207 lines
5.5 KiB
ArmAsm
207 lines
5.5 KiB
ArmAsm
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// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2005-2017 Andes Technology Corporation
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#include <linux/linkage.h>
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#include <linux/init.h>
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#include <asm/ptrace.h>
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#include <asm/asm-offsets.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/sizes.h>
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#include <asm/thread_info.h>
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#ifdef CONFIG_CPU_BIG_ENDIAN
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#define OF_DT_MAGIC 0xd00dfeed
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#else
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#define OF_DT_MAGIC 0xedfe0dd0
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#endif
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.globl swapper_pg_dir
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.equ swapper_pg_dir, TEXTADDR - 0x4000
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/*
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* Kernel startup entry point.
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*/
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.section ".head.text", "ax"
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.type _stext, %function
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ENTRY(_stext)
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setgie.d ! Disable interrupt
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isb
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/*
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* Disable I/D-cache and enable it at a proper time
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*/
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mfsr $r0, $mr8
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li $r1, #~(CACHE_CTL_mskIC_EN|CACHE_CTL_mskDC_EN)
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and $r0, $r0, $r1
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mtsr $r0, $mr8
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/*
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* Process device tree blob
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*/
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andi $r0,$r2,#0x3
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li $r10, 0
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bne $r0, $r10, _nodtb
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lwi $r0, [$r2]
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li $r1, OF_DT_MAGIC
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bne $r0, $r1, _nodtb
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move $r10, $r2
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_nodtb:
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/*
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* Create a temporary mapping area for booting, before start_kernel
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*/
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sethi $r4, hi20(swapper_pg_dir)
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li $p0, (PAGE_OFFSET - PHYS_OFFSET)
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sub $r4, $r4, $p0
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tlbop FlushAll ! invalidate TLB\n"
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isb
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mtsr $r4, $L1_PPTB ! load page table pointer\n"
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#ifdef CONFIG_CPU_DCACHE_DISABLE
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#define MMU_CTL_NTCC MMU_CTL_CACHEABLE_NON
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#else
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#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
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#define MMU_CTL_NTCC MMU_CTL_CACHEABLE_WT
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#else
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#define MMU_CTL_NTCC MMU_CTL_CACHEABLE_WB
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#endif
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#endif
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/* set NTC cacheability, mutliple page size in use */
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mfsr $r3, $MMU_CTL
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#if CONFIG_MEMORY_START >= 0xc0000000
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ori $r3, $r3, (MMU_CTL_NTCC << MMU_CTL_offNTC3)
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#elif CONFIG_MEMORY_START >= 0x80000000
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ori $r3, $r3, (MMU_CTL_NTCC << MMU_CTL_offNTC2)
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#elif CONFIG_MEMORY_START >= 0x40000000
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ori $r3, $r3, (MMU_CTL_NTCC << MMU_CTL_offNTC1)
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#else
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ori $r3, $r3, (MMU_CTL_NTCC << MMU_CTL_offNTC0)
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#endif
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#ifdef CONFIG_ANDES_PAGE_SIZE_4KB
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ori $r3, $r3, #(MMU_CTL_mskMPZIU)
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#else
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ori $r3, $r3, #(MMU_CTL_mskMPZIU|MMU_CTL_D8KB)
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#endif
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#ifdef CONFIG_HW_SUPPORT_UNALIGNMENT_ACCESS
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li $r0, #MMU_CTL_UNA
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or $r3, $r3, $r0
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#endif
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mtsr $r3, $MMU_CTL
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isb
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/* set page size and size of kernel image */
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mfsr $r0, $MMU_CFG
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srli $r3, $r0, MMU_CFG_offfEPSZ
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zeb $r3, $r3
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bnez $r3, _extra_page_size_support
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#ifdef CONFIG_ANDES_PAGE_SIZE_4KB
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li $r5, #SZ_4K ! Use 4KB page size
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#else
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li $r5, #SZ_8K ! Use 8KB page size
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li $r3, #1
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#endif
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mtsr $r3, $TLB_MISC
