来自基于 ARM Cortex A9 的主板的日志消息。运行Linux。
[Sat Apr 12 19:33:50.207 2014]
[Sat Apr 12 19:33:50.207 2014]
[Sat Apr 12 19:33:50.207 2014] U-Boot 2013.07 (Apr 09 2014 - 12:31:52)
[Sat Apr 12 19:33:50.207 2014]
[Sat Apr 12 19:33:50.207 2014] Memory: ECC disabled
[Sat Apr 12 19:33:50.207 2014] DRAM: 1 GiB
[Sat Apr 12 19:33:50.224 2014] MMC: zynq_sdhci: 0
[Sat Apr 12 19:33:50.224 2014] SF: Detected N25Q128A with page size 64 KiB, total 16 MiB
[Sat Apr 12 19:33:50.245 2014] In: serial
[Sat Apr 12 19:33:50.245 2014] Out: serial
[Sat Apr 12 19:33:50.245 2014] Err: serial
[Sat Apr 12 19:33:50.245 2014]
[Sat Apr 12 19:33:50.245 2014] boot Petalinux
[Sat Apr 12 19:33:50.303 2014] Device: zynq_sdhci
[Sat Apr 12 19:33:50.303 2014] Manufacturer ID: 2
[Sat Apr 12 19:33:50.303 2014] OEM: 544d
[Sat Apr 12 19:33:50.303 2014] Name: SA04G
[Sat Apr 12 19:33:50.303 2014] Tran Speed: 50000000
[Sat Apr 12 19:33:50.303 2014] Rd Block Len: 512
[Sat Apr 12 19:33:50.303 2014] SD version 3.0
[Sat Apr 12 19:33:50.303 2014] High Capacity: Yes
[Sat Apr 12 19:33:50.303 2014] Capacity: 3.7 GiB
[Sat Apr 12 19:33:50.303 2014] Bus Width: 4-bit
[Sat Apr 12 19:33:50.303 2014] reading image.ub
[Sat Apr 12 19:33:50.520 2014] 1395836 bytes read in 166 ms (8 MiB/s)
[Sat Apr 12 19:33:50.520 2014] ## Loading kernel from FIT Image at 01000000 ...
[Sat Apr 12 19:33:50.520 2014] Using 'conf@1' configuration
[Sat Apr 12 19:33:50.520 2014] Trying 'kernel@1' kernel subimage
[Sat Apr 12 19:33:50.520 2014] Description: PetaLinux Kernel
[Sat Apr 12 19:33:50.520 2014] Type: Kernel Image
[Sat Apr 12 19:33:50.520 2014] Compression: gzip compressed
[Sat Apr 12 19:33:50.520 2014] Data Start: 0x010000f0
[Sat Apr 12 19:33:50.520 2014] Data Size: 1383397 Bytes = 1.3 MiB
[Sat Apr 12 19:33:50.520 2014] Architecture: ARM
[Sat Apr 12 19:33:50.520 2014] OS: Linux
[Sat Apr 12 19:33:50.520 2014] Load Address: 0x00008000
[Sat Apr 12 19:33:50.520 2014] Entry Point: 0x00008000
[Sat Apr 12 19:33:50.520 2014] Hash algo: crc32
[Sat Apr 12 19:33:50.520 2014] Hash value: c02e0858
[Sat Apr 12 19:33:50.520 2014] Verifying Hash Integrity ... crc32+ OK
[Sat Apr 12 19:33:50.579 2014] ## Loading fdt from FIT Image at 01000000 ...
[Sat Apr 12 19:33:50.579 2014] Using 'conf@1' configuration
[Sat Apr 12 19:33:50.579 2014] Trying 'fdt@1' fdt subimage
[Sat Apr 12 19:33:50.579 2014] Description: Flattened Device Tree blob
[Sat Apr 12 19:33:50.579 2014] Type: Flat Device Tree
[Sat Apr 12 19:33:50.579 2014] Compression: uncompressed
[Sat Apr 12 19:33:50.579 2014] Data Start: 0x01151dbc
[Sat Apr 12 19:33:50.579 2014] Data Size: 11101 Bytes = 10.8 KiB
[Sat Apr 12 19:33:50.579 2014] Architecture: ARM
[Sat Apr 12 19:33:50.579 2014] Hash algo: crc32
[Sat Apr 12 19:33:50.579 2014] Hash value: 5e16707d
[Sat Apr 12 19:33:50.579 2014] Hash algo: sha1
[Sat Apr 12 19:33:50.579 2014] Hash value: 0af07559d7f0578246fb91abe17c7987dcee216a
[Sat Apr 12 19:33:50.579 2014] Verifying Hash Integrity ... crc32+ sha1+ OK
[Sat Apr 12 19:33:50.596 2014] Booting using the fdt blob at 0x1151dbc
[Sat Apr 12 19:33:50.596 2014] Uncompressing Kernel Image ... OK
[Sat Apr 12 19:33:50.692 2014] Loading Device Tree to 07ffa000, end 07fffb5c ... OK
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:50.692 2014] Starting kernel ...
