[PATCH 5/6] PCIERR : interfaces for synchronous I/O error detection

Hidetoshi Seto
2006-03-24T07:51:07Z

This patch is 4/4 of PCIERR implementation for IA64.

This part defines ia64_mca_barrier.
This barrier makes sure that the passed value is poisoned or not.
It can say that this will work as light-version of PAL_MC_DRAIN.
Please refer the comment in patch to get more detail.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>

-----
arch/ia64/kernel/mca.c | 4 +
arch/ia64/kernel/mca_asm.S | 30 +++++++++++++
include/asm-ia64/io.h | 98 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 132 insertions(+)

Index: linux-2.6.16_WORK/arch/ia64/kernel/mca.c
=================================--- linux-2.6.16_WORK.orig/arch/ia64/kernel/mca.c
+++ linux-2.6.16_WORK/arch/ia64/kernel/mca.c
@@ -103,6 +103,10 @@
/* In mca_asm.S */
extern void ia64_os_init_dispatch_monarch (void);
extern void ia64_os_init_dispatch_slave (void);
+#ifdef CONFIG_PCIERR_CHECK
+extern void ia64_mca_barrier (unsigned long value);
+EXPORT_SYMBOL(ia64_mca_barrier);
+#endif

static int monarch_cpu = -1;

Index: linux-2.6.16_WORK/arch/ia64/kernel/mca_asm.S
=================================--- linux-2.6.16_WORK.orig/arch/ia64/kernel/mca_asm.S
+++ linux-2.6.16_WORK/arch/ia64/kernel/mca_asm.S
@@ -19,6 +19,9 @@
// 12/08/05 Keith Owens <kaos@sgi.com>
// Use per cpu MCA/INIT stacks for all data.
//
+// 06/03/22 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
+// Added ia64_mca_barrier.
+//
#include <linux/config.h>
#include <linux/threads.h>

@@ -39,6 +42,7 @@
.global ia64_os_mca_dispatch
.global ia64_os_init_dispatch_monarch
.global ia64_os_init_dispatch_slave
+ .global ia64_mca_barrier

.text
.align 16
@@ -413,6 +417,32 @@

//EndMain//////////////////////////////////////////////////////////////////////

+//StartMain////////////////////////////////////////////////////////////////////
+
+//
+// ia64_mca_barrier:
+//
+// Some chipset may poison the data read, instead of signaling a BERR.
+// The consummation of poisoned data triggers a MCA, which tells us the
+// polluted address.
+// Note that the read operation by itself does not consume the bad data,
+// so we have to do something with it before it is too late.
+//
+// Calling this function forces a consumption of the passed value since
+// the compiler will have to copy it from whatever register it was in to
+// an "out" register to pass to the function.
+// To avoid possible optimization by compiler, and to make doubly sure,
+// this assenbly clearly consumes the value by moving it to r8.
+//
+// In this way, the value is guaranteed secure, not poisoned, and sanity.
+//
+
+ia64_mca_barrier:
+ mov r8=r32
+ br.ret.sptk.many rp
+
+//EndMain//////////////////////////////////////////////////////////////////////
+
// common defines for the stubs
#define ms r4
#define regs r5
Index: linux-2.6.16_WORK/include/asm-ia64/io.h
=================================--- linux-2.6.16_WORK.orig/include/asm-ia64/io.h
+++ linux-2.6.16_WORK/include/asm-ia64/io.h
@@ -165,6 +165,51 @@
* during optimization, which is why we use "volatile" pointers.
*/

+#ifdef CONFIG_PCIERR_CHECK
+
+extern void ia64_mca_barrier(unsigned long value);
+
+static inline unsigned int
+___ia64_inb (unsigned long port)
+{
+ volatile unsigned char *addr = __ia64_mk_io_addr(port);
+ unsigned char ret;
+
+ ret = *addr;
+ __ia64_mf_a();
+ ia64_mca_barrier(ret);
+
+ return ret;
+}
+
+static inline unsigned int
+___ia64_inw (unsigned long port)
+{
+ volatile unsigned short *addr = __ia64_mk_io_addr(port);
+ unsigned short ret;
+
+ ret = *addr;
+ __ia64_mf_a();
+ ia64_mca_barrier(ret);
+
+ return ret;
+}
+
+static inline unsigned int
+___ia64_inl (unsigned long port)
+{
+ volatile unsigned int *addr = __ia64_mk_io_addr(port);
+ unsigned int ret;
+
+ ret = *addr;
+ __ia64_mf_a();
+ ia64_mca_barrier(ret);
+
+ return ret;
+}
+
+#else /* CONFIG_PCIERR_CHECK */
+
static inline unsigned int
___ia64_inb (unsigned long port)
{
@@ -198,6 +243,8 @@
return ret;
}

+#endif /* CONFIG_PCIERR_CHECK */
+
static inline void
___ia64_outb (unsigned char val, unsigned long port)
{
@@ -314,6 +361,55 @@
* a good idea). Writes are ok though for all existing ia64 platforms (and
* hopefully it'll stay that way).
*/
+
+#ifdef CONFIG_PCIERR_CHECK
+
+static inline unsigned char
+___ia64_readb (const volatile void __iomem *addr)
+{
+ unsigned char val;
+
+ val = *(volatile unsigned char __force *)addr;
+ ia64_mca_barrier(val);
+
+ return val;
+}
+
+static inline unsigned short
+___ia64_readw (const volatile void __iomem *addr)
+{
+ unsigned short val;
+
+ val = *(volatile unsigned short __force *)addr;
+ ia64_mca_barrier(val);
+
+ return val;
+}
+
+static inline unsigned int
+___ia64_readl (const volatile void __iomem *addr)
+{
+ unsigned int val;
+
+ val = *(volatile unsigned int __force *) addr;
+ ia64_mca_barrier(val);
+
+ return val;
+}
+
+static inline unsigned long
+___ia64_readq (const volatile void __iomem *addr)
+{
+ unsigned long val;
+
+ val = *(volatile unsigned long __force *) addr;
+ ia64_mca_barrier(val);
+
+ return val;
+}
+
+#else /* CONFIG_PCIERR_CHECK */
+
static inline unsigned char
___ia64_readb (const volatile void __iomem *addr)
{
@@ -338,6 +434,8 @@
return *(volatile unsigned long __force *) addr;
}

+#endif /* CONFIG_PCIERR_CHECK */
+
static inline void
__writeb (unsigned char val, volatile void __iomem *addr)
{