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    SubjectRe: [PATCHv5 3/4] tracing: Add register read/write tracing support
    On Mon, Dec 6, 2021 at 9:28 AM Sai Prakash Ranjan
    <quic_saipraka@quicinc.com> wrote:
    > diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
    > index 420ff4bc67fd..9f55bcc51de1 100644
    > --- a/kernel/trace/Kconfig
    > +++ b/kernel/trace/Kconfig
    > @@ -95,6 +95,13 @@ config RING_BUFFER_ALLOW_SWAP
    > Allow the use of ring_buffer_swap_cpu.
    > Adds a very slight overhead to tracing when enabled.
    >
    > +config TRACE_MMIO_ACCESS
    > + bool "Register read/write tracing"
    > + depends on TRACING
    > + help
    > + Create tracepoints for MMIO read/write operations. These trace events
    > + can be used for logging all MMIO read/write operations.

    I think this needs a 'depends on ARCH_HAVE_TRACE_MMIO_ACCESS'
    or similar.

    > +void log_read_mmio(u8 width, const volatile void __iomem *addr)
    > +{
    > + trace_rwmmio_read(CALLER_ADDR0, CALLER_ADDR1, width, addr);
    > +}

    Here, it may be better to pass the caller address as an argument, I think
    CALLER_ADDR1 is not always reliable, though it's possible that it is
    in the configurations when this file gets enabled.

    Arnd

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