[lttng-modules.git] / instrumentation / syscalls / README

LTTng system call tracing

1) lttng-syscall-extractor

You need to build a kernel with CONFIG_FTRACE_SYSCALLS=y and
CONFIG_KALLSYMS_ALL=y for extraction. Apply the linker patch to get your
kernel to keep the system call metadata after boot.  Then build and load
the LTTng syscall extractor module. The module will fail to load (this
is expected). See the dmesg output for system call metadata.

2) Generate system call TRACE_EVENT().

Take the dmesg data and feed it to lttng-syscalls-generate-headers.sh from
the instrumentation/syscalls directory. See the script header for usage
example. It should be run for both the integers and pointers types.

After these are created, you just need to follow the new system call additions,
no need to regenerate the whole thing, since system calls are only appended to.

3) Override headers

You need to provide override headers (even if they don't contain
overrides) for each architecture. Those are meant to contain manual
overrides for specific system calls for cases where the script do not
generate the correct typing for specific system calls.

4) Integrating the new architecture, updating architecture header

Edit instrumentation/syscalls/headers/syscalls_integers.h and
syscalls_pointers.h. Add the new architecture
(e.g. CONFIG_X86_64) to the newly-generated headers
(e.g. changing the current x86-64-syscalls-3.10.0-rc7_<CLASS>.h into
x86-64-syscalls-3.13.7_<CLASS>.h), then rebuild lttng-modules.
Commit	Line	Data
5fee13fd MD	1	LTTng system call tracing
	2
	3	1) lttng-syscall-extractor
	4
deeaaf53 MD	5	You need to build a kernel with CONFIG_FTRACE_SYSCALLS=y and
	6	CONFIG_KALLSYMS_ALL=y for extraction. Apply the linker patch to get your
	7	kernel to keep the system call metadata after boot. Then build and load
	8	the LTTng syscall extractor module. The module will fail to load (this
	9	is expected). See the dmesg output for system call metadata.
5fee13fd MD	10
	11	2) Generate system call TRACE_EVENT().
	12
e709527c MJ	13	Take the dmesg data and feed it to lttng-syscalls-generate-headers.sh from
	14	the instrumentation/syscalls directory. See the script header for usage
	15	example. It should be run for both the integers and pointers types.
5fee13fd	16
e709527c	17	After these are created, you just need to follow the new system call additions,
5fee13fd	18	no need to regenerate the whole thing, since system calls are only appended to.
94f9e233 MD	19
	20	3) Override headers
	21
	22	You need to provide override headers (even if they don't contain
	23	overrides) for each architecture. Those are meant to contain manual
	24	overrides for specific system calls for cases where the script do not
	25	generate the correct typing for specific system calls.
	26
	27	4) Integrating the new architecture, updating architecture header
	28
	29	Edit instrumentation/syscalls/headers/syscalls_integers.h and
	30	syscalls_pointers.h. Add the new architecture
	31	(e.g. CONFIG_X86_64) to the newly-generated headers
	32	(e.g. changing the current x86-64-syscalls-3.10.0-rc7_<CLASS>.h into
	33	x86-64-syscalls-3.13.7_<CLASS>.h), then rebuild lttng-modules.