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:51.298 2014] Booting Linux on physical CPU 0x0
[Sat Apr 12 19:33:51.298 2014] Linux version 3.8.11 (root@xilinx) (gcc version 4.7.3 (Sourcery CodeBench Lite 2013.05-40) ) #2 SMP PREEMPT Sat Apr 12 19:11:59 IST 2014
[Sat Apr 12 19:33:51.298 2014] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=18c53c7d
[Sat Apr 12 19:33:51.298 2014] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[Sat Apr 12 19:33:51.298 2014] Machine: Xilinx Zynq Platform, model: Xilinx-ZC702-14.7
[Sat Apr 12 19:33:51.298 2014] Memory policy: ECC disabled, Data cache writealloc
[Sat Apr 12 19:33:51.298 2014] PERCPU: Embedded 7 pages/cpu @c0af2000 s5568 r8192 d14912 u32768
[Sat Apr 12 19:33:51.298 2014] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 260096
[Sat Apr 12 19:33:51.342 2014] Kernel command line: console=ttyPS0,115200
[Sat Apr 12 19:33:51.342 2014] PID hash table entries: 4096 (order: 2, 16384 bytes)
[Sat Apr 12 19:33:51.342 2014] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[Sat Apr 12 19:33:51.342 2014] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[Sat Apr 12 19:33:51.343 2014] __ex_table already sorted, skipping sort
[Sat Apr 12 19:33:51.343 2014] Memory: 1024MB = 1024MB total
[Sat Apr 12 19:33:51.343 2014] Memory: 1036484k/1036484k available, 12092k reserved, 270336K highmem
[Sat Apr 12 19:33:51.343 2014] Virtual kernel memory layout:
[Sat Apr 12 19:33:51.343 2014] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[Sat Apr 12 19:33:51.343 2014] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
[Sat Apr 12 19:33:51.387 2014] vmalloc : 0xf0000000 - 0xff000000 ( 240 MB)
[Sat Apr 12 19:33:51.387 2014] lowmem : 0xc0000000 - 0xef800000 ( 760 MB)
[Sat Apr 12 19:33:51.387 2014] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[Sat Apr 12 19:33:51.387 2014] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[Sat Apr 12 19:33:51.387 2014] .text : 0xc0008000 - 0xc0208d94 (2052 kB)
[Sat Apr 12 19:33:51.387 2014] .init : 0xc0209000 - 0xc02b55c0 ( 690 kB)
[Sat Apr 12 19:33:51.387 2014] .data : 0xc02b6000 - 0xc02d3ea0 ( 120 kB)
[Sat Apr 12 19:33:51.387 2014] .bss : 0xc02d3ea0 - 0xc02e6898 ( 75 kB)
[Sat Apr 12 19:33:51.387 2014] Preemptible hierarchical RCU implementation.
[Sat Apr 12 19:33:51.387 2014] RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=2.
[Sat Apr 12 19:33:51.435 2014] NR_IRQS:16 nr_irqs:16 16
[Sat Apr 12 19:33:51.435 2014] MIO pin 47 not assigned(00001220)
[Sat Apr 12 19:33:51.435 2014] xslcr mapped to f0002000
[Sat Apr 12 19:33:51.435 2014] Zynq clock init
[Sat Apr 12 19:33:51.435 2014] sched_clock: 16 bits at 54kHz, resolution 18432ns, wraps every 1207ms
[Sat Apr 12 19:33:51.435 2014] ps7-ttc #0 at f0004000, irq=43
[Sat Apr 12 19:33:51.435 2014] Console: colour dummy device 80x30
[Sat Apr 12 19:33:51.435 2014] Calibrating delay loop... 1332.01 BogoMIPS (lpj=6660096)
[Sat Apr 12 19:33:51.435 2014] pid_max: default: 4096 minimum: 301
[Sat Apr 12 19:33:51.435 2014] Mount-cache hash table entries: 512
[Sat Apr 12 19:33:51.435 2014] CPU: Testing write buffer coherency: ok
[Sat Apr 12 19:33:51.435 2014] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[Sat Apr 12 19:33:51.435 2014] Setting up static identity map for 0x1b6990 - 0x1b69c4
[Sat Apr 12 19:33:51.476 2014] L310 cache controller enabled
[Sat Apr 12 19:33:51.476 2014] l2x0: 8 ways, CACHE_ID 0x000000c0, AUX_CTRL 0x72360000, Cache size: 524288 B
[Sat Apr 12 19:33:51.476 2014] CPU1: Booted secondary processor
[Sat Apr 12 19:33:51.476 2014] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[Sat Apr 12 19:33:51.476 2014] Brought up 2 CPUs
[Sat Apr 12 19:33:51.476 2014] SMP: Total of 2 processors activated (2664.03 BogoMIPS).
