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    Subject[PATCH 3.12 010/181] ftrace/x86: Call text_ip_addr() instead of the duplicated code
    Date
    From: Petr Mladek <pmladek@suse.cz>

    3.12-stable review patch. If anyone has any objections, please let me know.

    ===============

    commit 964f7b6b785651a75ef1cbad43a393ca52d4b4f7 upstream.

    I just went over this when looking at some Xen-related ftrace initialization
    problems. They were related to Xen code that is not upstream but this clean up
    would make sense here.

    I think that this was already the intention when text_ip_addr() was introduced
    in the commit 87fbb2ac6073a703930 (ftrace/x86: Use breakpoints for converting
    function graph caller). Anyway, better do it now before it shots people into
    their leg ;-)

    Link: http://lkml.kernel.org/p/1401812601-2359-1-git-send-email-pmladek@suse.cz

    Signed-off-by: Petr Mladek <pmladek@suse.cz>
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
    Signed-off-by: Jiri Slaby <jslaby@suse.cz>
    ---
    arch/x86/kernel/ftrace.c | 11 +----------
    1 file changed, 1 insertion(+), 10 deletions(-)

    diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
    index 1ffc32dbe450..f8ab203fb676 100644
    --- a/arch/x86/kernel/ftrace.c
    +++ b/arch/x86/kernel/ftrace.c
    @@ -297,16 +297,7 @@ int ftrace_int3_handler(struct pt_regs *regs)

    static int ftrace_write(unsigned long ip, const char *val, int size)
    {
    - /*
    - * On x86_64, kernel text mappings are mapped read-only with
    - * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead
    - * of the kernel text mapping to modify the kernel text.
    - *
    - * For 32bit kernels, these mappings are same and we can use
    - * kernel identity mapping to modify code.
    - */
    - if (within(ip, (unsigned long)_text, (unsigned long)_etext))
    - ip = (unsigned long)__va(__pa_symbol(ip));
    + ip = text_ip_addr(ip);

    return probe_kernel_write((void *)ip, val, size);
    }
    --
    2.0.0


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