1. 根目录:
2. arch
3. parisc
4. include
5. asm
6. compat_rt_sigframe.h

#include<linux/compat.h>
#include<linux/compat_siginfo.h>
#include<asm/compat_ucontext.h>

#ifndef _ASM_PARISC_COMPAT_RT_SIGFRAME_H
#define _ASM_PARISC_COMPAT_RT_SIGFRAME_H

/* In a deft move of uber-hackery, we decide to carry the top half of all
 * 64-bit registers in a non-portable, non-ABI, hidden structure.
 * Userspace can read the hidden structure if it *wants* but is never
 * guaranteed to be in the same place. Infact the uc_sigmask from the 
 * ucontext_t structure may push the hidden register file downards
 */
struct compat_regfile {
	/* Upper half of all the 64-bit registers that were truncated
	   on a copy to a 32-bit userspace */
	compat_int_t rf_gr[32];
	compat_int_t rf_iasq[2];
	compat_int_t rf_iaoq[2];
	compat_int_t rf_sar;
};

#define COMPAT_SIGRETURN_TRAMP 4
#define COMPAT_SIGRESTARTBLOCK_TRAMP 5 
#define COMPAT_TRAMP_SIZE (COMPAT_SIGRETURN_TRAMP + COMPAT_SIGRESTARTBLOCK_TRAMP)

struct compat_rt_sigframe {
	/* XXX: Must match trampoline size in arch/parisc/kernel/signal.c 
	        Secondary to that it must protect the ERESTART_RESTARTBLOCK
		trampoline we left on the stack (we were bad and didn't 
		change sp so we could run really fast.) */
	compat_uint_t tramp[COMPAT_TRAMP_SIZE];
	compat_siginfo_t info;
	struct compat_ucontext uc;
	/* Hidden location of truncated registers, *must* be last. */
	struct compat_regfile regs; 
};

/*
 * The 32-bit ABI wants at least 48 bytes for a function call frame:
 * 16 bytes for arg0-arg3, and 32 bytes for magic (the only part of
 * which Linux/parisc uses is sp-20 for the saved return pointer...)
 * Then, the stack pointer must be rounded to a cache line (64 bytes).
 */
#define SIGFRAME32		64
#define FUNCTIONCALLFRAME32	48
#define PARISC_RT_SIGFRAME_SIZE32					\
	(((sizeof(struct compat_rt_sigframe) + FUNCTIONCALLFRAME32) + SIGFRAME32) & -SIGFRAME32)

#endif