Failure after v6.1-rc3-2-g5e5ff73c2e58: asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info:

Results changed to -10 # build_abe binutils: -9 # build_abe stage1: -5 # build_abe qemu: -2 # linux_n_obj: 21472 # First few build errors in logs: # 00:51:18 make[1]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 1 # 00:51:18 make: *** [Makefile:1236: vmlinux] Error 2

from -10 # build_abe binutils: -9 # build_abe stage1: -5 # build_abe qemu: -2 # linux_n_obj: 21476 # linux build successful: all

THIS IS THE END OF INTERESTING STUFF. BELOW ARE LINKS TO BUILDS, REPRODUCTION INSTRUCTIONS, AND THE RAW COMMIT.

For latest status see comments in https://linaro.atlassian.net/browse/GNU-681 . Status of v6.1-rc3-2-g5e5ff73c2e58 commit for tcwg_kernel: commit 5e5ff73c2e5863f93fc5fd78d178cd8f2af12464 Author: Sai Prakash Ranjan quic_saipraka@quicinc.com Date: Mon Oct 17 20:04:50 2022 +0530

asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info

Due to compiler optimizations like inlining, there are cases where MMIO traces using _THIS_IP_ for caller information might not be sufficient to provide accurate debug traces.

1) With optimizations (Seen with GCC):

In this case, _THIS_IP_ works fine and prints the caller information since it will be inlined into the caller and we get the debug traces on who made the MMIO access, for ex:

rwmmio_read: qcom_smmu_tlb_sync+0xe0/0x1b0 width=32 addr=0xffff8000087447f4 rwmmio_post_read: qcom_smmu_tlb_sync+0xe0/0x1b0 width=32 val=0x0 addr=0xffff8000087447f4

2) Without optimizations (Seen with Clang):

_THIS_IP_ will not be sufficient in this case as it will print only the MMIO accessors itself which is of not much use since it is not inlined as below for example:

rwmmio_read: readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: readl+0x48/0x80 width=32 val=0x4 addr=0xffff8000087447f4

So in order to handle this second case as well irrespective of the compiler optimizations, add _RET_IP_ to MMIO trace to make it provide more accurate debug information in all these scenarios.

Before:

rwmmio_read: readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: readl+0x48/0x80 width=32 val=0x4 addr=0xffff8000087447f4

After:

rwmmio_read: qcom_smmu_tlb_sync+0xe0/0x1b0 -> readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: qcom_smmu_tlb_sync+0xe0/0x1b0 -> readl+0x4/0x80 width=32 val=0x0 addr=0xffff8000087447f4

Fixes: 210031971cdd ("asm-generic/io: Add logging support for MMIO accessors") Signed-off-by: Sai Prakash Ranjan quic_saipraka@quicinc.com Signed-off-by: Arnd Bergmann arnd@arndb.de * gnu-release-aarch64-next-allyesconfig ** Failure after v6.1-rc3-2-g5e5ff73c2e58: asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info: ** https://ci.linaro.org/job/tcwg_kernel-gnu-build-gnu-release-aarch64-next-all...

Bad build: https://ci.linaro.org/job/tcwg_kernel-gnu-build-gnu-release-aarch64-next-all... Good build: https://ci.linaro.org/job/tcwg_kernel-gnu-build-gnu-release-aarch64-next-all...

Reproduce current build: <cut> mkdir -p investigate-linux-5e5ff73c2e5863f93fc5fd78d178cd8f2af12464 cd investigate-linux-5e5ff73c2e5863f93fc5fd78d178cd8f2af12464

# Fetch scripts git clone https://git.linaro.org/toolchain/jenkins-scripts

# Fetch manifests for bad and good builds mkdir -p bad/artifacts good/artifacts curl -o bad/artifacts/manifest.sh https://ci.linaro.org/job/tcwg_kernel-gnu-build-gnu-release-aarch64-next-all... --fail curl -o good/artifacts/manifest.sh https://ci.linaro.org/job/tcwg_kernel-gnu-build-gnu-release-aarch64-next-all... --fail

# Reproduce bad build (cd bad; ../jenkins-scripts/tcwg_kernel-build.sh ^^ true %%rr[top_artifacts] artifacts) # Reproduce good build (cd good; ../jenkins-scripts/tcwg_kernel-build.sh ^^ true %%rr[top_artifacts] artifacts) </cut>

Full commit (up to 1000 lines): <cut> commit 5e5ff73c2e5863f93fc5fd78d178cd8f2af12464 Author: Sai Prakash Ranjan quic_saipraka@quicinc.com Date: Mon Oct 17 20:04:50 2022 +0530

asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info

Due to compiler optimizations like inlining, there are cases where MMIO traces using _THIS_IP_ for caller information might not be sufficient to provide accurate debug traces.

