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868 lines
23 KiB
868 lines
23 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs |
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* |
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson |
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* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes |
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* 2000-2002 x86-64 support by Andi Kleen |
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*/ |
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|
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/sched.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/mm.h> |
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#include <linux/smp.h> |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/wait.h> |
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#include <linux/tracehook.h> |
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#include <linux/unistd.h> |
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#include <linux/stddef.h> |
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#include <linux/personality.h> |
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#include <linux/uaccess.h> |
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#include <linux/user-return-notifier.h> |
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#include <linux/uprobes.h> |
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#include <linux/context_tracking.h> |
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#include <linux/entry-common.h> |
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#include <linux/syscalls.h> |
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|
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#include <asm/processor.h> |
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#include <asm/ucontext.h> |
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#include <asm/fpu/internal.h> |
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#include <asm/fpu/signal.h> |
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#include <asm/vdso.h> |
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#include <asm/mce.h> |
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#include <asm/sighandling.h> |
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#include <asm/vm86.h> |
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#ifdef CONFIG_X86_64 |
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#include <linux/compat.h> |
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#include <asm/proto.h> |
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#include <asm/ia32_unistd.h> |
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#endif /* CONFIG_X86_64 */ |
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|
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#include <asm/syscall.h> |
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#include <asm/sigframe.h> |
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#include <asm/signal.h> |
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#ifdef CONFIG_X86_64 |
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/* |
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* If regs->ss will cause an IRET fault, change it. Otherwise leave it |
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* alone. Using this generally makes no sense unless |
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* user_64bit_mode(regs) would return true. |
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*/ |
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static void force_valid_ss(struct pt_regs *regs) |
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{ |
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u32 ar; |
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asm volatile ("lar %[old_ss], %[ar]\n\t" |
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"jz 1f\n\t" /* If invalid: */ |
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"xorl %[ar], %[ar]\n\t" /* set ar = 0 */ |
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"1:" |
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: [ar] "=r" (ar) |
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: [old_ss] "rm" ((u16)regs->ss)); |
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|
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/* |
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* For a valid 64-bit user context, we need DPL 3, type |
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* read-write data or read-write exp-down data, and S and P |
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* set. We can't use VERW because VERW doesn't check the |
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* P bit. |
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*/ |
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ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK; |
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if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) && |
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ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN)) |
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regs->ss = __USER_DS; |
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} |
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# define CONTEXT_COPY_SIZE offsetof(struct sigcontext, reserved1) |
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#else |
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# define CONTEXT_COPY_SIZE sizeof(struct sigcontext) |
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#endif |
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static int restore_sigcontext(struct pt_regs *regs, |
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struct sigcontext __user *usc, |
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unsigned long uc_flags) |
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{ |
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struct sigcontext sc; |
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|
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/* Always make any pending restarted system calls return -EINTR */ |
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current->restart_block.fn = do_no_restart_syscall; |
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|
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if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE)) |
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return -EFAULT; |
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#ifdef CONFIG_X86_32 |
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set_user_gs(regs, sc.gs); |
