v4.19.13 snapshot.
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
new file mode 100644
index 0000000..746565a
--- /dev/null
+++ b/arch/arm/kernel/entry-common.S
@@ -0,0 +1,464 @@
+/*
+ * linux/arch/arm/kernel/entry-common.S
+ *
+ * Copyright (C) 2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <asm/assembler.h>
+#include <asm/unistd.h>
+#include <asm/ftrace.h>
+#include <asm/unwind.h>
+#include <asm/memory.h>
+#ifdef CONFIG_AEABI
+#include <asm/unistd-oabi.h>
+#endif
+
+ .equ NR_syscalls, __NR_syscalls
+
+#ifdef CONFIG_NEED_RET_TO_USER
+#include <mach/entry-macro.S>
+#else
+ .macro arch_ret_to_user, tmp1, tmp2
+ .endm
+#endif
+
+#include "entry-header.S"
+
+saved_psr .req r8
+#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING)
+saved_pc .req r9
+#define TRACE(x...) x
+#else
+saved_pc .req lr
+#define TRACE(x...)
+#endif
+
+ .section .entry.text,"ax",%progbits
+ .align 5
+#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING) || \
+ IS_ENABLED(CONFIG_DEBUG_RSEQ))
+/*
+ * This is the fast syscall return path. We do as little as possible here,
+ * such as avoiding writing r0 to the stack. We only use this path if we
+ * have tracing, context tracking and rseq debug disabled - the overheads
+ * from those features make this path too inefficient.
+ */
+ret_fast_syscall:
+__ret_fast_syscall:
+ UNWIND(.fnstart )
+ UNWIND(.cantunwind )
+ disable_irq_notrace @ disable interrupts
+ ldr r2, [tsk, #TI_ADDR_LIMIT]
+ cmp r2, #TASK_SIZE
+ blne addr_limit_check_failed
+ ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
+ tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+ bne fast_work_pending
+
+
+ /* perform architecture specific actions before user return */
+ arch_ret_to_user r1, lr
+
+ restore_user_regs fast = 1, offset = S_OFF
+ UNWIND(.fnend )
+ENDPROC(ret_fast_syscall)
+
+ /* Ok, we need to do extra processing, enter the slow path. */
+fast_work_pending:
+ str r0, [sp, #S_R0+S_OFF]! @ returned r0
+ /* fall through to work_pending */
+#else
+/*
+ * The "replacement" ret_fast_syscall for when tracing, context tracking,
+ * or rseq debug is enabled. As we will need to call out to some C functions,
+ * we save r0 first to avoid needing to save registers around each C function
+ * call.
+ */
+ret_fast_syscall:
+__ret_fast_syscall:
+ UNWIND(.fnstart )
+ UNWIND(.cantunwind )
+ str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
+#if IS_ENABLED(CONFIG_DEBUG_RSEQ)
+ /* do_rseq_syscall needs interrupts enabled. */
+ mov r0, sp @ 'regs'
+ bl do_rseq_syscall
+#endif
+ disable_irq_notrace @ disable interrupts
+ ldr r2, [tsk, #TI_ADDR_LIMIT]
+ cmp r2, #TASK_SIZE
+ blne addr_limit_check_failed
+ ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
+ tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+ beq no_work_pending
+ UNWIND(.fnend )
+ENDPROC(ret_fast_syscall)
+
+ /* Slower path - fall through to work_pending */
+#endif
+
+ tst r1, #_TIF_SYSCALL_WORK
+ bne __sys_trace_return_nosave
+slow_work_pending:
+ mov r0, sp @ 'regs'
+ mov r2, why @ 'syscall'
+ bl do_work_pending
+ cmp r0, #0
+ beq no_work_pending
+ movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
+ ldmia sp, {r0 - r6} @ have to reload r0 - r6
+ b local_restart @ ... and off we go
+ENDPROC(ret_fast_syscall)
+
+/*
+ * "slow" syscall return path. "why" tells us if this was a real syscall.
+ * IRQs may be enabled here, so always disable them. Note that we use the
+ * "notrace" version to avoid calling into the tracing code unnecessarily.
+ * do_work_pending() will update this state if necessary.
+ */
+ENTRY(ret_to_user)
+ret_slow_syscall:
+#if IS_ENABLED(CONFIG_DEBUG_RSEQ)
+ /* do_rseq_syscall needs interrupts enabled. */
+ enable_irq_notrace @ enable interrupts
+ mov r0, sp @ 'regs'
+ bl do_rseq_syscall
+#endif
+ disable_irq_notrace @ disable interrupts
+ENTRY(ret_to_user_from_irq)
+ ldr r2, [tsk, #TI_ADDR_LIMIT]
+ cmp r2, #TASK_SIZE
+ blne addr_limit_check_failed
+ ldr r1, [tsk, #TI_FLAGS]
+ tst r1, #_TIF_WORK_MASK
+ bne slow_work_pending
+no_work_pending:
+ asm_trace_hardirqs_on save = 0
+
+ /* perform architecture specific actions before user return */
+ arch_ret_to_user r1, lr
+ ct_user_enter save = 0
+
+ restore_user_regs fast = 0, offset = 0
+ENDPROC(ret_to_user_from_irq)
+ENDPROC(ret_to_user)
+
+/*
+ * This is how we return from a fork.
