Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 252 insertions, 0 deletions

diff --git a/arch/unicore32/kernel/head.S b/arch/unicore32/kernel/head.S
new file mode 100644
index 000000000..e8f0b98c0
--- /dev/null
+++ b/arch/unicore32/kernel/head.S
@@ -0,0 +1,252 @@
+/*
+ * linux/arch/unicore32/kernel/head.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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 <linux/linkage.h>
+#include <linux/init.h>
+
+#include <asm/assembler.h>
+#include <asm/ptrace.h>
+#include <generated/asm-offsets.h>
+#include <asm/memory.h>
+#include <asm/thread_info.h>
+#include <asm/hwdef-copro.h>
+#include <asm/pgtable-hwdef.h>
+
+#if (PHYS_OFFSET & 0x003fffff)
+#error "PHYS_OFFSET must be at an even 4MiB boundary!"
+#endif
+
+#define KERNEL_RAM_VADDR	(PAGE_OFFSET + KERNEL_IMAGE_START)
+#define KERNEL_RAM_PADDR	(PHYS_OFFSET + KERNEL_IMAGE_START)
+
+#define KERNEL_PGD_PADDR	(KERNEL_RAM_PADDR - 0x1000)
+#define KERNEL_PGD_VADDR	(KERNEL_RAM_VADDR - 0x1000)
+
+#define KERNEL_START		KERNEL_RAM_VADDR
+#define KERNEL_END		_end
+
+/*
+ * swapper_pg_dir is the virtual address of the initial page table.
+ * We place the page tables 4K below KERNEL_RAM_VADDR.  Therefore, we must
+ * make sure that KERNEL_RAM_VADDR is correctly set.  Currently, we expect
+ * the least significant 16 bits to be 0x8000, but we could probably
+ * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x1000.
+ */
+#if (KERNEL_RAM_VADDR & 0xffff) != 0x8000
+#error KERNEL_RAM_VADDR must start at 0xXXXX8000
+#endif
+
+	.globl	swapper_pg_dir
+	.equ	swapper_pg_dir, KERNEL_RAM_VADDR - 0x1000
+
+/*
+ * Kernel startup entry point.
+ * ---------------------------
+ *
+ * This is normally called from the decompressor code.  The requirements
+ * are: MMU = off, D-cache = off, I-cache = dont care
+ *
+ * This code is mostly position independent, so if you link the kernel at
+ * 0xc0008000, you call this at __pa(0xc0008000).
+ */
+	__HEAD
+ENTRY(stext)
+	@ set asr
+	mov	r0, #PRIV_MODE			@ ensure priv mode
+	or	r0, #PSR_R_BIT | PSR_I_BIT	@ disable irqs
+	mov.a	asr, r0
+
+	@ process identify
+	movc	r0, p0.c0, #0			@ cpuid
+	movl	r1, 0xff00ffff			@ mask
+	movl	r2, 0x4d000863			@ value
+	and	r0, r1, r0
+	cxor.a	r0, r2
+	bne	__error_p			@ invalid processor id
+
+	/*
+	 * Clear the 4K level 1 swapper page table
+	 */
+	movl	r0, #KERNEL_PGD_PADDR		@ page table address
+	mov	r1, #0
+	add	r2, r0, #0x1000
+101:	stw.w	r1, [r0]+, #4
+	stw.w	r1, [r0]+, #4
+	stw.w	r1, [r0]+, #4
+	stw.w	r1, [r0]+, #4
+	cxor.a	r0, r2
+	bne	101b
+
+	movl	r4, #KERNEL_PGD_PADDR		@ page table address
+	mov	r7, #PMD_TYPE_SECT | PMD_PRESENT	@ page size: section
+	or	r7, r7, #PMD_SECT_CACHEABLE		@ cacheable
+	or	r7, r7, #PMD_SECT_READ | PMD_SECT_WRITE | PMD_SECT_EXEC
+
+	/*
+	 * Create identity mapping for first 4MB of kernel to
+	 * cater for the MMU enable.  This identity mapping
+	 * will be removed by paging_init().  We use our current program
+	 * counter to determine corresponding section base address.
+	 */
+	mov	r6, pc
+	mov	r6, r6 >> #22			@ start of kernel section
+	or	r1, r7, r6 << #22		@ flags + kernel base
+	stw	r1, [r4+], r6 << #2		@ identity mapping
+
+	/*
+	 * Now setup the pagetables for our kernel direct
+	 * mapped region.
