5b7b15afee
With Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> UML skas0 stub has been miscompiling for many people (incidentally not the authors), depending on the used GCC versions. I think (and testing on some GCC versions shows) this patch avoids the fundamental issue which is behind this, namely gcc using the stack when we have just replaced it, behind gcc's back. The remapping and storage of the return value is hidden in a blob of asm, hopefully giving gcc no room for creativity. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
107 lines
2.3 KiB
C
107 lines
2.3 KiB
C
/*
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* Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
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* Licensed under the GPL
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*/
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#ifndef __SYSDEP_STUB_H
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#define __SYSDEP_STUB_H
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#include <sys/mman.h>
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#include <asm/unistd.h>
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#include <sysdep/ptrace_user.h>
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#include "stub-data.h"
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#include "kern_constants.h"
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#include "uml-config.h"
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extern void stub_segv_handler(int sig);
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extern void stub_clone_handler(void);
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#define STUB_SYSCALL_RET PT_INDEX(RAX)
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#define STUB_MMAP_NR __NR_mmap
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#define MMAP_OFFSET(o) (o)
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#define __syscall_clobber "r11","rcx","memory"
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#define __syscall "syscall"
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static inline long stub_syscall0(long syscall)
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{
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long ret;
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__asm__ volatile (__syscall
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: "=a" (ret)
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: "0" (syscall) : __syscall_clobber );
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return ret;
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}
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static inline long stub_syscall2(long syscall, long arg1, long arg2)
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{
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long ret;
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__asm__ volatile (__syscall
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: "=a" (ret)
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: "0" (syscall), "D" (arg1), "S" (arg2) : __syscall_clobber );
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return ret;
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}
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static inline long stub_syscall3(long syscall, long arg1, long arg2, long arg3)
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{
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long ret;
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__asm__ volatile (__syscall
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: "=a" (ret)
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: "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3)
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: __syscall_clobber );
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return ret;
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}
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static inline long stub_syscall4(long syscall, long arg1, long arg2, long arg3,
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long arg4)
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{
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long ret;
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__asm__ volatile ("movq %5,%%r10 ; " __syscall
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: "=a" (ret)
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: "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
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"g" (arg4)
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: __syscall_clobber, "r10" );
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return ret;
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}
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static inline long stub_syscall5(long syscall, long arg1, long arg2, long arg3,
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long arg4, long arg5)
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{
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long ret;
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__asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; " __syscall
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: "=a" (ret)
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: "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
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"g" (arg4), "g" (arg5)
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: __syscall_clobber, "r10", "r8" );
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return ret;
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}
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static inline void trap_myself(void)
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{
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__asm("int3");
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}
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static inline void remap_stack(long fd, unsigned long offset)
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{
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__asm__ volatile ("movq %4,%%r10 ; movq %5,%%r8 ; "
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"movq %6, %%r9; " __syscall "; movq %7, %%rbx ; "
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"movq %%rax, (%%rbx)":
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: "a" (STUB_MMAP_NR), "D" (UML_CONFIG_STUB_DATA),
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"S" (UM_KERN_PAGE_SIZE),
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"d" (PROT_READ | PROT_WRITE),
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"g" (MAP_FIXED | MAP_SHARED), "g" (fd),
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"g" (offset),
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"i" (&((struct stub_data *) UML_CONFIG_STUB_DATA)->err)
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: __syscall_clobber, "r10", "r8", "r9" );
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}
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#endif
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