+ */
+ENTRY(ret_from_fork)
+ bl schedule_tail
+ cmp r5, #0
+ movne r0, r4
+ badrne lr, 1f
+ retne r5
+1: get_thread_info tsk
+ b ret_slow_syscall
+ENDPROC(ret_from_fork)
+
+/*=============================================================================
+ * SWI handler
+ *-----------------------------------------------------------------------------
+ */
+
+ .align 5
+ENTRY(vector_swi)
+#ifdef CONFIG_CPU_V7M
+ v7m_exception_entry
+#else
+ sub sp, sp, #PT_REGS_SIZE
+ stmia sp, {r0 - r12} @ Calling r0 - r12
+ ARM( add r8, sp, #S_PC )
+ ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
+ THUMB( mov r8, sp )
+ THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
+ mrs saved_psr, spsr @ called from non-FIQ mode, so ok.
+ TRACE( mov saved_pc, lr )
+ str saved_pc, [sp, #S_PC] @ Save calling PC
+ str saved_psr, [sp, #S_PSR] @ Save CPSR
+ str r0, [sp, #S_OLD_R0] @ Save OLD_R0
+#endif
+ zero_fp
+ alignment_trap r10, ip, __cr_alignment
+ asm_trace_hardirqs_on save=0
+ enable_irq_notrace
+ ct_user_exit save=0
+
+ /*
+ * Get the system call number.
+ */
+
+#if defined(CONFIG_OABI_COMPAT)
+
+ /*
+ * If we have CONFIG_OABI_COMPAT then we need to look at the swi
+ * value to determine if it is an EABI or an old ABI call.
+ */
+#ifdef CONFIG_ARM_THUMB
+ tst saved_psr, #PSR_T_BIT
+ movne r10, #0 @ no thumb OABI emulation
+ USER( ldreq r10, [saved_pc, #-4] ) @ get SWI instruction
+#else
+ USER( ldr r10, [saved_pc, #-4] ) @ get SWI instruction
+#endif
+ ARM_BE8(rev r10, r10) @ little endian instruction
+
+#elif defined(CONFIG_AEABI)
+
+ /*
+ * Pure EABI user space always put syscall number into scno (r7).
+ */
+#elif defined(CONFIG_ARM_THUMB)
+ /* Legacy ABI only, possibly thumb mode. */
+ tst saved_psr, #PSR_T_BIT @ this is SPSR from save_user_regs
+ addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
+ USER( ldreq scno, [saved_pc, #-4] )
+
+#else
+ /* Legacy ABI only. */
+ USER( ldr scno, [saved_pc, #-4] ) @ get SWI instruction
+#endif
+
+ /* saved_psr and saved_pc are now dead */
+
+ uaccess_disable tbl
+
+ adr tbl, sys_call_table @ load syscall table pointer
+
+#if defined(CONFIG_OABI_COMPAT)
+ /*
+ * If the swi argument is zero, this is an EABI call and we do nothing.
+ *
+ * If this is an old ABI call, get the syscall number into scno and
+ * get the old ABI syscall table address.
+ */
+ bics r10, r10, #0xff000000
+ eorne scno, r10, #__NR_OABI_SYSCALL_BASE
+ ldrne tbl, =sys_oabi_call_table
+#elif !defined(CONFIG_AEABI)
+ bic scno, scno, #0xff000000 @ mask off SWI op-code
+ eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
+#endif
+ get_thread_info tsk
+ /*
+ * Reload the registers that may have been corrupted on entry to
+ * the syscall assembly (by tracing or context tracking.)
+ */
+ TRACE( ldmia sp, {r0 - r3} )
+
+local_restart:
+ ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
+ stmdb sp!, {r4, r5} @ push fifth and sixth args
+
+ tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
+ bne __sys_trace
+
+ invoke_syscall tbl, scno, r10, __ret_fast_syscall
+
+ add r1, sp, #S_OFF
+2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
+ eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
+ bcs arm_syscall
+ mov why, #0 @ no longer a real syscall
+ b sys_ni_syscall @ not private func
+
+#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
+ /*
+ * We failed to handle a fault trying to access the page
+ * containing the swi instruction, but we're not really in a
+ * position to return -EFAULT. Instead, return back to the
+ * instruction and re-enter the user fault handling path trying
+ * to page it in. This will likely result in sending SEGV to the
+ * current task.
+ */
+9001:
+ sub lr, saved_pc, #4
+ str lr, [sp, #S_PC]
+ get_thread_info tsk
+ b ret_fast_syscall
+#endif
+ENDPROC(vector_swi)
+
+ /*
+ * This is the really slow path. We're going to be doing
+ * context switches, and waiting for our parent to respond.
+ */
+__sys_trace:
+ mov r1, scno
+ add r0, sp, #S_OFF
+ bl syscall_trace_enter
+ mov scno, r0
+ invoke_syscall tbl, scno, r10, __sys_trace_return, reload=1
+ cmp scno, #-1 @ skip the syscall?
