Messages in this thread Patch in this message |  | | From | Jim Cromie <> | Subject | [RFC PATCH v6 20/34] dyndbg: RFC handle __dyndbg* sections in module.lds.h | Date | Sat, 29 May 2021 14:00:15 -0600 |
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Up until now, loadable modules have tacitly linked the 2 __dyndbg* sections into the .ko, as observable in log by enabling module.c's pr_debugs and loading a module.
But now, we need to explicitly compose our named output sections, placing the header sections in front of their respective __dyndbg* input sections. We reuse input section names for the output.
This gives us the placement we need for the header record, which we can see in the "add-module:"s and elements "0 0" below:
"0 0" lines are headers: predicate (function==module && !lineno) "X debug prints in" are 1 too high, they count headers. we are adding tables for empty modules (1st 2 below)
[ 7.578873] dyndbg: add-module: ghash_clmulni_intel [ 7.579716] dyndbg: 0 0 ghash_clmulni_intel.ghash_clmulni_intel.0 [ 7.608995] dyndbg: 1 debug prints in module ghash_clmulni_intel [ 8.078085] dyndbg: add-module: rapl [ 8.078977] dyndbg: 0 0 rapl.rapl.0 [ 8.079584] dyndbg: 1 debug prints in module rapl [ 8.082009] RAPL PMU: API unit is 2^-32 Joules, 0 fixed counters, 10737418240 ms ovfl timer [ 8.099294] dyndbg: add-module: intel_rapl_common [ 8.100177] dyndbg: 0 0 intel_rapl_common.intel_rapl_common.0 [ 8.101026] dyndbg: 1 1 intel_rapl_common.rapl_remove_package.1279 [ 8.101931] dyndbg: 2 2 intel_rapl_common.rapl_detect_domains.1245 [ 8.102836] dyndbg: 3 3 intel_rapl_common.rapl_detect_domains.1242 [ 8.103778] dyndbg: 4 4 intel_rapl_common.rapl_package_register_powercap.1159 [ 8.104960] dyndbg: 5 5 intel_rapl_common.rapl_package_register_powercap.1145 [ 8.106246] dyndbg: 6 6 intel_rapl_common.rapl_package_register_powercap.1114 [ 8.107302] dyndbg: 7 7 intel_rapl_common.rapl_package_register_powercap.1108 [ 8.108338] dyndbg: 8 8 intel_rapl_common.rapl_update_domain_data.1083 [ 8.109278] dyndbg: 9 9 intel_rapl_common.rapl_check_unit_atom.824 [ 8.110255] dyndbg: 10 10 intel_rapl_common.rapl_check_unit_core.796 [ 8.111361] dyndbg: 11 11 intel_rapl_common.rapl_read_data_raw.722 [ 8.112301] dyndbg: 12 12 intel_rapl_common.contraint_to_pl.303 [ 8.113276] dyndbg: 13 debug prints in module intel_rapl_common [ 8.130452] dyndbg: add-module: intel_rapl_msr [ 8.131140] dyndbg: 0 0 intel_rapl_msr.intel_rapl_msr.0 [ 8.132026] dyndbg: 1 1 intel_rapl_msr.rapl_msr_probe.172 [ 8.132818] dyndbg: 2 2 intel_rapl_msr.rapl_msr_read_raw.104 [ 8.133794] dyndbg: 3 debug prints in module intel_rapl_msr
This gives us the property we need:
fixed offset from &__dyndbg[N] to &__dyndbg[0] container_of gets &header header has ptr to __dyndbg_sites[] we can (in principle) drop __dyndbg.site ptr (after we adapt header to keep it)
TODO:
At this point, for loaded modules, ddebug_add_module() sees the header as 0'th element, as we need in order to drop site (and regain worst case footprint parity).
It could/should properly init this header to support the _sites[n] lookup for loaded mods. Or at least handle it explicitly. Or at least see what proc-show does with it currently.
Note that for builtins, decided by (__start <= dp < __stop), we use __start___dyndbg_sites[N] directly, and dont need the header.
But maybe we should use it anyway, double-checking/BUGing when wrong.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- include/asm-generic/module.lds.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/include/asm-generic/module.lds.h b/include/asm-generic/module.lds.h index f210d5c1b78b..70e744c953f5 100644 --- a/include/asm-generic/module.lds.h +++ b/include/asm-generic/module.lds.h @@ -4,7 +4,14 @@ /* * <asm/module.lds.h> can specify arch-specific sections for linking modules. - * Empty for the asm-generic header. + * + * Normally, sections get thru tacitly, but for CONFIG_DYNAMIC_DEBUG, + * we need to insert the .gnu.linkonce sections into the output + * sections, so we have to say everything explicitly. */ +SECTIONS { +__dyndbg_sites : ALIGN(8) { *(.gnu.linkonce.dyndbg_site) *(__dyndbg_sites) } +__dyndbgs : ALIGN(8) { *(.gnu.linkonce.dyndbg) *(__dyndbgs) } +} #endif /* __ASM_GENERIC_MODULE_LDS_H */ -- 2.31.1
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