1) With optimizations (Seen with GCC):

In this case, _THIS_IP_ works fine and prints the caller information since it will be inlined into the caller and we get the debug traces on who made the MMIO access, for ex:

rwmmio_read: qcom_smmu_tlb_sync+0xe0/0x1b0 width=32 addr=0xffff8000087447f4 rwmmio_post_read: qcom_smmu_tlb_sync+0xe0/0x1b0 width=32 val=0x0 addr=0xffff8000087447f4

2) Without optimizations (Seen with Clang):

_THIS_IP_ will not be sufficient in this case as it will print only the MMIO accessors itself which is of not much use since it is not inlined as below for example:

rwmmio_read: readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: readl+0x48/0x80 width=32 val=0x4 addr=0xffff8000087447f4

So in order to handle this second case as well irrespective of the compiler optimizations, add _RET_IP_ to MMIO trace to make it provide more accurate debug information in all these scenarios.

Before:

rwmmio_read: readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: readl+0x48/0x80 width=32 val=0x4 addr=0xffff8000087447f4

After:

rwmmio_read: qcom_smmu_tlb_sync+0xe0/0x1b0 -> readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: qcom_smmu_tlb_sync+0xe0/0x1b0 -> readl+0x4/0x80 width=32 val=0x0 addr=0xffff8000087447f4

Fixes: 210031971cdd ("asm-generic/io: Add logging support for MMIO accessors") Signed-off-by: Sai Prakash Ranjan quic_saipraka@quicinc.com Signed-off-by: Arnd Bergmann arnd@arndb.de --- include/asm-generic/io.h | 80 +++++++++++++++++++++---------------------- include/trace/events/rwmmio.h | 43 ++++++++++++++--------- lib/trace_readwrite.c | 16 ++++----- 3 files changed, 75 insertions(+), 64 deletions(-)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index a68f8fbf423b..4c44a29b5e8e 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -80,24 +80,24 @@ 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); + unsigned long caller_addr, unsigned long caller_addr0); void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr, - unsigned long caller_addr); + unsigned long caller_addr, unsigned long caller_addr0); void log_read_mmio(u8 width, const volatile void __iomem *addr, - unsigned long caller_addr); + unsigned long caller_addr, unsigned long caller_addr0); void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr, - unsigned long caller_addr); + unsigned long caller_addr, unsigned long caller_addr0);

#else

static inline void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr, - unsigned long caller_addr) {} + unsigned long caller_addr, unsigned long caller_addr0) {} static inline void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr, - unsigned long caller_addr) {} + unsigned long caller_addr, unsigned long caller_addr0) {} static inline void log_read_mmio(u8 width, const volatile void __iomem *addr, - unsigned long caller_addr) {} + unsigned long caller_addr, unsigned long caller_addr0) {} static inline void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr, - unsigned long caller_addr) {} + unsigned long caller_addr, unsigned long caller_addr0) {}

#endif /* CONFIG_TRACE_MMIO_ACCESS */

@@ -188,11 +188,11 @@ static inline u8 readb(const volatile void __iomem *addr) { u8 val;

- log_read_mmio(8, addr, _THIS_IP_); + 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_); + log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -203,11 +203,11 @@ static inline u16 readw(const volatile void __iomem *addr) { u16 val;

- log_read_mmio(16, addr, _THIS_IP_); + 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_); + log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -218,11 +218,11 @@ static inline u32 readl(const volatile void __iomem *addr) { u32 val;

- log_read_mmio(32, addr, _THIS_IP_); + 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_); + log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -234,11 +234,11 @@ static inline u64 readq(const volatile void __iomem *addr) { u64 val;

- log_read_mmio(64, addr, _THIS_IP_); + log_read_mmio(64, addr, _THIS_IP_, _RET_IP_); __io_br(); val = __le64_to_cpu(__raw_readq(addr)); __io_ar(val); - log_post_read_mmio(val, 64, addr, _THIS_IP_); + log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -248,11 +248,11 @@ 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_); + 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_); + log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); } #endif

