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tracing: Add register read/write tracing support
Generic MMIO read/write i.e., __raw_{read,write}{b,l,w,q} accessors are typically used to read/write from/to memory mapped registers and can cause hangs or some undefined behaviour in following few cases, * If the access to the register space is unclocked, for example: if there is an access to multimedia(MM) block registers without MM clocks. * If the register space is protected and not set to be accessible from non-secure world, for example: only EL3 (EL: Exception level) access is allowed and any EL2/EL1 access is forbidden. * If xPU(memory/register protection units) is controlling access to certain memory/register space for specific clients. and more... Such cases usually results in instant reboot/SErrors/NOC or interconnect hangs and tracing these register accesses can be very helpful to debug such issues during initial development stages and also in later stages. So use ftrace trace events to log such MMIO register accesses which provides rich feature set such as early enablement of trace events, filtering capability, dumping ftrace logs on console and many more. Sample output: rwmmio_read: qcom_geni_serial_poll_bit+0xe4/0x108 width=32 addr=0xfffffbfffdbff610 rwmmio_write: qcom_geni_serial_wr_char+0x78/0x80 width=32 val=0x2020205b addr=0xfffffbfffdbff700 rwmmio_write: __qcom_geni_serial_console_write+0x130/0x198 width=32 val=0x40000000 addr=0xfffffbfffdbff618 rwmmio_read: qcom_geni_serial_poll_bit+0xe4/0x108 width=32 addr=0xfffffbfffdbff610 Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org> [saiprakash: Rewrote commit msg and trace event field edits] Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
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/* SPDX-License-Identifier: GPL-2.0-only */ | ||
/* | ||
* Copyright (c) 2021 Qualcomm Innovation Center, Inc. All rights reserved. | ||
*/ | ||
#undef TRACE_SYSTEM | ||
#define TRACE_SYSTEM rwmmio | ||
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#if !defined(_TRACE_RWMMIO_H) || defined(TRACE_HEADER_MULTI_READ) | ||
#define _TRACE_RWMMIO_H | ||
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#include <linux/tracepoint.h> | ||
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TRACE_EVENT(rwmmio_write, | ||
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TP_PROTO(unsigned long caller, unsigned long parent, u64 val, | ||
u8 width, volatile void __iomem *addr), | ||
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TP_ARGS(caller, parent, val, width, addr), | ||
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TP_STRUCT__entry( | ||
__field(u64, caller) | ||
__field(u64, parent) | ||
__field(u64, val) | ||
__field(u64, addr) | ||
__field(u8, width) | ||
), | ||
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TP_fast_assign( | ||
__entry->caller = caller; | ||
__entry->parent = parent; | ||
__entry->val = val; | ||
__entry->addr = (unsigned long)(void *)addr; | ||
__entry->width = width; | ||
), | ||
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TP_printk("%pS <- %pS width=%d val=%#llx addr=%#llx", | ||
(void *)(unsigned long)__entry->caller, (void *)(unsigned long)__entry->parent, | ||
__entry->width, __entry->val, __entry->addr) | ||
); | ||
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TRACE_EVENT(rwmmio_read, | ||
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TP_PROTO(unsigned long caller, unsigned long parent, u8 width, | ||
const volatile void __iomem *addr), | ||
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TP_ARGS(caller, parent, width, addr), | ||
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TP_STRUCT__entry( | ||
__field(u64, caller) | ||
__field(u64, parent) | ||
__field(u64, addr) | ||
__field(u8, width) | ||
), | ||
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TP_fast_assign( | ||
__entry->caller = caller; | ||
__entry->parent = parent; | ||
__entry->addr = (unsigned long)(void *)addr; | ||
__entry->width = width; | ||
), | ||
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TP_printk("%pS <- %pS width=%d addr=%#llx", | ||
(void *)(unsigned long)__entry->caller, (void *)(unsigned long)__entry->parent, | ||
__entry->width, __entry->addr) | ||
); | ||
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#endif /* _TRACE_RWMMIO_H */ | ||
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#include <trace/define_trace.h> |
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// SPDX-License-Identifier: GPL-2.0-only | ||
/* | ||
* Register read and write tracepoints | ||
* | ||
* Copyright (c) 2021 Qualcomm Innovation Center, Inc. All rights reserved. | ||
*/ | ||
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#include <linux/ftrace.h> | ||
#include <linux/module.h> | ||
#include <asm-generic/io.h> | ||
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#define CREATE_TRACE_POINTS | ||
#include <trace/events/rwmmio.h> | ||
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#ifdef CONFIG_TRACE_MMIO_ACCESS | ||
void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr) | ||
{ | ||
trace_rwmmio_write(CALLER_ADDR0, CALLER_ADDR1, val, width, addr); | ||
} | ||
EXPORT_SYMBOL_GPL(log_write_mmio); | ||
EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_write); | ||
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void log_read_mmio(u8 width, const volatile void __iomem *addr) | ||
{ | ||
trace_rwmmio_read(CALLER_ADDR0, CALLER_ADDR1, width, addr); | ||
} | ||
EXPORT_SYMBOL_GPL(log_read_mmio); | ||
EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_read); | ||
#endif /* CONFIG_TRACE_MMIO_ACCESS */ |