9786a8f3cb
This patch implements the clone-stub mechanism, which allows skas0 to run with proc_mm==0, even if the clib in UML uses modify_ldt. Note: There is a bug in skas3.v7 host patch, that avoids UML-skas from running properly on a SMP-box. In full skas3, I never really saw problems, but in skas0 they showed up. More commentary by jdike - What this patch does is makes sure that the host parent of each new host process matches the UML parent of the corresponding UML process. This ensures that any changed LDTs are inherited. This is done by having clone actually called by the UML process from its stub, rather than by the kernel. We have special syscall stubs that are loaded onto the stub code page because that code must be completely self-contained. These stubs are given C interfaces, and used like normal C functions, but there are subtleties. Principally, we have to be careful about stack variables in stub_clone_handler after the clone. The code is written so that there aren't any - everything boils down to a fixed address. If there were any locals, references to them after the clone would be wrong because the stack just changed. Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
52 lines
1.9 KiB
C
52 lines
1.9 KiB
C
/*
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* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#ifndef __SKAS_H
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#define __SKAS_H
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#include "mm_id.h"
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#include "sysdep/ptrace.h"
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extern int userspace_pid[];
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extern int proc_mm, ptrace_faultinfo;
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extern void switch_threads(void *me, void *next);
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extern void thread_wait(void *sw, void *fb);
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extern void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
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void (*handler)(int));
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extern int start_idle_thread(void *stack, void *switch_buf_ptr,
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void **fork_buf_ptr);
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extern int user_thread(unsigned long stack, int flags);
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extern void userspace(union uml_pt_regs *regs);
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extern void new_thread_proc(void *stack, void (*handler)(int sig));
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extern void remove_sigstack(void);
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extern void new_thread_handler(int sig);
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extern void handle_syscall(union uml_pt_regs *regs);
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extern int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
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int r, int w, int x, int phys_fd, unsigned long long offset);
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extern int unmap(struct mm_id * mm_idp, void *addr, unsigned long len);
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extern int protect(struct mm_id * mm_idp, unsigned long addr,
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unsigned long len, int r, int w, int x);
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extern void user_signal(int sig, union uml_pt_regs *regs, int pid);
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extern int new_mm(int from);
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extern int start_userspace(unsigned long stub_stack);
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extern int copy_context_skas0(unsigned long stack, int pid);
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extern void get_skas_faultinfo(int pid, struct faultinfo * fi);
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extern long execute_syscall_skas(void *r);
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extern unsigned long current_stub_stack(void);
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#endif
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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