Hi. When the kernel fails to boot and its log console is silent, I use earlycon and I often find the cause of error with it. But, I have been wondering if there is an easy-to-use debug tip which is available after earlycon is disabled. I noticed the current mainline would not boot on my ARMv8 board. According to the following log, I am guessing something wrong is happening after the "bootconsole [uniphier0] disabled" log. Is there a good practice to see more log? [ 0.000000] Booting Linux on physical CPU 0x0 [ 0.000000] Linux version 4.7.0-02346-g3601fbc-dirty (yamada@beagle) (gcc version 4.9.4 20151028 (prerelease) (Linaro GCC 4.9-2016.02) ) #19 SMP PREEMPT Wed Jul 27 10:01:35 JST 2016 [ 0.000000] Boot CPU: AArch64 Processor [410fd034] [ 0.000000] earlycon: uniphier0 at MMIO 0x0000000054006800 (options '115200n8') [ 0.000000] bootconsole [uniphier0] enabled [ 0.000000] efi: Getting EFI parameters from FDT: [ 0.000000] efi: UEFI not found. [ 0.000000] cma: Reserved 16 MiB at 0x00000000bec00000 [ 0.000000] percpu: Embedded 21 pages/cpu @ffff80003ffb3000 s48128 r8192 d29696 u86016 [ 0.000000] Detected VIPT I-cache on CPU0 [ 0.000000] CPU features: enabling workaround for ARM erratum 845719 [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 258048 [ 0.000000] Kernel command line: earlycon [ 0.000000] PID hash table entries: 4096 (order: 3, 32768 bytes) [ 0.000000] Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes) [ 0.000000] Inode-cache hash table entries: 65536 (order: 7, 524288 bytes) [ 0.000000] software IO TLB [mem 0xb9c00000-0xbdc00000] (64MB) mapped at [ffff800039c00000-ffff80003dbfffff] [ 0.000000] Memory: 933680K/1048576K available (7512K kernel code, 648K rwdata, 3172K rodata, 960K init, 259K bss, 98512K reserved, 16384K cma-reserved) [ 0.000000] Virtual kernel memory layout: [ 0.000000] modules : 0xffff000000000000 - 0xffff000008000000 ( 128 MB) [ 0.000000] vmalloc : 0xffff000008000000 - 0xffff7dffbfff0000 (129022 GB) [ 0.000000] .text : 0xffff000008080000 - 0xffff0000087d0000 ( 7488 KB) [ 0.000000] .rodata : 0xffff0000087d0000 - 0xffff000008af0000 ( 3200 KB) [ 0.000000] .init : 0xffff000008af0000 - 0xffff000008be0000 ( 960 KB) [ 0.000000] .data : 0xffff000008be0000 - 0xffff000008c82000 ( 648 KB) [ 0.000000] .bss : 0xffff000008c82000 - 0xffff000008cc2d40 ( 260 KB) [ 0.000000] fixed : 0xffff7dfffe7fd000 - 0xffff7dfffec00000 ( 4108 KB) [ 0.000000] PCI I/O : 0xffff7dfffee00000 - 0xffff7dffffe00000 ( 16 MB) [ 0.000000] vmemmap : 0xffff7e0000000000 - 0xffff800000000000 ( 2048 GB maximum) [ 0.000000] 0xffff7e0000000000 - 0xffff7e0001000000 ( 16 MB actual) [ 0.000000] memory : 0xffff800000000000 - 0xffff800040000000 ( 1024 MB) [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1 [ 0.000000] Preemptible hierarchical RCU implementation. [ 0.000000] Build-time adjustment of leaf fanout to 64. [ 0.000000] RCU restricting CPUs from NR_CPUS=64 to nr_cpu_ids=2. [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=2 [ 0.000000] NR_IRQS:64 nr_irqs:64 0 [ 0.000000] GICv3: GIC: Using split EOI/Deactivate mode [ 0.000000] GICv3: CPU0: found redistributor 0 region 0:0x000000005fe40000 [ 0.000000] Architected cp15 timer(s) running at 50.00MHz (phys). [ 0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0xb8812736b, max_idle_ns: 440795202655 ns [ 0.000004] sched_clock: 56 bits at 50MHz, resolution 20ns, wraps every 4398046511100ns [ 0.008254] Console: colour dummy device 80x25 [ 0.012700] console [tty0] enabled [ 0.016110] bootconsole [uniphier0] disabled -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
