forked from Minki/linux
1930a6e739
This set of changes removes tracehook.h, moves modification of all of the ptrace fields inside of siglock to remove races, adds a missing permission check to ptrace.c The removal of tracehook.h is quite significant as it has been a major source of confusion in recent years. Much of that confusion was around task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the semantics clearer). For people who don't know tracehook.h is a vestiage of an attempt to implement uprobes like functionality that was never fully merged, and was later superseeded by uprobes when uprobes was merged. For many years now we have been removing what tracehook functionaly a little bit at a time. To the point where now anything left in tracehook.h is some weird strange thing that is difficult to understand. Eric W. Biederman (15): ptrace: Move ptrace_report_syscall into ptrace.h ptrace/arm: Rename tracehook_report_syscall report_syscall ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h ptrace: Remove arch_syscall_{enter,exit}_tracehook ptrace: Remove tracehook_signal_handler task_work: Remove unnecessary include from posix_timers.h task_work: Introduce task_work_pending task_work: Call tracehook_notify_signal from get_signal on all architectures task_work: Decouple TIF_NOTIFY_SIGNAL and task_work signal: Move set_notify_signal and clear_notify_signal into sched/signal.h resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume resume_user_mode: Move to resume_user_mode.h tracehook: Remove tracehook.h ptrace: Move setting/clearing ptrace_message into ptrace_stop ptrace: Return the signal to continue with from ptrace_stop Jann Horn (1): ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE Yang Li (1): ptrace: Remove duplicated include in ptrace.c MAINTAINERS | 1 - arch/Kconfig | 5 +- arch/alpha/kernel/ptrace.c | 5 +- arch/alpha/kernel/signal.c | 4 +- arch/arc/kernel/ptrace.c | 5 +- arch/arc/kernel/signal.c | 4 +- arch/arm/kernel/ptrace.c | 12 +- arch/arm/kernel/signal.c | 4 +- arch/arm64/kernel/ptrace.c | 14 +-- arch/arm64/kernel/signal.c | 4 +- arch/csky/kernel/ptrace.c | 5 +- arch/csky/kernel/signal.c | 4 +- arch/h8300/kernel/ptrace.c | 5 +- arch/h8300/kernel/signal.c | 4 +- arch/hexagon/kernel/process.c | 4 +- arch/hexagon/kernel/signal.c | 1 - arch/hexagon/kernel/traps.c | 6 +- arch/ia64/kernel/process.c | 4 +- arch/ia64/kernel/ptrace.c | 6 +- arch/ia64/kernel/signal.c | 1 - arch/m68k/kernel/ptrace.c | 5 +- arch/m68k/kernel/signal.c | 4 +- arch/microblaze/kernel/ptrace.c | 5 +- arch/microblaze/kernel/signal.c | 4 +- arch/mips/kernel/ptrace.c | 5 +- arch/mips/kernel/signal.c | 4 +- arch/nds32/include/asm/syscall.h | 2 +- arch/nds32/kernel/ptrace.c | 5 +- arch/nds32/kernel/signal.c | 4 +- arch/nios2/kernel/ptrace.c | 5 +- arch/nios2/kernel/signal.c | 4 +- arch/openrisc/kernel/ptrace.c | 5 +- arch/openrisc/kernel/signal.c | 4 +- arch/parisc/kernel/ptrace.c | 7 +- arch/parisc/kernel/signal.c | 4 +- arch/powerpc/kernel/ptrace/ptrace.c | 8 +- arch/powerpc/kernel/signal.c | 4 +- arch/riscv/kernel/ptrace.c | 5 +- arch/riscv/kernel/signal.c | 4 +- arch/s390/include/asm/entry-common.h | 1 - arch/s390/kernel/ptrace.c | 1 - arch/s390/kernel/signal.c | 5 +- arch/sh/kernel/ptrace_32.c | 5 +- arch/sh/kernel/signal_32.c | 4 +- arch/sparc/kernel/ptrace_32.c | 5 +- arch/sparc/kernel/ptrace_64.c | 5 +- arch/sparc/kernel/signal32.c | 1 - arch/sparc/kernel/signal_32.c | 4 +- arch/sparc/kernel/signal_64.c | 4 +- arch/um/kernel/process.c | 4 +- arch/um/kernel/ptrace.c | 5 +- arch/x86/kernel/ptrace.c | 1 - arch/x86/kernel/signal.c | 5 +- arch/x86/mm/tlb.c | 1 + arch/xtensa/kernel/ptrace.c | 5 +- arch/xtensa/kernel/signal.c | 4 +- block/blk-cgroup.c | 2 +- fs/coredump.c | 1 - fs/exec.c | 1 - fs/io-wq.c | 6 +- fs/io_uring.c | 11 +- fs/proc/array.c | 1 - fs/proc/base.c | 1 - include/asm-generic/syscall.h | 2 +- include/linux/entry-common.h | 47 +------- include/linux/entry-kvm.h | 2 +- include/linux/posix-timers.h | 1 - include/linux/ptrace.h | 81 ++++++++++++- include/linux/resume_user_mode.h | 64 ++++++++++ include/linux/sched/signal.h | 17 +++ include/linux/task_work.h | 5 + include/linux/tracehook.h | 226 ----------------------------------- include/uapi/linux/ptrace.h | 2 +- kernel/entry/common.c | 19 +-- kernel/entry/kvm.c | 9 +- kernel/exit.c | 3 +- kernel/livepatch/transition.c | 1 - kernel/ptrace.c | 47 +++++--- kernel/seccomp.c | 1 - kernel/signal.c | 62 +++++----- kernel/task_work.c | 4 +- kernel/time/posix-cpu-timers.c | 1 + mm/memcontrol.c | 2 +- security/apparmor/domain.c | 1 - security/selinux/hooks.c | 1 - 85 files changed, 372 insertions(+), 495 deletions(-) Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEgjlraLDcwBA2B+6cC/v6Eiajj0AFAmJCQkoACgkQC/v6Eiaj j0DCWQ/5AZVFU+hX32obUNCLackHTwgcCtSOs3JNBmNA/zL/htPiYYG0ghkvtlDR Dw5J5DnxC6P7PVAdAqrpvx2uX2FebHYU0bRlyLx8LYUEP5dhyNicxX9jA882Z+vw Ud0Ue9EojwGWS76dC9YoKUj3slThMATbhA2r4GVEoof8fSNJaBxQIqath44t0FwU DinWa+tIOvZANGBZr6CUUINNIgqBIZCH/R4h6ArBhMlJpuQ5Ufk2kAaiWFwZCkX4 0LuuAwbKsCKkF8eap5I2KrIg/7zZVgxAg9O3cHOzzm8OPbKzRnNnQClcDe8perqp S6e/f3MgpE+eavd1EiLxevZ660cJChnmikXVVh8ZYYoefaMKGqBaBSsB38bNcLjY 3+f2dB+TNBFRnZs1aCujK3tWBT9QyjZDKtCBfzxDNWBpXGLhHH6j6lA5Lj+Cef5K /HNHFb+FuqedlFZh5m1Y+piFQ70hTgCa2u8b+FSOubI2hW9Zd+WzINV0ANaZ2LvZ 4YGtcyDNk1q1+c87lxP9xMRl/xi6rNg+B9T2MCo4IUnHgpSVP6VEB3osgUmrrrN0 eQlUI154G/AaDlqXLgmn1xhRmlPGfmenkxpok1AuzxvNJsfLKnpEwQSc13g3oiZr disZQxNY0kBO2Nv3G323Z6PLinhbiIIFez6cJzK5v0YJ2WtO3pY= =uEro -----END PGP SIGNATURE----- Merge tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull ptrace cleanups from Eric Biederman: "This set of changes removes tracehook.h, moves modification of all of the ptrace fields inside of siglock to remove races, adds a missing permission check to ptrace.c The removal of tracehook.h is quite significant as it has been a major source of confusion in recent years. Much of that confusion was around task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the semantics clearer). For people who don't know tracehook.h is a vestiage of an attempt to implement uprobes like functionality that was never fully merged, and was later superseeded by uprobes when uprobes was merged. For many years now we have been removing what tracehook functionaly a little bit at a time. To the point where anything left in tracehook.h was some weird strange thing that was difficult to understand" * tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ptrace: Remove duplicated include in ptrace.c ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE ptrace: Return the signal to continue with from ptrace_stop ptrace: Move setting/clearing ptrace_message into ptrace_stop tracehook: Remove tracehook.h resume_user_mode: Move to resume_user_mode.h resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume signal: Move set_notify_signal and clear_notify_signal into sched/signal.h task_work: Decouple TIF_NOTIFY_SIGNAL and task_work task_work: Call tracehook_notify_signal from get_signal on all architectures task_work: Introduce task_work_pending task_work: Remove unnecessary include from posix_timers.h ptrace: Remove tracehook_signal_handler ptrace: Remove arch_syscall_{enter,exit}_tracehook ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h ptrace/arm: Rename tracehook_report_syscall report_syscall ptrace: Move ptrace_report_syscall into ptrace.h
590 lines
16 KiB
C
590 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* PA-RISC architecture-specific signal handling support.
