a37d4032ed
Current code, which copies the potential syscall arguments into the current frame, puts an arbitrary limit on the number of syscall arguments. Apparently, mmap(2) and lseek(2) (?) require larger number. But there is an issue that stack is only need to be mapped to contain the number of arguments required by the syscall, so copying arbitrary large number of words from the stack is not completely safe. Use different approach to convert lcall frame into int $0x80 frame in place, by doing the retl in kernel. This also allows to stop proceed vfork case specially, and stop making assumptions about %cs at the syscall time. Also, improve comments with the formulations provided by bde. Reviewed and tested by: bde Sponsored by: The FreeBSD Foundation MFC after: 1 week
120 lines
3.5 KiB
ArmAsm
120 lines
3.5 KiB
ArmAsm
/*-
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* Copyright (c) 2003 Peter Wemm
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include "opt_compat.h"
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#include <machine/asmacros.h>
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#include <sys/syscall.h>
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#include "ia32_assym.h"
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.text
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.code32
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/*
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* Signal trampoline, copied to top of user stack
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* XXX may need to be MD to match backend sendsig handoff protocol
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*/
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ALIGN_TEXT
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.globl ia32_sigcode
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ia32_sigcode:
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calll *IA32_SIGF_HANDLER(%esp)
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leal IA32_SIGF_UC(%esp),%eax /* get ucontext */
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pushl %eax
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movl $SYS_sigreturn,%eax
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pushl %eax /* junk to fake return addr. */
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int $0x80 /* enter kernel with args */
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/* on stack */
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1:
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jmp 1b
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#ifdef COMPAT_FREEBSD4
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ALIGN_TEXT
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freebsd4_ia32_sigcode:
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calll *IA32_SIGF_HANDLER(%esp)
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leal IA32_SIGF_UC4(%esp),%eax/* get ucontext */
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pushl %eax
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movl $344,%eax /* 4.x SYS_sigreturn */
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pushl %eax /* junk to fake return addr. */
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int $0x80 /* enter kernel with args */
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/* on stack */
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1:
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jmp 1b
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#endif
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#ifdef COMPAT_43
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ALIGN_TEXT
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ia32_osigcode:
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calll *IA32_SIGF_HANDLER(%esp)/* call signal handler */
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leal IA32_SIGF_SC(%esp),%eax /* get sigcontext */
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pushl %eax
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movl $103,%eax /* 3.x SYS_sigreturn */
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pushl %eax /* junk to fake return addr. */
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int $0x80 /* enter kernel with args */
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1:
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jmp 1b
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/*
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* Our lcall $7,$0 handler remains in user mode (ring 3), since lcalls
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* don't change the interrupt mask, so if this one went directly to the
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* kernel then there would be a window with interrupts enabled in kernel
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* mode, and all interrupt handlers would have to be almost as complicated
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* as the NMI handler to support this.
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*
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* Instead, convert the lcall to an int0x80 call. The kernel does most
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* of the conversion by popping the lcall return values off the user
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* stack and returning to them instead of to here, except when the
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* conversion itself fails. Adjusting the stack here is impossible for
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* vfork() and harder for other syscalls.
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*/
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ALIGN_TEXT
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lcall_tramp:
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int $0x80
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1: jmp 1b
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#endif
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ALIGN_TEXT
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esigcode:
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.data
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.globl sz_ia32_sigcode
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sz_ia32_sigcode:
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.long esigcode-ia32_sigcode
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#ifdef COMPAT_FREEBSD4
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.globl sz_freebsd4_ia32_sigcode
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sz_freebsd4_ia32_sigcode:
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.long esigcode-freebsd4_ia32_sigcode
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#endif
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#ifdef COMPAT_43
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.globl sz_ia32_osigcode
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sz_ia32_osigcode:
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.long esigcode-ia32_osigcode
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.globl sz_lcall_tramp
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sz_lcall_tramp:
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.long esigcode-lcall_tramp
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#endif
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