1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * S390 version
4 *
5 * Derived from "include/asm-i386/usr.h"
6 */
7
8 #ifndef _S390_USER_H
9 #define _S390_USER_H
10
11 #include <asm/page.h>
12 #include <asm/ptrace.h>
13 /* Core file format: The core file is written in such a way that gdb
14 can understand it and provide useful information to the user (under
15 linux we use the 'trad-core' bfd). There are quite a number of
16 obstacles to being able to view the contents of the floating point
17 registers, and until these are solved you will not be able to view the
18 contents of them. Actually, you can read in the core file and look at
19 the contents of the user struct to find out what the floating point
20 registers contain.
21 The actual file contents are as follows:
22 UPAGE: 1 page consisting of a user struct that tells gdb what is present
23 in the file. Directly after this is a copy of the task_struct, which
24 is currently not used by gdb, but it may come in useful at some point.
25 All of the registers are stored as part of the upage. The upage should
26 always be only one page.
27 DATA: The data area is stored. We use current->end_text to
28 current->brk to pick up all of the user variables, plus any memory
29 that may have been malloced. No attempt is made to determine if a page
30 is demand-zero or if a page is totally unused, we just cover the entire
31 range. All of the addresses are rounded in such a way that an integral
32 number of pages is written.
33 STACK: We need the stack information in order to get a meaningful
34 backtrace. We need to write the data from (esp) to
35 current->start_stack, so we round each of these off in order to be able
36 to write an integer number of pages.
37 The minimum core file size is 3 pages, or 12288 bytes.
38 */
39
40
41 /*
42 * This is the old layout of "struct pt_regs", and
43 * is still the layout used by user mode (the new
44 * pt_regs doesn't have all registers as the kernel
45 * doesn't use the extra segment registers)
46 */
47
48 /* When the kernel dumps core, it starts by dumping the user struct -
49 this will be used by gdb to figure out where the data and stack segments
50 are within the file, and what virtual addresses to use. */
51 struct user {
52 /* We start with the registers, to mimic the way that "memory" is returned
53 from the ptrace(3,...) function. */
54 struct user_regs_struct regs; /* Where the registers are actually stored */
55 /* The rest of this junk is to help gdb figure out what goes where */
56 unsigned long int u_tsize; /* Text segment size (pages). */
57 unsigned long int u_dsize; /* Data segment size (pages). */
58 unsigned long int u_ssize; /* Stack segment size (pages). */
59 unsigned long start_code; /* Starting virtual address of text. */
60 unsigned long start_stack; /* Starting virtual address of stack area.
61 This is actually the bottom of the stack,
62 the top of the stack is always found in the
63 esp register. */
64 long int signal; /* Signal that caused the core dump. */
65 unsigned long u_ar0; /* Used by gdb to help find the values for */
66 /* the registers. */
67 unsigned long magic; /* To uniquely identify a core file */
68 char u_comm[32]; /* User command that was responsible */
69 };
70
71 #endif /* _S390_USER_H */
72
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