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*
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* Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
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* Copyright (C) 2000 Linuxcare, Inc.
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* Copyright (C) 2000-2022 Helge Deller <deller@gmx.de>
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* Copyright (C) 2022 John David Anglin <dave.anglin@bell.net>
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*
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* Based on the ia64, i386, and alpha versions.
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*/
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#include <linux/sched.h>
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#include <linux/sched/debug.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/signal.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/ptrace.h>
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#include <linux/resume_user_mode.h>
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#include <linux/unistd.h>
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#include <linux/stddef.h>
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#include <linux/compat.h>
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#include <linux/elf.h>
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#include <asm/ucontext.h>
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#include <asm/rt_sigframe.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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#include <asm/asm-offsets.h>
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#include <asm/vdso.h>
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#ifdef CONFIG_COMPAT
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#include "signal32.h"
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#endif
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#define DEBUG_SIG 0
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#define DEBUG_SIG_LEVEL 2
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#if DEBUG_SIG
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#define DBG(LEVEL, ...) \
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((DEBUG_SIG_LEVEL >= LEVEL) \
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? printk(__VA_ARGS__) : (void) 0)
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#else
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#define DBG(LEVEL, ...)
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#endif
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/* gcc will complain if a pointer is cast to an integer of different
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* size. If you really need to do this (and we do for an ELF32 user
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* application in an ELF64 kernel) then you have to do a cast to an
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* integer of the same size first. The A() macro accomplishes
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* this. */
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#define A(__x) ((unsigned long)(__x))
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/*
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* Do a signal return - restore sigcontext.
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*/
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static long
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restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
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{
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long err = 0;
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err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
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err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
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err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
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err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
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err |= __get_user(regs->sar, &sc->sc_sar);
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DBG(2, "%s: iaoq is %#lx / %#lx\n",
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__func__, regs->iaoq[0], regs->iaoq[1]);
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DBG(2, "%s: r28 is %ld\n", __func__, regs->gr[28]);
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return err;
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}
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void
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sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
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{
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struct rt_sigframe __user *frame;
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sigset_t set;
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unsigned long usp = (regs->gr[30] & ~(0x01UL));
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unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
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#ifdef CONFIG_64BIT
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struct compat_rt_sigframe __user * compat_frame;
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if (is_compat_task())
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sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
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#endif
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current->restart_block.fn = do_no_restart_syscall;
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/* Unwind the user stack to get the rt_sigframe structure. */
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frame = (struct rt_sigframe __user *)
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(usp - sigframe_size);
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DBG(2, "%s: frame is %p pid %d\n", __func__, frame, task_pid_nr(current));
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regs->orig_r28 = 1; /* no restarts for sigreturn */
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#ifdef CONFIG_64BIT
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compat_frame = (struct compat_rt_sigframe __user *)frame;
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if (is_compat_task()) {
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if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
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goto give_sigsegv;
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} else
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#endif
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{
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
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goto give_sigsegv;
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}
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set_current_blocked(&set);
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/* Good thing we saved the old gr[30], eh? */
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#ifdef CONFIG_64BIT
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if (is_compat_task()) {
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DBG(1, "%s: compat_frame->uc.uc_mcontext 0x%p\n",
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__func__, &compat_frame->uc.uc_mcontext);
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// FIXME: Load upper half from register file
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if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
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&compat_frame->regs, regs))
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goto give_sigsegv;
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DBG(1, "%s: usp %#08lx stack 0x%p\n",
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__func__, usp, &compat_frame->uc.uc_stack);
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if (compat_restore_altstack(&compat_frame->uc.uc_stack))
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goto give_sigsegv;
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} else
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#endif
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{
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DBG(1, "%s: frame->uc.uc_mcontext 0x%p\n",
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__func__, &frame->uc.uc_mcontext);
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if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
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goto give_sigsegv;
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DBG(1, "%s: usp %#08lx stack 0x%p\n",
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__func__, usp, &frame->uc.uc_stack);
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if (restore_altstack(&frame->uc.uc_stack))
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goto give_sigsegv;
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}
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/* If we are on the syscall path IAOQ will not be restored, and
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* if we are on the interrupt path we must not corrupt gr31.
