Часть 4: Всё-таки запускаем Linux на RocketChip RISC-V

wqcwaewtqxjju-xcycuspdxaipe.jpegНа картинке Linux kernel шлёт вам привет через GPIO.

В этой части истории с портированием RISC-V RocketChip на китайскую плату с Cyclone IV мы всё-таки запустим Linux, а также научимся сами конфигурировать IP Core контроллера памяти и чуть подредактируем dts-описание аппаратуры. Эта статья является продолжением третьей части, но, в отличие от изрядно разросшейся предыдущей, она будет довольно короткой.

… Поскольку setup_smp вызывается, только если ядро сконфигурировано с поддержкой SMP, можно попробовать отключить многоядерность. Будет неприятно, если мне нужно будет ещё и реализовывать в модуле памяти поддержку атомарности (мне казалось, с этим кеш возится самостоятельно), но в одноядерном случае оно нам помешать не должно.


Всё равно не взлетело…
[    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
[    0.000000] Linux version 4.19.0-sifive-1+ (trosinenko@trosinenko-pc) (gcc version 8.3.0 (Buildroot 2019.02-07449-g4eddd28f99)) #1 Thu Jul 4 18:38:10 MSK 2019
[    0.000000] bootconsole [early0] enabled
[    0.000000] Initial ramdisk at: 0x(____ptrval____) (16777216 bytes)
[    0.000000] Zone ranges:
[    0.000000]   DMA32    [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000]   Normal   [mem 0x00000000c0000000-0x00000bffffffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] software IO TLB: mapped [mem 0xbb1fc000-0xbf1fc000] (64MB)
[    0.000000] Unable to find "cpu" devicetree entry
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 258055
[    0.000000] Kernel command line: debug console=ttySIF0,125200 root=/dev/mmcblk0p2 loglevel=7 rootwait
[    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] Sorting __ex_table...
[    0.000000] BUG: Bad page state in process swapper  pfn:80bf7
[    0.000000] page:ffffffe03f029e08 count:0 mapcount:-65280 mapping:0000000000000000 index:0x1
[    0.000000] flags: 0x0()
[    0.000000] raw: 0000000000000000 0000000000000100 0000000000000200 0000000000000000
[    0.000000] raw: 0000000000000001 0000000000000000 00000000ffff00ff
[    0.000000] page dumped because: nonzero mapcount
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-sifive-1+ #1
[    0.000000] Call Trace:
[    0.000000] [] walk_stackframe+0x0/0xa0
[    0.000000] [] show_stack+0x2a/0x34
[    0.000000] [] chachachllachachachTradeonachachach_inachachipachachachachllachachachTradeonachachachdevachachachypachachachllachachachTradeona+0x20/0x28
[    0.000000] [] bad_page+0xe4/0x102
[    0.000000] [] free_pages_check_bad+0x38/0x7a
[    0.000000] [] free_pcppages_bulk+0x106/0x36c
[    0.000000] [] free_unref_page_commit.isra.23+0x86/0x8e
[    0.000000] [] free_unref_page+0x44/0x58
[    0.000000] [] __free_pages.part.28+0xe/0x22
[    0.000000] [] __free_pages_bootmem+0x86/0x90
[    0.000000] [] free_all_bootmem+0x156/0x1ba
[    0.000000] [] mem_init+0x36/0x44
[    0.000000] [] start_kernel+0x1aa/0x328
[    0.000000] [] _sinittext+0x58/0x5c
[    0.000000] Disabling lock debugging due to kernel taint
[    0.000000] BUG: Bad page state in process swapper  pfn:80bf9
[    0.000000] page:ffffffe03f029e78 count:0 mapcount:-65280 mapping:0000000000000000 index:0x0
[    0.000000] flags: 0x0()
[    0.000000] raw: 0000000000000000 ffffffe03f020080 ffffffe03f020080 0000000000000000
[    0.000000] raw: 0000000000000000 0000000000000000 00000000ffff00ff
[    0.000000] page dumped because: nonzero mapcount
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Tainted: G    B             4.19.0-sifive-1+ #1
[    0.000000] Call Trace:
[    0.000000] [] walk_stackframe+0x0/0xa0
[    0.000000] [] show_stack+0x2a/0x34
[    0.000000] [] chachachllachachachTradeonachachach_inachachipachachachachllachachachTradeonachachachdevachachachypachachachllachachachTradeona+0x20/0x28
[    0.000000] [] bad_page+0xe4/0x102
[    0.000000] [] free_pages_check_bad+0x38/0x7a
[    0.000000] [] __free_pages_ok+0x3fe/0x430
[    0.000000] [] __free_pages.part.28+0x1a/0x22
[    0.000000] [] __free_pages_bootmem+0x86/0x90
[    0.000000] [] free_all_bootmem+0x156/0x1ba
[    0.000000] [] mem_init+0x36/0x44
[    0.000000] [] start_kernel+0x1aa/0x328
[    0.000000] [] _sinittext+0x58/0x5c
[    0.000000] BUG: Bad page state in process swapper  pfn:80bfa
[    0.000000] page:ffffffe03f029eb0 count:0 mapcount:-65280 mapping:0000000000000000 index:0x0
[    0.000000] flags: 0x0()
[    0.000000] raw: 0000000000000000 ffffffe03f0200b8 ffffffe03f0200b8 0000000000000000
[    0.000000] raw: 0000000000000000 0000000000000000 00000000ffff00ff
[    0.000000] page dumped because: nonzero mapcount
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Tainted: G    B             4.19.0-sifive-1+ #1
[    0.000000] Call Trace:
[    0.000000] [] walk_stackframe+0x0/0xa0
[    0.000000] [] show_stack+0x2a/0x34
[    0.000000] [] chachachllachachachTradeonachachach_inachachipachachachachllachachachTradeonachachachdevachachachypachachachllachachachTradeona+0x20/0x28
[    0.000000] [] bad_page+0xe4/0x102
[    0.000000] [] free_pages_check_bad+0x38/0x7a
[    0.000000] [] __free_pages_ok+0x3fe/0x430
[    0.000000] [] __free_pages.part.28+0x1a/0x22
[    0.000000] [] __free_pages_bootmem+0x86/0x90
[    0.000000] [] free_all_bootmem+0x156/0x1ba
[    0.000000] [] mem_init+0x36/0x44
[    0.000000] [] start_kernel+0x1aa/0x328
[    0.000000] [] _sinittext+0x58/0x5c
[    0.000000] BUG: Bad page state in process swapper  pfn:80bfb
[    0.000000] page:ffffffe03f029ee8 count:0 mapcount:-65280 mapping:0000000000000000 index:0x0
[    0.000000] flags: 0x0()
[    0.000000] raw: 0000000000000000 ffffffe03f0200f0 ffffffe03f0200f0 0000000000000000
[    0.000000] raw: 0000000000000000 0000000000000000 00000000ffff00ff
[    0.000000] page dumped because: nonzero mapcount
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Tainted: G    B             4.19.0-sifive-1+ #1
[    0.000000] Call Trace:
[    0.000000] [] walk_stackframe+0x0/0xa0
[    0.000000] [] show_stack+0x2a/0x34
[    0.000000] [] chachachllachachachTradeonachachach_inachachipachachachachllachachachTradeonachachachdevachachachypachachachllachachachTradeona+0x20/0x28
[    0.000000] [] bad_page+0xe4/0x102
[    0.000000] [] free_pages_check_bad+0x38/0x7a
[    0.000000] [] __free_pages_ok+0x3fe/0x430
[    0.000000] [] __free_pages.part.28+0x1a/0x22
[    0.000000] [] __free_pages_bootmem+0x86/0x90
[    0.000000] [] free_all_bootmem+0x156/0x1ba
[    0.000000] [] mem_init+0x36/0x44
[    0.000000] [] start_kernel+0x1aa/0x328
[    0.000000] [] _sinittext+0x58/0x5c
[    0.000000] BUG: Bad page state in process swapper  pfn:80bfc
[    0.000000] page:ffffffe03f029f20 count:0 mapcount:-65280 mapping:0000000000000000 index:0x0
[    0.000000] flags: 0x0()
[    0.000000] raw: 0000000000000000 ffffffe03f020028 ffffffe03f020028 0000000000000000
[    0.000000] raw: 0000000000000000 0000000000000000 00000000ffff00ff
...