@@ -260,11 +260,11 @@ 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_); + 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_); + log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); } #endif

@@ -272,11 +272,11 @@ 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_); + 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_); + log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); } #endif

@@ -285,11 +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_); + log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); __io_bw(); __raw_writeq(__cpu_to_le64(value), addr); __io_aw(); - log_post_write_mmio(value, 64, addr, _THIS_IP_); + log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); } #endif #endif /* CONFIG_64BIT */ @@ -305,9 +305,9 @@ static inline u8 readb_relaxed(const volatile void __iomem *addr) { u8 val;

- log_read_mmio(8, addr, _THIS_IP_); + log_read_mmio(8, addr, _THIS_IP_, _RET_IP_); val = __raw_readb(addr); - log_post_read_mmio(val, 8, addr, _THIS_IP_); + log_post_read_mmio(val, 8, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -318,9 +318,9 @@ static inline u16 readw_relaxed(const volatile void __iomem *addr) { u16 val;

- log_read_mmio(16, addr, _THIS_IP_); + log_read_mmio(16, addr, _THIS_IP_, _RET_IP_); val = __le16_to_cpu(__raw_readw(addr)); - log_post_read_mmio(val, 16, addr, _THIS_IP_); + log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -331,9 +331,9 @@ static inline u32 readl_relaxed(const volatile void __iomem *addr) { u32 val;

- log_read_mmio(32, addr, _THIS_IP_); + log_read_mmio(32, addr, _THIS_IP_, _RET_IP_); val = __le32_to_cpu(__raw_readl(addr)); - log_post_read_mmio(val, 32, addr, _THIS_IP_); + log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -344,9 +344,9 @@ static inline u64 readq_relaxed(const volatile void __iomem *addr) { u64 val;

- log_read_mmio(64, addr, _THIS_IP_); + log_read_mmio(64, addr, _THIS_IP_, _RET_IP_); val = __le64_to_cpu(__raw_readq(addr)); - log_post_read_mmio(val, 64, addr, _THIS_IP_); + log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_); return val; } #endif @@ -355,9 +355,9 @@ 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_); + log_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); __raw_writeb(value, addr); - log_post_write_mmio(value, 8, addr, _THIS_IP_); + log_post_write_mmio(value, 8, addr, _THIS_IP_, _RET_IP_); } #endif

@@ -365,9 +365,9 @@ 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_); + log_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); __raw_writew(cpu_to_le16(value), addr); - log_post_write_mmio(value, 16, addr, _THIS_IP_); + log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_); } #endif

@@ -375,9 +375,9 @@ 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_); + log_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); __raw_writel(__cpu_to_le32(value), addr); - log_post_write_mmio(value, 32, addr, _THIS_IP_); + log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_); } #endif

@@ -385,9 +385,9 @@ 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_); + log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); __raw_writeq(__cpu_to_le64(value), addr); - log_post_write_mmio(value, 64, addr, _THIS_IP_); + log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_); } #endif

diff --git a/include/trace/events/rwmmio.h b/include/trace/events/rwmmio.h index de41159216c1..a43e5dd7436b 100644 --- a/include/trace/events/rwmmio.h +++ b/include/trace/events/rwmmio.h @@ -12,12 +12,14 @@

DECLARE_EVENT_CLASS(rwmmio_rw_template,

- TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void __iomem *addr), + TP_PROTO(unsigned long caller, unsigned long caller0, u64 val, u8 width, + volatile void __iomem *addr),

- TP_ARGS(caller, val, width, addr), + TP_ARGS(caller, caller0, val, width, addr),

TP_STRUCT__entry( __field(unsigned long, caller) + __field(unsigned long, caller0) __field(unsigned long, addr) __field(u64, val) __field(u8, width) @@ -25,56 +27,64 @@ DECLARE_EVENT_CLASS(rwmmio_rw_template,

TP_fast_assign( __entry->caller = caller; + __entry->caller0 = caller0; __entry->val = val; __entry->addr = (unsigned long)addr; __entry->width = width; ),

- TP_printk("%pS width=%d val=%#llx addr=%#lx", - (void *)__entry->caller, __entry->width, + TP_printk("%pS -> %pS width=%d val=%#llx addr=%#lx", + (void *)__entry->caller0, (void *)__entry->caller, __entry->width, __entry->val, __entry->addr) );