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*/
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if (in_syscall)
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regs->gr[31] = regs->iaoq[0];
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return;
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give_sigsegv:
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DBG(1, "%s: Sending SIGSEGV\n", __func__);
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force_sig(SIGSEGV);
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return;
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}
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/*
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* Set up a signal frame.
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*/
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static inline void __user *
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get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
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{
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/*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
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don't use the parameter it doesn't matter */
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DBG(1, "%s: ka = %#lx, sp = %#lx, frame_size = %zu\n",
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__func__, (unsigned long)ka, sp, frame_size);
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/* Align alternate stack and reserve 64 bytes for the signal
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handler's frame marker. */
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if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
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sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
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DBG(1, "%s: Returning sp = %#lx\n", __func__, (unsigned long)sp);
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return (void __user *) sp; /* Stacks grow up. Fun. */
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}
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static long
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setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
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{
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unsigned long flags = 0;
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long err = 0;
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if (on_sig_stack((unsigned long) sc))
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flags |= PARISC_SC_FLAG_ONSTACK;
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if (in_syscall) {
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flags |= PARISC_SC_FLAG_IN_SYSCALL;
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/* regs->iaoq is undefined in the syscall return path */
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err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
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err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
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err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
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err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
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DBG(1, "%s: iaoq %#lx / %#lx (in syscall)\n",
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__func__, regs->gr[31], regs->gr[31]+4);
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} else {
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err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
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err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
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DBG(1, "%s: iaoq %#lx / %#lx (not in syscall)\n",
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__func__, regs->iaoq[0], regs->iaoq[1]);
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}
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err |= __put_user(flags, &sc->sc_flags);
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err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
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err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
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err |= __put_user(regs->sar, &sc->sc_sar);
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DBG(1, "%s: r28 is %ld\n", __func__, regs->gr[28]);
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return err;
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}
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static long
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setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
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int in_syscall)
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{
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struct rt_sigframe __user *frame;
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unsigned long rp, usp;
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unsigned long haddr, sigframe_size;
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unsigned long start;
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int err = 0;
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#ifdef CONFIG_64BIT
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struct compat_rt_sigframe __user * compat_frame;
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#endif
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usp = (regs->gr[30] & ~(0x01UL));
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sigframe_size = PARISC_RT_SIGFRAME_SIZE;
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#ifdef CONFIG_64BIT
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if (is_compat_task()) {
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/* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
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usp = (compat_uint_t)usp;
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sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
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}
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#endif
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frame = get_sigframe(&ksig->ka, usp, sigframe_size);
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DBG(1, "%s: frame %p info %p\n", __func__, frame, &ksig->info);
