c5c3a6d8fe
To make UML build and run on s390, I needed to do these two little changes: 1) UML includes some of the subarch's (s390) headers. I had to change one of them with the following one-liner, to make this compile. AFAICS, this change doesn't break compilation of s390 itself. 2) UML needs to intercept syscalls via ptrace to invalidate the syscall, read syscall's parameters and write the result with the result of UML's syscall processing. Also, UML needs to make sure, that the host does no syscall restart processing. On i386 for example, this can be done by writing -1 to orig_eax on the 2nd syscall interception (orig_eax is the syscall number, which after the interception is used as a "interrupt was a syscall" flag only. Unfortunately, s390 holds syscall number and syscall result in gpr2 and its "interrupt was a syscall" flag (trap) is unreachable via ptrace. So I changed the host to set trap to -1, if the syscall number is changed to an invalid value on the first syscall interception. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
77 lines
3.3 KiB
C
77 lines
3.3 KiB
C
/*
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* include/asm-s390/user.h
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*
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* S390 version
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*
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* Derived from "include/asm-i386/usr.h"
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*/
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#ifndef _S390_USER_H
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#define _S390_USER_H
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#include <asm/page.h>
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#include <asm/ptrace.h>
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/* Core file format: The core file is written in such a way that gdb
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can understand it and provide useful information to the user (under
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linux we use the 'trad-core' bfd). There are quite a number of
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obstacles to being able to view the contents of the floating point
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registers, and until these are solved you will not be able to view the
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contents of them. Actually, you can read in the core file and look at
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the contents of the user struct to find out what the floating point
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registers contain.
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The actual file contents are as follows:
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UPAGE: 1 page consisting of a user struct that tells gdb what is present
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in the file. Directly after this is a copy of the task_struct, which
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is currently not used by gdb, but it may come in useful at some point.
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All of the registers are stored as part of the upage. The upage should
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always be only one page.
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DATA: The data area is stored. We use current->end_text to
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current->brk to pick up all of the user variables, plus any memory
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that may have been malloced. No attempt is made to determine if a page
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is demand-zero or if a page is totally unused, we just cover the entire
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range. All of the addresses are rounded in such a way that an integral
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number of pages is written.
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STACK: We need the stack information in order to get a meaningful
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backtrace. We need to write the data from (esp) to
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current->start_stack, so we round each of these off in order to be able
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to write an integer number of pages.
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The minimum core file size is 3 pages, or 12288 bytes.
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*/
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/*
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* This is the old layout of "struct pt_regs", and
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* is still the layout used by user mode (the new
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* pt_regs doesn't have all registers as the kernel
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* doesn't use the extra segment registers)
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*/
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/* When the kernel dumps core, it starts by dumping the user struct -
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this will be used by gdb to figure out where the data and stack segments
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are within the file, and what virtual addresses to use. */
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struct user {
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/* We start with the registers, to mimic the way that "memory" is returned
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from the ptrace(3,...) function. */
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struct user_regs_struct regs; /* Where the registers are actually stored */
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/* The rest of this junk is to help gdb figure out what goes where */
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unsigned long int u_tsize; /* Text segment size (pages). */
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unsigned long int u_dsize; /* Data segment size (pages). */
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unsigned long int u_ssize; /* Stack segment size (pages). */
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unsigned long start_code; /* Starting virtual address of text. */
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unsigned long start_stack; /* Starting virtual address of stack area.
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This is actually the bottom of the stack,
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the top of the stack is always found in the
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esp register. */
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long int signal; /* Signal that caused the core dump. */
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struct user_regs_struct *u_ar0;
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/* Used by gdb to help find the values for */
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/* the registers. */
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unsigned long magic; /* To uniquely identify a core file */
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char u_comm[32]; /* User command that was responsible */
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};
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#define NBPG PAGE_SIZE
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#define UPAGES 1
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#define HOST_TEXT_START_ADDR (u.start_code)
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#define HOST_STACK_END_ADDR (u.start_stack + u.u_ssize * NBPG)
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#endif /* _S390_USER_H */
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