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author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-04 20:44:23 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-04 20:44:23 -0700 |
commit | 6cbf0c704d7c3bb215ae7e0381b1ff2ad5931f35 (patch) | |
tree | f2979bdafe0e0644fb82975a30993d03da7f8fd4 | |
parent | 4d4700707c0d4be0efc968989fb1cd01c60c0a35 (diff) | |
download | op-kernel-dev-6cbf0c704d7c3bb215ae7e0381b1ff2ad5931f35.zip op-kernel-dev-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>
-rw-r--r-- | lib/iomap.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/lib/iomap.c b/lib/iomap.c index 4d43f37..a57d262 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); |