Занятно, что после всей отладки я решил посмотреть, как должен выглядеть «референсный» вывод ядра, сказал make qemu, и увидел аналогичную ошибку.

Увы, следующий уровень (Linux kernel) сложнее: GDB, подключённый через JTAG к RocketChip, работает, по-видимому, с физическими адресами вне зависимости от того, как настроено MMU, а ядро в интересующий нас момент уже настроило отображение адресов, поэтому просто сказать display/10i $pc не получится — увидим лишь много unimp. Зато, если мы уже выяснили смещение (похоже, что 0x80200000 -> 0xffffffe000000000), то можно схитрить:

1: x/10i $pc
=> 0xffffffe000002436 :      unimp
   0xffffffe000002438 :    unimp
   0xffffffe00000243a :    unimp
   0xffffffe00000243c :    unimp
   0xffffffe00000243e :    unimp
   0xffffffe000002440 :   unimp
   0xffffffe000002442 :   unimp
   0xffffffe000002444 :   unimp
   0xffffffe000002446 :   unimp
   0xffffffe000002448 :   unimp
(gdb) undisplay 1
(gdb) display/10i ($pc - 0xffffffe000002436 + 0x80202436)
2: x/10i ($pc - 0xffffffe000002436 + 0x80202436)
   0x80202436:  addi    sp,sp,-96
   0x80202438:  sd      s0,80(sp)
   0x8020243a:  sd      s1,72(sp)
   0x8020243c:  sd      s2,64(sp)
   0x8020243e:  sd      s3,56(sp)
   0x80202440:  sd      s4,48(sp)
   0x80202442:  sd      s5,40(sp)
   0x80202444:  sd      s6,32(sp)
   0x80202446:  sd      s7,24(sp)
   0x80202448:  sd      s8,16(sp)

Брекпоинты проставляются аналогично:

(gdb) p setup_smp
$1 = {} 0xffffffe000002436 
(gdb) b *0x80202436
Breakpoint 1 at 0x80202436
(gdb) c
Continuing.

Program received signal SIGTRAP, Trace/breakpoint trap.
setup_smp () at /home/trosinenko/freedom-u-sdk/linux/arch/riscv/kernel/smpboot.c:58
58              while ((dn = of_find_node_by_type(dn, "cpu"))) {
(gdb) bt
#0  setup_smp () at /home/trosinenko/freedom-u-sdk/linux/arch/riscv/kernel/smpboot.c:58
#1  0xffffffe0000022a2 in setup_arch () at /home/trosinenko/freedom-u-sdk/linux/arch/riscv/kernel/setup.c:253
#2  0x0000000000000000 in ?? ()
Backtrace stopped: frame did not save the PC

Вот только их приходится вручную снимать, чтобы пойти дальше — для GDB это какой-то совершенно непонятный trap. Ах да, если вы случайно скажете s или n вместо si, gdb попытается вставить неявный брекпоинт, который по понятным причинам не выставится, но и отговорить GDB уже никак. Но не спешите перезагружать плату — по моим наблюдениям, достаточно перезапустить только gdb (учтите, что старые breakpoint-ы, возможно, не исчезнут).

Собственно, придётся разбираться с изначальной проблемой: расстановка отладочных printk в функцию of_find_node_by_type, используемую кодом поиска загрузочного процессорного ядра, показывает, что оно видит какой-то мусор вместо названий типов устройств. Например, оно откуда-то берёт строчку «Serial port», хотя такого явно нет в dtb в поле device_type. Поискав эти байты в образе ядра, я их нашёл, посмотрел на смещение, и понял очевидное: размер ядра в параметрах загрузки явно недооценён: ему выделено 8Mb, а занимает оно больше десяти. Выделил 16Mb, но странности не прекратились. После плясок с чтением FDT с разных адресов (штатно адрес передаётся ядру в регистре a1), я, наконец, решил трассировать, а что же сейчас там парсится. К счастью, вместо хождений с отладчиком (а мы помним, что есть нюансы с трансляцией адресов, которые ещё нужно так или иначе решить), можно просто и костыльно в файле drivers/of/fdt.c указать #define pr_debug printk. В итоге получилось:


добавление отладочного вывода
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 3db0d71d128b..fac47df9d1db 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -173,6 +173,7 @@ asmlinkage void __init setup_vm(void)

 void __init parse_dtb(unsigned int hartid, void *dtb)
 {
+       printk("HART = %u DTB = %lx\n", hartid, dtb);
        early_init_dt_scan(__va(dtb));
 }

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 74eaedd5b860..c019e4158e1d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -940,10 +940,12 @@ struct device_node *of_find_node_by_type(struct device_node *from,
        unsigned long flags;

        raw_spin_lock_irqsave(&devtree_lock, flags);
-       for_each_of_allnodes_from(from, np)
+       for_each_of_allnodes_from(from, np) {
+               printk("%lx %lx [%s] | [%s]\n", from, np, np->type, type);
                if (np->type && (of_node_cmp(np->type, type) == 0)
                    && of_node_get(np))
                        break;
+       }
        of_node_put(from);
        raw_spin_unlock_irqrestore(&devtree_lock, flags);
        return np;
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 800ad252cf9c..2b45870ebada 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -31,6 +31,8 @@

 #include "of_private.h"

+#define pr_debug printk
+
 /*
  * of_fdt_limit_memory - limit the number of regions in the /memory node
  * @limit: maximum entries
@@ -1253,6 +1255,7 @@ bool __init early_init_dt_scan(void *params)
  */
 void __init unflatten_device_tree(void)
 {
+       printk("INITIAL: %lx\n", initial_boot_params);
        __unflatten_device_tree(initial_boot_params, NULL, &of_root,
                                early_init_dt_alloc_memory_arch, false);


Вывод на железе
                SIFIVE, INC.