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regs->fs = sc.fs; |
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regs->es = sc.es; |
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regs->ds = sc.ds; |
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#endif /* CONFIG_X86_32 */ |
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regs->bx = sc.bx; |
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regs->cx = sc.cx; |
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regs->dx = sc.dx; |
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regs->si = sc.si; |
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regs->di = sc.di; |
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regs->bp = sc.bp; |
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regs->ax = sc.ax; |
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regs->sp = sc.sp; |
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regs->ip = sc.ip; |
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#ifdef CONFIG_X86_64 |
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regs->r8 = sc.r8; |
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regs->r9 = sc.r9; |
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regs->r10 = sc.r10; |
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regs->r11 = sc.r11; |
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regs->r12 = sc.r12; |
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regs->r13 = sc.r13; |
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regs->r14 = sc.r14; |
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regs->r15 = sc.r15; |
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#endif /* CONFIG_X86_64 */ |
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|
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/* Get CS/SS and force CPL3 */ |
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regs->cs = sc.cs | 0x03; |
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regs->ss = sc.ss | 0x03; |
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|
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regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS); |
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/* disable syscall checks */ |
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regs->orig_ax = -1; |
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#ifdef CONFIG_X86_64 |
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/* |
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* Fix up SS if needed for the benefit of old DOSEMU and |
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* CRIU. |
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*/ |
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if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs))) |
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force_valid_ss(regs); |
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#endif |
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|
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return fpu__restore_sig((void __user *)sc.fpstate, |
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IS_ENABLED(CONFIG_X86_32)); |
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} |
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static __always_inline int |
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__unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, |
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struct pt_regs *regs, unsigned long mask) |
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{ |
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#ifdef CONFIG_X86_32 |
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unsafe_put_user(get_user_gs(regs), |
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(unsigned int __user *)&sc->gs, Efault); |
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unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault); |
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unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault); |
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unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault); |
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#endif /* CONFIG_X86_32 */ |
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|
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unsafe_put_user(regs->di, &sc->di, Efault); |
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unsafe_put_user(regs->si, &sc->si, Efault); |
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unsafe_put_user(regs->bp, &sc->bp, Efault); |
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unsafe_put_user(regs->sp, &sc->sp, Efault); |
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unsafe_put_user(regs->bx, &sc->bx, Efault); |
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unsafe_put_user(regs->dx, &sc->dx, Efault); |
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unsafe_put_user(regs->cx, &sc->cx, Efault); |
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unsafe_put_user(regs->ax, &sc->ax, Efault); |
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#ifdef CONFIG_X86_64 |
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unsafe_put_user(regs->r8, &sc->r8, Efault); |
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unsafe_put_user(regs->r9, &sc->r9, Efault); |
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unsafe_put_user(regs->r10, &sc->r10, Efault); |
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unsafe_put_user(regs->r11, &sc->r11, Efault); |
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unsafe_put_user(regs->r12, &sc->r12, Efault); |
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unsafe_put_user(regs->r13, &sc->r13, Efault); |
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unsafe_put_user(regs->r14, &sc->r14, Efault); |
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unsafe_put_user(regs->r15, &sc->r15, Efault); |
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#endif /* CONFIG_X86_64 */ |
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unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault); |
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unsafe_put_user(current->thread.error_code, &sc->err, Efault); |
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unsafe_put_user(regs->ip, &sc->ip, Efault); |
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#ifdef CONFIG_X86_32 |
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unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault); |
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unsafe_put_user(regs->flags, &sc->flags, Efault); |