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b _image_size_check
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_extra_page_size_support: ! Use epzs pages size
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clz $r6, $r3
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subri $r2, $r6, #31
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li $r3, #1
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sll $r3, $r3, $r2
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/* MMU_CFG.EPSZ value -> meaning */
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mul $r5, $r3, $r3
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slli $r5, $r5, #14
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/* MMU_CFG.EPSZ -> TLB_MISC.ACC_PSZ */
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addi $r3, $r2, #0x2
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mtsr $r3, $TLB_MISC
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_image_size_check:
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/* calculate the image maximum size accepted by TLB config */
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andi $r6, $r0, MMU_CFG_mskTBW
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andi $r0, $r0, MMU_CFG_mskTBS
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srli $r6, $r6, MMU_CFG_offTBW
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srli $r0, $r0, MMU_CFG_offTBS
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/*
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* we just map the kernel to the maximum way - 1 of tlb
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* reserver one way for UART VA mapping
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* it will cause page fault if UART mapping cover the kernel mapping
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*
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* direct mapping is not supported now.
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*/
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li $r2, 't'
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beqz $r6, __error ! MMU_CFG.TBW = 0 is direct mappin
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addi $r0, $r0, #0x2 ! MMU_CFG.TBS value -> meaning
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sll $r0, $r6, $r0 ! entries = k-way * n-set
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mul $r6, $r0, $r5 ! max size = entries * page size
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/* check kernel image size */
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la $r3, (_end - PAGE_OFFSET)
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li $r2, 's'
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bgt $r3, $r6, __error
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li $r2, #(PHYS_OFFSET + TLB_DATA_kernel_text_attr)
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li $r3, PAGE_OFFSET
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add $r6, $r6, $r3
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_tlb:
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mtsr $r3, $TLB_VPN
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dsb
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tlbop $r2, RWR
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isb
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add $r3, $r3, $r5
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add $r2, $r2, $r5
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bgt $r6, $r3, _tlb
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mfsr $r3, $TLB_MISC ! setup access page size
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li $r2, #~0xf
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and $r3, $r3, $r2
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#ifdef CONFIG_ANDES_PAGE_SIZE_8KB
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ori $r3, $r3, #0x1
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#endif
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mtsr $r3, $TLB_MISC
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mfsr $r0, $MISC_CTL ! Enable BTB and RTP and shadow sp
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ori $r0, $r0, #MISC_init
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mtsr $r0, $MISC_CTL
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mfsr $p1, $PSW
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li $r15, #~PSW_clr ! clear WBNA|DME|IME|DT|IT|POM|INTL|GIE
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and $p1, $p1, $r15
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ori $p1, $p1, #PSW_init
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mtsr $p1, $IPSW ! when iret, it will automatically enable MMU
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la $lp, __mmap_switched
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mtsr $lp, $IPC
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iret
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nop
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.type __switch_data, %object
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__switch_data:
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.long __bss_start ! $r6
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.long _end ! $r7
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.long __atags_pointer ! $atag_pointer
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.long init_task ! $r9, move to $r25
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.long init_thread_union + THREAD_SIZE ! $sp
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/*
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* The following fragment of code is executed with the MMU on in MMU mode,
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* and uses absolute addresses; this is not position independent.
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*/
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.align
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.type __mmap_switched, %function
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__mmap_switched:
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la $r3, __switch_data
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lmw.bim $r6, [$r3], $r9, #0b0001
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move $r25, $r9
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move $fp, #0 ! Clear BSS (and zero $fp)
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beq $r7, $r6, _RRT
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1: swi.bi $fp, [$r6], #4
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bne $r7, $r6, 1b
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swi $r10, [$r8]
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_RRT:
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b start_kernel
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__error:
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b __error
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