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Subject[PATCH v2 07/27] pci: Add arch_can_pci_mmap_io() on architectures which can mmap() I/O space
Date
From: David Woodhouse <dwmw@amazon.co.uk>

This is relatively esoteric, and knowing that we don't have it makes
life easier in some cases rather than just an eventual -EINVAL from
pci_mmap_page_range().

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
Documentation/filesystems/sysfs-pci.txt | 3 ++-
arch/microblaze/include/asm/pci.h | 3 ++-
arch/powerpc/include/asm/pci.h | 1 +
arch/sparc/include/asm/pci_64.h | 1 +
arch/xtensa/include/asm/pci.h | 3 ++-
drivers/pci/pci-sysfs.c | 13 ++++++++-----
drivers/pci/proc.c | 11 +++++++----
include/linux/pci.h | 3 +++
8 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 25b7f1c..46b95d8 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -119,7 +119,8 @@ useful return codes should be provided.

Platforms which support write-combining maps of PCI resources must define
arch_can_pci_mmap_wc() which shall evaluate to non-zero at runtime when
-write-combining is permitted.
+write-combining is permitted. Platforms which support maps of I/O resources
+define arch_can_pci_mmap_io() similarly.

Legacy resources are protected by the HAVE_PCI_LEGACY define. Platforms
wishing to support legacy functionality should define it and provide
diff --git a/arch/microblaze/include/asm/pci.h b/arch/microblaze/include/asm/pci.h
index ab381d2..efd4983 100644
--- a/arch/microblaze/include/asm/pci.h
+++ b/arch/microblaze/include/asm/pci.h
@@ -48,7 +48,8 @@ extern int pci_proc_domain(struct pci_bus *bus);
struct vm_area_struct;

/* Tell drivers/pci/proc.c that we have pci_mmap_page_range() */
-#define HAVE_PCI_MMAP 1
+#define HAVE_PCI_MMAP 1
+#define arch_can_pci_mmap_io() 1

extern int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val,
size_t count);
diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
index 55887d1..c8975da 100644
--- a/arch/powerpc/include/asm/pci.h
+++ b/arch/powerpc/include/asm/pci.h
@@ -80,6 +80,7 @@ struct vm_area_struct;

/* Tell drivers/pci/proc.c that we have pci_mmap_page_range() and it does WC */
#define HAVE_PCI_MMAP 1
+#define arch_can_pci_mmap_io() 1
#define arch_can_pci_mmap_wc() 1

extern int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val,
diff --git a/arch/sparc/include/asm/pci_64.h b/arch/sparc/include/asm/pci_64.h
index 516fda7..b957ca5 100644
--- a/arch/sparc/include/asm/pci_64.h
+++ b/arch/sparc/include/asm/pci_64.h
@@ -42,6 +42,7 @@ static inline int pci_proc_domain(struct pci_bus *bus)
/* Platform support for /proc/bus/pci/X/Y mmap()s. */

#define HAVE_PCI_MMAP
+#define arch_can_pci_mmap_io() 1
#define HAVE_ARCH_PCI_GET_UNMAPPED_AREA
#define get_pci_unmapped_area get_fb_unmapped_area

diff --git a/arch/xtensa/include/asm/pci.h b/arch/xtensa/include/asm/pci.h
index bb5510b..e4f366a 100644
--- a/arch/xtensa/include/asm/pci.h
+++ b/arch/xtensa/include/asm/pci.h
@@ -47,7 +47,8 @@ struct pci_dev;
#define PCI_DMA_BUS_IS_PHYS (1)

/* Tell drivers/pci/proc.c that we have pci_mmap_page_range() */
-#define HAVE_PCI_MMAP 1
+#define HAVE_PCI_MMAP 1
+#define arch_can_pci_mmap_io() 1

#endif /* __KERNEL__ */

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 7d494bd..cb04bc2 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1174,11 +1174,14 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine)
} else {
pdev->res_attr[num] = res_attr;
sprintf(res_attr_name, "resource%d", num);
- res_attr->mmap = pci_mmap_resource_uc;
- }
- if (pci_resource_flags(pdev, num) & IORESOURCE_IO) {
- res_attr->read = pci_read_resource_io;
- res_attr->write = pci_write_resource_io;
+ if (pci_resource_flags(pdev, num) & IORESOURCE_IO) {
+ res_attr->read = pci_read_resource_io;
+ res_attr->write = pci_write_resource_io;
+ if (arch_can_pci_mmap_io())
+ res_attr->mmap = pci_mmap_resource_uc;
+ } else {
+ res_attr->mmap = pci_mmap_resource_uc;
+ }
}
res_attr->attr.name = res_attr_name;
res_attr->attr.mode = S_IRUSR | S_IWUSR;
diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
index a2aa58a..45e5cf7 100644
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -202,6 +202,8 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,

#ifdef HAVE_PCI_MMAP
case PCIIOC_MMAP_IS_IO:
+ if (!arch_can_pci_mmap_io())
+ return -EINVAL;
fpriv->mmap_state = pci_mmap_io;
break;

@@ -232,15 +234,16 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma)
{
struct pci_dev *dev = PDE_DATA(file_inode(file));
struct pci_filp_private *fpriv = file->private_data;
- int i, ret, write_combine = 0, res_bit;
+ int i, ret, write_combine = 0, res_bit = IORESOURCE_MEM;

if (!capable(CAP_SYS_RAWIO))
return -EPERM;

- if (fpriv->mmap_state == pci_mmap_io)
+ if (fpriv->mmap_state == pci_mmap_io) {
+ if (!arch_can_pci_mmap_io())
+ return -EINVAL;
res_bit = IORESOURCE_IO;
- else
- res_bit = IORESOURCE_MEM;
+ }

/* Make sure the caller is mapping a real resource for this device */
for (i = 0; i < PCI_ROM_RESOURCE; i++) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index e7bb4b62..590cfcf 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1636,6 +1636,9 @@ int pci_mmap_page_range(struct pci_dev *pdev, struct vm_area_struct *vma,
#ifndef arch_can_pci_mmap_wc
#define arch_can_pci_mmap_wc() 0
#endif
+#ifndef arch_can_pci_mmap_io
+#define arch_can_pci_mmap_io() 0
+#endif

#ifndef pci_root_bus_fwnode
#define pci_root_bus_fwnode(bus) NULL
--
2.9.3
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