[PATCH 5/5] sandbox: add dummy memory-mapped I/O port region

[Ahmad Fatoum]

Super I/O devices on x86 have their base usually located at one of two
I/O ports. They are probed by writing a "passcode" to the I/O port
and then a value is read back.

When COMPILE_TESTing these drivers and running them on sandbox,
this fails with a segfault because all I/O port access lead to
zero page dereference on that architecture. Even without running
barebox, static analyzers correctly flag these accesses as invoking
undefined behavior. Adding a dummy I/O region solves both issues.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 arch/sandbox/board/devices.c  | 3 +++
 arch/sandbox/include/asm/io.h | 6 +++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/sandbox/board/devices.c b/arch/sandbox/board/devices.c
index 72e62552a3b8..1fd1913ae60f 100644
--- a/arch/sandbox/board/devices.c
+++ b/arch/sandbox/board/devices.c
@@ -9,6 +9,9 @@
 #include <mach/linux.h>
 #include <init.h>
 #include <mach/linux.h>
+#include <asm/io.h>
+
+unsigned char __pci_iobase[IO_SPACE_LIMIT];
 
 static LIST_HEAD(sandbox_device_list);
 
diff --git a/arch/sandbox/include/asm/io.h b/arch/sandbox/include/asm/io.h
index 6a0e77aead42..9f9cd3a42ab1 100644
--- a/arch/sandbox/include/asm/io.h
+++ b/arch/sandbox/include/asm/io.h
@@ -1,7 +1,11 @@
 #ifndef __ASM_SANDBOX_IO_H
 #define __ASM_SANDBOX_IO_H
 
-#define	IO_SPACE_LIMIT 0
+#define	IO_SPACE_LIMIT 0xffff
+/* pacify static analyzers */
+#define PCI_IOBASE     ((void __iomem *)__pci_iobase)
+
+extern unsigned char __pci_iobase[IO_SPACE_LIMIT];
 
 #include <asm-generic/io.h>
 #include <asm-generic/bitio.h>
-- 
2.28.0