[PATCH] ppc32: handle access to non-present IO ports on 8xx
This adds exception table entries for I/O instructions on and
changes MachineCheckException() slightly to cover 8xx specifics (on
8xx the MCE can be generated while executing the IO access instruction
itself, which is not the case on PowerMac's, as the comment on traps.c
details).
Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-ppc/io.h b/include/asm-ppc/io.h
index f7f614d..2bfdf9c 100644
--- a/include/asm-ppc/io.h
+++ b/include/asm-ppc/io.h
@@ -237,9 +237,9 @@
#define outsl(port, buf, nl) _outsl_ns((port)+___IO_BASE, (buf), (nl))
/*
- * On powermacs, we will get a machine check exception if we
- * try to read data from a non-existent I/O port. Because the
- * machine check is an asynchronous exception, it isn't
+ * On powermacs and 8xx we will get a machine check exception
+ * if we try to read data from a non-existent I/O port. Because
+ * the machine check is an asynchronous exception, it isn't
* well-defined which instruction SRR0 will point to when the
* exception occurs.
* With the sequence below (twi; isync; nop), we have found that
@@ -258,7 +258,7 @@
{ \
unsigned int x; \
__asm__ __volatile__( \
- op " %0,0,%1\n" \
+ "0:" op " %0,0,%1\n" \
"1: twi 0,%0,0\n" \
"2: isync\n" \
"3: nop\n" \
@@ -269,6 +269,7 @@
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
+ " .long 0b,5b\n" \
" .long 1b,5b\n" \
" .long 2b,5b\n" \
" .long 3b,5b\n" \
@@ -282,11 +283,12 @@
extern __inline__ void name(unsigned int val, unsigned int port) \
{ \
__asm__ __volatile__( \
- op " %0,0,%1\n" \
+ "0:" op " %0,0,%1\n" \
"1: sync\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
+ " .long 0b,2b\n" \
" .long 1b,2b\n" \
".previous" \
: : "r" (val), "r" (port + ___IO_BASE)); \