[PATCH v5 44/44] asm-generic/io.h: Remove I/O port accessors for HAS_IOPORT=n

Niklas Schnelle
2023-05-22T10:55:52Z

With all subsystems and drivers either declaring their dependence on
HAS_IOPORT or fencing I/O port specific code sections we can finally
make inb()/outb() and friends compile-time dependent on HAS_IOPORT as
suggested by Linus in the linked mail. The main benefit of this is that
on platforms such as s390 which have no meaningful way of implementing
inb()/outb() their use without the proper HAS_IOPORT dependency will
result in easy to catch and fix compile-time errors instead of compiling
code that can never work.

Link: https://lore.kernel.org/lkml/CAHk-=wg80je=K7madF4e7WrRNp37e3qh6y10Svhdc7O8SZ_-8g@mail.gmail.com/
Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
include/asm-generic/io.h | 60 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 587e7e9b9a37..6ab2b6dfb6b1 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -539,6 +539,7 @@ static inline void writesq(volatile void __iomem *addr, const void *buffer,

#if !defined(inb) && !defined(_inb)
#define _inb _inb
+#ifdef CONFIG_HAS_IOPORT
static inline u8 _inb(unsigned long addr)
{
u8 val;
@@ -548,10 +549,15 @@ static inline u8 _inb(unsigned long addr)
__io_par(val);
return val;
}
+#else
+u8 _inb(unsigned long addr)
+ __compiletime_error("inb()) requires CONFIG_HAS_IOPORT");
+#endif
#endif

#if !defined(inw) && !defined(_inw)
#define _inw _inw
+#ifdef CONFIG_HAS_IOPORT
static inline u16 _inw(unsigned long addr)
{
u16 val;
@@ -561,10 +567,15 @@ static inline u16 _inw(unsigned long addr)
__io_par(val);
return val;
}
+#else
+u16 _inw(unsigned long addr)
+ __compiletime_error("inw() requires CONFIG_HAS_IOPORT");
+#endif
#endif

#if !defined(inl) && !defined(_inl)
#define _inl _inl
+#ifdef CONFIG_HAS_IOPORT
static inline u32 _inl(unsigned long addr)
{
u32 val;
@@ -574,36 +585,55 @@ static inline u32 _inl(unsigned long addr)
__io_par(val);
return val;
}
+#else
+u32 _inl(unsigned long addr)
+ __compiletime_error("inl() requires CONFIG_HAS_IOPORT");
+#endif
#endif

#if !defined(outb) && !defined(_outb)
#define _outb _outb
+#ifdef CONFIG_HAS_IOPORT
static inline void _outb(u8 value, unsigned long addr)
{
__io_pbw();
__raw_writeb(value, PCI_IOBASE + addr);
__io_paw();
}
+#else
+void _outb(u8 value, unsigned long addr)
+ __compiletime_error("outb() requires CONFIG_HAS_IOPORT");
+#endif
#endif

#if !defined(outw) && !defined(_outw)
#define _outw _outw
+#ifdef CONFIG_HAS_IOPORT
static inline void _outw(u16 value, unsigned long addr)
{
__io_pbw();
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
__io_paw();
}
+#else
+void _outw(u16 value, unsigned long addr)
+ __compiletime_error("outw() requires CONFIG_HAS_IOPORT");
+#endif
#endif

#if !defined(outl) && !defined(_outl)
#define _outl _outl
+#ifdef CONFIG_HAS_IOPORT
static inline void _outl(u32 value, unsigned long addr)
{
__io_pbw();
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
__io_paw();
}
+#else
+void _outl(u32 value, unsigned long addr)
+ __compiletime_error("outl() requires CONFIG_HAS_IOPORT");
+#endif
#endif

#include <linux/logic_pio.h>
@@ -687,53 +717,83 @@ static inline void outl_p(u32 value, unsigned long addr)

#ifndef insb
#define insb insb
+#ifdef CONFIG_HAS_IOPORT
static inline void insb(unsigned long addr, void *buffer, unsigned int count)
{
readsb(PCI_IOBASE + addr, buffer, count);
}
+#else
+void insb(unsigned long addr, void *buffer, unsigned int count)
+ __compiletime_error("insb() requires HAS_IOPORT");
+#endif
#endif

#ifndef insw
#define insw insw
+#ifdef CONFIG_HAS_IOPORT
static inline void insw(unsigned long addr, void *buffer, unsigned int count)
{
readsw(PCI_IOBASE + addr, buffer, count);
}
+#else
+void insw(unsigned long addr, void *buffer, unsigned int count)
+ __compiletime_error("insw() requires HAS_IOPORT");
+#endif
#endif

#ifndef insl
#define insl insl
+#ifdef CONFIG_HAS_IOPORT
static inline void insl(unsigned long addr, void *buffer, unsigned int count)
{
readsl(PCI_IOBASE + addr, buffer, count);
}
+#else
+void insl(unsigned long addr, void *buffer, unsigned int count)
+ __compiletime_error("insl() requires HAS_IOPORT");
+#endif
#endif

#ifndef outsb
#define outsb outsb
+#ifdef CONFIG_HAS_IOPORT
static inline void outsb(unsigned long addr, const void *buffer,
unsigned int count)
{
writesb(PCI_IOBASE + addr, buffer, count);
}
+#else
+void outsb(unsigned long addr, const void *buffer, unsigned int count)
+ __compiletime_error("outsb() requires HAS_IOPORT");
+#endif
#endif

#ifndef outsw
#define outsw outsw
+#ifdef CONFIG_HAS_IOPORT
static inline void outsw(unsigned long addr, const void *buffer,
unsigned int count)
{
writesw(PCI_IOBASE + addr, buffer, count);
}
+#else
+void outsw(unsigned long addr, const void *buffer, unsigned int count)
+ __compiletime_error("outsw() requires HAS_IOPORT");
+#endif
#endif

#ifndef outsl
#define outsl outsl
+#ifdef CONFIG_HAS_IOPORT
static inline void outsl(unsigned long addr, const void *buffer,
unsigned int count)
{
writesl(PCI_IOBASE + addr, buffer, count);
}
+#else
+void outsl(unsigned long addr, const void *buffer, unsigned int count)
+ __compiletime_error("outsl() requires HAS_IOPORT");
+#endif
#endif

#ifndef insb_p
--
2.39.2