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start = (unsigned long) frame;
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if (start >= TASK_SIZE_MAX - sigframe_size)
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return -EFAULT;
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#ifdef CONFIG_64BIT
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compat_frame = (struct compat_rt_sigframe __user *)frame;
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if (is_compat_task()) {
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DBG(1, "%s: frame->info = 0x%p\n", __func__, &compat_frame->info);
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err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
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err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
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DBG(1, "%s: frame->uc = 0x%p\n", __func__, &compat_frame->uc);
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DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
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__func__, &compat_frame->uc.uc_mcontext);
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err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
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&compat_frame->regs, regs, in_syscall);
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err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
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sizeof(compat_sigset_t));
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} else
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#endif
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{
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DBG(1, "%s: frame->info = 0x%p\n", __func__, &frame->info);
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err |= copy_siginfo_to_user(&frame->info, &ksig->info);
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err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
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DBG(1, "%s: frame->uc = 0x%p\n", __func__, &frame->uc);
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DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
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__func__, &frame->uc.uc_mcontext);
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err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
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/* FIXME: Should probably be converted as well for the compat case */
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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}
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if (err)
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return -EFAULT;
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#ifdef CONFIG_64BIT
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if (!is_compat_task())
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rp = VDSO64_SYMBOL(current, sigtramp_rt);
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else
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#endif
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rp = VDSO32_SYMBOL(current, sigtramp_rt);
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if (in_syscall)
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rp += 4*4; /* skip 4 instructions and start at ldi 1,%r25 */
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haddr = A(ksig->ka.sa.sa_handler);
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/* The sa_handler may be a pointer to a function descriptor */
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#ifdef CONFIG_64BIT
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if (is_compat_task()) {
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#endif
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if (haddr & PA_PLABEL_FDESC) {
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Elf32_Fdesc fdesc;
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Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
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err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
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if (err)
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return -EFAULT;
|
|
|
|
haddr = fdesc.addr;
|
|
regs->gr[19] = fdesc.gp;
|
|
}
|
|
#ifdef CONFIG_64BIT
|
|
} else {
|
|
Elf64_Fdesc fdesc;
|
|
Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
|
|
|
|
err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
|
|
|
|
if (err)
|
|
return -EFAULT;
|
|
|
|
haddr = fdesc.addr;
|
|
regs->gr[19] = fdesc.gp;
|
|
DBG(1, "%s: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
|
|
__func__, haddr, regs->gr[19], in_syscall);
|
|
}
|
|
#endif
|
|
|
|
/* The syscall return path will create IAOQ values from r31.
|
|
*/
|
|
if (in_syscall) {
|
|
regs->gr[31] = haddr;
|
|
#ifdef CONFIG_64BIT
|
|
if (!test_thread_flag(TIF_32BIT))
|
|
sigframe_size |= 1; /* XXX ???? */
|
|
#endif
|
|
} else {
|
|
unsigned long psw = USER_PSW;
|
|
#ifdef CONFIG_64BIT
|
|
if (!test_thread_flag(TIF_32BIT))
|
|
psw |= PSW_W;
|
|
#endif
|
|
|
|
/* If we are singlestepping, arrange a trap to be delivered
|
|
when we return to userspace. Note the semantics -- we
|
|
should trap before the first insn in the handler is
|
|
executed. Ref:
|
|
http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
|
|
*/
|
|
if (pa_psw(current)->r) {
|
|
pa_psw(current)->r = 0;
|
|
psw |= PSW_R;
|
|
mtctl(-1, 0);
|
|
}
|
|
|
|
regs->gr[0] = psw;
|
|
regs->iaoq[0] = haddr | PRIV_USER;
|
|
regs->iaoq[1] = regs->iaoq[0] + 4;
|
|
}
|
|
|
|
regs->gr[2] = rp; /* userland return pointer */
|
|
regs->gr[26] = ksig->sig; /* signal number */
|
|
|
|
#ifdef CONFIG_64BIT
|
|
if (is_compat_task()) {
|
|
regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
|
|
regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
|
|
} else
|
|
#endif
|
|
{
|
|
regs->gr[25] = A(&frame->info); /* siginfo pointer */
|
|
regs->gr[24] = A(&frame->uc); /* ucontext pointer */
|
|
}
|
|
|
|
DBG(1, "%s: making sigreturn frame: %#lx + %#lx = %#lx\n", __func__,
|
|
regs->gr[30], sigframe_size,
|
|
regs->gr[30] + sigframe_size);
|
|
/* Raise the user stack pointer to make a proper call frame. */
|
|
regs->gr[30] = (A(frame) + sigframe_size);
|
|
|
|
|
|
DBG(1, "%s: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
|
|
__func__, current->comm, current->pid, frame, regs->gr[30],
|
|
regs->iaoq[0], regs->iaoq[1], rp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* OK, we're invoking a handler.
