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器件型号：AM4378 你(们)好！
我正在尝试优化 Linux 映像的引导时间。 我观察到、从 u-boot 跳转到内核时需要4到5秒。
我需要的 目标是 在10秒内达到启动(SPL / u-boot /内核/用户空间)、但 u-boot 本身大约需要6到7秒。
tisdk-default-image-AM437X-EVM 的日志、其中 u-boot 跳转到内核大约需要4到5秒
[2023-06-14 12:52:56.175] WDT: Not found! [2023-06-14 12:52:56.175] Trying to boot from MMC1 [2023-06-14 12:52:56.272] SPL: Please implement spl_start_uboot() for your board [2023-06-14 12:52:56.272] SPL: Direct Linux boot not active! [2023-06-14 12:52:56.607] [2023-06-14 12:52:56.607] [2023-06-14 12:52:56.607] U-Boot 2021.01-g44a87e3ab8 (Jun 02 2022 - 22:28:36 +0000) [2023-06-14 12:52:56.623] [2023-06-14 12:52:56.623] CPU : AM437X-GP rev 1.2 [2023-06-14 12:52:56.623] Model: TI AM437x SK EVM [2023-06-14 12:52:56.623] DRAM: 1 GiB [2023-06-14 12:52:56.735] PMIC: TPS65218 [2023-06-14 12:52:56.735] NAND: 0 MiB [2023-06-14 12:52:57.140] MMC: OMAP SD/MMC: 0 [2023-06-14 12:52:57.140] Loading Environment from FAT... *** Warning - bad CRC, using default environment [2023-06-14 12:52:57.231] [2023-06-14 12:52:57.231] Net: eth2: ethernet@4a100000 [2023-06-14 12:52:57.263] Hit any key to stop autoboot: 2 1 0 [2023-06-14 12:52:59.344] switch to partitions #0, OK [2023-06-14 12:52:59.344] mmc0 is current device [2023-06-14 12:52:59.424] SD/MMC found on device 0 [2023-06-14 12:52:59.424] Failed to load 'boot.scr' [2023-06-14 12:52:59.424] 717 bytes read in 1 ms (700.2 KiB/s) [2023-06-14 12:52:59.441] Loaded env from uEnv.txt [2023-06-14 12:52:59.441] Importing environment from mmc0 ... [2023-06-14 12:52:59.519] switch to partitions #0, OK [2023-06-14 12:52:59.519] mmc0 is current device [2023-06-14 12:52:59.599] SD/MMC found on device 0 [2023-06-14 12:52:59.859] 4989440 bytes read in 250 ms (19 MiB/s) [2023-06-14 12:52:59.871] 112940 bytes read in 8 ms (13.5 MiB/s) [2023-06-14 12:52:59.871] ## Flattened Device Tree blob at 88000000 [2023-06-14 12:52:59.871] Booting using the fdt blob at 0x88000000 [2023-06-14 12:52:59.871] Loading Device Tree to 8ffe1000, end 8ffff92b ... OK [2023-06-14 12:52:59.886] [2023-06-14 12:52:59.886] Starting kernel ... [2023-06-14 12:52:59.886] [2023-06-14 12:53:04.099] [ 0.000000] Booting Linux on physical CPU 0x0 [2023-06-14 12:53:04.099] [ 0.000000] Linux version 5.10.100-rt62-g204ec708dc (oe-user@oe-host) (arm-none-linux-gnueabihf-gcc (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)) 9.2.1 20191025, GNU ld (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)) 2.33.1.20191209) #1 PREEMPT_RT Thu Jun 2 22:32:00 UTC 2022 [2023-06-14 12:53:04.144] [ 0.000000] CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c53c7d [2023-06-14 12:53:04.144] [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache [2023-06-14 12:53:04.159] [ 0.000000] OF: fdt: Machine model: TI AM437x SK e2e.ti.com/.../configure [2023-06-14 12:53:04.159] [ 0.000000] Memory policy: Data cache writeback [2023-06-14 12:53:04.159] [ 0.000000] efi: UEFI not found.
