v4.19.13 snapshot.
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
new file mode 100644
index 0000000..6e0375e
--- /dev/null
+++ b/arch/arm/kernel/head-common.S
@@ -0,0 +1,246 @@
+/*
+ * linux/arch/arm/kernel/head-common.S
+ *
+ * Copyright (C) 1994-2002 Russell King
+ * Copyright (c) 2003 ARM Limited
+ * All Rights Reserved
+ *
+ * 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>
+
+#define ATAG_CORE 0x54410001
+#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
+#define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2)
+
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define OF_DT_MAGIC 0xd00dfeed
+#else
+#define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */
+#endif
+
+/*
+ * Exception handling. Something went wrong and we can't proceed. We
+ * ought to tell the user, but since we don't have any guarantee that
+ * we're even running on the right architecture, we do virtually nothing.
+ *
+ * If CONFIG_DEBUG_LL is set we try to print out something about the error
+ * and hope for the best (useful if bootloader fails to pass a proper
+ * machine ID for example).
+ */
+ __HEAD
+
+/* Determine validity of the r2 atags pointer. The heuristic requires
+ * that the pointer be aligned, in the first 16k of physical RAM and
+ * that the ATAG_CORE marker is first and present. If CONFIG_OF_FLATTREE
+ * is selected, then it will also accept a dtb pointer. Future revisions
+ * of this function may be more lenient with the physical address and
+ * may also be able to move the ATAGS block if necessary.
+ *
+ * Returns:
+ * r2 either valid atags pointer, valid dtb pointer, or zero
+ * r5, r6 corrupted
+ */
+__vet_atags:
+ tst r2, #0x3 @ aligned?
+ bne 1f
+
+ ldr r5, [r2, #0]
+#ifdef CONFIG_OF_FLATTREE
+ ldr r6, =OF_DT_MAGIC @ is it a DTB?
+ cmp r5, r6
+ beq 2f
+#endif
+ cmp r5, #ATAG_CORE_SIZE @ is first tag ATAG_CORE?
+ cmpne r5, #ATAG_CORE_SIZE_EMPTY
+ bne 1f
+ ldr r5, [r2, #4]
+ ldr r6, =ATAG_CORE
+ cmp r5, r6
+ bne 1f
+
+2: ret lr @ atag/dtb pointer is ok
+
+1: mov r2, #0
+ ret lr
+ENDPROC(__vet_atags)
+
+/*
+ * The following fragment of code is executed with the MMU on in MMU mode,
+ * and uses absolute addresses; this is not position independent.
+ *
+ * r0 = cp#15 control register
+ * r1 = machine ID
+ * r2 = atags/dtb pointer
+ * r9 = processor ID
+ */
+ __INIT
+__mmap_switched:
+
+ mov r7, r1
+ mov r8, r2
+ mov r10, r0
+
+ adr r4, __mmap_switched_data
+ mov fp, #0
+
+#if defined(CONFIG_XIP_DEFLATED_DATA)
+ ARM( ldr sp, [r4], #4 )
+ THUMB( ldr sp, [r4] )
+ THUMB( add r4, #4 )
+ bl __inflate_kernel_data @ decompress .data to RAM
+ teq r0, #0
+ bne __error
+#elif defined(CONFIG_XIP_KERNEL)
+ ARM( ldmia r4!, {r0, r1, r2, sp} )
+ THUMB( ldmia r4!, {r0, r1, r2, r3} )
+ THUMB( mov sp, r3 )
+ sub r2, r2, r1
+ bl memcpy @ copy .data to RAM
+#endif
+
+ ARM( ldmia r4!, {r0, r1, sp} )
+ THUMB( ldmia r4!, {r0, r1, r3} )
+ THUMB( mov sp, r3 )
+ sub r2, r1, r0
+ mov r1, #0
+ bl memset @ clear .bss
+
+ ldmia r4, {r0, r1, r2, r3}
+ str r9, [r0] @ Save processor ID
+ str r7, [r1] @ Save machine type