|
|
*/
|
|
|
|
static void
|
|
handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
|
|
{
|
|
int ret;
|
|
sigset_t *oldset = sigmask_to_save();
|
|
|
|
DBG(1, "%s: sig=%d, ka=%p, info=%p, oldset=%p, regs=%p\n",
|
|
__func__, ksig->sig, &ksig->ka, &ksig->info, oldset, regs);
|
|
|
|
/* Set up the stack frame */
|
|
ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
|
|
|
|
signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
|
|
test_thread_flag(TIF_BLOCKSTEP));
|
|
|
|
DBG(1, "%s: Exit (success), regs->gr[28] = %ld\n",
|
|
__func__, regs->gr[28]);
|
|
}
|
|
|
|
/*
|
|
* Check how the syscall number gets loaded into %r20 within
|
|
* the delay branch in userspace and adjust as needed.
|
|
*/
|
|
|
|
static void check_syscallno_in_delay_branch(struct pt_regs *regs)
|
|
{
|
|
u32 opcode, source_reg;
|
|
u32 __user *uaddr;
|
|
int err;
|
|
|
|
/* Usually we don't have to restore %r20 (the system call number)
|
|
* because it gets loaded in the delay slot of the branch external
|
|
* instruction via the ldi instruction.
|
|
* In some cases a register-to-register copy instruction might have
|
|
* been used instead, in which case we need to copy the syscall
|
|
* number into the source register before returning to userspace.
|
|
*/
|
|
|
|
/* A syscall is just a branch, so all we have to do is fiddle the
|
|
* return pointer so that the ble instruction gets executed again.
|
|
*/
|
|
regs->gr[31] -= 8; /* delayed branching */
|
|
|
|
/* Get assembler opcode of code in delay branch */
|
|
uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
|
|
err = get_user(opcode, uaddr);
|
|
if (err)
|
|
return;
|
|
|
|
/* Check if delay branch uses "ldi int,%r20" */
|
|
if ((opcode & 0xffff0000) == 0x34140000)
|
|
return; /* everything ok, just return */
|
|
|
|
/* Check if delay branch uses "nop" */
|
|
if (opcode == INSN_NOP)
|
|
return;
|
|
|
|
/* Check if delay branch uses "copy %rX,%r20" */
|
|
if ((opcode & 0xffe0ffff) == 0x08000254) {
|
|
source_reg = (opcode >> 16) & 31;
|
|
regs->gr[source_reg] = regs->gr[20];
|
|
return;
|
|
}
|
|
|
|
pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
|
|
current->comm, task_pid_nr(current), opcode);
|
|
}
|
|
|
|
static inline void
|
|
syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
|
|
{
|
|
if (regs->orig_r28)
|
|
return;
|
|
regs->orig_r28 = 1; /* no more restarts */
|
|
|
|
DBG(1, "%s: orig_r28 = %ld pid %d r20 %ld\n",
|
|
__func__, regs->orig_r28, task_pid_nr(current), regs->gr[20]);
|
|
|
|
/* Check the return code */
|
|
switch (regs->gr[28]) {
|
|
case -ERESTART_RESTARTBLOCK:
|
|
case -ERESTARTNOHAND:
|
|
DBG(1, "%s: ERESTARTNOHAND: returning -EINTR\n", __func__);
|
|
regs->gr[28] = -EINTR;
|
|
break;
|
|
case -ERESTARTSYS:
|
|
if (!(ka->sa.sa_flags & SA_RESTART)) {
|
|
DBG(1, "%s: ERESTARTSYS: putting -EINTR pid %d\n",
|
|
__func__, task_pid_nr(current));
|
|
regs->gr[28] = -EINTR;
|
|
break;
|
|
}
|
|
fallthrough;
|
|
case -ERESTARTNOINTR:
|
|
DBG(1, "%s: %ld\n", __func__, regs->gr[28]);
|
|
check_syscallno_in_delay_branch(regs);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
insert_restart_trampoline(struct pt_regs *regs)
|
|
{
|
|
if (regs->orig_r28)
|
|
return;
|
|
regs->orig_r28 = 1; /* no more restarts */
|
|
|
|
DBG(2, "%s: gr28 = %ld pid %d\n",
|
|
__func__, regs->gr[28], task_pid_nr(current));
|
|
|
|
switch (regs->gr[28]) {
|
|
case -ERESTART_RESTARTBLOCK: {
|
|
/* Restart the system call - no handlers present */
|
|
unsigned int *usp = (unsigned int *)regs->gr[30];
|
|
unsigned long rp;
|
|
long err = 0;
|
|
|
|
/* check that we don't exceed the stack */
|
|
if (A(&usp[0]) >= TASK_SIZE_MAX - 5 * sizeof(int))
|
|
return;
|
|
|
|
/* Call trampoline in vdso to restart the syscall
|
|
* with __NR_restart_syscall.
