[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/arch/ppc/kernel/misc.S b/arch/ppc/kernel/misc.S
index 3056ede..ae6af29 100644
--- a/arch/ppc/kernel/misc.S
+++ b/arch/ppc/kernel/misc.S
@@ -25,6 +25,11 @@
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
+#ifdef CONFIG_8xx
+#define ISYNC_8xx isync
+#else
+#define ISYNC_8xx
+#endif
.text
.align 5
@@ -800,8 +805,18 @@
subi r4,r4,1
blelr-
00: lbz r5,0(r3)
- eieio
- stbu r5,1(r4)
+01: eieio
+02: stbu r5,1(r4)
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -811,8 +826,18 @@
subi r4,r4,1
blelr-
00: lbzu r5,1(r4)
- stb r5,0(r3)
- eieio
+01: stb r5,0(r3)
+02: eieio
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -822,8 +847,18 @@
subi r4,r4,2
blelr-
00: lhbrx r5,0,r3
- eieio
- sthu r5,2(r4)
+01: eieio
+02: sthu r5,2(r4)
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -833,8 +868,18 @@
subi r4,r4,2
blelr-
00: lhzu r5,2(r4)
- eieio
- sthbrx r5,0,r3
+01: eieio
+02: sthbrx r5,0,r3
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -844,8 +889,18 @@
subi r4,r4,4
blelr-
00: lwbrx r5,0,r3
- eieio
- stwu r5,4(r4)
+01: eieio
+02: stwu r5,4(r4)
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -855,8 +910,18 @@
subi r4,r4,4
blelr-
00: lwzu r5,4(r4)
- stwbrx r5,0,r3
- eieio
+01: stwbrx r5,0,r3
+02: eieio
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -867,8 +932,18 @@
subi r4,r4,2
blelr-
00: lhz r5,0(r3)
- eieio
- sthu r5,2(r4)
+01: eieio
+02: sthu r5,2(r4)
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -879,8 +954,18 @@
subi r4,r4,2
blelr-
00: lhzu r5,2(r4)
- sth r5,0(r3)
- eieio
+01: sth r5,0(r3)
+02: eieio
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -891,8 +976,18 @@
subi r4,r4,4
blelr-
00: lwz r5,0(r3)
- eieio
- stwu r5,4(r4)
+01: eieio
+02: stwu r5,4(r4)
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
@@ -903,8 +998,18 @@
subi r4,r4,4
blelr-
00: lwzu r5,4(r4)
- stw r5,0(r3)
- eieio
+01: stw r5,0(r3)
+02: eieio
+ ISYNC_8xx
+ .section .fixup,"ax"
+03: blr
+ .text
+ .section __ex_table, "a"
+ .align 2
+ .long 00b, 03b
+ .long 01b, 03b
+ .long 02b, 03b
+ .text
bdnz 00b
blr
diff --git a/arch/ppc/kernel/traps.c b/arch/ppc/kernel/traps.c
index 16adde6..42d980e 100644
--- a/arch/ppc/kernel/traps.c
+++ b/arch/ppc/kernel/traps.c
@@ -159,7 +159,7 @@
*/
static inline int check_io_access(struct pt_regs *regs)
{
-#ifdef CONFIG_PPC_PMAC
+#if defined CONFIG_PPC_PMAC || defined CONFIG_8xx
unsigned long msr = regs->msr;
const struct exception_table_entry *entry;
unsigned int *nip = (unsigned int *)regs->nip;
@@ -178,7 +178,11 @@
nip -= 2;
else if (*nip == 0x4c00012c) /* isync */
--nip;
- if (*nip == 0x7c0004ac || (*nip >> 26) == 3) {
+ /* eieio from I/O string functions */
+ else if ((*nip) == 0x7c0006ac || *(nip+1) == 0x7c0006ac)
+ nip += 2;
+ if (*nip == 0x7c0004ac || (*nip >> 26) == 3 ||
+ (*(nip+1) >> 26) == 3) {
/* sync or twi */
unsigned int rb;
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)); \