[Sat Apr 12 19:33:51.476 2014] devtmpfs: initialized
[Sat Apr 12 19:33:51.476 2014] NET: Registered protocol family 16
[Sat Apr 12 19:33:51.476 2014] I reach build/linux/kernel/xlnx-3.8/source/net/socket.c:
[Sat Apr 12 19:33:51.476 2014] DMA: preallocated 256 KiB pool for atomic coherent allocations
[Sat Apr 12 19:33:51.476 2014] xgpiops e000a000.ps7-gpio: gpio at 0xe000a000 mapped to 0xf004e000
[Sat Apr 12 19:33:51.518 2014] GPIO IRQ not connected
[Sat Apr 12 19:33:51.518 2014] XGpio: /amba@0/gpio@41220000: registered, base is 255
[Sat Apr 12 19:33:51.518 2014] GPIO IRQ not connected
[Sat Apr 12 19:33:51.518 2014] XGpio: /amba@0/gpio@41200000: registered, base is 251
[Sat Apr 12 19:33:51.518 2014] usbcore: registered new interface driver usbfs
[Sat Apr 12 19:33:51.518 2014] usbcore: registered new interface driver hub
[Sat Apr 12 19:33:51.518 2014] usbcore: registered new device driver usb
[Sat Apr 12 19:33:51.518 2014] Switching to clocksource xttcps_clocksource
[Sat Apr 12 19:33:51.518 2014] e0001000.serial: ttyPS0 at MMIO 0xe0001000 (irq = 82) is a xuartps
[Sat Apr 12 19:33:51.518 2014] console [ttyPS0] enabled
[Sat Apr 12 19:33:51.534 2014] xdevcfg f8007000.ps7-dev-cfg: ioremap f8007000 to f0052000 with size 100
[Sat Apr 12 19:33:51.548 2014] xqspips e000d000.ps7-qspi: master is unqueued, this is deprecated
[Sat Apr 12 19:33:51.566 2014] m25p80 spi32766.0: found n25q128, expected n25q128
[Sat Apr 12 19:33:51.566 2014] m25p80 spi32766.0: n25q128 (16384 Kbytes)
[Sat Apr 12 19:33:51.566 2014] 4 ofpart partitions found on MTD device spi32766.0
[Sat Apr 12 19:33:51.566 2014] Creating 4 MTD partitions on "spi32766.0":
[Sat Apr 12 19:33:51.566 2014] 0x000000000000-0x000000500000 : "boot"
[Sat Apr 12 19:33:51.566 2014] 0x000000500000-0x000000520000 : "bootenv"
[Sat Apr 12 19:33:51.580 2014] 0x000000520000-0x0000006416c0 : "image"
[Sat Apr 12 19:33:51.580 2014] mtd: partition "image" doesn't end on an erase block -- force read-only
[Sat Apr 12 19:33:51.580 2014] 0x0000006416c0-0x000000a416c0 : "jffs2"
[Sat Apr 12 19:33:51.580 2014] mtd: partition "jffs2" doesn't start on an erase block boundary -- force read-only
[Sat Apr 12 19:33:51.598 2014] xqspips e000d000.ps7-qspi: at 0xE000D000 mapped to 0xF0054000, irq=51
[Sat Apr 12 19:33:51.598 2014] libphy: XEMACPS mii bus: probed
[Sat Apr 12 19:33:51.613 2014] xemacps e000b000.ps7-ethernet: invalid address, use assigned
[Sat Apr 12 19:33:51.613 2014] xemacps e000b000.ps7-ethernet: MAC updated ce:5e:a9:56:ee:44
[Sat Apr 12 19:33:51.613 2014] xemacps e000b000.ps7-ethernet: pdev->id -1, baseaddr 0xe000b000, irq 54
[Sat Apr 12 19:33:51.630 2014] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[Sat Apr 12 19:33:51.630 2014] ULPI transceiver vendor/product ID 0x0424/0x0007
[Sat Apr 12 19:33:51.630 2014] Found SMSC USB3320 ULPI transceiver.
[Sat Apr 12 19:33:51.630 2014] ULPI integrity check: passed.