         5555555555555555555555555
        5555                   5555
       5555                     5555
      5555                       5555
     5555       5555555555555555555555
    5555       555555555555555555555555
   5555                             5555
  5555                               5555
 5555                                 5555
5555555555555555555555555555          55555
 55555           555555555           55555
   55555           55555           55555
     55555           5           55555
       55555                   55555
         55555               55555
           55555           55555
             55555       55555
               55555   55555
                 555555555
                   55555
                     5

           SiFive RISC-V Core IP
 {
  #address-cells = <0x00000001>;
  #size-cells = <0x00000001>;
  compatible = "freechips,rocketchip-unknown-dev";
  model = "freechips,rocketchip-unknown";
  chosen {
    linux,initrd-start = <0x82000000>;
    riscv,kernel-end = <0x81200000>;
    riscv,kernel-start = <0x80200000>;
    #address-cells = <0x00000001>;
    #size-cells = <0x00000000>;
    bootargs = <0x64656275 0x6720636f 0x6e736f6c 0x653d7474 0x79534946 0x302c3132 0x35323030 0x20726f6f 0x743d2f64 0x65762f6d 0x6d63626c 0x6b307032 0x206c6f67 0x6c657665 0x6c3d3720 0x726f6f74 0x77616974>;
  }
  firmware {
    sifive,uboot = "YYYY-MM-DD";
  }
  aliases {
    serial0 = <0x2f736f63 0x2f736572 0x69616c40 0x36343030 0x30303030>;
  }
  cpus {
    #address-cells = <0x00000001>;
    #size-cells = <0x00000000>;
    cpu@0 {
      device_type = "cpu";
      clock-frequency = <0x00000000>;
      compatible = "sifive,rocket0", "riscv";
      d-cache-block-size = <0x00000010>;
      d-cache-sets = <0x00000040>;
      d-cache-size = <0x00001000>;
      d-tlb-sets = <0x00000001>;
      d-tlb-size = <0x00000020>;
      i-cache-block-size = <0x00000010>;
      i-cache-sets = <0x00000040>;
      i-cache-size = <0x00001000>;
      i-tlb-sets = <0x00000001>;
      i-tlb-size = <0x00000020>;
      mmu-type = "riscv,sv39";
      next-level-cache = <0x00000001>;
      reg = <0x00000000>;
      riscv,isa = "rv64imafdc";
      status = "okay";
      timebase-frequency = <0x000f4240>;
      tlb-split;
      interrupt-controller {
        #interrupt-cells = <0x00000001>;
        compatible = "riscv,cpu-intc";
        interrupt-controller;
        phandle = <0x00000002>;
      }
    }
  }
  ram@80000000 {
    device_type = "memory";
    reg = <0x80000000 0x40000000>;
    reg-names = "mem";
    phandle = <0x00000001>;
  }
  soc {
    #address-cells = <0x00000001>;
    #size-cells = <0x00000001>;
    compatible = "freechips,rocketchip-unknown-soc", "simple-bus";
    ranges;
    clint@2000000 {
      compatible = "riscv,clint0";
      interrupts-extended = <0x00000002 0x00000003 0x00000002 0x00000007>;
      reg = <0x02000000 0x00010000>;
      reg-names = "control";
    }
    debug-controller@0 {
      compatible = "sifive,debug-013", "riscv,debug-013";
      interrupts-extended = <0x00000002 0x0000ffff>;
      reg = <0x00000000 0x00001000>;
      reg-names = "control";
    }
    gpio@64002000 {
      #gpio-cells = <0x00000002>;
      #interrupt-cells = <0x00000002>;
      compatible = "sifive,gpio0";
      gpio-controller;
      interrupt-controller;
      interrupt-parent = <0x00000003>;
      interrupts = <0x00000003 0x00000004 0x00000005 0x00000006 0x00000007 0x00000008>;
      reg = <0x64002000 0x00001000>;
      reg-names = "control";
    }
    interrupt-controller@c000000 {
      #interrupt-cells = <0x00000001>;
      compatible = "riscv,plic0";
      interrupt-controller;
      interrupts-extended = <0x00000002 0x0000000b 0x00000002 0x00000009>;
      reg = <0x0c000000 0x04000000>;
      reg-names = "control";
      riscv,max-priority = <0x00000007>;
      riscv,ndev = <0x00000008>;
      phandle = <0x00000003>;
    }
    rom@10000 {
      compatible = "sifive,maskrom0";
      reg = <0x00010000 0x00002000>;
      reg-names = "mem";
    }
    serial@64000000 {
      compatible = "sifive,uart0";
      interrupt-parent = <0x00000003>;
      interrupts = <0x00000002>;
      reg = <0x64000000 0x00001000>;
      reg-names = "control";
    }
    spi@64001000 {
      #address-cells = <0x00000001>;
      #size-cells = <0x00000000>;
      compatible = "sifive,spi0";
      interrupt-parent = <0x00000003>;
      interrupts = <0x00000001>;
      reg = <0x64001000 0x00001000>;
      reg-names = "control";
      mmc@0 {
        compatible = "mmc-spi-slot";
        disable-wp;
        reg = <0x00000000>;
        spi-max-frequency = <0x01312d00>;
        voltage-ranges = <0x00000ce4 0x00000ce4>;
      }
    }
    tlclk {
      #clock-cells = <0x00000000>;
      clock-frequency = <0x017d7840>;
      clock-output-names = "tlclk";
      compatible = "fixed-clock";
    }
  }
}
[    0.000000] HART = 0 DTB = 81200000
[    0.000000] search "chosen", depth: 0, uname:
[    0.000000] search "chosen", depth: 1, uname: chosen
[    0.000000] Looking for initrd properties...
[    0.000000] Command line is: debug console=ttySIF0,125200 root=/dev/mmcblk0p2 loglevel=7 rootwait
[    0.000000] dt_root_size_cells = 1
[    0.000000] dt_root_addr_cells = 1
[    0.000000] memory scan node ram@80000000, reg size 8,
[    0.000000]  - 80000000 ,  40000000
[    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
[    0.000000] Linux version 4.19.0-sifive-1+ (trosinenko@trosinenko-pc) (gcc version 8.3.0 (Buildroot 2019.02-07449-g4eddd28f99)) #1 SMP Sat Jul 6 12:14:41 MSK 2019
[    0.000000] bootconsole [early0] enabled
[    0.000000] initrd not found or empty - disabling initrd
[    0.000000] Zone ranges:
[    0.000000]   DMA32    [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000]   Normal   [mem 0x00000000c0000000-0x00000bffffffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] INITIAL: ffffffe001000000
[    0.000000]  -> unflatten_device_tree()
[    0.000000] Unflattening device tree:
[    0.000000] magic: d00dfeed
[    0.000000] size: 00001000
[    0.000000] version: 00000011
[    0.000000]   size is 13512, allocating...
[    0.000000]   unflattening (____ptrval____)...
[    0.000000] fixed up name for  ->
[    0.000000] fixed up name for chosen -> chosen
[    0.000000] fixed up name for firmware -> firmware
[    0.000000] fixed up name for aliases -> aliases
[    0.000000] fixed up name for cpus -> cpus
[    0.000000] fixed up name for cpu@0 -> cpu
[    0.000000] fixed up name for interrupt-controller -> interrupt-controller
[    0.000000] fixed up name for ram@80000000 -> ram
[    0.000000] fixed up name for soc -> soc
[    0.000000] fixed up name for clint@2000000 -> clint
[    0.000000] fixed up name for debug-controller@0 -> debug-controller
[    0.000000] fixed up name for gpio@64002000 -> gpio
[    0.000000] fixed up name for interrupt-controller@c000000 -> interrupt-controller
[    0.000000] fixed up name for rom@10000 -> rom
[    0.000000] fixed up name for serial@64000000 -> serial
[    0.000000] fixed up name for spi@64001000 -> spi
[    0.000000] fixed up name for mmc@0 -> mmc
[    0.000000] fixed up name for tlclk -> tlclk
[    0.000000]  <- unflatten_device_tree()
[    0.000000] software IO TLB: mapped [mem 0xbb1fc000-0xbf1fc000] (64MB)
[    0.000000] 0 ffffffe03effcab0 [attach() failed for %s with error %d
[    0.000000] ] | [cpu]
[    0.000000] 0 ffffffe03eff0020 [(null)] | [cpu]


Вывод в QEMU
                SIFIVE, INC.

