Mikael Pettersson <[email protected]> writes:
> Write to the fpstate ->mxcsr and ->swd fields in the sigaction handler's 
> uc_mcontext.

To me, "sigaction handler's uc_mcontext" sounds like userspace, which really 
confuses me:
Even in most recent glibc-2.17, uc_mcontext is of type mcontext_t, which us 
defined as:

typedef struct {
  gregset_t gregs;
  fpregset_t fpregs;
} mcontext_t;

typedef struct fpregset {
    union {
        struct fpchip_state {
            int state[27];
            int status;
        } fpchip_state;
        struct fp_emul_space {
            char fp_emul[246];
            char fp_epad[2];
        } fp_emul_space;
        int f_fpregs[62];
    } fp_reg_set;
    long int f_wregs[33];
} fpregset_t;

So there is no fpstate whatsoever.

However, these elements seem to be available in the uc_mcontext definition of 
the
kernel, but I can't have a sigaction handler there, can I? Then, how does the
kernel's uc_mcontext definition help me in my (userspace) signal handler?
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