• Hirokazu Takata's avatar
    [PATCH] m32r: Fix pt_regs for !COFNIG_ISA_DSP_LEVEL2 target · 8e8ff02c
    Hirokazu Takata authored
    This modification is required to fix debugging function for m32r targets
    with !CONFIG_ISA_DSP_LEVEL2, by unifying 'struct pt_regs' and 'struct
    sigcontext' size for all M32R ISA.
    
    Some m32r processor core with !CONFIG_ISA_DSP_LEVEL2 configuration has only
    single accumulator a0 (ex.  VDEC2 core, M32102 core, etc.), the others with
    CONFIG_ISA_DSP_LEVEL2 has two accumulators, a0 and a1.
    
    This means there are two variations of thread context.  So far, we reduced
    and changed stackframe size at a syscall for their context size.  However,
    this causes a problem that a GDB for processors with CONFIG_ISA_DSP_LEVEL2
    cannot be used for processors with !CONFIG_ISA_DSP_LEVEL2.
    
    From the viewpoint of GDB support, we should reduce such variation of
    stackframe size for simplicity.
    
    In this patch, dummy members are added to 'struct pt_regs' and 'struct
    sigcontext' to adjust their size for !CONFIG_ISA_DSP_LEVEL2.
    
    This modification is also a one step for a GDB update in future.
    Currently, on the m32r, GDB can access process's context by using ptrace
    functions in a simple way of register by register access.  By unifying
    stackframe size, we have a possibility to make use of ptrace functions of
    not only a single register access but also block register access,
    PTRACE_{GETREGS,PUTREGS}.
    
    However, for this purpose, we might have to modify stackframe structure
    some more; for example, PSW (processor status word) register should be
    pre-processed before pushing to stack at a syscall, and so on.  In this
    case, we must update carefully both kernel and GDB at a time...
    Signed-off-by: default avatarHayato Fujiwara <fujiwara@linux-m32r.org>
    Signed-off-by: default avatarHirokazu Takata <takata@linux-m32r.org>
    Cc: Kei Sakamoto <ksakamot@linux-m32r.org>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    8e8ff02c
assembler.h 4.01 KB