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unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault); |
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unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault); |
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#else /* !CONFIG_X86_32 */ |
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unsafe_put_user(regs->flags, &sc->flags, Efault); |
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unsafe_put_user(regs->cs, &sc->cs, Efault); |
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unsafe_put_user(0, &sc->gs, Efault); |
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unsafe_put_user(0, &sc->fs, Efault); |
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unsafe_put_user(regs->ss, &sc->ss, Efault); |
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#endif /* CONFIG_X86_32 */ |
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unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault); |
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/* non-iBCS2 extensions.. */ |
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unsafe_put_user(mask, &sc->oldmask, Efault); |
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unsafe_put_user(current->thread.cr2, &sc->cr2, Efault); |
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return 0; |
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Efault: |
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return -EFAULT; |
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} |
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#define unsafe_put_sigcontext(sc, fp, regs, set, label) \ |
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do { \ |
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if (__unsafe_setup_sigcontext(sc, fp, regs, set->sig[0])) \ |
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goto label; \ |
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} while(0); |
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#define unsafe_put_sigmask(set, frame, label) \ |
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unsafe_put_user(*(__u64 *)(set), \ |
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(__u64 __user *)&(frame)->uc.uc_sigmask, \ |
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label) |
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/* |
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* Set up a signal frame. |
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*/ |
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/* |
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* Determine which stack to use.. |
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*/ |
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static unsigned long align_sigframe(unsigned long sp) |
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{ |
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#ifdef CONFIG_X86_32 |
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/* |
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* Align the stack pointer according to the i386 ABI, |
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* i.e. so that on function entry ((sp + 4) & 15) == 0. |
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*/ |
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sp = ((sp + 4) & -16ul) - 4; |
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#else /* !CONFIG_X86_32 */ |
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sp = round_down(sp, 16) - 8; |
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#endif |
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return sp; |
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} |
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static void __user * |
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get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, |
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void __user **fpstate) |
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{ |
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/* Default to using normal stack */ |
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unsigned long math_size = 0; |
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unsigned long sp = regs->sp; |
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unsigned long buf_fx = 0; |
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int onsigstack = on_sig_stack(sp); |
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int ret; |
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/* redzone */ |
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if (IS_ENABLED(CONFIG_X86_64)) |
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sp -= 128; |
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/* This is the X/Open sanctioned signal stack switching. */ |
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if (ka->sa.sa_flags & SA_ONSTACK) { |
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if (sas_ss_flags(sp) == 0) |
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sp = current->sas_ss_sp + current->sas_ss_size; |
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} else if (IS_ENABLED(CONFIG_X86_32) && |
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!onsigstack && |
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regs->ss != __USER_DS && |
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!(ka->sa.sa_flags & SA_RESTORER) && |
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ka->sa.sa_restorer) { |
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/* This is the legacy signal stack switching. */ |
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sp = (unsigned long) ka->sa.sa_restorer; |
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} |
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sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), |
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&buf_fx, &math_size); |
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*fpstate = (void __user *)sp; |
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sp = align_sigframe(sp - frame_size); |
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/* |
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* If we are on the alternate signal stack and would overflow it, don't. |
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* Return an always-bogus address instead so we will die with SIGSEGV. |
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*/ |
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if (onsigstack && !likely(on_sig_stack(sp))) |
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return (void __user *)-1L; |