         5555555555555555555555555
        5555                   5555
       5555                     5555
      5555                       5555
     5555       5555555555555555555555
    5555       555555555555555555555555
   5555                             5555
  5555                               5555
 5555                                 5555
5555555555555555555555555555          55555
 55555           555555555           55555
   55555           55555           55555
     55555           5           55555
       55555                   55555
         55555               55555
           55555           55555
             55555       55555
               55555   55555
                 555555555
                   55555
                     5

           SiFive RISC-V Core IP
 {
  #address-cells = <0x00000002>;
  #size-cells = <0x00000002>;
  compatible = "riscv-virtio";
  model = "riscv-virtio,qemu";
  chosen {
    linux,initrd-start = <0x00000000 0x88000000>;
    linux,initrd-end = <0x00000000 0x88442b86>;
    riscv,kernel-start = <0x00000000 0x80200000>;
    riscv,kernel-end = <0x00000000 0x80c482ac>;
    bootargs = "";
    stdout-path = <0x2f756172 0x74403130 0x30303030>;
  }
  uart@10000000 {
    interrupts = <0x0000000a>;
    interrupt-parent = <0x00000002>;
    clock-frequency = <0x00384000>;
    reg = <0x00000000 0x10000000 0x00000000 0x00000100>;
    compatible = "ns16550a";
  }
  test@100000 {
    reg = <0x00000000 0x00100000 0x00000000 0x00001000>;
    compatible = "sifive,test0";
  }
  virtio_mmio@10008000 {
    interrupts = <0x00000008>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10008000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  virtio_mmio@10007000 {
    interrupts = <0x00000007>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10007000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  virtio_mmio@10006000 {
    interrupts = <0x00000006>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10006000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  virtio_mmio@10005000 {
    interrupts = <0x00000005>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10005000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  virtio_mmio@10004000 {
    interrupts = <0x00000004>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10004000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  virtio_mmio@10003000 {
    interrupts = <0x00000003>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10003000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  virtio_mmio@10002000 {
    interrupts = <0x00000002>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10002000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  virtio_mmio@10001000 {
    interrupts = <0x00000001>;
    interrupt-parent = <0x00000002>;
    reg = <0x00000000 0x10001000 0x00000000 0x00001000>;
    compatible = "virtio,mmio";
  }
  cpus {
    #address-cells = <0x00000001>;
    #size-cells = <0x00000000>;
    timebase-frequency = <0x00989680>;
    cpu@0 {
      device_type = "cpu";
      reg = <0x00000000>;
      status = "okay";
      compatible = "riscv";
      riscv,isa = "rv64imafdcsu";
      mmu-type = "riscv,sv48";
      clock-frequency = <0x3b9aca00>;
      interrupt-controller {
        #interrupt-cells = <0x00000001>;
        interrupt-controller;
        compatible = "riscv,cpu-intc";
        linux,phandle = <0x00000001>;
        phandle = <0x00000001>;
      }
    }
  }
  memory@80000000 {
    device_type = "memory";
    reg = <0x00000000 0x80000000 0x00000000 0x40000000>;
  }
  soc {
    #address-cells = <0x00000002>;
    #size-cells = <0x00000002>;
    compatible = "simple-bus";
    ranges;
    pci@30000000 {
      interrupt-map-mask = <0x00001800 0x00000000 0x00000000 0x00000007>;
      interrupt-map = <0x00000000 0x00000000 0x00000000 0x00000001 0x00000002 0x00000020 0x00000000 0x00000000 0x00000000 0x00000002 0x00000002 0x00000021 0x00000000 0x00000000 0x00000000 0x00000003 0x00000002 0x00000022 0x00000000 0x00000000 0x00000000 0x00000004 0x00000002 0x00000023 0x00000800 0x00000000 0x00000000 0x00000001 0x00000002 0x00000021 0x00000800 0x00000000 0x00000000 0x00000002 0x00000002 0x00000022 0x00000800 0x00000000 0x00000000 0x00000003 0x00000002 0x00000023 0x00000800 0x00000000 0x00000000 0x00000004 0x00000002 0x00000020 0x00001000 0x00000000 0x00000000 0x00000001 0x00000002 0x00000022 0x00001000 0x00000000 0x00000000 0x00000002 0x00000002 0x00000023 0x00001000 0x00000000 0x00000000 0x00000003 0x00000002 0x00000020 0x00001000 0x00000000 0x00000000 0x00000004 0x00000002 0x00000021 0x00001800 0x00000000 0x00000000 0x00000001 0x00000002 0x00000023 0x00001800 0x00000000 0x00000000 0x00000002 0x00000002 0x00000020 0x00001800 0x00000000 0x00000000 0x00000003 0x00000002 0x00000021 0x00001800 0x00000000 0x00000000 0x00000004 0x00000002 0x00000022>;
      ranges = <0x01000000 0x00000000 0x00000000 0x00000000 0x03000000 0x00000000 0x00010000 0x02000000 0x00000000 0x40000000 0x00000000 0x40000000 0x00000000 0x40000000>;
      reg = <0x00000000 0x30000000 0x00000000 0x10000000>;
      dma-coherent;
      bus-range = <0x00000000 0x000002ff>;
      linux,pci-domain = <0x00000000>;
      device_type = "pci";
      compatible = "pci-host-ecam-generic";
      #size-cells = <0x00000002>;
      #interrupt-cells = <0x00000001>;
      #address-cells = <0x00000003>;
    }
    interrupt-controller@c000000 {
      linux,phandle = <0x00000002>;
      phandle = <0x00000002>;
      riscv,ndev = <0x00000035>;
      riscv,max-priority = <0x00000007>;
      reg-names = "control";
      reg = <0x00000000 0x0c000000 0x00000000 0x04000000>;
      interrupts-extended = <0x00000001 0x0000000b 0x00000001 0x00000009>;
      interrupt-controller;
      compatible = "riscv,plic0";
      #interrupt-cells = <0x00000001>;
      #address-cells = <0x00000000>;
    }
    clint@2000000 {
      interrupts-extended = <0x00000001 0x00000003 0x00000001 0x00000007>;
      reg = <0x00000000 0x02000000 0x00000000 0x00010000>;
      compatible = "riscv,clint0";
    }
  }
}
[    0.000000] HART = 0 DTB = 80e00000
[    0.000000] search "chosen", depth: 0, uname:
[    0.000000] search "chosen", depth: 1, uname: chosen
[    0.000000] Looking for initrd properties...
[    0.000000] initrd_start=0x88000000  initrd_end=0x88442b86
[    0.000000] Command line is: earlyprintk
[    0.000000] dt_root_size_cells = 2
[    0.000000] dt_root_addr_cells = 2
[    0.000000] memory scan node memory@80000000, reg size 16,
[    0.000000]  - 80000000 ,  40000000
[    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
[    0.000000] Linux version 4.19.0-sifive-1+ (trosinenko@trosinenko-pc) (gcc version 8.3.0 (Buildroot 2019.02-07449-g4eddd28f99)) #1 SMP Sat Jul 6 12:14:41 MSK 2019
[    0.000000] bootconsole [early0] enabled
[    0.000000] Initial ramdisk at: 0x(____ptrval____) (4467590 bytes)
[    0.000000] Zone ranges:
[    0.000000]   DMA32    [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000]   Normal   [mem 0x00000000c0000000-0x00000bffffffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] INITIAL: ffffffe000c00000
