启动linux内核时打印不一致
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【中文标题】启动linux内核时打印不一致【英文标题】：Print inconsistency when booting linux kernel 【发布时间】：2017-08-03 19:02:44 【问题描述】：我正在尝试将内核 4.12 移植到我的主板上，但我遇到了一个非常奇怪的问题。
一些上下文：我使用 u-boot 作为引导加载程序，从具有设备树支持的 zImage 引导。该板有一个 Sitara AM3352。
发生的情况是有时内核会开始打印东西，但大多数情况下它什么都不做。
情况1：
U-Boot# bootz $kloadaddr - $fdtaddr
## Current stack ends at 0x83ee8bf8 Kernel image @ 0x80007fc0 [ 0x00000000 - 0x002d9430 ]
## Flattened Device Tree blob at 88000000
Booting using the fdt blob at 0x88000000
using: FDT
using: FDT
Loading Device Tree to 83edd000, end 83ee7337 ... OK
## Transferring control to Linux (at address 80007fc0)...
Starting kernel ...
情况2：
U-Boot# bootz $kloadaddr - $fdtaddr
## Current stack ends at 0x83ee8bf8 Kernel image @ 0x80007fc0 [ 0x00000000 - 0x002d9430 ]
## Flattened Device Tree blob at 88000000
Booting using the fdt blob at 0x88000000
using: FDT
using: FDT
Loading Device Tree to 83edd000, end 83ee7337 ... OK
## Transferring control to Linux (at address 80007fc0)...
Starting kernel ...
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 4.12.0R01-Beta (guilherme@epoch) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0) ) #4 Thu Aug 3 14:30:16 BRT 2017
[ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[ 0.000000] OF: fdt: Machine model: Test Board
[ 0.000000] earlycon: omapserial0 at MMIO 0x44e09000 (options '')
[ 0.000000] bootconsole [omapserial0] enabled
[ 0.000000] Memory policy: Data cache writeback
[ 0.000000] CPU: All CPU(s) started in SVC mode.
[ 0.000000] AM335X ES2.1 (neon)
[ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16256
[ 0.000000] Kernel command line: console=ttyO0,115200n8 root=/dev/mtdblock10 rw rootfstype=jffs2 noinitrd earlycon
[ 0.000000] PID hash table entries: 256 (order: -2, 1024 bytes)
[ 0.000000] Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
[ 0.000000] Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.000000] Memory: 56952K/65536K available (4096K kernel code, 179K rwdata, 1484K rodata, 1024K init, 438K bss, 8584K reserved, 0K cma-reserved, 0K highmem)
[ 0.000000] Virtual kernel memory layout:
[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[ 0.000000] fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
[ 0.000000] vmalloc : 0xc4800000 - 0xff800000 ( 944 MB)
[ 0.000000] lowmem : 0xc0000000 - 0xc4000000 ( 64 MB)
[ 0.000000] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[ 0.000000] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[ 0.000000] .text : 0xc0008000 - 0xc0500000 (5088 kB)
[ 0.000000] .init : 0xc0700000 - 0xc0800000 (1024 kB)
[ 0.000000] .data : 0xc0800000 - 0xc082cd90 ( 180 kB)
[ 0.000000] .bss : 0xc0831794 - 0xc089f2c8 ( 439 kB)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.000000] NR_IRQS:16 nr_irqs:16 16
[ 0.000000] IRQ: Found an INTC at 0xfa200000 (revision 5.0) with 128 interrupts
[ 0.000000] OMAP clockevent source: timer2 at 24000000 Hz
[ 0.000020] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
[ 0.008003] clocksource: timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
[ 0.017467] OMAP clocksource: timer1 at 24000000 Hz
[ 0.022622] clocksource_probe: no matching clocksources found
[ 0.028583] Calibrating delay loop... 599.04 BogoMIPS (lpj=1198080)
[ 0.059960] pid_max: default: 32768 minimum: 301
[ 0.064987] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.071729] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.079579] CPU: Testing write buffer coherency: ok
[ 0.085216] Setting up static identity map for 0x80100000 - 0x80100060
[ 0.095211] devtmpfs: initialized
[ 0.107961] VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 3
[ 0.116265] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[ 0.126579] futex hash table entries: 256 (order: -1, 3072 bytes)
[ 0.132888] pinctrl core: initialized pinctrl subsystem
[ 0.139759] NET: Registered protocol family 16
[ 0.145433] DMA: preallocated 256 KiB pool for atomic coherent allocations
[ 0.165036] omap_hwmod: debugss: _wait_target_disable failed
[ 0.171060] Unhandled fault: external abort on non-linefetch (0x1028) at 0xf9e3e078
