Messages in this thread | | | Date | Sat, 29 Oct 2022 10:44:32 -0400 | Subject | Re: [RFC PATCH 1/2] tracing/user_events: Use remote writes for event enablement | From | Mathieu Desnoyers <> |
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On 2022-10-27 18:40, Beau Belgrave wrote:
[...] > diff --git a/include/linux/user_events.h b/include/linux/user_events.h > index 592a3fbed98e..4c3bd16395a9 100644 > --- a/include/linux/user_events.h > +++ b/include/linux/user_events.h > @@ -33,12 +33,16 @@ struct user_reg { > /* Input: Size of the user_reg structure being used */ > __u32 size; > > + /* Input: Flags/common settings */ > + __u32 enable_bit : 5, /* Bit in enable address to use (0-31) */ > + __reserved : 27;
I'm always worried about using C/C++ bitfields in uapi, because some compilers (e.g. MS Windows Compiler) have different implementation of the bitfields. See
gcc(1)
-Wnopacked-bitfield-compat -mms-bitfields / -mno-ms-bitfields
Thanks,
Mathieu
> + > + /* Input: Address to update when enabled */ > + __u64 enable_addr; > + > /* Input: Pointer to string with event name, description and flags */ > __u64 name_args; > > - /* Output: Bitwise index of the event within the status page */ > - __u32 status_bit; > - > /* Output: Index of the event to use when writing data */ > __u32 write_index; > } __attribute__((__packed__)); > diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c-- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com
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