Commit 2e433a94 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: OSL: Fix and clean up acpi_os_read/write_port() 



First, remove type casts that make acpi_os_read_port() only work on
little endian and are generally not needed.

Second, avoid clearing the memory pointed to by the value return
pointer in acpi_os_read_port() if it is the dummy on the stack (in
which case clearing it is not necessary).

Finally, prevent both acpi_os_read_port() and acpi_os_write_port()
from crashing the kernel when they receive an unsupported width
value and make them print a debug message and return an error instead.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e783362e

drivers/acpi/osl.c

+11 −8
Original line number Diff line number Diff line
@@ -646,18 +646,20 @@ acpi_status acpi_os_read_port(acpi_io_address port, u32 * value, u32 width) 
{

	u32 dummy;



	if (!value)

	if (value)

		*value = 0;

	else

		value = &dummy;



	*value = 0;

	if (width <= 8) {

		*(u8 *) value = inb(port);

		*value = inb(port);

	} else if (width <= 16) {

		*(u16 *) value = inw(port);

		*value = inw(port);

	} else if (width <= 32) {

		*(u32 *) value = inl(port);

		*value = inl(port);

	} else {

		BUG();

		pr_debug("%s: Access width %d not supported\n", __func__, width);

		return AE_BAD_PARAMETER;

	}



	return AE_OK;
@@ -674,7 +676,8 @@ acpi_status acpi_os_write_port(acpi_io_address port, u32 value, u32 width) 
	} else if (width <= 32) {

		outl(value, port);

	} else {

		BUG();

		pr_debug("%s: Access width %d not supported\n", __func__, width);

		return AE_BAD_PARAMETER;

	}



	return AE_OK;