[    0.000000]  -> unflatten_device_tree()
[    0.000000] Unflattening device tree:
[    0.000000] magic: d00dfeed
[    0.000000] size: 00000d56
[    0.000000] version: 00000011
[    0.000000]   size is 14192, allocating...
[    0.000000]   unflattening (____ptrval____)...
[    0.000000] fixed up name for  ->
[    0.000000] fixed up name for chosen -> chosen
[    0.000000] fixed up name for uart@10000000 -> uart
[    0.000000] fixed up name for test@100000 -> test
[    0.000000] fixed up name for virtio_mmio@10008000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10007000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10006000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10005000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10004000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10003000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10002000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10001000 -> virtio_mmio
[    0.000000] fixed up name for cpus -> cpus
[    0.000000] fixed up name for cpu@0 -> cpu
[    0.000000] fixed up name for interrupt-controller -> interrupt-controller
[    0.000000] fixed up name for memory@80000000 -> memory
[    0.000000] fixed up name for soc -> soc
[    0.000000] fixed up name for pci@30000000 -> pci
[    0.000000] fixed up name for interrupt-controller@c000000 -> interrupt-controller
[    0.000000] fixed up name for clint@2000000 -> clint
[    0.000000]  <- unflatten_device_tree()
[    0.000000] software IO TLB: mapped [mem 0xbb1fc000-0xbf1fc000] (64MB)
[    0.000000] 0 ffffffe03effc808 [] | [cpu]
[    0.000000] 0 ffffffe03effca78 [] | [cpu]
[    0.000000] 0 ffffffe03effcd98 [] | [cpu]
[    0.000000] 0 ffffffe03effd068 [] | [cpu]
[    0.000000] 0 ffffffe03effd230 [] | [cpu]
[    0.000000] 0 ffffffe03effd4b8 [] | [cpu]
[    0.000000] 0 ffffffe03effd740 [] | [cpu]
[    0.000000] 0 ffffffe03effd9c8 [] | [cpu]
[    0.000000] 0 ffffffe03effdc50 [] | [cpu]
[    0.000000] 0 ffffffe03effded8 [] | [cpu]
[    0.000000] 0 ffffffe03effe160 [] | [cpu]
[    0.000000] 0 ffffffe03effe3e8 [] | [cpu]
[    0.000000] 0 ffffffe03effe670 [] | [cpu]
[    0.000000] 0 ffffffe03effe888 [cpu] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03effec00 [] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03effeee8 [memory] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efff0b0 [] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efff320 [pci] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efff858 [] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efffd58 [] | [cpu]
[    0.000000] 0 ffffffe03effc808 [] | [cpu]
[    0.000000] 0 ffffffe03effca78 [] | [cpu]
[    0.000000] 0 ffffffe03effcd98 [] | [cpu]
[    0.000000] 0 ffffffe03effd068 [] | [cpu]
[    0.000000] 0 ffffffe03effd230 [] | [cpu]
[    0.000000] 0 ffffffe03effd4b8 [] | [cpu]
[    0.000000] 0 ffffffe03effd740 [] | [cpu]
[    0.000000] 0 ffffffe03effd9c8 [] | [cpu]
[    0.000000] 0 ffffffe03effdc50 [] | [cpu]
[    0.000000] 0 ffffffe03effded8 [] | [cpu]
[    0.000000] 0 ffffffe03effe160 [] | [cpu]
[    0.000000] 0 ffffffe03effe3e8 [] | [cpu]
[    0.000000] 0 ffffffe03effe670 [] | [cpu]
[    0.000000] 0 ffffffe03effe888 [cpu] | [cpu]
[    0.000000] elf_hwcap is 0x112d
[    0.000000] percpu: Embedded 17 pages/cpu @(____ptrval____) s29400 r8192 d32040 u69632
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 258055
[    0.000000] Kernel command line: earlyprintk
[    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] Sorting __ex_table...
[    0.000000] Memory: 949716K/1046528K available (6565K kernel code, 342K rwdata, 2564K rodata, 208K init, 832K bss, 96812K reserved, 0K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] rcu: Hierarchical RCU implementation.
[    0.000000] rcu:     RCU event tracing is enabled.
[    0.000000] rcu:     RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=1.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[    0.000000] NR_IRQS: 0, nr_irqs: 0, preallocated irqs: 0
[    0.000000] plic: mapped 53 interrupts to 2 (out of 2) handlers.
[    0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x24e6a1710, max_idle_ns: 440795202120 ns
[    0.000000] Console: colour dummy device 80x25
[    0.000000] console [tty0] enabled
[    0.000000] bootconsole [early0] disabled
[    0.000000] HART = 0 DTB = 80e00000
[    0.000000] search "chosen", depth: 0, uname:
[    0.000000] search "chosen", depth: 1, uname: chosen
[    0.000000] Looking for initrd properties...
[    0.000000] initrd_start=0x88000000  initrd_end=0x88442b86
[    0.000000] Command line is: earlyprintk
[    0.000000] dt_root_size_cells = 2
[    0.000000] dt_root_addr_cells = 2
[    0.000000] memory scan node memory@80000000, reg size 16,
[    0.000000]  - 80000000 ,  40000000
[    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
[    0.000000] Linux version 4.19.0-sifive-1+ (trosinenko@trosinenko-pc) (gcc version 8.3.0 (Buildroot 2019.02-07449-g4eddd28f99)) #1 SMP Sat Jul 6 12:14:41 MSK 2019
[    0.000000] bootconsole [early0] enabled
[    0.000000] Initial ramdisk at: 0x(____ptrval____) (4467590 bytes)
[    0.000000] Zone ranges:
[    0.000000]   DMA32    [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000]   Normal   [mem 0x00000000c0000000-0x00000bffffffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] INITIAL: ffffffe000c00000
[    0.000000]  -> unflatten_device_tree()
[    0.000000] Unflattening device tree:
[    0.000000] magic: d00dfeed
[    0.000000] size: 00000d56
[    0.000000] version: 00000011
[    0.000000]   size is 14192, allocating...
[    0.000000]   unflattening (____ptrval____)...
[    0.000000] fixed up name for  ->
[    0.000000] fixed up name for chosen -> chosen
[    0.000000] fixed up name for uart@10000000 -> uart
[    0.000000] fixed up name for test@100000 -> test
[    0.000000] fixed up name for virtio_mmio@10008000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10007000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10006000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10005000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10004000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10003000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10002000 -> virtio_mmio
[    0.000000] fixed up name for virtio_mmio@10001000 -> virtio_mmio
[    0.000000] fixed up name for cpus -> cpus
[    0.000000] fixed up name for cpu@0 -> cpu
[    0.000000] fixed up name for interrupt-controller -> interrupt-controller
[    0.000000] fixed up name for memory@80000000 -> memory
[    0.000000] fixed up name for soc -> soc
[    0.000000] fixed up name for pci@30000000 -> pci
[    0.000000] fixed up name for interrupt-controller@c000000 -> interrupt-controller
[    0.000000] fixed up name for clint@2000000 -> clint
[    0.000000]  <- unflatten_device_tree()
[    0.000000] software IO TLB: mapped [mem 0xbb1fc000-0xbf1fc000] (64MB)
[    0.000000] 0 ffffffe03effc808 [] | [cpu]
[    0.000000] 0 ffffffe03effca78 [] | [cpu]
[    0.000000] 0 ffffffe03effcd98 [] | [cpu]