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|
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/* save i387 and extended state */ |
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ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size); |
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if (ret < 0) |
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return (void __user *)-1L; |
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return (void __user *)sp; |
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} |
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#ifdef CONFIG_X86_32 |
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static const struct { |
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u16 poplmovl; |
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u32 val; |
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u16 int80; |
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} __attribute__((packed)) retcode = { |
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0xb858, /* popl %eax; movl $..., %eax */ |
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__NR_sigreturn, |
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0x80cd, /* int $0x80 */ |
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}; |
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static const struct { |
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u8 movl; |
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u32 val; |
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u16 int80; |
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u8 pad; |
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} __attribute__((packed)) rt_retcode = { |
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0xb8, /* movl $..., %eax */ |
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__NR_rt_sigreturn, |
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0x80cd, /* int $0x80 */ |
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0 |
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}; |
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static int |
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__setup_frame(int sig, struct ksignal *ksig, sigset_t *set, |
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struct pt_regs *regs) |
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{ |
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struct sigframe __user *frame; |
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void __user *restorer; |
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void __user *fp = NULL; |
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frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
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if (!user_access_begin(frame, sizeof(*frame))) |
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return -EFAULT; |
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unsafe_put_user(sig, &frame->sig, Efault); |
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unsafe_put_sigcontext(&frame->sc, fp, regs, set, Efault); |
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unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); |
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if (current->mm->context.vdso) |
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restorer = current->mm->context.vdso + |
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vdso_image_32.sym___kernel_sigreturn; |
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else |
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restorer = &frame->retcode; |
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if (ksig->ka.sa.sa_flags & SA_RESTORER) |
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restorer = ksig->ka.sa.sa_restorer; |
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/* Set up to return from userspace. */ |
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unsafe_put_user(restorer, &frame->pretcode, Efault); |
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/* |
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* This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 |
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* |
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* WE DO NOT USE IT ANY MORE! It's only left here for historical |
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* reasons and because gdb uses it as a signature to notice |
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* signal handler stack frames. |
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*/ |
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unsafe_put_user(*((u64 *)&retcode), (u64 *)frame->retcode, Efault); |
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user_access_end(); |
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|
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/* Set up registers for signal handler */ |
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regs->sp = (unsigned long)frame; |
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regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
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regs->ax = (unsigned long)sig; |
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regs->dx = 0; |
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regs->cx = 0; |
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regs->ds = __USER_DS; |
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regs->es = __USER_DS; |
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regs->ss = __USER_DS; |
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regs->cs = __USER_CS; |
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return 0; |
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|
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Efault: |
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user_access_end(); |
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return -EFAULT; |
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} |
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static int __setup_rt_frame(int sig, struct ksignal *ksig, |
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sigset_t *set, struct pt_regs *regs) |
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{ |
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struct rt_sigframe __user *frame; |
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void __user *restorer; |
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void __user *fp = NULL; |
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frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
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if (!user_access_begin(frame, sizeof(*frame))) |
