forked from Minki/linux
ac2081cdc4
Although the arm64 single-step state machine can be fast-forwarded in cases where we wish to generate a SIGTRAP without actually executing an instruction, this has two major limitations outside of simply skipping an instruction due to emulation. 1. Stepping out of a ptrace signal stop into a signal handler where SIGTRAP is blocked. Fast-forwarding the stepping state machine in this case will result in a forced SIGTRAP, with the handler reset to SIG_DFL. 2. The hardware implicitly fast-forwards the state machine when executing an SVC instruction for issuing a system call. This can interact badly with subsequent ptrace stops signalled during the execution of the system call (e.g. SYSCALL_EXIT or seccomp traps), as they may corrupt the stepping state by updating the PSTATE for the tracee. Resolve both of these issues by injecting a pseudo-singlestep exception on entry to a signal handler and also on return to userspace following a system call. Cc: <stable@vger.kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Tested-by: Luis Machado <luis.machado@linaro.org> Reported-by: Keno Fischer <keno@juliacomputing.com> Signed-off-by: Will Deacon <will@kernel.org>
125 lines
3.7 KiB
C
125 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Based on arch/arm/include/asm/thread_info.h
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*
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* Copyright (C) 2002 Russell King.
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* Copyright (C) 2012 ARM Ltd.
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*/
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#ifndef __ASM_THREAD_INFO_H
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#define __ASM_THREAD_INFO_H
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#include <linux/compiler.h>
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#ifndef __ASSEMBLY__
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struct task_struct;
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#include <asm/memory.h>
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#include <asm/stack_pointer.h>
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#include <asm/types.h>
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typedef unsigned long mm_segment_t;
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/*
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* low level task data that entry.S needs immediate access to.
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*/
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struct thread_info {
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unsigned long flags; /* low level flags */
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mm_segment_t addr_limit; /* address limit */
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#ifdef CONFIG_ARM64_SW_TTBR0_PAN
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u64 ttbr0; /* saved TTBR0_EL1 */
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#endif
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union {
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u64 preempt_count; /* 0 => preemptible, <0 => bug */
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struct {
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#ifdef CONFIG_CPU_BIG_ENDIAN
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u32 need_resched;
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u32 count;
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#else
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u32 count;
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u32 need_resched;
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#endif
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} preempt;
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};
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#ifdef CONFIG_SHADOW_CALL_STACK
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void *scs_base;
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void *scs_sp;
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#endif
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};
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#define thread_saved_pc(tsk) \
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((unsigned long)(tsk->thread.cpu_context.pc))
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#define thread_saved_sp(tsk) \
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((unsigned long)(tsk->thread.cpu_context.sp))
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#define thread_saved_fp(tsk) \
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((unsigned long)(tsk->thread.cpu_context.fp))
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void arch_setup_new_exec(void);
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#define arch_setup_new_exec arch_setup_new_exec
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void arch_release_task_struct(struct task_struct *tsk);
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#endif
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#define TIF_SIGPENDING 0 /* signal pending */
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#define TIF_NEED_RESCHED 1 /* rescheduling necessary */
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#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
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#define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */
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#define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */
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#define TIF_FSCHECK 5 /* Check FS is USER_DS on return */
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#define TIF_SYSCALL_TRACE 8 /* syscall trace active */
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#define TIF_SYSCALL_AUDIT 9 /* syscall auditing */
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#define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */
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#define TIF_SECCOMP 11 /* syscall secure computing */
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#define TIF_SYSCALL_EMU 12 /* syscall emulation active */
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#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
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#define TIF_FREEZE 19
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#define TIF_RESTORE_SIGMASK 20
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#define TIF_SINGLESTEP 21
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#define TIF_32BIT 22 /* 32bit process */
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#define TIF_SVE 23 /* Scalable Vector Extension in use */
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#define TIF_SVE_VL_INHERIT 24 /* Inherit sve_vl_onexec across exec */
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#define TIF_SSBD 25 /* Wants SSB mitigation */
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#define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */
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#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
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#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
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#define _TIF_FOREIGN_FPSTATE (1 << TIF_FOREIGN_FPSTATE)
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#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
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#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
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#define _TIF_SECCOMP (1 << TIF_SECCOMP)
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#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
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#define _TIF_UPROBE (1 << TIF_UPROBE)
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#define _TIF_FSCHECK (1 << TIF_FSCHECK)
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#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
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#define _TIF_32BIT (1 << TIF_32BIT)
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#define _TIF_SVE (1 << TIF_SVE)
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#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
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_TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
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_TIF_UPROBE | _TIF_FSCHECK)
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#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
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_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
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_TIF_SYSCALL_EMU)
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#ifdef CONFIG_SHADOW_CALL_STACK
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#define INIT_SCS \
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.scs_base = init_shadow_call_stack, \
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.scs_sp = init_shadow_call_stack,
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#else
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#define INIT_SCS
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#endif
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.flags = _TIF_FOREIGN_FPSTATE, \
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.preempt_count = INIT_PREEMPT_COUNT, \
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.addr_limit = KERNEL_DS, \
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INIT_SCS \
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}
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#endif /* __ASM_THREAD_INFO_H */
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