[    0.000000] 0 ffffffe03effd068 [] | [cpu]
[    0.000000] 0 ffffffe03effd230 [] | [cpu]
[    0.000000] 0 ffffffe03effd4b8 [] | [cpu]
[    0.000000] 0 ffffffe03effd740 [] | [cpu]
[    0.000000] 0 ffffffe03effd9c8 [] | [cpu]
[    0.000000] 0 ffffffe03effdc50 [] | [cpu]
[    0.000000] 0 ffffffe03effded8 [] | [cpu]
[    0.000000] 0 ffffffe03effe160 [] | [cpu]
[    0.000000] 0 ffffffe03effe3e8 [] | [cpu]
[    0.000000] 0 ffffffe03effe670 [] | [cpu]
[    0.000000] 0 ffffffe03effe888 [cpu] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03effec00 [] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03effeee8 [memory] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efff0b0 [] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efff320 [pci] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efff858 [] | [cpu]
[    0.000000] ffffffe03effe888 ffffffe03efffd58 [] | [cpu]
[    0.000000] 0 ffffffe03effc808 [] | [cpu]
[    0.000000] 0 ffffffe03effca78 [] | [cpu]
[    0.000000] 0 ffffffe03effcd98 [] | [cpu]
[    0.000000] 0 ffffffe03effd068 [] | [cpu]
[    0.000000] 0 ffffffe03effd230 [] | [cpu]
[    0.000000] 0 ffffffe03effd4b8 [] | [cpu]
[    0.000000] 0 ffffffe03effd740 [] | [cpu]
[    0.000000] 0 ffffffe03effd9c8 [] | [cpu]
[    0.000000] 0 ffffffe03effdc50 [] | [cpu]
[    0.000000] 0 ffffffe03effded8 [] | [cpu]
[    0.000000] 0 ffffffe03effe160 [] | [cpu]
[    0.000000] 0 ffffffe03effe3e8 [] | [cpu]
[    0.000000] 0 ffffffe03effe670 [] | [cpu]
[    0.000000] 0 ffffffe03effe888 [cpu] | [cpu]
[    0.000000] elf_hwcap is 0x112d
[    0.000000] percpu: Embedded 17 pages/cpu @(____ptrval____) s29400 r8192 d32040 u69632
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 258055
[    0.000000] Kernel command line: earlyprintk
[    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] Sorting __ex_table...
[    0.000000] Memory: 949716K/1046528K available (6565K kernel code, 342K rwdata, 2564K rodata, 208K init, 832K bss, 96812K reserved, 0K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] rcu: Hierarchical RCU implementation.
[    0.000000] rcu:     RCU event tracing is enabled.
[    0.000000] rcu:     RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=1.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[    0.000000] NR_IRQS: 0, nr_irqs: 0, preallocated irqs: 0
[    0.000000] plic: mapped 53 interrupts to 2 (out of 2) handlers.
[    0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x24e6a1710, max_idle_ns: 440795202120 ns
[    0.000000] Console: colour dummy device 80x25
[    0.000000] console [tty0] enabled
[    0.000000] bootconsole [early0] disabled
[    0.000000] Calibrating delay loop (skipped), value calculated using timer frequency.. 20.00 BogoMIPS (lpj=100000)
[    0.000000] pid_max: default: 32768 minimum: 301
[    0.000000] Mount-cache hash table entries: 2048 (order: 2, 16384 bytes)
[    0.000000] Mountpoint-cache hash table entries: 2048 (order: 2, 16384 bytes)
[    0.020000] rcu: Hierarchical SRCU implementation.
[    0.020000] smp: Bringing up secondary CPUs ...
[    0.020000] smp: Brought up 1 node, 1 CPU
[    0.050000] devtmpfs: initialized
[    0.050000] 0 ffffffe03effc808 [] | [cpu]
[    0.050000] 0 ffffffe03effca78 [] | [cpu]
[    0.050000] 0 ffffffe03effcd98 [] | [cpu]
[    0.050000] 0 ffffffe03effd068 [] | [cpu]
[    0.050000] 0 ffffffe03effd230 [] | [cpu]
[    0.050000] 0 ffffffe03effd4b8 [] | [cpu]
[    0.050000] 0 ffffffe03effd740 [] | [cpu]
[    0.050000] 0 ffffffe03effd9c8 [] | [cpu]
[    0.050000] 0 ffffffe03effdc50 [] | [cpu]
[    0.050000] 0 ffffffe03effded8 [] | [cpu]
[    0.050000] 0 ffffffe03effe160 [] | [cpu]
[    0.050000] 0 ffffffe03effe3e8 [] | [cpu]
[    0.050000] 0 ffffffe03effe670 [] | [cpu]
[    0.050000] 0 ffffffe03effe888 [cpu] | [cpu]
[    0.050000] random: get_random_u32 called from bucket_table_alloc+0x76/0x17a with crng_init=0
[    0.050000] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.050000] futex hash table entries: 256 (order: 2, 16384 bytes)
[    0.060000] NET: Registered protocol family 16
[    0.090000] vgaarb: loaded
[    0.090000] SCSI subsystem initialized
[    0.090000] usbcore: registered new interface driver usbfs
[    0.090000] usbcore: registered new interface driver hub
[    0.090000] usbcore: registered new device driver usb
[    0.090000] pps_core: LinuxPPS API ver. 1 registered
[    0.090000] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti 
[    0.090000] PTP clock support registered
[    0.100000] Advanced Linux Sound Architecture Driver Initialized.
[    0.100000] clocksource: Switched to clocksource riscv_clocksource
[    0.110000] NET: Registered protocol family 2
[    0.110000] tcp_listen_portaddr_hash hash table entries: 512 (order: 1, 8192 bytes)
[    0.110000] TCP established hash table entries: 8192 (order: 4, 65536 bytes)
[    0.110000] TCP bind hash table entries: 8192 (order: 5, 131072 bytes)
[    0.110000] TCP: Hash tables configured (established 8192 bind 8192)
[    0.110000] UDP hash table entries: 512 (order: 2, 16384 bytes)
[    0.110000] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
[    0.110000] NET: Registered protocol family 1
[    0.120000] Unpacking initramfs...
[    0.590000] workingset: timestamp_bits=62 max_order=18 bucket_order=0
[    0.620000] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
[    0.620000] io scheduler noop registered
[    0.620000] io scheduler deadline registered
[    0.620000] io scheduler cfq registered (default)
[    0.620000] io scheduler mq-deadline registered
[    0.620000] io scheduler kyber registered
[    0.620000] shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
[    0.690000] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[    0.690000] 10000000.uart: ttyS0 at MMIO 0x10000000 (irq = 10, base_baud = 230400) is a 16550A
[    0.720000] console [ttyS0] enabled
[    0.720000] [drm] radeon kernel modesetting enabled.
[    0.720000] [drm] amdgpu kernel modesetting enabled.
[    0.730000] loop: module loaded
[    0.730000] libphy: Fixed MDIO Bus: probed
[    0.740000] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
[    0.740000] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
[    0.740000] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[    0.740000] ehci-pci: EHCI PCI platform driver
[    0.740000] ehci-platform: EHCI generic platform driver
[    0.740000] mousedev: PS/2 mouse device common for all mice
[    0.740000] usbcore: registered new interface driver usbhid
[    0.740000] usbhid: USB HID core driver
[    0.740000] usbcore: registered new interface driver snd-usb-audio
[    0.740000] NET: Registered protocol family 10
[    0.750000] Segment Routing with IPv6
[    0.750000] sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
[    0.750000] NET: Registered protocol family 17
[    0.750000] Key type dns_resolver registered
[    0.760000] ALSA device list:
[    0.760000]   No soundcards found.
[    0.770000] Freeing unused kernel memory: 208K
[    0.770000] This architecture does not have kernel memory protection.
[    0.770000] Run /init as init process

