From c28e15d88c5fa480d29219366a733d36ffdde331 Mon Sep 17 00:00:00 2001 From: Varad Gautam Date: Sun, 30 Mar 2025 16:42:29 +0000 Subject: [PATCH] FROMLIST: asm-generic/io.h: Skip trace helpers if rwmmio events are disabled 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 Fixes: 210031971cdd ("asm-generic/io: Add logging support for MMIO accessors") Cc: 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. --- include/asm-generic/io.h | 98 +++++++++++++++++++++++++++------------- 1 file changed, 66 insertions(+), 32 deletions(-) diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index bac63e874c7b..52db695436bb 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -74,6 +74,7 @@ #if IS_ENABLED(CONFIG_TRACE_MMIO_ACCESS) && !(defined(__DISABLE_TRACE_MMIO__)) #include +#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, @@ -188,11 +190,13 @@ static inline u8 readb(const volatile void __iomem *addr) { u8 val; - log_read_mmio(8, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_read)) + log_read_mmio(8, addr, _THIS_IP_, _RET_IP_); __io_br(); val = __raw_readb(addr); __io_ar(val); - log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -203,11 +207,13 @@ static inline u16 readw(const volatile void __iomem *addr) { u16 val; - log_read_mmio(16, addr, _THIS_IP_, _RET_IP_); + 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); - log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -218,11 +224,13 @@ static inline u32 readl(const volatile void __iomem *addr) { u32 val; - log_read_mmio(32, addr, _THIS_IP_, _RET_IP_); + 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); - log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -234,11 +242,13 @@ static inline u64 readq(const volatile void __iomem *addr) { u64 val; - log_read_mmio(64, addr, _THIS_IP_, _RET_IP_); + 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); - log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -248,11 +258,13 @@ 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_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_write)) + log_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); __io_bw(); __raw_writeb(value, addr); __io_aw(); - log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); } #endif @@ -260,11 +272,13 @@ static inline void writeb(u8 value, volatile void __iomem *addr) #define writew writew static inline void writew(u16 value, volatile void __iomem *addr) { - log_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); + 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(); - log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); } #endif @@ -272,11 +286,13 @@ static inline void writew(u16 value, volatile void __iomem *addr) #define writel writel static inline void writel(u32 value, volatile void __iomem *addr) { - log_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); + 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(); - log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); } #endif @@ -285,11 +301,13 @@ 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_, _RET_IP_); + 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(); - log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); } #endif #endif /* CONFIG_64BIT */ @@ -305,9 +323,11 @@ static inline u8 readb_relaxed(const volatile void __iomem *addr) { u8 val; - log_read_mmio(8, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_read)) + log_read_mmio(8, addr, _THIS_IP_, _RET_IP_); val = __raw_readb(addr); - log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -318,9 +338,11 @@ static inline u16 readw_relaxed(const volatile void __iomem *addr) { u16 val; - log_read_mmio(16, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_read)) + log_read_mmio(16, addr, _THIS_IP_, _RET_IP_); val = __le16_to_cpu((__le16 __force)__raw_readw(addr)); - log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -331,9 +353,11 @@ static inline u32 readl_relaxed(const volatile void __iomem *addr) { u32 val; - log_read_mmio(32, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_read)) + log_read_mmio(32, addr, _THIS_IP_, _RET_IP_); val = __le32_to_cpu((__le32 __force)__raw_readl(addr)); - log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -344,9 +368,11 @@ static inline u64 readq_relaxed(const volatile void __iomem *addr) { u64 val; - log_read_mmio(64, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_read)) + log_read_mmio(64, addr, _THIS_IP_, _RET_IP_); val = __le64_to_cpu((__le64 __force)__raw_readq(addr)); - log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_read)) + log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -355,9 +381,11 @@ 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) { - log_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_write)) + log_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); __raw_writeb(value, addr); - log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); } #endif @@ -365,9 +393,11 @@ 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) { - log_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); + 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); - log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); } #endif @@ -375,9 +405,11 @@ 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) { - log_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); + 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); - log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); } #endif @@ -385,9 +417,11 @@ 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) { - log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); + 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); - log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); + if (rwmmio_tracepoint_enabled(rwmmio_post_write)) + log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); } #endif