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Syscalls are not allowed inside restartable sequences, so add a call to rseq_syscall() at the very beginning of the system call exit path when CONFIG_DEBUG_RSEQ=y. This will help us to detect whether there is a syscall issued erroneously inside a restartable sequence. Signed-off-by: Paul Burton <paul.burton@mips.com> Reviewed-by: James Hogan <jhogan@kernel.org> Patchwork: https://patchwork.linux-mips.org/patch/19522/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
187 lines
4.3 KiB
ArmAsm
187 lines
4.3 KiB
ArmAsm
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
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* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
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* Copyright (C) 2001 MIPS Technologies, Inc.
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*/
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#include <asm/asm.h>
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#include <asm/asmmacro.h>
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#include <asm/compiler.h>
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#include <asm/irqflags.h>
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#include <asm/regdef.h>
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#include <asm/mipsregs.h>
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#include <asm/stackframe.h>
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#include <asm/isadep.h>
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#include <asm/thread_info.h>
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#include <asm/war.h>
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#ifndef CONFIG_PREEMPT
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#define resume_kernel restore_all
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#else
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#define __ret_from_irq ret_from_exception
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#endif
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.text
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.align 5
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#ifndef CONFIG_PREEMPT
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FEXPORT(ret_from_exception)
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local_irq_disable # preempt stop
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b __ret_from_irq
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#endif
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FEXPORT(ret_from_irq)
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LONG_S s0, TI_REGS($28)
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FEXPORT(__ret_from_irq)
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/*
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* We can be coming here from a syscall done in the kernel space,
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* e.g. a failed kernel_execve().
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*/
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resume_userspace_check:
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LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
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andi t0, t0, KU_USER
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beqz t0, resume_kernel
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resume_userspace:
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local_irq_disable # make sure we dont miss an
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# interrupt setting need_resched
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# between sampling and return
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LONG_L a2, TI_FLAGS($28) # current->work
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andi t0, a2, _TIF_WORK_MASK # (ignoring syscall_trace)
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bnez t0, work_pending
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j restore_all
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#ifdef CONFIG_PREEMPT
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resume_kernel:
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local_irq_disable
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lw t0, TI_PRE_COUNT($28)
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bnez t0, restore_all
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need_resched:
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LONG_L t0, TI_FLAGS($28)
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andi t1, t0, _TIF_NEED_RESCHED
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beqz t1, restore_all
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LONG_L t0, PT_STATUS(sp) # Interrupts off?
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andi t0, 1
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beqz t0, restore_all
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jal preempt_schedule_irq
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b need_resched
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#endif
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FEXPORT(ret_from_kernel_thread)
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jal schedule_tail # a0 = struct task_struct *prev
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move a0, s1
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jal s0
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j syscall_exit
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FEXPORT(ret_from_fork)
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jal schedule_tail # a0 = struct task_struct *prev
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FEXPORT(syscall_exit)
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#ifdef CONFIG_DEBUG_RSEQ
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move a0, sp
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jal rseq_syscall
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#endif
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local_irq_disable # make sure need_resched and
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# signals dont change between
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# sampling and return
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LONG_L a2, TI_FLAGS($28) # current->work
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li t0, _TIF_ALLWORK_MASK
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and t0, a2, t0
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bnez t0, syscall_exit_work
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restore_all: # restore full frame
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.set noat
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RESTORE_TEMP
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RESTORE_AT
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RESTORE_STATIC
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restore_partial: # restore partial frame
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#ifdef CONFIG_TRACE_IRQFLAGS
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SAVE_STATIC
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SAVE_AT
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SAVE_TEMP
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LONG_L v0, PT_STATUS(sp)
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#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
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and v0, ST0_IEP
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#else
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and v0, ST0_IE
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#endif
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beqz v0, 1f
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jal trace_hardirqs_on
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b 2f
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1: jal trace_hardirqs_off
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2:
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RESTORE_TEMP
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RESTORE_AT
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RESTORE_STATIC
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#endif
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RESTORE_SOME
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RESTORE_SP_AND_RET
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.set at
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work_pending:
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andi t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
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beqz t0, work_notifysig
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work_resched:
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TRACE_IRQS_OFF
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jal schedule
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local_irq_disable # make sure need_resched and
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# signals dont change between
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# sampling and return
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LONG_L a2, TI_FLAGS($28)
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andi t0, a2, _TIF_WORK_MASK # is there any work to be done
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# other than syscall tracing?
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beqz t0, restore_all
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andi t0, a2, _TIF_NEED_RESCHED
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bnez t0, work_resched
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work_notifysig: # deal with pending signals and
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# notify-resume requests
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move a0, sp
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li a1, 0
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jal do_notify_resume # a2 already loaded
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j resume_userspace_check
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FEXPORT(syscall_exit_partial)
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#ifdef CONFIG_DEBUG_RSEQ
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move a0, sp
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jal rseq_syscall
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#endif
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local_irq_disable # make sure need_resched doesn't
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# change between and return
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LONG_L a2, TI_FLAGS($28) # current->work
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li t0, _TIF_ALLWORK_MASK
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and t0, a2
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beqz t0, restore_partial
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SAVE_STATIC
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syscall_exit_work:
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LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
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andi t0, t0, KU_USER
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beqz t0, resume_kernel
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li t0, _TIF_WORK_SYSCALL_EXIT
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and t0, a2 # a2 is preloaded with TI_FLAGS
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beqz t0, work_pending # trace bit set?
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local_irq_enable # could let syscall_trace_leave()
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# call schedule() instead
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TRACE_IRQS_ON
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move a0, sp
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jal syscall_trace_leave
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b resume_userspace
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#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) || \
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defined(CONFIG_MIPS_MT)
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/*
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* MIPS32R2 Instruction Hazard Barrier - must be called
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*
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* For C code use the inline version named instruction_hazard().
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*/
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LEAF(mips_ihb)
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.set MIPS_ISA_LEVEL_RAW
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jr.hb ra
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nop
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END(mips_ihb)
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#endif /* CONFIG_CPU_MIPSR2 or CONFIG_CPU_MIPSR6 or CONFIG_MIPS_MT */
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