|
|
* Original return addresses are on stack like this:
|
|
*
|
|
* 0: <return address (orig r31)>
|
|
* 4: <2nd half for 64-bit>
|
|
*/
|
|
#ifdef CONFIG_64BIT
|
|
if (!is_compat_task()) {
|
|
err |= put_user(regs->gr[31] >> 32, &usp[0]);
|
|
err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
|
|
rp = VDSO64_SYMBOL(current, restart_syscall);
|
|
} else
|
|
#endif
|
|
{
|
|
err |= put_user(regs->gr[31], &usp[0]);
|
|
rp = VDSO32_SYMBOL(current, restart_syscall);
|
|
}
|
|
WARN_ON(err);
|
|
|
|
regs->gr[31] = rp;
|
|
DBG(1, "%s: ERESTART_RESTARTBLOCK\n", __func__);
|
|
return;
|
|
}
|
|
case -EINTR:
|
|
/* ok, was handled before and should be returned. */
|
|
break;
|
|
case -ERESTARTNOHAND:
|
|
case -ERESTARTSYS:
|
|
case -ERESTARTNOINTR:
|
|
DBG(1, "%s: Type %ld\n", __func__, regs->gr[28]);
|
|
check_syscallno_in_delay_branch(regs);
|
|
return;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We need to be able to restore the syscall arguments (r21-r26) to
|
|
* restart syscalls. Thus, the syscall path should save them in the
|
|
* pt_regs structure (it's okay to do so since they are caller-save
|
|
* registers). As noted below, the syscall number gets restored for
|
|
* us due to the magic of delayed branching.
|
|
*/
|
|
static void do_signal(struct pt_regs *regs, long in_syscall)
|
|
{
|
|
struct ksignal ksig;
|
|
int restart_syscall;
|
|
bool has_handler;
|
|
|
|
has_handler = get_signal(&ksig);
|
|
|
|
restart_syscall = 0;
|
|
if (in_syscall)
|
|
restart_syscall = 1;
|
|
|
|
if (has_handler) {
|
|
/* Restart a system call if necessary. */
|
|
if (restart_syscall)
|
|
syscall_restart(regs, &ksig.ka);
|
|
|
|
handle_signal(&ksig, regs, in_syscall);
|
|
DBG(1, "%s: Handled signal pid %d\n",
|
|
__func__, task_pid_nr(current));
|
|
return;
|
|
}
|
|
|
|
/* Do we need to restart the system call? */
|
|
if (restart_syscall)
|
|
insert_restart_trampoline(regs);
|
|
|
|
DBG(1, "%s: Exit (not delivered), regs->gr[28] = %ld orig_r28 = %ld pid %d\n",
|
|
__func__, regs->gr[28], regs->orig_r28, task_pid_nr(current));
|
|
|
|
restore_saved_sigmask();
|
|
}
|
|
|
|
void do_notify_resume(struct pt_regs *regs, long in_syscall)
|
|
{
|
|
if (test_thread_flag(TIF_SIGPENDING) ||
|
|
test_thread_flag(TIF_NOTIFY_SIGNAL))
|
|
do_signal(regs, in_syscall);
|
|
|
|
if (test_thread_flag(TIF_NOTIFY_RESUME))
|
|
resume_user_mode_work(regs);
|
|
}
|