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return -EFAULT; |
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|
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unsafe_put_user(sig, &frame->sig, Efault); |
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unsafe_put_user(&frame->info, &frame->pinfo, Efault); |
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unsafe_put_user(&frame->uc, &frame->puc, Efault); |
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|
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/* Create the ucontext. */ |
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if (static_cpu_has(X86_FEATURE_XSAVE)) |
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unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault); |
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else |
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unsafe_put_user(0, &frame->uc.uc_flags, Efault); |
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unsafe_put_user(0, &frame->uc.uc_link, Efault); |
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unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); |
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|
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/* Set up to return from userspace. */ |
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restorer = current->mm->context.vdso + |
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vdso_image_32.sym___kernel_rt_sigreturn; |
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if (ksig->ka.sa.sa_flags & SA_RESTORER) |
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restorer = ksig->ka.sa.sa_restorer; |
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unsafe_put_user(restorer, &frame->pretcode, Efault); |
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|
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/* |
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* This is movl $__NR_rt_sigreturn, %ax ; int $0x80 |
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* |
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* WE DO NOT USE IT ANY MORE! It's only left here for historical |
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* reasons and because gdb uses it as a signature to notice |
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* signal handler stack frames. |
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*/ |
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unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault); |
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unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
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unsafe_put_sigmask(set, frame, Efault); |
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user_access_end(); |
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|
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if (copy_siginfo_to_user(&frame->info, &ksig->info)) |
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return -EFAULT; |
|
|
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/* Set up registers for signal handler */ |
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regs->sp = (unsigned long)frame; |
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regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
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regs->ax = (unsigned long)sig; |
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regs->dx = (unsigned long)&frame->info; |
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regs->cx = (unsigned long)&frame->uc; |
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|
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regs->ds = __USER_DS; |
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regs->es = __USER_DS; |
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regs->ss = __USER_DS; |
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regs->cs = __USER_CS; |
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|
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return 0; |
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Efault: |
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user_access_end(); |
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return -EFAULT; |
|
} |
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#else /* !CONFIG_X86_32 */ |
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static unsigned long frame_uc_flags(struct pt_regs *regs) |
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{ |
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unsigned long flags; |
|
|
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if (boot_cpu_has(X86_FEATURE_XSAVE)) |
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flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS; |
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else |
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flags = UC_SIGCONTEXT_SS; |
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|
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if (likely(user_64bit_mode(regs))) |
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flags |= UC_STRICT_RESTORE_SS; |
|
|
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return flags; |
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} |
|
|
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static int __setup_rt_frame(int sig, struct ksignal *ksig, |
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sigset_t *set, struct pt_regs *regs) |
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{ |
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struct rt_sigframe __user *frame; |
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void __user *fp = NULL; |
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unsigned long uc_flags; |
|
|
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/* x86-64 should always use SA_RESTORER. */ |
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if (!(ksig->ka.sa.sa_flags & SA_RESTORER)) |
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return -EFAULT; |
|
|
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frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); |
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uc_flags = frame_uc_flags(regs); |
|
|
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if (!user_access_begin(frame, sizeof(*frame))) |
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return -EFAULT; |
|
|
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/* Create the ucontext. */ |
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unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault); |
