arch/arm/include/asm/user.h

Source file repositories/reference/linux-study-clean/arch/arm/include/asm/user.h

File Facts

System
Linux kernel
Corpus path
arch/arm/include/asm/user.h
Extension
.h
Size
4155 bytes
Lines
101
Domain
Architecture Layer
Bucket
arch/arm
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct user_fp {
	struct fp_reg {
		unsigned int sign1:1;
		unsigned int unused:15;
		unsigned int sign2:1;
		unsigned int exponent:14;
		unsigned int j:1;
		unsigned int mantissa1:31;
		unsigned int mantissa0:32;
	} fpregs[8];
	unsigned int fpsr:32;
	unsigned int fpcr:32;
	unsigned char ftype[8];
	unsigned int init_flag;
};

/* When the kernel dumps core, it starts by dumping the user struct -
   this will be used by gdb to figure out where the data and stack segments
   are within the file, and what virtual addresses to use. */
struct user{
/* We start with the registers, to mimic the way that "memory" is returned
   from the ptrace(3,...) function.  */
  struct pt_regs regs;		/* Where the registers are actually stored */
/* ptrace does not yet supply these.  Someday.... */
  int u_fpvalid;		/* True if math co-processor being used. */
                                /* for this mess. Not yet used. */
/* The rest of this junk is to help gdb figure out what goes where */
  unsigned long int u_tsize;	/* Text segment size (pages). */
  unsigned long int u_dsize;	/* Data segment size (pages). */
  unsigned long int u_ssize;	/* Stack segment size (pages). */
  unsigned long start_code;     /* Starting virtual address of text. */
  unsigned long start_stack;	/* Starting virtual address of stack area.
				   This is actually the bottom of the stack,
				   the top of the stack is always found in the
				   esp register.  */
  long int signal;     		/* Signal that caused the core dump. */
  int reserved;			/* No longer used */
  unsigned long u_ar0;		/* Used by gdb to help find the values for */
				/* the registers. */
  unsigned long magic;		/* To uniquely identify a core file */
  char u_comm[32];		/* User command that was responsible */
  int u_debugreg[8];		/* No longer used */
  struct user_fp u_fp;		/* FP state */
  struct user_fp_struct * u_fp0;/* Used by gdb to help find the values for */
  				/* the FP registers. */
};

/*
 * User specific VFP registers. If only VFPv2 is present, registers 16 to 31
 * are ignored by the ptrace system call and the signal handler.
 */
struct user_vfp {
	unsigned long long fpregs[32];
	unsigned long fpscr;
};

/*
 * VFP exception registers exposed to user space during signal delivery.
 * Fields not relavant to the current VFP architecture are ignored.
 */
struct user_vfp_exc {
	unsigned long	fpexc;
	unsigned long	fpinst;
	unsigned long	fpinst2;
};

#endif /* _ARM_USER_H */

Annotation

Implementation Notes