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asm-generic/io: Add logging support for MMIO accessors
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Add logging support for MMIO high level accessors such as read{b,w,l,q}
and their relaxed versions to aid in debugging unexpected crashes/hangs
caused by the corresponding MMIO operation.

Signed-off-by: Sai Prakash Ranjan <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
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@arndb
Sai Prakash Ranjan authored and arndb committed Jun 15, 2022
1 parent 451f2f1 commit 2100319
Showing 1 changed file with 87 additions and 4 deletions.
91 changes: 87 additions & 4 deletions include/asm-generic/io.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
#include <asm/page.h> /* I/O is all done through memory accesses */
#include <linux/string.h> /* for memset() and memcpy() */
#include <linux/types.h>
#include <linux/instruction_pointer.h>

#ifdef CONFIG_GENERIC_IOMAP
#include <asm-generic/iomap.h>
Expand Down Expand Up @@ -61,6 +62,44 @@
#define __io_par(v) __io_ar(v)
#endif

/*
* "__DISABLE_TRACE_MMIO__" flag can be used to disable MMIO tracing for
* specific kernel drivers in case of excessive/unwanted logging.
*
* Usage: Add a #define flag at the beginning of the driver file.
* Ex: #define __DISABLE_TRACE_MMIO__
* #include <...>
* ...
*/
#if IS_ENABLED(CONFIG_TRACE_MMIO_ACCESS) && !(defined(__DISABLE_TRACE_MMIO__))
#include <linux/tracepoint-defs.h>

DECLARE_TRACEPOINT(rwmmio_write);
DECLARE_TRACEPOINT(rwmmio_post_write);
DECLARE_TRACEPOINT(rwmmio_read);
DECLARE_TRACEPOINT(rwmmio_post_read);

void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
unsigned long caller_addr);
void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
unsigned long caller_addr);
void log_read_mmio(u8 width, const volatile void __iomem *addr,
unsigned long caller_addr);
void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr,
unsigned long caller_addr);

#else

static inline void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
unsigned long caller_addr) {}
static inline void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
unsigned long caller_addr) {}
static inline void log_read_mmio(u8 width, const volatile void __iomem *addr,
unsigned long caller_addr) {}
static inline void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr,
unsigned long caller_addr) {}

#endif /* CONFIG_TRACE_MMIO_ACCESS */

/*
* __raw_{read,write}{b,w,l,q}() access memory in native endianness.
Expand Down Expand Up @@ -149,9 +188,11 @@ static inline u8 readb(const volatile void __iomem *addr)
{
u8 val;

log_read_mmio(8, addr, _THIS_IP_);
__io_br();
val = __raw_readb(addr);
__io_ar(val);
log_post_read_mmio(val, 8, addr, _THIS_IP_);
return val;
}
#endif
Expand All @@ -162,9 +203,11 @@ static inline u16 readw(const volatile void __iomem *addr)
{
u16 val;

log_read_mmio(16, addr, _THIS_IP_);
__io_br();
val = __le16_to_cpu((__le16 __force)__raw_readw(addr));
__io_ar(val);
log_post_read_mmio(val, 16, addr, _THIS_IP_);
return val;
}
#endif
Expand All @@ -175,9 +218,11 @@ static inline u32 readl(const volatile void __iomem *addr)
{
u32 val;

log_read_mmio(32, addr, _THIS_IP_);
__io_br();
val = __le32_to_cpu((__le32 __force)__raw_readl(addr));
__io_ar(val);
log_post_read_mmio(val, 32, addr, _THIS_IP_);
return val;
}
#endif
Expand All @@ -189,9 +234,11 @@ static inline u64 readq(const volatile void __iomem *addr)
{
u64 val;

log_read_mmio(64, addr, _THIS_IP_);
__io_br();
val = __le64_to_cpu(__raw_readq(addr));
__io_ar(val);
log_post_read_mmio(val, 64, addr, _THIS_IP_);
return val;
}
#endif
Expand All @@ -201,29 +248,35 @@ static inline u64 readq(const volatile void __iomem *addr)
#define writeb writeb
static inline void writeb(u8 value, volatile void __iomem *addr)
{
log_write_mmio(value, 8, addr, _THIS_IP_);
__io_bw();
__raw_writeb(value, addr);
__io_aw();
log_post_write_mmio(value, 8, addr, _THIS_IP_);
}
#endif