[Sat Apr 12 19:33:51.646 2014] xusbps-ehci xusbps-ehci.0: Xilinx PS USB EHCI Host Controller
[Sat Apr 12 19:33:51.646 2014] xusbps-ehci xusbps-ehci.0: new USB bus registered, assigned bus number 1
[Sat Apr 12 19:33:51.660 2014] xusbps-ehci xusbps-ehci.0: irq 53, io mem 0x00000000
[Sat Apr 12 19:33:51.677 2014] xusbps-ehci xusbps-ehci.0: USB 2.0 started, EHCI 1.00
[Sat Apr 12 19:33:51.696 2014] hub 1-0:1.0: USB hub found
[Sat Apr 12 19:33:51.696 2014] hub 1-0:1.0: 1 port detected
[Sat Apr 12 19:33:51.696 2014] xi2cps e0004000.ps7-i2c: 400 kHz mmio e0004000 irq 57
[Sat Apr 12 19:33:51.696 2014] xadcps f8007100.ps7-xadc: enabled: yes reference: external
[Sat Apr 12 19:33:51.716 2014] xwdtps f8005000.ps7-wdt: Xilinx Watchdog Timer at f0074000 with timeout 10s
[Sat Apr 12 19:33:51.716 2014] sdhci: Secure Digital Host Controller Interface driver
[Sat Apr 12 19:33:51.716 2014] sdhci: Copyright(c) Pierre Ossman
[Sat Apr 12 19:33:51.716 2014] sdhci-pltfm: SDHCI platform and OF driver helper
[Sat Apr 12 19:33:51.736 2014] usbcore: registered new interface driver usbhid
[Sat Apr 12 19:33:51.736 2014] usbhid: USB HID core driver
[Sat Apr 12 19:33:51.736 2014] I am at build/linux/kernel/xlnx-3.8/source/drivers/hid/usbhid/hid-core.c
[Sat Apr 12 19:33:51.736 2014] VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4
[Sat Apr 12 19:33:51.746 2014] Freeing init memory: 688K
[Sat Apr 12 19:33:51.759 2014]
[Sat Apr 12 19:33:51.759 2014] Hello world from myinit.c!
问题就在这里：
[Sat Apr 12 19:33:50.692 2014] Starting kernel ...
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:51.298 2014] Booting Linux on physical CPU 0x0
大约 0.6 秒后开始启动。我怎样才能让它更快？我希望启动应该在 0.1 秒后开始Starting kernel ...
我应该重点改进什么？
更新
我又带着同样的问题回来了。
我想知道“之后调用了什么函数”启动内核...“。我已将几个 printf 和 printk 语句放入以下文件中，但到目前为止没有得到任何有用的东西：
1-引导程序
2-安装程序.c
3-主程序
我仍然收到这些消息：
[Sat Apr 12 19:33:50.692 2014] Starting kernel ...
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:51.298 2014] Booting Linux on physical CPU 0x0
我无法找到这两条消息之间的时间间隔。即使我知道这两条线之间的软件控制，它也会帮助我找到根本原因。
我特别想知道这两条消息之间正在执行哪一行代码。
我知道这些行之间可能会发生一些初始化，但是相同的代码在哪里？
问题是没有 main() 函数，所以我无法在上面的文件中找到函数调用的顺序。
答案1
在这 0.6 秒内，事情发生了。 U-Boot 打印“Starting kernel”之前的所有消息。Linux 内核打印“Booting Linux”之后的所有消息。内核需要初始化自己的数据结构和许多外围设备（足以打印跟踪）。这需要时间。
您可以通过阅读以下内容来了解内核正在做什么main。 “Booting Linux”消息来自拨电至smp_setup_processor_id。
您可以在调试器中跟踪代码以查看它在哪里花费了时间。例如，可能正在初始化一些不必要的硬件。但目前不太可能有任何收获。
答案2
我猜想这与引导加载程序和内核的方式有很大关系胶合。 Hallinan's Embedded Linux Primer 中的第 5.1.3 节（引导加载程序）对此有以下说明：
一些引导加载程序对内核映像执行校验和验证，并且大多数引导加载程序会解压缩并重新定位内核映像。在这种情况下，引导加载程序和引导加载程序之间的区别很简单：引导加载程序在加电时控制主板，并且不以任何方式依赖 Linux 内核。相比之下，引导加载程序的主要目的是充当裸机引导加载程序和 Linux 内核之间的粘合剂。引导加载程序负责为内核运行提供适当的上下文，并执行必要的步骤来解压缩和重新定位内核二进制映像
如果你看到它的图像，你会发现在内核实际执行之前，head.s汇编head-<arch>.s例程被执行。由于内核不在内存中，因此必须完成一些其他任务，例如内核解压到内存内核本身形式 ( vmlinux) 但被压缩并且胶合将这些例程作为piggy.gz图像。
虽然这是特定于架构的，但我认为它可以解释从 Uboot 切换到内核之间的额外时间。
答案3
您从函数开始do_bootm_linux，bootm.c然后逐步编写代码。您还可以尝试添加参数debug或loglevel=7在启动内核时获取更多信息。