+ bne 2b
+ add sp, sp, #S_OFF @ restore stack
+ b ret_slow_syscall
+
+__sys_trace_return:
+ str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
+ mov r0, sp
+ bl syscall_trace_exit
+ b ret_slow_syscall
+
+__sys_trace_return_nosave:
+ enable_irq_notrace
+ mov r0, sp
+ bl syscall_trace_exit
+ b ret_slow_syscall
+
+ .align 5
+#ifdef CONFIG_ALIGNMENT_TRAP
+ .type __cr_alignment, #object
+__cr_alignment:
+ .word cr_alignment
+#endif
+ .ltorg
+
+ .macro syscall_table_start, sym
+ .equ __sys_nr, 0
+ .type \sym, #object
+ENTRY(\sym)
+ .endm
+
+ .macro syscall, nr, func
+ .ifgt __sys_nr - \nr
+ .error "Duplicated/unorded system call entry"
+ .endif
+ .rept \nr - __sys_nr
+ .long sys_ni_syscall
+ .endr
+ .long \func
+ .equ __sys_nr, \nr + 1
+ .endm
+
+ .macro syscall_table_end, sym
+ .ifgt __sys_nr - __NR_syscalls
+ .error "System call table too big"
+ .endif
+ .rept __NR_syscalls - __sys_nr
+ .long sys_ni_syscall
+ .endr
+ .size \sym, . - \sym
+ .endm
+
+#define NATIVE(nr, func) syscall nr, func
+
+/*
+ * This is the syscall table declaration for native ABI syscalls.
+ * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
+ */
+ syscall_table_start sys_call_table
+#define COMPAT(nr, native, compat) syscall nr, native
+#ifdef CONFIG_AEABI
+#include <calls-eabi.S>
+#else
+#include <calls-oabi.S>
+#endif
+#undef COMPAT
+ syscall_table_end sys_call_table
+
+/*============================================================================
+ * Special system call wrappers
+ */
+@ r0 = syscall number
+@ r8 = syscall table
+sys_syscall:
+ bic scno, r0, #__NR_OABI_SYSCALL_BASE
+ cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
+ cmpne scno, #NR_syscalls @ check range
+#ifdef CONFIG_CPU_SPECTRE
+ movhs scno, #0
+ csdb
+#endif
+ stmloia sp, {r5, r6} @ shuffle args
+ movlo r0, r1
+ movlo r1, r2
+ movlo r2, r3
+ movlo r3, r4
+ ldrlo pc, [tbl, scno, lsl #2]
+ b sys_ni_syscall
+ENDPROC(sys_syscall)
+
+sys_sigreturn_wrapper:
+ add r0, sp, #S_OFF
+ mov why, #0 @ prevent syscall restart handling
+ b sys_sigreturn
+ENDPROC(sys_sigreturn_wrapper)
+
+sys_rt_sigreturn_wrapper:
+ add r0, sp, #S_OFF
+ mov why, #0 @ prevent syscall restart handling
+ b sys_rt_sigreturn
+ENDPROC(sys_rt_sigreturn_wrapper)
+
+sys_statfs64_wrapper:
+ teq r1, #88
+ moveq r1, #84
+ b sys_statfs64
+ENDPROC(sys_statfs64_wrapper)
+
+sys_fstatfs64_wrapper:
+ teq r1, #88
+ moveq r1, #84
+ b sys_fstatfs64
+ENDPROC(sys_fstatfs64_wrapper)
+
+/*
+ * Note: off_4k (r5) is always units of 4K. If we can't do the requested
+ * offset, we return EINVAL.
+ */
+sys_mmap2:
+ str r5, [sp, #4]
+ b sys_mmap_pgoff
+ENDPROC(sys_mmap2)
+
+#ifdef CONFIG_OABI_COMPAT
+
+/*
+ * These are syscalls with argument register differences
+ */
+
+sys_oabi_pread64:
+ stmia sp, {r3, r4}
+ b sys_pread64
+ENDPROC(sys_oabi_pread64)
+
+sys_oabi_pwrite64:
+ stmia sp, {r3, r4}
+ b sys_pwrite64
+ENDPROC(sys_oabi_pwrite64)
+
+sys_oabi_truncate64:
+ mov r3, r2
+ mov r2, r1
+ b sys_truncate64
+ENDPROC(sys_oabi_truncate64)
+
+sys_oabi_ftruncate64:
+ mov r3, r2
+ mov r2, r1
+ b sys_ftruncate64
+ENDPROC(sys_oabi_ftruncate64)
+
+sys_oabi_readahead:
+ str r3, [sp]
+ mov r3, r2
+ mov r2, r1
+ b sys_readahead
+ENDPROC(sys_oabi_readahead)
+
+/*
+ * Let's declare a second syscall table for old ABI binaries
+ * using the compatibility syscall entries.
+ */
+ syscall_table_start sys_oabi_call_table
+#define COMPAT(nr, native, compat) syscall nr, compat
+#include <calls-oabi.S>
+ syscall_table_end sys_oabi_call_table
+
+#endif
+