• Steven Rostedt (VMware)'s avatar
    tracing/arm64: Have max stack tracer handle the case of return address after data · f7edb451
    Steven Rostedt (VMware) authored
    Most archs (well at least x86) store the function call return address on the
    stack before storing the local variables for the function. The max stack
    tracer depends on this in its algorithm to display the stack size of each
    function it finds in the back trace.
    
    Some archs (arm64), may store the return address (from its link register)
    just before calling a nested function. There's no reason to save the link
    register on leaf functions, as it wont be updated. This breaks the algorithm
    of the max stack tracer.
    
    Add a new define ARCH_FTRACE_SHIFT_STACK_TRACER that an architecture may set
    if it stores the return address (link register) after it stores the
    function's local variables, and have the stack trace shift the values of the
    mapped stack size to the appropriate functions.
    
    Link: 20190802094103.163576-1-jiping.ma2@windriver.com
    Reported-by: default avatarJiping Ma <jiping.ma2@windriver.com>
    Acked-by: default avatarWill Deacon <will@kernel.org>
    Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
    f7edb451
ftrace.h 2.32 KB