File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
new file mode 100644
index 0000000..db07793
--- /dev/null
+++ b/arch/mips/kernel/entry.S
@@ -0,0 +1,197 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2001 MIPS Technologies, Inc.
+ */
+
+#include <asm/asm.h>
+#include <asm/asmmacro.h>
+#include <asm/compiler.h>
+#include <asm/irqflags.h>
+#include <asm/regdef.h>
+#include <asm/mipsregs.h>
+#include <asm/stackframe.h>
+#include <asm/isadep.h>
+#include <asm/thread_info.h>
+#include <asm/war.h>
+
+#ifndef CONFIG_PREEMPT
+#define resume_kernel restore_all
+#else
+#define __ret_from_irq ret_from_exception
+#endif
+
+ .text
+ .align 5
+#ifndef CONFIG_PREEMPT
+FEXPORT(ret_from_exception)
+ local_irq_disable # preempt stop
+ b __ret_from_irq
+#endif
+FEXPORT(ret_from_irq)
+ LONG_S s0, TI_REGS($28)
+FEXPORT(__ret_from_irq)
+/*
+ * We can be coming here from a syscall done in the kernel space,
+ * e.g. a failed kernel_execve().
+ */
+resume_userspace_check:
+ LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
+ andi t0, t0, KU_USER
+ beqz t0, resume_kernel
+
+resume_userspace:
+ local_irq_disable # make sure we dont miss an
+ # interrupt setting need_resched
+ # between sampling and return
+#ifdef CONFIG_MIPSR2_TO_R6_EMULATOR
+ lw k0, TI_R2_EMUL_RET($28)
+ bnez k0, restore_all_from_r2_emul
+#endif
+
+ LONG_L a2, TI_FLAGS($28) # current->work
+ andi t0, a2, _TIF_WORK_MASK # (ignoring syscall_trace)
+ bnez t0, work_pending
+ j restore_all
+
+#ifdef CONFIG_PREEMPT
+resume_kernel:
+ local_irq_disable
+ lw t0, TI_PRE_COUNT($28)
+ bnez t0, restore_all
+need_resched:
+ LONG_L t0, TI_FLAGS($28)
+ andi t1, t0, _TIF_NEED_RESCHED
+ beqz t1, restore_all
+ LONG_L t0, PT_STATUS(sp) # Interrupts off?
+ andi t0, 1
+ beqz t0, restore_all
+ jal preempt_schedule_irq
+ b need_resched
+#endif
+
+FEXPORT(ret_from_kernel_thread)
+ jal schedule_tail # a0 = struct task_struct *prev
+ move a0, s1
+ jal s0
+ j syscall_exit
+
+FEXPORT(ret_from_fork)
+ jal schedule_tail # a0 = struct task_struct *prev
+
+FEXPORT(syscall_exit)
+ local_irq_disable # make sure need_resched and
+ # signals dont change between
+ # sampling and return
+ LONG_L a2, TI_FLAGS($28) # current->work
+ li t0, _TIF_ALLWORK_MASK
+ and t0, a2, t0
+ bnez t0, syscall_exit_work
+
+restore_all: # restore full frame
+ .set noat
+ RESTORE_TEMP
+ RESTORE_AT
+ RESTORE_STATIC
+restore_partial: # restore partial frame
+#ifdef CONFIG_TRACE_IRQFLAGS
+ SAVE_STATIC
+ SAVE_AT
+ SAVE_TEMP
+ LONG_L v0, PT_STATUS(sp)
+#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+ and v0, ST0_IEP
+#else
+ and v0, ST0_IE
+#endif
+ beqz v0, 1f
+ jal trace_hardirqs_on
+ b 2f
+1: jal trace_hardirqs_off
+2:
+ RESTORE_TEMP
+ RESTORE_AT
+ RESTORE_STATIC
+#endif
+ RESTORE_SOME
+ RESTORE_SP_AND_RET
+ .set at
+
+#ifdef CONFIG_MIPSR2_TO_R6_EMULATOR
+restore_all_from_r2_emul: # restore full frame
+ .set noat
+ sw zero, TI_R2_EMUL_RET($28) # reset it
+ RESTORE_TEMP
+ RESTORE_AT
+ RESTORE_STATIC
+ RESTORE_SOME
+ LONG_L sp, PT_R29(sp)
+ eretnc
+ .set at
+#endif
+
+work_pending:
+ andi t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
+ beqz t0, work_notifysig
+work_resched:
+ TRACE_IRQS_OFF
+ jal schedule
+
+ local_irq_disable # make sure need_resched and
+ # signals dont change between
+ # sampling and return
+ LONG_L a2, TI_FLAGS($28)
+ andi t0, a2, _TIF_WORK_MASK # is there any work to be done
+ # other than syscall tracing?
+ beqz t0, restore_all
+ andi t0, a2, _TIF_NEED_RESCHED
+ bnez t0, work_resched
+
+work_notifysig: # deal with pending signals and
+ # notify-resume requests
+ move a0, sp
+ li a1, 0
+ jal do_notify_resume # a2 already loaded
+ j resume_userspace_check
+
+FEXPORT(syscall_exit_partial)
+ local_irq_disable # make sure need_resched doesn't
+ # change between and return
+ LONG_L a2, TI_FLAGS($28) # current->work
+ li t0, _TIF_ALLWORK_MASK
+ and t0, a2
+ beqz t0, restore_partial
+ SAVE_STATIC
+syscall_exit_work:
+ LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
+ andi t0, t0, KU_USER
+ beqz t0, resume_kernel
+ li t0, _TIF_WORK_SYSCALL_EXIT
+ and t0, a2 # a2 is preloaded with TI_FLAGS
+ beqz t0, work_pending # trace bit set?
+ local_irq_enable # could let syscall_trace_leave()
+ # call schedule() instead
+ TRACE_IRQS_ON
+ move a0, sp
+ jal syscall_trace_leave
+ b resume_userspace
+
+#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) || \
+ defined(CONFIG_MIPS_MT)
+
+/*
+ * MIPS32R2 Instruction Hazard Barrier - must be called
+ *
+ * For C code use the inline version named instruction_hazard().
+ */
+LEAF(mips_ihb)
+ .set MIPS_ISA_LEVEL_RAW
+ jr.hb ra
+ nop
+ END(mips_ihb)
+
+#endif /* CONFIG_CPU_MIPSR2 or CONFIG_CPU_MIPSR6 or CONFIG_MIPS_MT */