• S
    tracing: allow to change permissions for text with dynamic ftrace enabled · 883242dd
    Steven Rostedt 提交于
    The commit 74e08179
    x86-64: align RODATA kernel section to 2MB with CONFIG_DEBUG_RODATA
    prevents text sections from becoming read/write using set_memory_rw.
    
    The dynamic ftrace changes all text pages to read/write just before
    converting the calls to tracing to nops, and vice versa.
    
    I orginally just added a flag to allow this transaction when ftrace
    did the change, but I also found that when the CPA testing was running
    it would remove the read/write as well, and ftrace does not do the text
    conversion on boot up, and the CPA changes caused the dynamic tracer
    to fail on self tests.
    
    The current solution I have is to simply not to prevent
    change_page_attr from setting the RW bit for kernel text pages.
    Reported-by: NIngo Molnar <mingo@elte.hu>
    Cc: Suresh Siddha <suresh.b.siddha@intel.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
    883242dd
pageattr.c 31.3 KB