6 /* Core file format: The core file is written in such a way that gdb
7 can understand it and provide useful information to the user.
8 There are quite a number of obstacles to being able to view the
9 contents of the floating point registers, and until these are
10 solved you will not be able to view the contents of them.
11 Actually, you can read in the core file and look at the contents of
12 the user struct to find out what the floating point registers
15 The actual file contents are as follows:
16 UPAGE: 1 page consisting of a user struct that tells gdb what is present
17 in the file. Directly after this is a copy of the task_struct, which
18 is currently not used by gdb, but it may come in useful at some point.
19 All of the registers are stored as part of the upage. The upage should
20 always be only one page.
21 DATA: The data area is stored. We use current->end_text to
22 current->brk to pick up all of the user variables, plus any memory
23 that may have been malloced. No attempt is made to determine if a page
24 is demand-zero or if a page is totally unused, we just cover the entire
25 range. All of the addresses are rounded in such a way that an integral
26 number of pages is written.
27 STACK: We need the stack information in order to get a meaningful
28 backtrace. We need to write the data from (esp) to
29 current->start_stack, so we round each of these off in order to be able
30 to write an integer number of pages.
31 The minimum core file size is 3 pages, or 12288 bytes. */
34 * Pentium III FXSR, SSE support
35 * Gareth Hughes <gareth@valinux.com>, May 2000
37 * Provide support for the GDB 5.0+ PTRACE_{GET|SET}FPXREGS requests for
38 * interacting with the FXSR-format floating point environment. Floating
39 * point data can be accessed in the regular format in the usual manner,
40 * and both the standard and SIMD floating point data can be accessed via
41 * the new ptrace requests. In either case, changes to the FPU environment
42 * will be reflected in the task's state as expected.
44 * x86-64 support by Andi Kleen.
47 /* This matches the 64bit FXSAVE format as defined by AMD. It is the same
48 as the 32bit format defined by Intel, except that the selector:offset pairs
49 for data and eip are replaced with flat 64bit pointers. */
50 struct user_i387_struct {
53 unsigned short twd; /* Note this is not the same as
54 the 32bit/x87/FSAVE twd */
60 __u32 st_space[32]; /* 8*16 bytes for each FP-reg = 128 bytes */
61 __u32 xmm_space[64]; /* 16*16 bytes for each XMM-reg = 256 bytes */
66 * Segment register layout in coredumps.
68 struct user_regs_struct {
84 unsigned long orig_ax;
90 unsigned long fs_base;
91 unsigned long gs_base;
98 /* When the kernel dumps core, it starts by dumping the user struct -
99 this will be used by gdb to figure out where the data and stack segments
100 are within the file, and what virtual addresses to use. */
103 /* We start with the registers, to mimic the way that "memory" is returned
104 from the ptrace(3,...) function. */
105 struct user_regs_struct regs; /* Where the registers are actually stored */
106 /* ptrace does not yet supply these. Someday.... */
107 int u_fpvalid; /* True if math co-processor being used. */
108 /* for this mess. Not yet used. */
110 struct user_i387_struct i387; /* Math Co-processor registers. */
111 /* The rest of this junk is to help gdb figure out what goes where */
112 unsigned long int u_tsize; /* Text segment size (pages). */
113 unsigned long int u_dsize; /* Data segment size (pages). */
114 unsigned long int u_ssize; /* Stack segment size (pages). */
115 unsigned long start_code; /* Starting virtual address of text. */
116 unsigned long start_stack; /* Starting virtual address of stack area.
117 This is actually the bottom of the stack,
118 the top of the stack is always found in the
120 long int signal; /* Signal that caused the core dump. */
121 int reserved; /* No longer used */
123 unsigned long u_ar0; /* Used by gdb to help find the values for */
125 struct user_i387_struct *u_fpstate; /* Math Co-processor pointer. */
126 unsigned long magic; /* To uniquely identify a core file */
127 char u_comm[32]; /* User command that was responsible */
128 unsigned long u_debugreg[8];
129 unsigned long error_code; /* CPU error code or 0 */
130 unsigned long fault_address; /* CR3 or 0 */
132 #define NBPG PAGE_SIZE
134 #define HOST_TEXT_START_ADDR (u.start_code)
135 #define HOST_STACK_END_ADDR (u.start_stack + u.u_ssize * NBPG)
137 #endif /* _X86_64_USER_H */