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    Fix write endianness/size problem for fast tracepoint enabled flag · 35fd2deb
    Par Olsson authored
    I am sending this fix on behalf of Par Olsson, as a follow-up of this
    one:
    
    https://www.sourceware.org/ml/gdb-patches/2015-10/msg00196.html
    
    This problem is exposed when enabling/disabling fast tracepoints on big
    endian machines.  The flag is defined as an int8_t, but is written from
    gdbserver as an integer (usually 32 bits).  When the agent code reads it
    as an int8_t, it only considers the most significant byte, which is
    always 0.
    
    Also, we were writing 32 bits in an 8 bits field, so the write would
    overflow, but since the following bytes are padding (the next field is
    an uint64_t), it luckily didn't cause any issue on little endian
    systems.
    
    The fix was originally tested on ARM big endian systems, but I don't
    have access to such a system.  However, thanks to Marcin's PowerPC fast
    tracepoint patches and gcc110 (big endian Power7) on the gcc compile
    farm, I was able to reproduce the problem, test the fix and write a
    test (the following patch).
    
    gdb/gdbserver/ChangeLog:
    
    YYYY-MM-DD  Par Olsson  <par.olsson@windriver.com>
    
    	* tracepoint.c (write_inferior_int8): New function.
    	(cmd_qtenable_disable): Write enable flag using
    	write_inferior_int8.
    35fd2deb