[PATCH] PCI: Block config access during BIST

Some PCI adapters (eg.  ipr scsi adapters) have an exposure today in that they
issue BIST to the adapter to reset the card.  If, during the time it takes to
complete BIST, userspace attempts to access PCI config space, the host bus
bridge will master abort the access since the ipr adapter does not respond on
the PCI bus for a brief period of time when running BIST.  On PPC64 hardware,
this master abort results in the host PCI bridge isolating that PCI device
from the rest of the system, making the device unusable until Linux is
rebooted.  This patch is an attempt to close that exposure by introducing some
blocking code in the PCI code.  When blocked, writes will be humored and reads
will return the cached value.  Ben Herrenschmidt has also mentioned that he
plans to use this in PPC power management.

Signed-off-by: Brian King <brking@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

 drivers/pci/access.c    |   89 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/pci/pci-sysfs.c |   20 +++++-----
 drivers/pci/pci.h       |    7 +++
 drivers/pci/proc.c      |   28 +++++++--------
 drivers/pci/syscall.c   |   14 +++----
 include/linux/pci.h     |    7 +++
 6 files changed, 134 insertions(+), 31 deletions(-)

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/pci/syscall.c b/drivers/pci/syscall.c
index c071790cc983..87fafc08cb9d 100644
--- a/drivers/pci/syscall.c
+++ b/drivers/pci/syscall.c
@@ -13,7 +13,7 @@
 #include <linux/smp_lock.h>
 #include <linux/syscalls.h>
 #include <asm/uaccess.h>
-
+#include "pci.h"
 
 asmlinkage long
 sys_pciconfig_read(unsigned long bus, unsigned long dfn,
@@ -38,13 +38,13 @@ sys_pciconfig_read(unsigned long bus, unsigned long dfn,
         lock_kernel();
         switch (len) {
         case 1:
-                cfg_ret = pci_read_config_byte(dev, off, &byte);
+                cfg_ret = pci_user_read_config_byte(dev, off, &byte);
                 break;
         case 2:
-                cfg_ret = pci_read_config_word(dev, off, &word);
+                cfg_ret = pci_user_read_config_word(dev, off, &word);
                 break;
         case 4:
-                cfg_ret = pci_read_config_dword(dev, off, &dword);
+                cfg_ret = pci_user_read_config_dword(dev, off, &dword);
                 break;
         default:
                 err = -EINVAL;
@@ -112,7 +112,7 @@ sys_pciconfig_write(unsigned long bus, unsigned long dfn,
                 err = get_user(byte, (u8 __user *)buf);
                 if (err)
                         break;
-                err = pci_write_config_byte(dev, off, byte);
+                err = pci_user_write_config_byte(dev, off, byte);
                 if (err != PCIBIOS_SUCCESSFUL)
                         err = -EIO;
                 break;
@@ -121,7 +121,7 @@ sys_pciconfig_write(unsigned long bus, unsigned long dfn,
                 err = get_user(word, (u16 __user *)buf);
                 if (err)
                         break;
-                err = pci_write_config_word(dev, off, word);
+                err = pci_user_write_config_word(dev, off, word);
                 if (err != PCIBIOS_SUCCESSFUL)
                         err = -EIO;
                 break;
@@ -130,7 +130,7 @@ sys_pciconfig_write(unsigned long bus, unsigned long dfn,
                 err = get_user(dword, (u32 __user *)buf);
                 if (err)
                         break;
-                err = pci_write_config_dword(dev, off, dword);
+                err = pci_user_write_config_dword(dev, off, dword);
                 if (err != PCIBIOS_SUCCESSFUL)
                         err = -EIO;
                 break;