#ifndef writew
#define writew writew
static inline void writew(u16 value, volatile void __iomem *addr)
{
log_write_mmio(value, 16, addr, _THIS_IP_);
__io_bw();
__raw_writew((u16 __force)cpu_to_le16(value), addr);
__io_aw();
log_post_write_mmio(value, 16, addr, _THIS_IP_);
}
#endif

#ifndef writel
#define writel writel
static inline void writel(u32 value, volatile void __iomem *addr)
{
log_write_mmio(value, 32, addr, _THIS_IP_);
__io_bw();
__raw_writel((u32 __force)__cpu_to_le32(value), addr);
__io_aw();
log_post_write_mmio(value, 32, addr, _THIS_IP_);
}
#endif

Expand All @@ -232,9 +285,11 @@ static inline void writel(u32 value, volatile void __iomem *addr)
#define writeq writeq
static inline void writeq(u64 value, volatile void __iomem *addr)
{
log_write_mmio(value, 64, addr, _THIS_IP_);
__io_bw();
__raw_writeq(__cpu_to_le64(value), addr);
__io_aw();
log_post_write_mmio(value, 64, addr, _THIS_IP_);
}
#endif
#endif /* CONFIG_64BIT */
Expand All @@ -248,63 +303,91 @@ static inline void writeq(u64 value, volatile void __iomem *addr)
#define readb_relaxed readb_relaxed
static inline u8 readb_relaxed(const volatile void __iomem *addr)
{
return __raw_readb(addr);
u8 val;

log_read_mmio(8, addr, _THIS_IP_);
val = __raw_readb(addr);
log_post_read_mmio(val, 8, addr, _THIS_IP_);
return val;
}
#endif

#ifndef readw_relaxed
#define readw_relaxed readw_relaxed
static inline u16 readw_relaxed(const volatile void __iomem *addr)
{
return __le16_to_cpu(__raw_readw(addr));
u16 val;

log_read_mmio(16, addr, _THIS_IP_);
val = __le16_to_cpu(__raw_readw(addr));
log_post_read_mmio(val, 16, addr, _THIS_IP_);
return val;
}
#endif

#ifndef readl_relaxed
#define readl_relaxed readl_relaxed
static inline u32 readl_relaxed(const volatile void __iomem *addr)
{
return __le32_to_cpu(__raw_readl(addr));
u32 val;

log_read_mmio(32, addr, _THIS_IP_);
val = __le32_to_cpu(__raw_readl(addr));
log_post_read_mmio(val, 32, addr, _THIS_IP_);
return val;
}
#endif

#if defined(readq) && !defined(readq_relaxed)
#define readq_relaxed readq_relaxed
static inline u64 readq_relaxed(const volatile void __iomem *addr)
{
return __le64_to_cpu(__raw_readq(addr));
u64 val;

log_read_mmio(64, addr, _THIS_IP_);
val = __le64_to_cpu(__raw_readq(addr));
log_post_read_mmio(val, 64, addr, _THIS_IP_);
return val;
}
#endif

#ifndef writeb_relaxed
#define writeb_relaxed writeb_relaxed
static inline void writeb_relaxed(u8 value, volatile void __iomem *addr)
{
log_write_mmio(value, 8, addr, _THIS_IP_);
__raw_writeb(value, addr);
log_post_write_mmio(value, 8, addr, _THIS_IP_);
}
#endif

#ifndef writew_relaxed
#define writew_relaxed writew_relaxed
static inline void writew_relaxed(u16 value, volatile void __iomem *addr)
{
log_write_mmio(value, 16, addr, _THIS_IP_);
__raw_writew(cpu_to_le16(value), addr);
log_post_write_mmio(value, 16, addr, _THIS_IP_);
}
#endif

#ifndef writel_relaxed
#define writel_relaxed writel_relaxed
static inline void writel_relaxed(u32 value, volatile void __iomem *addr)
{
log_write_mmio(value, 32, addr, _THIS_IP_);
__raw_writel(__cpu_to_le32(value), addr);
log_post_write_mmio(value, 32, addr, _THIS_IP_);
}
#endif

#if defined(writeq) && !defined(writeq_relaxed)
#define writeq_relaxed writeq_relaxed
static inline void writeq_relaxed(u64 value, volatile void __iomem *addr)
{
log_write_mmio(value, 64, addr, _THIS_IP_);
__raw_writeq(__cpu_to_le64(value), addr);
log_post_write_mmio(value, 64, addr, _THIS_IP_);
}
#endif

Expand Down

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