path: root/arch/s390/include/asm/user.h
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Diffstat (limited to 'arch/s390/include/asm/user.h')
1 files changed, 76 insertions, 0 deletions
diff --git a/arch/s390/include/asm/user.h b/arch/s390/include/asm/user.h
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+ * include/asm-s390/user.h
+ *
+ * S390 version
+ *
+ * Derived from "include/asm-i386/usr.h"
+ */
+#ifndef _S390_USER_H
+#define _S390_USER_H
+#include <asm/page.h>
+#include <asm/ptrace.h>
+/* Core file format: The core file is written in such a way that gdb
+ can understand it and provide useful information to the user (under
+ linux we use the 'trad-core' bfd). There are quite a number of
+ obstacles to being able to view the contents of the floating point
+ registers, and until these are solved you will not be able to view the
+ contents of them. Actually, you can read in the core file and look at
+ the contents of the user struct to find out what the floating point
+ registers contain.
+ The actual file contents are as follows:
+ UPAGE: 1 page consisting of a user struct that tells gdb what is present
+ in the file. Directly after this is a copy of the task_struct, which
+ is currently not used by gdb, but it may come in useful at some point.
+ All of the registers are stored as part of the upage. The upage should
+ always be only one page.
+ DATA: The data area is stored. We use current->end_text to
+ current->brk to pick up all of the user variables, plus any memory
+ that may have been malloced. No attempt is made to determine if a page
+ is demand-zero or if a page is totally unused, we just cover the entire
+ range. All of the addresses are rounded in such a way that an integral
+ number of pages is written.
+ STACK: We need the stack information in order to get a meaningful
+ backtrace. We need to write the data from (esp) to
+ current->start_stack, so we round each of these off in order to be able
+ to write an integer number of pages.
+ The minimum core file size is 3 pages, or 12288 bytes.
+ * This is the old layout of "struct pt_regs", and
+ * is still the layout used by user mode (the new
+ * pt_regs doesn't have all registers as the kernel
+ * doesn't use the extra segment registers)
+ */
+/* 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 user_regs_struct regs; /* Where the registers are actually stored */
+/* 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. */
+ 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 */
+#define UPAGES 1
+#define HOST_TEXT_START_ADDR (u.start_code)
+#define HOST_STACK_END_ADDR (u.start_stack + u.u_ssize * NBPG)
+#endif /* _S390_USER_H */

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