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unsafe_put_user(0, &frame->uc.uc_link, Efault); |
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unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); |
|
|
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/* Set up to return from userspace. If provided, use a stub |
|
already in userspace. */ |
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unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault); |
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unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
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unsafe_put_sigmask(set, frame, Efault); |
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user_access_end(); |
|
|
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if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
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if (copy_siginfo_to_user(&frame->info, &ksig->info)) |
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return -EFAULT; |
|
} |
|
|
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/* Set up registers for signal handler */ |
|
regs->di = sig; |
|
/* In case the signal handler was declared without prototypes */ |
|
regs->ax = 0; |
|
|
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/* This also works for non SA_SIGINFO handlers because they expect the |
|
next argument after the signal number on the stack. */ |
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regs->si = (unsigned long)&frame->info; |
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regs->dx = (unsigned long)&frame->uc; |
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regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
|
|
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regs->sp = (unsigned long)frame; |
|
|
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/* |
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* Set up the CS and SS registers to run signal handlers in |
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* 64-bit mode, even if the handler happens to be interrupting |
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* 32-bit or 16-bit code. |
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* |
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* SS is subtle. In 64-bit mode, we don't need any particular |
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* SS descriptor, but we do need SS to be valid. It's possible |
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* that the old SS is entirely bogus -- this can happen if the |
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* signal we're trying to deliver is #GP or #SS caused by a bad |
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* SS value. We also have a compatbility issue here: DOSEMU |
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* relies on the contents of the SS register indicating the |
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* SS value at the time of the signal, even though that code in |
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* DOSEMU predates sigreturn's ability to restore SS. (DOSEMU |
|
* avoids relying on sigreturn to restore SS; instead it uses |
|
* a trampoline.) So we do our best: if the old SS was valid, |
|
* we keep it. Otherwise we replace it. |
|
*/ |
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regs->cs = __USER_CS; |
|
|
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if (unlikely(regs->ss != __USER_DS)) |
|
force_valid_ss(regs); |
|
|
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return 0; |
|
|
|
Efault: |
|
user_access_end(); |
|
return -EFAULT; |
|
} |
|
#endif /* CONFIG_X86_32 */ |
|
|
|
#ifdef CONFIG_X86_X32_ABI |
|
static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to, |
|
const struct kernel_siginfo *from) |
|
{ |
|
struct compat_siginfo new; |
|
|
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copy_siginfo_to_external32(&new, from); |
|
if (from->si_signo == SIGCHLD) { |
|
new._sifields._sigchld_x32._utime = from->si_utime; |
|
new._sifields._sigchld_x32._stime = from->si_stime; |
|
} |
|
if (copy_to_user(to, &new, sizeof(struct compat_siginfo))) |
|
return -EFAULT; |
|
return 0; |
|
} |
|
|
|
int copy_siginfo_to_user32(struct compat_siginfo __user *to, |
|
const struct kernel_siginfo *from) |
|
{ |
|
if (in_x32_syscall()) |
|
return x32_copy_siginfo_to_user(to, from); |
|
return __copy_siginfo_to_user32(to, from); |
|
} |
|
#endif /* CONFIG_X86_X32_ABI */ |
|
|
|
static int x32_setup_rt_frame(struct ksignal *ksig, |
|
compat_sigset_t *set, |
|
struct pt_regs *regs) |
|
{ |
|
#ifdef CONFIG_X86_X32_ABI |
|
struct rt_sigframe_x32 __user *frame; |
|
unsigned long uc_flags; |
|
void __user *restorer; |
|
void __user *fp = NULL; |
|
|
|
if (!(ksig->ka.sa.sa_flags & SA_RESTORER)) |
|
return -EFAULT; |
|
|
|
frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
|
|
|
uc_flags = frame_uc_flags(regs); |
|
|
|
if (!user_access_begin(frame, sizeof(*frame))) |
|
return -EFAULT; |
|
|
|
/* Create the ucontext. */ |
|
unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault); |
|
unsafe_put_user(0, &frame->uc.uc_link, Efault); |
|
unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); |
|
unsafe_put_user(0, &frame->uc.uc__pad0, Efault); |
|
restorer = ksig->ka.sa.sa_restorer; |
|
unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault); |
|
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
|
unsafe_put_sigmask(set, frame, Efault); |
|
user_access_end(); |
|
|
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
|
if (x32_copy_siginfo_to_user(&frame->info, &ksig->info)) |
|
return -EFAULT; |
|
} |
|
|
|
/* Set up registers for signal handler */ |
|
regs->sp = (unsigned long) frame; |
|
regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
|
|
|
/* We use the x32 calling convention here... */ |
|
regs->di = ksig->sig; |
|
regs->si = (unsigned long) &frame->info; |
|
regs->dx = (unsigned long) &frame->uc; |
|
|
|
loadsegment(ds, __USER_DS); |
|
loadsegment(es, __USER_DS); |
|
|
|
regs->cs = __USER_CS; |
|
regs->ss = __USER_DS; |
|
#endif /* CONFIG_X86_X32_ABI */ |
|
|
|
return 0; |
|
#ifdef CONFIG_X86_X32_ABI |
|
Efault: |
|
user_access_end(); |
|
return -EFAULT; |
|
#endif |
|
} |
|
|
|
/* |
|
* Do a signal return; undo the signal stack. |
|
*/ |
|
#ifdef CONFIG_X86_32 |
|
SYSCALL_DEFINE0(sigreturn) |
|
{ |
|
struct pt_regs *regs = current_pt_regs(); |
|
struct sigframe __user *frame; |
|
sigset_t set; |
|
|
|
frame = (struct sigframe __user *)(regs->sp - 8); |
|
|
|
if (!access_ok(frame, sizeof(*frame))) |
|
goto badframe; |
|
if (__get_user(set.sig[0], &frame->sc.oldmask) || |
|
__get_user(set.sig[1], &frame->extramask[0])) |
|