[ 0.178849] pgd = c0004000
[ 0.181618] [f9e3e078] *pgd=44e11452(bad)
[ 0.185740] Internal error: : 1028 [#1] ARM
[ 0.190019] Modules linked in:
[ 0.193157] CPU: 0 PID: 1 Comm: swapper Not tainted 4.12.0R01-Beta #4
[ 0.199760] Hardware name: Generic AM33XX (Flattened Device Tree)
[ 0.206019] task: c3830000 task.stack: c382e000
[ 0.210684] PC is at _update_sysc_cache+0x2c/0x94
[ 0.215494] LR is at _enable+0x240/0x2a8
[ 0.219517] pc : [<c0120b24>] lr : [<c0121314>] psr: 40000013
[ 0.219517] sp : c382fe98 ip : c0124774 fp : 00000000
[ 0.231311] r10: c0721838 r9 : 00000045 r8 : c08317c0
[ 0.236673] r7 : c080abf0 r6 : 00000000 r5 : c0831c68 r4 : c080a5a4
[ 0.243377] r3 : f9e3e078 r2 : c080b084 r1 : f9e3e000 r0 : c080a5a4
[ 0.250083] Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 0.257409] Control: 10c5387d Table: 80004019 DAC: 00000051
[ 0.263307] Process swapper (pid: 1, stack limit = 0xc382e210)
[ 0.269296] Stack: (0xc382fe98 to 0xc3830000)
[ 0.273768] fe80: 00000000 c0121314
[ 0.282173] fea0: 00000000 a0000013 c08092a8 c0803048 c080a5a4 c080a5d4 c080a5e8 c0709328
[ 0.290574] fec0: c382fed4 d3053b52 c080ae5c d3053b52 c080a5a4 c0807808 c0709240 00000000
[ 0.298975] fee0: c08317c0 c0121718 0000100c c0803048 00000002 c07099c8 00000000 c0709a6c
[ 0.307377] ff00: 00000000 c0101794 00000154 c3ffed09 c0671b34 c0147200 000017c0 c0228d30
[ 0.315777] ff20: c0803048 c05edd2c c07005dc 00000000 00000002 00000002 00000000 c0803048
[ 0.324179] ff40: 00000000 c3ffed09 00000000 d3053b52 00000000 d3053b52 00000002 c072c0f8
[ 0.332580] ff60: 00000002 c0721820 c08317c0 c08317c0 00000045 c0700dc8 00000002 00000002
[ 0.340981] ff80: 00000000 c07005dc 00000000 c04a7cc0 00000000 00000000 00000000 00000000
[ 0.349382] ffa0: 00000000 c04a7cc8 00000000 c010dd98 00000000 00000000 00000000 00000000
[ 0.357783] ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 0.366184] ffe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff fffffffb
[ 0.374609] [<c0120b24>] (_update_sysc_cache) from [<c0121314>] (_enable+0x240/0x2a8)
[ 0.382637] [<c0121314>] (_enable) from [<c0709328>] (_setup+0xe8/0x4e8)
[ 0.389516] [<c0709328>] (_setup) from [<c0121718>] (omap_hwmod_for_each+0x38/0x60)
[ 0.397378] [<c0121718>] (omap_hwmod_for_each) from [<c0709a6c>] (__omap_hwmod_setup_all+0xa4/0xac)
[ 0.406676] [<c0709a6c>] (__omap_hwmod_setup_all) from [<c0101794>] (do_one_initcall+0x50/0x18c)
[ 0.415708] [<c0101794>] (do_one_initcall) from [<c0700dc8>] (kernel_init_freeable+0x140/0x1dc)
[ 0.424650] [<c0700dc8>] (kernel_init_freeable) from [<c04a7cc8>] (kernel_init+0x8/0x10c)
[ 0.433052] [<c04a7cc8>] (kernel_init) from [<c010dd98>] (ret_from_fork+0x14/0x3c)
[ 0.440815] Code: e3110c01 e5901054 e6f13073 1a00000c (e5933000)
[ 0.447075] ---[ end trace 396cebd12b8145f9 ]---
[ 0.451867] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[ 0.451867]
[ 0.461190] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[ 0.461190]
[ 1.373583] random: fast init done
这是我的.dts 文件：
/dts-v1/;
#include "am33xx.dtsi"
#include <dt-bindings/interrupt-controller/irq.h>
/
model = "Test Board";
compatible = "guilherme,test_board", "ti,am33xx";
memory@80000000
device_type = "memory";
reg = <0x80000000 0x04000000>; /* 64 MB */
;
chosen
stdout-path = &uart0;
bootargs ="console=ttyO0,115200n8 root=/dev/mtdblock10 rw rootfstype=jffs2 noinitrd earlycon";
;
;
虽然我预计会遇到内核恐慌，但让我烦恼的是这种打印不一致。此外，我无法确定此问题是由于某些奇怪的 u-boot 配置还是与内核本身相关的原因造成的。
【问题讨论】：
你实际有多少内存？这是定制板吗？您是否更新了内存配置信息以知道您只有 dts 所说的 64MB？ 是定制板，内存大小确实是64MB。 我可能想到了错误的内存设置和/或地址。 “打印不一致” 表示启动失败。您可以间歇性地看到内核执行初始化的事实意味着 U-Boot 和内核加载地址是可以的。间歇性启动失败确实使内存功能受到质疑。您是否在您的这块板上进行过广泛的内存测试？ 首先，由于您只有 64MB，请检查您是否正确更新了内存初始化序列。其次，由于您只有 64MB，因此只有 0x80000000 和 0x84000000 之间的区域有效。您将设备树放置在 0x88000000 （距基础 +128MB）处，发现这意味着不，部分内存配置不正确，我认为它“镜像”了 0x80000000 处的内容。您可能需要检查使用的其他地址，因为一般假设是至少 256MB，而不是 64MB。 【参考方案1】：所以，找出问题所在！当我使用之前配置的 u-Boot 时，我尝试将 u-Boot 修改保持在最低限度。在这些先前存在的配置中，有一个setenv bootargs = ...。这个bootargs 定义会覆盖.dtb 文件中的定义，从而导致冲突。一旦我删除了这个变量定义，打印问题就解决了。
系统看似随机打印的原因是因为bootargs 定义取决于用于从 SDCard 中的图像引导的引脚状态。
【讨论】：
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