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FROMLIST: asm-generic/io.h: Skip trace helpers if rwmmio events are disabled

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With `CONFIG_TRACE_MMIO_ACCESS=y`, the `{read,write}{b,w,l,q}{_relaxed}()`
mmio accessors unconditionally call `log_{post_}{read,write}_mmio()`
helpers, which in turn call the ftrace ops for `rwmmio` trace events

This adds a performance penalty per mmio accessor call, even when
`rwmmio` events are disabled at runtime (~80% overhead on local
measurement).

Guard these with `tracepoint_enabled()`.

Change-Id: I9dd7f11919dcbbc06fd7a2dd7383daec5e5685fd
Signed-off-by: Varad Gautam <varadgautam@google.com>
Fixes: 210031971c ("asm-generic/io: Add logging support for MMIO accessors")
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/lkml/20250330164229.2174672-1-varadgautam@google.com/
Test: kprobe doesn't record log_{post_}{read,write}_mmio when disabled.
DISABLE_TOPIC_PROTECTOR: the topic was added after cherry-pick
  and gerrit isn't able to pick this up.
This commit is contained in:
Varad Gautam
2025-03-30 16:42:29 +00:00
committed by Matthias Männich
parent 421c7da597
commit c28e15d88c
1 changed files with 66 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
include/asm-generic/io.h
View File

@@ -74,6 +74,7 @@
#if IS_ENABLED(CONFIG_TRACE_MMIO_ACCESS) && !(defined(__DISABLE_TRACE_MMIO__))
#include <linux/tracepoint-defs.h>
#define rwmmio_tracepoint_enabled(tracepoint) tracepoint_enabled(tracepoint)
DECLARE_TRACEPOINT(rwmmio_write);
DECLARE_TRACEPOINT(rwmmio_post_write);
DECLARE_TRACEPOINT(rwmmio_read);
@@ -90,6 +91,7 @@ void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr,
#else
#define rwmmio_tracepoint_enabled(tracepoint) false
static inline void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
unsigned long caller_addr, unsigned long caller_addr0) {}
static inline void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
@@ -188,10 +190,12 @@ static inline u8 readb(const volatile void __iomem *addr)
{
u8 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(8, addr, _THIS_IP_, _RET_IP_);
__io_br();
val = __raw_readb(addr);
__io_ar(val);
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -203,10 +207,12 @@ static inline u16 readw(const volatile void __iomem *addr)
{
u16 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(16, addr, _THIS_IP_, _RET_IP_);
__io_br();
val = __le16_to_cpu((__le16 __force)__raw_readw(addr));
__io_ar(val);
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -218,10 +224,12 @@ static inline u32 readl(const volatile void __iomem *addr)
{
u32 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(32, addr, _THIS_IP_, _RET_IP_);
__io_br();
val = __le32_to_cpu((__le32 __force)__raw_readl(addr));
__io_ar(val);
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -234,10 +242,12 @@ static inline u64 readq(const volatile void __iomem *addr)
{
u64 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(64, addr, _THIS_IP_, _RET_IP_);
__io_br();
val = __le64_to_cpu((__le64 __force)__raw_readq(addr));
__io_ar(val);
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -248,10 +258,12 @@ static inline u64 readq(const volatile void __iomem *addr)
#define writeb writeb
static inline void writeb(u8 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_);
__io_bw();
__raw_writeb(value, addr);
__io_aw();
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_);
}
#endif
@@ -260,10 +272,12 @@ static inline void writeb(u8 value, volatile void __iomem *addr)
#define writew writew
static inline void writew(u16 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_);
__io_bw();
__raw_writew((u16 __force)cpu_to_le16(value), addr);
__io_aw();
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_);
}
#endif
@@ -272,10 +286,12 @@ static inline void writew(u16 value, volatile void __iomem *addr)
#define writel writel
static inline void writel(u32 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_);
__io_bw();
__raw_writel((u32 __force)__cpu_to_le32(value), addr);
__io_aw();
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_);
}
#endif
@@ -285,10 +301,12 @@ static inline void writel(u32 value, volatile void __iomem *addr)
#define writeq writeq
static inline void writeq(u64 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
__io_bw();
__raw_writeq((u64 __force)__cpu_to_le64(value), addr);
__io_aw();
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
}
#endif
@@ -305,8 +323,10 @@ static inline u8 readb_relaxed(const volatile void __iomem *addr)
{
u8 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(8, addr, _THIS_IP_, _RET_IP_);
val = __raw_readb(addr);
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -318,8 +338,10 @@ static inline u16 readw_relaxed(const volatile void __iomem *addr)
{
u16 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(16, addr, _THIS_IP_, _RET_IP_);
val = __le16_to_cpu((__le16 __force)__raw_readw(addr));
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -331,8 +353,10 @@ static inline u32 readl_relaxed(const volatile void __iomem *addr)
{
u32 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(32, addr, _THIS_IP_, _RET_IP_);
val = __le32_to_cpu((__le32 __force)__raw_readl(addr));
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -344,8 +368,10 @@ static inline u64 readq_relaxed(const volatile void __iomem *addr)
{
u64 val;
if (rwmmio_tracepoint_enabled(rwmmio_read))
log_read_mmio(64, addr, _THIS_IP_, _RET_IP_);
val = __le64_to_cpu((__le64 __force)__raw_readq(addr));
if (rwmmio_tracepoint_enabled(rwmmio_post_read))
log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_);
return val;
}
@@ -355,8 +381,10 @@ static inline u64 readq_relaxed(const volatile void __iomem *addr)
#define writeb_relaxed writeb_relaxed
static inline void writeb_relaxed(u8 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_);
__raw_writeb(value, addr);
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_);
}
#endif
@@ -365,8 +393,10 @@ static inline void writeb_relaxed(u8 value, volatile void __iomem *addr)
#define writew_relaxed writew_relaxed
static inline void writew_relaxed(u16 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_);
__raw_writew((u16 __force)cpu_to_le16(value), addr);
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_);
}
#endif
@@ -375,8 +405,10 @@ static inline void writew_relaxed(u16 value, volatile void __iomem *addr)
#define writel_relaxed writel_relaxed
static inline void writel_relaxed(u32 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_);
__raw_writel((u32 __force)__cpu_to_le32(value), addr);
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_);
}
#endif
@@ -385,8 +417,10 @@ static inline void writel_relaxed(u32 value, volatile void __iomem *addr)
#define writeq_relaxed writeq_relaxed
static inline void writeq_relaxed(u64 value, volatile void __iomem *addr)
{
if (rwmmio_tracepoint_enabled(rwmmio_write))
log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
__raw_writeq((u64 __force)__cpu_to_le64(value), addr);
if (rwmmio_tracepoint_enabled(rwmmio_post_write))
log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
}
#endif