x86/PCI: config space accessor functions should not ignore the segment argument

Without this change, the majority of the raw PCI config space access
functions silently ignore a non-zero segment argument, which is
certainly wrong.

Apart from pci_direct_conf1, all other non-MMCFG access methods get
used only for non-extended accesses (i.e. assigned to raw_pci_ops
only). Consequently, with the way raw_pci_{read,write}() work, it would
be a coding error to call these functions with a non-zero segment (with
the current call flow this cannot happen afaict).

The access method 1 accessor, as it can be used for extended accesses
(on AMD systems) instead gets checks added for the passed in segment to
be zero. This would be the case when on such a system having multiple
PCI segments (don't know whether any exist in practice) MMCFG for some
reason is not usable, and method 1 gets selected for doing extended
accesses. Rather than accessing the wrong device's config space, the
function will now error out.

v2: Convert BUG_ON() to WARN_ON(), and extend description as per Ingo's
request.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

5 files changed, 14 insertions, 2 deletions

diff --git a/arch/x86/pci/ce4100.c b/arch/x86/pci/ce4100.c
index 67858be4b52b..99176094500b 100644
--- a/arch/x86/pci/ce4100.c
+++ b/arch/x86/pci/ce4100.c
@@ -257,6 +257,7 @@ static int ce4100_conf_read(unsigned int seg, unsigned int bus,
 {
         int i;
 
+        WARN_ON(seg);
         if (bus == 1) {
                 for (i = 0; i < ARRAY_SIZE(bus1_fixups); i++) {
                         if (bus1_fixups[i].dev_func == devfn &&
@@ -282,6 +283,7 @@ static int ce4100_conf_write(unsigned int seg, unsigned int bus,
 {
         int i;
 
+        WARN_ON(seg);
         if (bus == 1) {
                 for (i = 0; i < ARRAY_SIZE(bus1_fixups); i++) {
                         if (bus1_fixups[i].dev_func == devfn &&
diff --git a/arch/x86/pci/direct.c b/arch/x86/pci/direct.c
index e6fd8473fb7b..4f2c70439d7f 100644
--- a/arch/x86/pci/direct.c
+++ b/arch/x86/pci/direct.c
@@ -22,7 +22,7 @@ static int pci_conf1_read(unsigned int seg, unsigned int bus,
 {
         unsigned long flags;
 
-        if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
+        if (seg || (bus > 255) || (devfn > 255) || (reg > 4095)) {
                 *value = -1;
                 return -EINVAL;
         }
@@ -53,7 +53,7 @@ static int pci_conf1_write(unsigned int seg, unsigned int bus,
 {
         unsigned long flags;
 
-        if ((bus > 255) || (devfn > 255) || (reg > 4095))
+        if (seg || (bus > 255) || (devfn > 255) || (reg > 4095))
                 return -EINVAL;
 
         raw_spin_lock_irqsave(&pci_config_lock, flags);
@@ -97,6 +97,7 @@ static int pci_conf2_read(unsigned int seg, unsigned int bus,
         unsigned long flags;
         int dev, fn;
 
+        WARN_ON(seg);
         if ((bus > 255) || (devfn > 255) || (reg > 255)) {
                 *value = -1;
                 return -EINVAL;
@@ -138,6 +139,7 @@ static int pci_conf2_write(unsigned int seg, unsigned int bus,
         unsigned long flags;
         int dev, fn;
 
+        WARN_ON(seg);
         if ((bus > 255) || (devfn > 255) || (reg > 255)) 
                 return -EINVAL;
 
diff --git a/arch/x86/pci/numaq_32.c b/arch/x86/pci/numaq_32.c
index 5c9e2458df4e..512a88c41501 100644
--- a/arch/x86/pci/numaq_32.c
+++ b/arch/x86/pci/numaq_32.c
@@ -34,6 +34,7 @@ static int pci_conf1_mq_read(unsigned int seg, unsigned int bus,
         unsigned long flags;
         void *adr __iomem = XQUAD_PORT_ADDR(0xcfc, BUS2QUAD(bus));
 
+        WARN_ON(seg);
         if (!value || (bus >= MAX_MP_BUSSES) || (devfn > 255) || (reg > 255))
                 return -EINVAL;
 
@@ -73,6 +74,7 @@ static int pci_conf1_mq_write(unsigned int seg, unsigned int bus,
         unsigned long flags;
         void *adr __iomem = XQUAD_PORT_ADDR(0xcfc, BUS2QUAD(bus));
 
+        WARN_ON(seg);
         if ((bus >= MAX_MP_BUSSES) || (devfn > 255) || (reg > 255)) 
                 return -EINVAL;
 
diff --git a/arch/x86/pci/olpc.c b/arch/x86/pci/olpc.c
index 13700ec8e2e4..5262603b04d9 100644
--- a/arch/x86/pci/olpc.c
+++ b/arch/x86/pci/olpc.c
@@ -206,6 +206,8 @@ static int pci_olpc_read(unsigned int seg, unsigned int bus,
 {
         uint32_t *addr;
 
+        WARN_ON(seg);
+
         /* Use the hardware mechanism for non-simulated devices */
         if (!is_simulated(bus, devfn))
                 return pci_direct_conf1.read(seg, bus, devfn, reg, len, value);
@@ -264,6 +266,8 @@ static int pci_olpc_read(unsigned int seg, unsigned int bus,
 static int pci_olpc_write(unsigned int seg, unsigned int bus,
                 unsigned int devfn, int reg, int len, uint32_t value)
 {
+        WARN_ON(seg);
+
         /* Use the hardware mechanism for non-simulated devices */
         if (!is_simulated(bus, devfn))
                 return pci_direct_conf1.write(seg, bus, devfn, reg, len, value);
diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c
index a5f7d0d63de0..f68553551467 100644
--- a/arch/x86/pci/pcbios.c
+++ b/arch/x86/pci/pcbios.c
@@ -181,6 +181,7 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
         unsigned long flags;
         unsigned long bx = (bus << 8) | devfn;
 
+        WARN_ON(seg);
         if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
                 return -EINVAL;
 
@@ -247,6 +248,7 @@ static int pci_bios_write(unsigned int seg, unsigned int bus,
         unsigned long flags;
         unsigned long bx = (bus << 8) | devfn;
 
+        WARN_ON(seg);
         if ((bus > 255) || (devfn > 255) || (reg > 255)) 
                 return -EINVAL;