81711cee93
The current tile rt_sigreturn() syscall pattern uses the common idiom of loading up pt_regs with all the saved registers from the time of the signal, then anticipating the fact that we will clobber the ABI "return value" register (r0) as we return from the syscall by setting the rt_sigreturn return value to whatever random value was in the pt_regs for r0. However, this breaks in our 64-bit kernel when running "compat" tasks, since we always sign-extend the "return value" register to properly handle returned pointers that are in the upper 2GB of the 32-bit compat address space. Doing this to the sigreturn path then causes occasional random corruption of the 64-bit r0 register. Instead, we stop doing the crazy "load the return-value register" hack in sigreturn. We already have some sigreturn-specific assembly code that we use to pass the pt_regs pointer to C code. We extend that code to also set the link register to point to a spot a few instructions after the usual syscall return address so we don't clobber the saved r0. Now it no longer matters what the rt_sigreturn syscall returns, and the pt_regs structure can be cleanly and completely reloaded. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
34 lines
1.1 KiB
C
34 lines
1.1 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#ifndef _ASM_TILE_SIGNAL_H
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#define _ASM_TILE_SIGNAL_H
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/* Do not notify a ptracer when this signal is handled. */
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#define SA_NOPTRACE 0x02000000u
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/* Used in earlier Tilera releases, so keeping for binary compatibility. */
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#define SA_RESTORER 0x04000000u
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#include <asm-generic/signal.h>
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#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
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struct pt_regs;
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int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);
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int setup_sigcontext(struct sigcontext __user *, struct pt_regs *);
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void do_signal(struct pt_regs *regs);
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#endif
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#endif /* _ASM_TILE_SIGNAL_H */
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