+ rwin, winsize)))
goto barf;
} while (window--);
}