(«Таймстемпнутыми» строчки выводит ядро, перед ними дерево выводит BBL) С одной стороны, FDT успешно читается, с другой — получается какая-то чепуха в распарсенном «объектном» дереве.

В процессе отладки я понял, что BBL не мог прочитать «двойной» адрес не потому, что в конфиге была ошибка, а просто потому, что у корневого узла был выставлен #address-cells = <1>; #size-cells = <1>;.

Расширив отладочный вывод, я увидел, что указатели на type и name «побились», причём довольно странным образом: у них обнулился первый (начиная с нуля) байт, что-то вроде 0xabcdef -> 0xab00ef. Пришлось воспользоваться знакомой тактикой: зная адреса, по которым находится повреждённая память, дописать в функцию printk печать этих данных. Ну и самих вызовов printk пораскидать, где их мало. Увы, сильно понятнее не стало. Тогда я стал, сверяясь с дизассемблированной objdump версией, вручную расставлять breakpoint-ы и по шагам проходить проблемный участок кода. И тут обнаружилось загадочное и неприятное: если сразу поставить точку останова куда-нибудь относительно далеко от known-good состояния, то, остановившись на ней, я увижу уже повреждённую память. Но если попытаться тихо подкрасться к ней по шагам, то ошибка успевает спрятаться! Дело пахнет битым контроллером памяти и кешом, скрывающим ошибку, если постоянно запрашивать нужное значение. А что если…


Заменяем память

Цепляясь за возможность решить проблему не на своей стороне, я предположил, что, может, мне просто пришла битая планка памяти. Тут я вспомнил, что нетбук десятилетней давности — это не только портативный компьютер, но и ценный источник DDR2 SO-DIMM. Бонусом, в него можно засунуть вынутую из платы память, и получить почти мгновенное зависание Memtest (Linux, кстати, при этом грузился почти до графической оболочки. Но лучше не повторяйте такой эксперимент, если вам дорога информация на подмонтированных дисках…). С одной стороны, можно предположить, что просто память не подошла конкретно к этому нетбуку. С другой стороны, он же смог загрузиться! Появилась надежда, что просто память «битая», и проблема не в моей обёртке.

Значит, нужно попробовать временно запуститься с нетбучной памятью. К сожалению, Quartus 18 не умеет апгрейдить этот IP Core так, чтобы его можно было редактировать. Значит, всё-таки пришло время научиться создавать новые инстансы. Всё оказалось довольно просто: ищем в IP Catalog пункт DDR2 SDRAM Controller with ALTMEMPHY Intel FPGA IP и получаем блок с таким же интерфейсом, как и раньше. Единственная проблема — это выставить правильные настройки памяти.


Получаем параметры модуля памяти

Есть относительно очевидный способ настроить модуль: прочитать параметры из SPD. Действительно, если обычный компьютер вычитывает данные SPD и настраивает по ним контроллер, то давайте вычитаем эти данные на имеющемся нетбуке и вобьём их в табличку.

На Ubuntu это делается весьма нехитро: нужно поставить пакет i2c-tools, загрузить модули eeprom и i2c-i801 (не уверен, правда, что второй драйвер подойдёт везде), после чего запустить decode-dimms:


Вывод decode-dimms
# decode-dimms version 6231 (2014-02-20 10:54:34 +0100)

Memory Serial Presence Detect Decoder
By Philip Edelbrock, Christian Zuckschwerdt, Burkart Lingner,
Jean Delvare, Trent Piepho and others

Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/0-0050
Guessing DIMM is in                             bank 1

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                   OK (0x00)
SPD Revision                                    Invalid
Fundamental Memory type                         Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                    Undefined
Part Number                                     Undefined

Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/4-0050
Guessing DIMM is in                             bank 1

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                   OK (0x00)
SPD Revision                                    Invalid
Fundamental Memory type                         Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                    Undefined
Part Number                                     Undefined

Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/6-0050
Guessing DIMM is in                             bank 1

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                   OK (0x76)
# of bytes written to SDRAM EEPROM              128
Total number of bytes in EEPROM                 256
Fundamental Memory type                         DDR2 SDRAM
SPD Revision                                    1.2

---=== Memory Characteristics ===---
Maximum module speed                            800 MHz (PC2-6400)
Size                                            1024 MB
Banks x Rows x Columns x Bits                   8 x 13 x 10 x 64
Ranks                                           2
SDRAM Device Width                              16 bits
Module Height                                   30.0 mm
Module Type                                     SO-DIMM (67.6 mm)
DRAM Package                                    Planar
Voltage Interface Level                         SSTL 1.8V
Module Configuration Type                       No Parity
Refresh Rate                                    Reduced (7.8 us) - Self Refresh
Supported Burst Lengths                         4, 8
tCL-tRCD-tRP-tRAS                               6-6-6-18
Supported CAS Latencies (tCL)                   6T, 5T, 4T
Minimum Cycle Time                              2.50 ns at CAS 6 (tCK min)
                                                3.00 ns at CAS 5
                                                3.75 ns at CAS 4
Maximum Access Time                             0.40 ns at CAS 6 (tAC)
                                                0.45 ns at CAS 5
                                                0.50 ns at CAS 4
Maximum Cycle Time (tCK max)                    8.00 ns