+	 */
+	add	r0, r4,  #(KERNEL_START & 0xff000000) >> 20
+	stw.w	r1, [r0+], #(KERNEL_START & 0x00c00000) >> 20
+	movl	r6, #(KERNEL_END - 1)
+	add	r0, r0, #4
+	add	r6, r4, r6 >> #20
+102:	csub.a	r0, r6
+	add	r1, r1, #1 << 22
+	bua	103f
+	stw.w	r1, [r0]+, #4
+	b	102b
+103:
+	/*
+	 * Then map first 4MB of ram in case it contains our boot params.
+	 */
+	add	r0, r4, #PAGE_OFFSET >> 20
+	or	r6, r7, #(PHYS_OFFSET & 0xffc00000)
+	stw	r6, [r0]
+
+	ldw	r15, __switch_data		@ address to jump to after
+
+	/*
+	 * Initialise TLB, Caches, and MMU state ready to switch the MMU
+	 * on.
+	 */
+	mov	r0, #0
+	movc	p0.c5, r0, #28			@ cache invalidate all
+	nop8
+	movc	p0.c6, r0, #6			@ TLB invalidate all
+	nop8
+
+	/*
+	 * ..V. .... ..TB IDAM
+	 * ..1. .... ..01 1111
+	 */
+	movl	r0, #0x201f			@ control register setting
+
+	/*
+	 * Setup common bits before finally enabling the MMU.  Essentially
+	 * this is just loading the page table pointer and domain access
+	 * registers.
+	 */
+	#ifndef CONFIG_ALIGNMENT_TRAP
+		andn	r0, r0, #CR_A
+	#endif
+	#ifdef CONFIG_CPU_DCACHE_DISABLE
+		andn	r0, r0, #CR_D
+	#endif
+	#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
+		andn	r0, r0, #CR_B
+	#endif
+	#ifdef CONFIG_CPU_ICACHE_DISABLE
+		andn	r0, r0, #CR_I
+	#endif
+
+	movc	p0.c2, r4, #0			@ set pgd
+	b	__turn_mmu_on
+ENDPROC(stext)
+
+/*
+ * Enable the MMU.  This completely changes the structure of the visible
+ * memory space.  You will not be able to trace execution through this.
+ *
+ *  r0  = cp#0 control register
+ *  r15 = *virtual* address to jump to upon completion
+ */
+	.align	5
+__turn_mmu_on:
+	mov	r0, r0
+	movc	p0.c1, r0, #0			@ write control reg
+	nop					@ fetch inst by phys addr
+	mov	pc, r15
+	nop8					@ fetch inst by phys addr
+ENDPROC(__turn_mmu_on)
+
+/*
+ * Setup the initial page tables.  We only setup the barest
+ * amount which are required to get the kernel running, which
+ * generally means mapping in the kernel code.
+ *
+ * r9  = cpuid
+ * r10 = procinfo
+ *
+ * Returns:
+ *  r0, r3, r6, r7 corrupted
+ *  r4 = physical page table address
+ */
+	.ltorg
+
+	.align	2
+	.type	__switch_data, %object
+__switch_data:
+	.long	__mmap_switched
+	.long	__bss_start			@ r6
+	.long	_end				@ r7
+	.long	cr_alignment			@ r8
+	.long	init_thread_union + THREAD_START_SP @ sp
+
+/*
+ * 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#0 control register
+ */
+__mmap_switched:
+	adr	r3, __switch_data + 4
+
+	ldm.w	(r6, r7, r8), [r3]+
+	ldw	sp, [r3]
+
+	mov	fp, #0				@ Clear BSS (and zero fp)
+203:	csub.a	r6, r7
+	bea	204f
+	stw.w	fp, [r6]+,#4
+	b	203b
+204:
+	andn	r1, r0, #CR_A			@ Clear 'A' bit
+	stm	(r0, r1), [r8]+			@ Save control register values
+	b	start_kernel
+ENDPROC(__mmap_switched)
+
+/*
+ * 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).
+ */
+__error_p:
+#ifdef CONFIG_DEBUG_LL
+	adr	r0, str_p1
+	b.l	printascii
+	mov	r0, r9
+	b.l	printhex8
+	adr	r0, str_p2
+	b.l	printascii
+901:	nop8
+	b	901b
+str_p1:	.asciz	"\nError: unrecognized processor variant (0x"
+str_p2:	.asciz	").\n"
+	.align
+#endif
+ENDPROC(__error_p)
+