DEFINE_EVENT(rwmmio_rw_template, rwmmio_write, - TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void __iomem *addr), - TP_ARGS(caller, val, width, addr) + TP_PROTO(unsigned long caller, unsigned long caller0, u64 val, u8 width, + volatile void __iomem *addr), + TP_ARGS(caller, caller0, val, width, addr) );

DEFINE_EVENT(rwmmio_rw_template, rwmmio_post_write, - TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void __iomem *addr), - TP_ARGS(caller, val, width, addr) + TP_PROTO(unsigned long caller, unsigned long caller0, u64 val, u8 width, + volatile void __iomem *addr), + TP_ARGS(caller, caller0, val, width, addr) );

TRACE_EVENT(rwmmio_read,

- TP_PROTO(unsigned long caller, u8 width, const volatile void __iomem *addr), + TP_PROTO(unsigned long caller, unsigned long caller0, u8 width, + const volatile void __iomem *addr),

- TP_ARGS(caller, width, addr), + TP_ARGS(caller, caller0, width, addr),

TP_STRUCT__entry( __field(unsigned long, caller) + __field(unsigned long, caller0) __field(unsigned long, addr) __field(u8, width) ),

TP_fast_assign( __entry->caller = caller; + __entry->caller0 = caller0; __entry->addr = (unsigned long)addr; __entry->width = width; ),

- TP_printk("%pS width=%d addr=%#lx", - (void *)__entry->caller, __entry->width, __entry->addr) + TP_printk("%pS -> %pS width=%d addr=%#lx", + (void *)__entry->caller0, (void *)__entry->caller, __entry->width, __entry->addr) );

TRACE_EVENT(rwmmio_post_read,

- TP_PROTO(unsigned long caller, u64 val, u8 width, const volatile void __iomem *addr), + TP_PROTO(unsigned long caller, unsigned long caller0, u64 val, u8 width, + const volatile void __iomem *addr),

- TP_ARGS(caller, val, width, addr), + TP_ARGS(caller, caller0, val, width, addr),

TP_STRUCT__entry( __field(unsigned long, caller) + __field(unsigned long, caller0) __field(unsigned long, addr) __field(u64, val) __field(u8, width) @@ -82,13 +92,14 @@ TRACE_EVENT(rwmmio_post_read,

TP_fast_assign( __entry->caller = caller; + __entry->caller0 = caller0; __entry->val = val; __entry->addr = (unsigned long)addr; __entry->width = width; ),

- TP_printk("%pS width=%d val=%#llx addr=%#lx", - (void *)__entry->caller, __entry->width, + TP_printk("%pS -> %pS width=%d val=%#llx addr=%#lx", + (void *)__entry->caller0, (void *)__entry->caller, __entry->width, __entry->val, __entry->addr) );

diff --git a/lib/trace_readwrite.c b/lib/trace_readwrite.c index 88637038b30c..62b4e8b3c733 100644 --- a/lib/trace_readwrite.c +++ b/lib/trace_readwrite.c @@ -14,33 +14,33 @@

#ifdef CONFIG_TRACE_MMIO_ACCESS void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr, - unsigned long caller_addr) + unsigned long caller_addr, unsigned long caller_addr0) { - trace_rwmmio_write(caller_addr, val, width, addr); + trace_rwmmio_write(caller_addr, caller_addr0, val, width, addr); } EXPORT_SYMBOL_GPL(log_write_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_write);

void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr, - unsigned long caller_addr) + unsigned long caller_addr, unsigned long caller_addr0) { - trace_rwmmio_post_write(caller_addr, val, width, addr); + trace_rwmmio_post_write(caller_addr, caller_addr0, val, width, addr); } EXPORT_SYMBOL_GPL(log_post_write_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_write);

void log_read_mmio(u8 width, const volatile void __iomem *addr, - unsigned long caller_addr) + unsigned long caller_addr, unsigned long caller_addr0) { - trace_rwmmio_read(caller_addr, width, addr); + trace_rwmmio_read(caller_addr, caller_addr0, width, addr); } EXPORT_SYMBOL_GPL(log_read_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_read);

void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr, - unsigned long caller_addr) + unsigned long caller_addr, unsigned long caller_addr0) { - trace_rwmmio_post_read(caller_addr, val, width, addr); + trace_rwmmio_post_read(caller_addr, caller_addr0, val, width, addr); } EXPORT_SYMBOL_GPL(log_post_read_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_read); </cut>