FTRACE's function tracer currently doesn't always work on ARM with MODULE_PLT option enabled. If the module is loaded too far, FTRACE's code modifier cannot cope with introduced veneers and turns the function tracer off globally. ARM64 already has a solution for the problem, refer to the following patches: arm64: ftrace: emit ftrace-mod.o contents through code arm64: module-plts: factor out PLT generation code for ftrace arm64: ftrace: fix !CONFIG_ARM64_MODULE_PLTS kernels arm64: ftrace: fix building without CONFIG_MODULES arm64: ftrace: add support for far branches to dynamic ftrace arm64: ftrace: don't validate branch via PLT in ftrace_make_nop() But the presented ARM variant has just a half of the footprint in terms of the changed LoCs. It also retains the code validation-before-modification instead of switching it off. Alexander Sverdlin (3): ftrace: Add module to ftrace_make_call() parameters ARM: PLT: Move struct plt_entries definition to header ftrace: Add MODULE_PLTS support arch/arm/include/asm/module.h | 10 ++++++ arch/arm/kernel/ftrace.c | 73 ++++++++++++++++++++++++++++++++------ arch/arm/kernel/module-plts.c | 58 +++++++++++++++++++----------- arch/arm64/kernel/ftrace.c | 3 +- arch/blackfin/kernel/ftrace.c | 3 +- arch/ia64/kernel/ftrace.c | 3 +- arch/metag/kernel/ftrace.c | 3 +- arch/microblaze/kernel/ftrace.c | 3 +- arch/mips/kernel/ftrace.c | 3 +- arch/powerpc/kernel/trace/ftrace.c | 3 +- arch/s390/kernel/ftrace.c | 3 +- arch/sh/kernel/ftrace.c | 3 +- arch/sparc/kernel/ftrace.c | 3 +- arch/tile/kernel/ftrace.c | 3 +- arch/x86/kernel/ftrace.c | 3 +- include/linux/ftrace.h | 4 ++- kernel/trace/ftrace.c | 6 ++-- 17 files changed, 140 insertions(+), 47 deletions(-) -- 2.4.6
