perf: Move mmap page data_head offset assertion out of header (b01c3a00) · Commits · 戴 / test

Having the build time assertion in header is making the perf build fail on x86 with: ../../include/linux/perf_event.h:411:32: error: variably modified \ ‘__assert_mmap_data_head_offset’ at file scope [-Werror] I'm moving the build time validation out of the header, because I think it's better than to lessen the perf build warn/error check. Signed-off-by:

Jiri Olsa <jolsa@redhat.com> Cc: acme@redhat.com Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: cjashfor@linux.vnet.ibm.com Cc: fweisbec@gmail.com Link: http://lkml.kernel.org/r/1332513680-7870-1-git-send-email-jolsa@redhat.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

include/linux/perf_event.h

+0 −7

Original line number	Diff line number	Diff line
		@@ -403,13 +403,6 @@ struct perf_event_mmap_page {
		__u64 data_tail; /* user-space written tail */
		};

		/*
		* Build time assertion that we keep the data_head at the intended location.
		* IOW, validation we got the __reserved[] size right.
		*/
		extern char __assert_mmap_data_head_offset
		[1 - 2*!!(offsetof(struct perf_event_mmap_page, data_head) != 1024)];

		#define PERF_RECORD_MISC_CPUMODE_MASK (7 << 0)
		#define PERF_RECORD_MISC_CPUMODE_UNKNOWN (0 << 0)
		#define PERF_RECORD_MISC_KERNEL (1 << 0)

kernel/events/core.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -7116,6 +7116,13 @@ void __init perf_event_init(void)

		/* do not patch jump label more than once per second */
		jump_label_rate_limit(&perf_sched_events, HZ);

		/*
		* Build time assertion that we keep the data_head at the intended
		* location. IOW, validation we got the __reserved[] size right.
		*/
		BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
		!= 1024);
		}

		static int __init perf_event_sysfs_init(void)

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