+ str r8, [r2] @ Save atags pointer
+ cmp r3, #0
+ strne r10, [r3] @ Save control register values
+ mov lr, #0
+ b start_kernel
+ENDPROC(__mmap_switched)
+
+ .align 2
+ .type __mmap_switched_data, %object
+__mmap_switched_data:
+#ifdef CONFIG_XIP_KERNEL
+#ifndef CONFIG_XIP_DEFLATED_DATA
+ .long _sdata @ r0
+ .long __data_loc @ r1
+ .long _edata_loc @ r2
+#endif
+ .long __bss_stop @ sp (temporary stack in .bss)
+#endif
+
+ .long __bss_start @ r0
+ .long __bss_stop @ r1
+ .long init_thread_union + THREAD_START_SP @ sp
+
+ .long processor_id @ r0
+ .long __machine_arch_type @ r1
+ .long __atags_pointer @ r2
+#ifdef CONFIG_CPU_CP15
+ .long cr_alignment @ r3
+#else
+ .long 0 @ r3
+#endif
+ .size __mmap_switched_data, . - __mmap_switched_data
+
+/*
+ * This provides a C-API version of __lookup_processor_type
+ */
+ENTRY(lookup_processor_type)
+ stmfd sp!, {r4 - r6, r9, lr}
+ mov r9, r0
+ bl __lookup_processor_type
+ mov r0, r5
+ ldmfd sp!, {r4 - r6, r9, pc}
+ENDPROC(lookup_processor_type)
+
+ __FINIT
+ .text
+
+/*
+ * Read processor ID register (CP#15, CR0), and look up in the linker-built
+ * supported processor list. Note that we can't use the absolute addresses
+ * for the __proc_info lists since we aren't running with the MMU on
+ * (and therefore, we are not in the correct address space). We have to
+ * calculate the offset.
+ *
+ * r9 = cpuid
+ * Returns:
+ * r3, r4, r6 corrupted
+ * r5 = proc_info pointer in physical address space
+ * r9 = cpuid (preserved)
+ */
+__lookup_processor_type:
+ adr r3, __lookup_processor_type_data
+ ldmia r3, {r4 - r6}
+ sub r3, r3, r4 @ get offset between virt&phys
+ add r5, r5, r3 @ convert virt addresses to
+ add r6, r6, r3 @ physical address space
+1: ldmia r5, {r3, r4} @ value, mask
+ and r4, r4, r9 @ mask wanted bits
+ teq r3, r4
+ beq 2f
+ add r5, r5, #PROC_INFO_SZ @ sizeof(proc_info_list)
+ cmp r5, r6
+ blo 1b
+ mov r5, #0 @ unknown processor
+2: ret lr
+ENDPROC(__lookup_processor_type)
+
+/*
+ * Look in <asm/procinfo.h> for information about the __proc_info structure.
+ */
+ .align 2
+ .type __lookup_processor_type_data, %object
+__lookup_processor_type_data:
+ .long .
+ .long __proc_info_begin
+ .long __proc_info_end
+ .size __lookup_processor_type_data, . - __lookup_processor_type_data
+
+__error_lpae:
+#ifdef CONFIG_DEBUG_LL
+ adr r0, str_lpae
+ bl printascii
+ b __error
+str_lpae: .asciz "\nError: Kernel with LPAE support, but CPU does not support LPAE.\n"
+#else
+ b __error
+#endif
+ .align
+ENDPROC(__error_lpae)
+
+__error_p:
+#ifdef CONFIG_DEBUG_LL
+ adr r0, str_p1
+ bl printascii
+ mov r0, r9
+ bl printhex8
+ adr r0, str_p2
+ bl printascii
+ b __error
+str_p1: .asciz "\nError: unrecognized/unsupported processor variant (0x"
+str_p2: .asciz ").\n"
+ .align
+#endif
+ENDPROC(__error_p)
+
+__error:
+#ifdef CONFIG_ARCH_RPC
+/*
+ * Turn the screen red on a error - RiscPC only.
+ */
+ mov r0, #0x02000000
+ mov r3, #0x11
+ orr r3, r3, r3, lsl #8
+ orr r3, r3, r3, lsl #16
+ str r3, [r0], #4
+ str r3, [r0], #4
+ str r3, [r0], #4
+ str r3, [r0], #4
+#endif
+1: mov r0, r0
+ b 1b
+ENDPROC(__error)