---=== Timing Parameters ===---
Address/Command Setup Time Before Clock (tIS)   0.17 ns
Address/Command Hold Time After Clock (tIH)     0.25 ns
Data Input Setup Time Before Strobe (tDS)       0.05 ns
Data Input Hold Time After Strobe (tDH)         0.12 ns
Minimum Row Precharge Delay (tRP)               15.00 ns
Minimum Row Active to Row Active Delay (tRRD)   10.00 ns
Minimum RAS# to CAS# Delay (tRCD)               15.00 ns
Minimum RAS# Pulse Width (tRAS)                 45.00 ns
Write Recovery Time (tWR)                       15.00 ns
Minimum Write to Read CMD Delay (tWTR)          7.50 ns
Minimum Read to Pre-charge CMD Delay (tRTP)     7.50 ns
Minimum Active to Auto-refresh Delay (tRC)      60.00 ns
Minimum Recovery Delay (tRFC)                   127.50 ns
Maximum DQS to DQ Skew (tDQSQ)                  0.20 ns
Maximum Read Data Hold Skew (tQHS)              0.30 ns

---=== Manufacturing Information ===---
Manufacturer                                    Samsung
Manufacturing Location Code                     0x02
Part Number                                     M4 70T2864QZ3-CF7
Revision Code                                   0x3351
Manufacturing Date                              2009-W34
Assembly Serial Number                          0x79C64E9A

Number of SDRAM DIMMs detected and decoded: 3

Проблема в том, что некоторых таймингов здесь не указано, поэтому пойдём по второму пути.

Что у нас написано на модулях:

kikowqnmhy2udulovzqtnnebg5s.jpeg7tg2l30tx8ylwijagknepu0im_o.jpeg

В данном случае интереснее надпись на самих микросхемах памяти: K4T1G164QQ-HCF7. Забив эту строчку в Гугл, получаем datasheet на несколько десятков страниц со всеми необходимыми параметрами, которые можно аккуратно перебить в свойства IP Core. Только обращайте внимание на единицы измерения: где-то ns, где-то — ps, а иногда и вообще доли tCK. Учить вас, на что нужно обращать внимание, я не буду — сам многое настраивал методом тыка (не могу при этом гарантировать, что так нельзя «сжечь» память или ПЛИС). Обращу лишь внимание вот на что: я очень долго не мог заставить контроллер работать, и последним шагом было осознание, что нужно проверить ширину всех интерфейсов к памяти на соответствие сгенерированному коду на Verilog: ведь когда в MemIfBundle указан val mem_ba = IO(Output(UInt(2.W))), а банков 8 (т.е. адрес шириной 3 бита), то всё, что у нас есть — висящий в воздухе output из контроллера памяти — проблема, но не критическая, поэтому всё синтезируется, но не работает.

Возможно, всё бы завелось и со старым модулем, если обновить контроллер, но пока что мне лень разбираться с потенциальными плавающими багами: мне и своих хватает.

Итак, после перемещения timebase-frequency в DTS с уровня конкретного CPU на уровень узла cpus (по вполне понятно сказанной просьбе ядра), получаем:


Скрытый текст
[    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
[    0.000000] Linux version 4.19.0-sifive-1+ (trosinenko@trosinenko-pc) (gcc version 8.3.0 (Buildroot 2019.02-07449-g4eddd28f99)) #1 SMP Tue Jul 9 22:42:36 MSK 2019
[    0.000000] bootconsole [early0] enabled
[    0.000000] Initial ramdisk at: 0x(____ptrval____) (16777216 bytes)
[    0.000000] Zone ranges:
[    0.000000]   DMA32    [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000]   Normal   [mem 0x00000000c0000000-0x00000bffffffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x00000000bfffffff]
[    0.000000] software IO TLB: mapped [mem 0xbb1fc000-0xbf1fc000] (64MB)
[    0.000000] elf_hwcap is 0x112d
[    0.000000] percpu: Embedded 17 pages/cpu @(____ptrval____) s29400 r8192 d32040 u69632
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 258055
[    0.000000] Kernel command line: debug console=ttySIF0,125200 root=/dev/mmcblk0p2 loglevel=7 rootwait
[    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] Sorting __ex_table...
[    0.000000] Memory: 937696K/1046528K available (6565K kernel code, 343K rwdata, 2564K rodata, 208K init, 832K bss, 108832K reserved, 0K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] rcu: Hierarchical RCU implementation.
[    0.000000] rcu:     RCU event tracing is enabled.
[    0.000000] rcu:     RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=1.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[    0.000000] NR_IRQS: 0, nr_irqs: 0, preallocated irqs: 0
[    0.000000] plic: mapped 8 interrupts to 1 (out of 2) handlers.
[    0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x1d854df40, max_idle_ns: 3526361616960 ns
[    0.000000] Console: colour dummy device 80x25
[    0.000000] Calibrating delay loop (skipped), value calculated using timer frequency.. 2.00 BogoMIPS (lpj=10000)
[    0.020000] pid_max: default: 32768 minimum: 301
[    0.030000] Mount-cache hash table entries: 2048 (order: 2, 16384 bytes)
[    0.040000] Mountpoint-cache hash table entries: 2048 (order: 2, 16384 bytes)
[    0.140000] rcu: Hierarchical SRCU implementation.
[    0.190000] smp: Bringing up secondary CPUs ...
[    0.190000] smp: Brought up 1 node, 1 CPU
[    0.220000] devtmpfs: initialized
[    0.300000] random: get_random_u32 called from bucket_table_alloc+0x76/0x17a with crng_init=0
[    0.330000] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.340000] futex hash table entries: 256 (order: 2, 16384 bytes)
[    0.380000] NET: Registered protocol family 16
[    1.850000] vgaarb: loaded
[    1.870000] SCSI subsystem initialized
[    1.900000] usbcore: registered new interface driver usbfs
[    1.910000] usbcore: registered new interface driver hub
[    1.920000] usbcore: registered new device driver usb
[    1.930000] pps_core: LinuxPPS API ver. 1 registered
[    1.940000] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti 
[    1.950000] PTP clock support registered
[    1.970000] Advanced Linux Sound Architecture Driver Initialized.
[    2.010000] clocksource: Switched to clocksource riscv_clocksource
[    2.600000] NET: Registered protocol family 2
[    2.640000] tcp_listen_portaddr_hash hash table entries: 512 (order: 1, 8192 bytes)
[    2.650000] TCP established hash table entries: 8192 (order: 4, 65536 bytes)
[    2.670000] TCP bind hash table entries: 8192 (order: 5, 131072 bytes)
[    2.700000] TCP: Hash tables configured (established 8192 bind 8192)
[    2.720000] UDP hash table entries: 512 (order: 2, 16384 bytes)
[    2.730000] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
[    2.750000] NET: Registered protocol family 1
[    2.770000] Unpacking initramfs...
[   23.980000] Initramfs unpacking failed: junk in compressed archive
[   24.030000] workingset: timestamp_bits=62 max_order=18 bucket_order=0
[   25.020000] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
[   25.030000] io scheduler noop registered
[   25.040000] io scheduler deadline registered
[   25.050000] io scheduler cfq registered (default)
[   25.060000
    
            

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