goto badframe; |
|
|
|
set_current_blocked(&set); |
|
|
|
/* |
|
* x86_32 has no uc_flags bits relevant to restore_sigcontext. |
|
* Save a few cycles by skipping the __get_user. |
|
*/ |
|
if (restore_sigcontext(regs, &frame->sc, 0)) |
|
goto badframe; |
|
return regs->ax; |
|
|
|
badframe: |
|
signal_fault(regs, frame, "sigreturn"); |
|
|
|
return 0; |
|
} |
|
#endif /* CONFIG_X86_32 */ |
|
|
|
SYSCALL_DEFINE0(rt_sigreturn) |
|
{ |
|
struct pt_regs *regs = current_pt_regs(); |
|
struct rt_sigframe __user *frame; |
|
sigset_t set; |
|
unsigned long uc_flags; |
|
|
|
frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); |
|
if (!access_ok(frame, sizeof(*frame))) |
|
goto badframe; |
|
if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask)) |
|
goto badframe; |
|
if (__get_user(uc_flags, &frame->uc.uc_flags)) |
|
goto badframe; |
|
|
|
set_current_blocked(&set); |
|
|
|
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
|
goto badframe; |
|
|
|
if (restore_altstack(&frame->uc.uc_stack)) |
|
goto badframe; |
|
|
|
return regs->ax; |
|
|
|
badframe: |
|
signal_fault(regs, frame, "rt_sigreturn"); |
|
return 0; |
|
} |
|
|
|
static inline int is_ia32_compat_frame(struct ksignal *ksig) |
|
{ |
|
return IS_ENABLED(CONFIG_IA32_EMULATION) && |
|
ksig->ka.sa.sa_flags & SA_IA32_ABI; |
|
} |
|
|
|
static inline int is_ia32_frame(struct ksignal *ksig) |
|
{ |
|
return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig); |
|
} |
|
|
|
static inline int is_x32_frame(struct ksignal *ksig) |
|
{ |
|
return IS_ENABLED(CONFIG_X86_X32_ABI) && |
|
ksig->ka.sa.sa_flags & SA_X32_ABI; |
|
} |
|
|
|
static int |
|
setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) |
|
{ |
|
int usig = ksig->sig; |
|
sigset_t *set = sigmask_to_save(); |
|
compat_sigset_t *cset = (compat_sigset_t *) set; |
|
|
|
/* Perform fixup for the pre-signal frame. */ |
|
rseq_signal_deliver(ksig, regs); |
|
|
|
/* Set up the stack frame */ |
|
if (is_ia32_frame(ksig)) { |
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
|
return ia32_setup_rt_frame(usig, ksig, cset, regs); |
|
else |
|
return ia32_setup_frame(usig, ksig, cset, regs); |
|
} else if (is_x32_frame(ksig)) { |
|
return x32_setup_rt_frame(ksig, cset, regs); |
|
} else { |
|
return __setup_rt_frame(ksig->sig, ksig, set, regs); |
|
} |
|
} |
|
|
|
static void |
|
handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
|
{ |
|
bool stepping, failed; |
|
struct fpu *fpu = ¤t->thread.fpu; |
|
|
|
if (v8086_mode(regs)) |
|
save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); |
|
|
|
/* Are we from a system call? */ |
|
if (syscall_get_nr(current, regs) >= 0) { |
|
/* If so, check system call restarting.. */ |
|
switch (syscall_get_error(current, regs)) { |
|
case -ERESTART_RESTARTBLOCK: |
|
case -ERESTARTNOHAND: |
|
regs->ax = -EINTR; |
|
break; |
|
|
|
case -ERESTARTSYS: |
|
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
|
regs->ax = -EINTR; |
|
break; |
|
} |
|
fallthrough; |
|
case -ERESTARTNOINTR: |
|
regs->ax = regs->orig_ax; |
|
regs->ip -= 2; |
|
break; |
|
} |
|
} |
|
|
|
/* |
|
* If TF is set due to a debugger (TIF_FORCED_TF), clear TF now |
|
* so that register information in the sigcontext is correct and |
|
* then notify the tracer before entering the signal handler. |
|
*/ |
|
stepping = test_thread_flag(TIF_SINGLESTEP); |
|
if (stepping) |
|
user_disable_single_step(current); |
|
|
|
failed = (setup_rt_frame(ksig, regs) < 0); |
|
if (!failed) { |
|
/* |
|
* Clear the direction flag as per the ABI for function entry. |
|
* |
|
* Clear RF when entering the signal handler, because |
|
* it might disable possible debug exception from the |
|
* signal handler. |
|
* |
|
* Clear TF for the case when it wasn't set by debugger to |
|
* avoid the recursive send_sigtrap() in SIGTRAP handler. |
|
*/ |
|
regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); |
|
/* |
|
* Ensure the signal handler starts with the new fpu state. |
|
*/ |
|
fpu__clear_user_states(fpu); |
|
} |
|
signal_setup_done(failed, ksig, stepping); |
|
} |
|
|
|
static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) |
|
{ |
|
#ifdef CONFIG_IA32_EMULATION |
|
if (current->restart_block.arch_data & TS_COMPAT) |
|
return __NR_ia32_restart_syscall; |
|
#endif |
|
#ifdef CONFIG_X86_X32_ABI |
|
return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); |
|
#else |
|
return __NR_restart_syscall; |
|
#endif |
|
} |
|
|
|
/* |
|
* Note that 'init' is a special process: it doesn't get signals it doesn't |
|
* want to handle. Thus you cannot kill init even with a SIGKILL even by |
|
* mistake. |
|
*/ |
|
void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) |
|
{ |
|
struct ksignal ksig; |
|
|
|
if (has_signal && get_signal(&ksig)) { |
|
/* Whee! Actually deliver the signal. */ |
|
handle_signal(&ksig, regs); |
|
return; |
|
} |
|
|
|
/* Did we come from a system call? */ |
|
if (syscall_get_nr(current, regs) >= 0) { |
|
/* Restart the system call - no handlers present */ |
|
switch (syscall_get_error(current, regs)) { |
|
case -ERESTARTNOHAND: |
|
case -ERESTARTSYS: |
|
case -ERESTARTNOINTR: |
|
regs->ax = regs->orig_ax; |
|
regs->ip -= 2; |
|
break; |
|
|
|
case -ERESTART_RESTARTBLOCK: |
|
regs->ax = get_nr_restart_syscall(regs); |
|
regs->ip -= 2; |
|
break; |
|
} |
|
} |
|
|
|
/* |
|
* If there's no signal to deliver, we just put the saved sigmask |
|
* back. |
|
*/ |
|
restore_saved_sigmask(); |
|
} |
|
|
|
void signal_fault(struct pt_regs *regs, void __user *frame, char *where) |
|
{ |
|
struct task_struct *me = current; |
|
|
|
if (show_unhandled_signals && printk_ratelimit()) { |
|
printk("%s" |
|
"%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", |
|
task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, |
|
me->comm, me->pid, where, frame, |
|
regs->ip, regs->sp, regs->orig_ax); |
|
print_vma_addr(KERN_CONT " in ", regs->ip); |
|
pr_cont("\n"); |
|
} |
|
|
|
force_sig(SIGSEGV); |
|
} |
|
|
|
#ifdef CONFIG_X86_X32_ABI |
|
COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn) |
|
{ |
|
struct pt_regs *regs = current_pt_regs(); |
|
struct rt_sigframe_x32 __user *frame; |
|
sigset_t set; |
|
unsigned long uc_flags; |
|
|
|
frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); |
|
|
|
if (!access_ok(frame, sizeof(*frame))) |
|
goto badframe; |
|
if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask)) |
|
goto badframe; |
|
if (__get_user(uc_flags, &frame->uc.uc_flags)) |
|
goto badframe; |
|
|
|
set_current_blocked(&set); |
|
|
|
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
|
goto badframe; |
|
|
|
if (compat_restore_altstack(&frame->uc.uc_stack)) |
|
goto badframe; |
|
|
|
return regs->ax; |
|
|
|
badframe: |
|
signal_fault(regs, frame, "x32 rt_sigreturn"); |
|
return 0; |
|
} |
|
#endif
|
|
|