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df24e1783e
Add minimal vDSO support, which provides the signal trampoline helpers, but none of the userspace syscall helpers like time wrappers. The big benefit of this vDSO implementation is, that we now don't need an executeable stack any longer. PA-RISC is one of the last architectures where an executeable stack was needed in oder to implement the signal trampolines by putting assembly instructions on the stack which then gets executed. Instead the kernel will provide the relevant code in the vDSO page and only put the pointers to the signal information on the stack. By dropping the need for executable stacks we avoid running into issues with applications which want non executable stacks for security reasons. Additionally, alternative stacks on memory areas without exec permissions are supported too. This code is based on an initial implementation by Randolph Chung from 2006: https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/ I did the porting and lifted the code to current code base. Dave fixed the unwind code so that gdb and glibc are able to backtrace through the code. An additional patch to gdb will be pushed upstream by Dave. Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Dave Anglin <dave.anglin@bell.net> Cc: Randolph Chung <randolph@tausq.org> Signed-off-by: Helge Deller <deller@gmx.de>
64 lines
2.3 KiB
C
64 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2001 Matthew Wilcox <willy at parisc-linux.org>
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* Copyright (C) 2003 Carlos O'Donell <carlos at parisc-linux.org>
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*/
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#ifndef _PARISC64_KERNEL_SIGNAL32_H
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#define _PARISC64_KERNEL_SIGNAL32_H
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#include <linux/compat.h>
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/* 32-bit ucontext as seen from an 64-bit kernel */
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struct compat_ucontext {
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compat_uint_t uc_flags;
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compat_uptr_t uc_link;
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compat_stack_t uc_stack; /* struct compat_sigaltstack (12 bytes)*/
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/* FIXME: Pad out to get uc_mcontext to start at an 8-byte aligned boundary */
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compat_uint_t pad[1];
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struct compat_sigcontext uc_mcontext;
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compat_sigset_t uc_sigmask; /* mask last for extensibility */
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};
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/* ELF32 signal handling */
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/* In a deft move of uber-hackery, we decide to carry the top half of all
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* 64-bit registers in a non-portable, non-ABI, hidden structure.
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* Userspace can read the hidden structure if it *wants* but is never
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* guaranteed to be in the same place. In fact the uc_sigmask from the
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* ucontext_t structure may push the hidden register file downards
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*/
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struct compat_regfile {
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/* Upper half of all the 64-bit registers that were truncated
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on a copy to a 32-bit userspace */
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compat_int_t rf_gr[32];
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compat_int_t rf_iasq[2];
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compat_int_t rf_iaoq[2];
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compat_int_t rf_sar;
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};
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struct compat_rt_sigframe {
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unsigned int tramp[2]; /* holds original return address */
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compat_siginfo_t info;
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struct compat_ucontext uc;
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/* Hidden location of truncated registers, *must* be last. */
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struct compat_regfile regs;
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};
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/*
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* The 32-bit ABI wants at least 48 bytes for a function call frame:
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* 16 bytes for arg0-arg3, and 32 bytes for magic (the only part of
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* which Linux/parisc uses is sp-20 for the saved return pointer...)
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* Then, the stack pointer must be rounded to a cache line (64 bytes).
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*/
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#define SIGFRAME32 64
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#define FUNCTIONCALLFRAME32 48
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#define PARISC_RT_SIGFRAME_SIZE32 (((sizeof(struct compat_rt_sigframe) + FUNCTIONCALLFRAME32) + SIGFRAME32) & -SIGFRAME32)
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long restore_sigcontext32(struct compat_sigcontext __user *sc,
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struct compat_regfile __user *rf,
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struct pt_regs *regs);
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long setup_sigcontext32(struct compat_sigcontext __user *sc,
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struct compat_regfile __user *rf,
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struct pt_regs *regs, int in_syscall);
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#endif
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