9f0b4807a4
The userspace stacks mostly have a stack (and in the case of the syscall stub we can just set their stack pointer) that points to the location of the stub data page already. Rework the stubs to use the stack pointer to derive the start of the data page, rather than requiring it to be hard-coded. In the clone stub, also integrate the int3 into the stack remap, since we really must not use the stack while we remap it. This prepares for putting the stub at a variable location that's not part of the normal address space of the userspace processes running inside the UML machine. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
111 lines
2.2 KiB
C
111 lines
2.2 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 <sysdep/ptrace_user.h>
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#include <generated/asm-offsets.h>
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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_and_trap(void)
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{
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__asm__ volatile (
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"movq %0,%%rax ;"
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"movq %%rsp,%%rdi ;"
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"andq %1,%%rdi ;"
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"movq %2,%%r10 ;"
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"movq %%rdi,%%r8 ; addq %3,%%r8 ; movq (%%r8),%%r8 ;"
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"movq %%rdi,%%r9 ; addq %4,%%r9 ; movq (%%r9),%%r9 ;"
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__syscall ";"
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"movq %%rsp,%%rdi ; andq %1,%%rdi ;"
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"addq %5,%%rdi ; movq %%rax, (%%rdi) ;"
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"int3"
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: :
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"g" (STUB_MMAP_NR),
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"g" (~(UM_KERN_PAGE_SIZE - 1)),
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"g" (MAP_FIXED | MAP_SHARED),
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"g" (UML_STUB_FIELD_FD),
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"g" (UML_STUB_FIELD_OFFSET),
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"g" (UML_STUB_FIELD_CHILD_ERR),
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"S" (UM_KERN_PAGE_SIZE),
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"d" (PROT_READ | PROT_WRITE)
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:
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__syscall_clobber, "r10", "r8", "r9");
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}
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#endif
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