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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-04 20:44:23 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-04 20:44:23 -0700
commit6cbf0c704d7c3bb215ae7e0381b1ff2ad5931f35 (patch)
treef2979bdafe0e0644fb82975a30993d03da7f8fd4 /lib/iomap.c
parent4d4700707c0d4be0efc968989fb1cd01c60c0a35 (diff)
downloadlinux-sh-6cbf0c704d7c3bb215ae7e0381b1ff2ad5931f35.tar.gz
iomap: make the default iomap functions fail softer
We used to BUG_ON() for a badly mapped IO port, which is certainly correct, but actually made it harder to debug the case where the ATA drivers had incorrectly mapped a nonconnected ATA port. So make badly mapped ports trigger a WARN_ON(), and throw the IO away instead (and return all ones for reads). For things like broken driver initialization - which is the most likely cause anyway - that should mean that the machine comes up and is usable (at least that was the case for the ATA breakage that triggered this patch). It tends to be a whole lot easier to do a "dmesg" on a working machine than to try to capture logs off a dead one. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/iomap.c')
-rw-r--r--lib/iomap.c27
1 files changed, 20 insertions, 7 deletions
diff --git a/lib/iomap.c b/lib/iomap.c
index 4d43f37c0154..a57d262a5ed9 100644
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -35,20 +35,28 @@
#define PIO_RESERVED 0x40000UL
#endif
+static void bad_io_access(unsigned long port, const char *access)
+{
+ static int count = 10;
+ if (count) {
+ count--;
+ printk(KERN_ERR "Bad IO access at port %lx (%s)\n", port, access);
+ WARN_ON(1);
+ }
+}
+
/*
* Ugly macros are a way of life.
*/
-#define VERIFY_PIO(port) BUG_ON((port & ~PIO_MASK) != PIO_OFFSET)
-
#define IO_COND(addr, is_pio, is_mmio) do { \
unsigned long port = (unsigned long __force)addr; \
- if (port < PIO_RESERVED) { \
- VERIFY_PIO(port); \
+ if (port >= PIO_RESERVED) { \
+ is_mmio; \
+ } else if (port > PIO_OFFSET) { \
port &= PIO_MASK; \
is_pio; \
- } else { \
- is_mmio; \
- } \
+ } else \
+ bad_io_access(port, #is_pio ); \
} while (0)
#ifndef pio_read16be
@@ -64,22 +72,27 @@
unsigned int fastcall ioread8(void __iomem *addr)
{
IO_COND(addr, return inb(port), return readb(addr));
+ return 0xff;
}
unsigned int fastcall ioread16(void __iomem *addr)
{
IO_COND(addr, return inw(port), return readw(addr));
+ return 0xffff;
}
unsigned int fastcall ioread16be(void __iomem *addr)
{
IO_COND(addr, return pio_read16be(port), return mmio_read16be(addr));
+ return 0xffff;
}
unsigned int fastcall ioread32(void __iomem *addr)
{
IO_COND(addr, return inl(port), return readl(addr));
+ return 0xffffffff;
}
unsigned int fastcall ioread32be(void __iomem *addr)
{
IO_COND(addr, return pio_read32be(port), return mmio_read32be(addr));
+ return 0xffffffff;
}
EXPORT_SYMBOL(ioread8);
EXPORT_SYMBOL(ioread16);