lkml.org 
[lkml]   [2018]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Subject[PATCH v2 0/2] ARM: Implement MODULE_PLT support in FTRACE
    Date
    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.

    Changelog:
    v2:
    * As suggested by Steven Rostedt, refrain from tree-wide API modification,
    save module pointer in dyn ftrace entry struct instead (PowerPC way)

    Alexander Sverdlin (2):
    ARM: PLT: Move struct plt_entries definition to header
    ARM: ftrace: Add MODULE_PLTS support

    arch/arm/include/asm/ftrace.h | 1 +
    arch/arm/include/asm/module.h | 10 ++++++++
    arch/arm/kernel/ftrace.c | 60 ++++++++++++++++++++++++++++++++++++-------
    arch/arm/kernel/module-plts.c | 58 ++++++++++++++++++++++++++---------------
    4 files changed, 100 insertions(+), 29 deletions(-)

    --
    2.4.6

    \
     
     \ /
      Last update: 2018-03-01 17:44    [W:3.777 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site