我们所创建的映像的日志和其中的启动时间也需要大约4秒的时间从 u-boot 跳转到内核
[2023-06-14 12:10:25.127] U-Boot SPL 2020.01-g999 (Jun 13 2023 - 12:22:51 +0000) [2023-06-14 12:10:25.127] WDT: Not found! [2023-06-14 12:10:25.143] Trying to boot from MMC1 [2023-06-14 12:10:25.241] SPL: Please implement spl_start_uboot() for your board [2023-06-14 12:10:25.241] SPL: Direct Linux boot not active! [2023-06-14 12:10:25.799] [2023-06-14 12:10:25.799] [2023-06-14 12:10:25.799] U-Boot 2020.01-g999 (Jun 13 2023 - 12:22:51 +0000) [2023-06-14 12:10:25.799] [2023-06-14 12:10:25.799] CPU : AM437X-GP rev 1.2 [2023-06-14 12:10:25.799] Model: TI AM437x SK EVM [2023-06-14 12:10:25.799] DRAM: 1 GiB [2023-06-14 12:10:25.912] PMIC: TPS65218 [2023-06-14 12:10:25.912] NAND: 0 MiB [2023-06-14 12:10:26.311] MMC: OMAP SD/MMC: 0 [2023-06-14 12:10:26.326] Loading Environment from FAT... OK [2023-06-14 12:10:26.424] Net: eth0: ethernet@4a100000 [2023-06-14 12:10:26.438] Hit any key to stop autoboot: 0 [2023-06-14 12:10:26.518] switch to partitions #0, OK [2023-06-14 12:10:26.536] mmc0 is current device [2023-06-14 12:10:26.598] SD/MMC found on device 0 [2023-06-14 12:10:26.615] 1396 bytes read in 3 ms (454.1 KiB/s) [2023-06-14 12:10:26.615] Loaded env from uEnv.txt [2023-06-14 12:10:26.615] Importing environment from mmc0 ... [2023-06-14 12:10:26.695] switch to partitions #0, OK [2023-06-14 12:10:26.695] mmc0 is current device [2023-06-14 12:10:26.777] SD/MMC found on device 0 [2023-06-14 12:10:26.777] ROOTFS_A exist [2023-06-14 12:10:26.793] Saving Environment to FAT... OK [2023-06-14 12:10:27.094] 5575168 bytes read in 275 ms (19.3 MiB/s) [2023-06-14 12:10:27.111] 112940 bytes read in 9 ms (12 MiB/s) [2023-06-14 12:10:27.111] ## Flattened Device Tree blob at 88000000 [2023-06-14 12:10:27.111] Booting using the fdt blob at 0x88000000 [2023-06-14 12:10:27.126] Loading Device Tree to 8ffe1000, end 8ffff92b ... OK [2023-06-14 12:10:27.126] [2023-06-14 12:10:27.126] Starting kernel ... [2023-06-14 12:10:27.126] [2023-06-14 12:10:27.126] [2023-06-14 12:10:27.126] at end of Starting kernel ... [2023-06-14 12:10:27.143] [2023-06-14 12:10:27.143] [2023-06-14 12:10:27.143] at announce_and_cleanup 1 ... [2023-06-14 12:10:27.143] [2023-06-14 12:10:27.143] point-1 [2023-06-14 12:10:27.143] point-1.1 [2023-06-14 12:10:27.143] point-2 the fake value is 0 [2023-06-14 12:10:27.143] [2023-06-14 12:10:27.143] before kernel_entry ..at the address of 82000000 the machid is 0 and r2 is 8ffe1000. [2023-06-14 12:10:27.159] [2023-06-14 12:10:32.087] [ 0.000000] I am the first statement in start_kernel in main.c [2023-06-14 12:10:32.103] [ 0.000000] at the start of smp_setup_processor_id [2023-06-14 12:10:32.103] [ 0.000000] Booting Linux on physical CPU 0x0 [2023-06-14 12:10:32.118] [ 0.000000] Linux version 5.10.162-rt79-g999 (oe-user@oe-host) (arm-poky-linux-gnueabi-gcc (GCC) 9.5.0, GNU ld (GNU Binutils) 2.34.0.20200910) #1 PREEMPT_RT Wed Jun 14 06:22:44 UTC 2023 [2023-06-14 12:10:32.150] [ 0.000000] CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c53c7d
为了验证 我是否完成了代码更改并添加了少量日志以确定添加的日志屏幕截图如下所示的大部分时间所用的位置
- 在 u-boot-ti-staging/arch/arm/lib/bootm.c 中
- 在静态 void boot_jump_linux (bootm_headers_t *images 中、int flag)中
/* Subcommand: GO */
static void boot_jump_linux(bootm_headers_t *images, int flag)
{
#ifdef CONFIG_ARM64
void (*kernel_entry)(void *fdt_addr, void *res0, void *res1,
void *res2);
int fake = (flag & BOOTM_STATE_OS_FAKE_GO);
kernel_entry = (void (*)(void *fdt_addr, void *res0, void *res1,
void *res2))images->ep;
debug("## Transferring control to Linux (at address %lx)...\n",
(ulong) kernel_entry);
bootstage_mark(BOOTSTAGE_ID_RUN_OS);
announce_and_cleanup(fake);
printf("\nat announce_and_cleanup ...\n\n");
if (!fake) {
#ifdef CONFIG_ARMV8_PSCI
armv8_setup_psci();
#endif
do_nonsec_virt_switch();
update_os_arch_secondary_cores(images->os.arch);
#ifdef CONFIG_ARMV8_SWITCH_TO_EL1
armv8_switch_to_el2((u64)images->ft_addr, 0, 0, 0,
(u64)switch_to_el1, ES_TO_AARCH64);
#else
if ((IH_ARCH_DEFAULT == IH_ARCH_ARM64) &&
(images->os.arch == IH_ARCH_ARM))
armv8_switch_to_el2(0, (u64)gd->bd->bi_arch_number,
(u64)images->ft_addr, 0,
(u64)images->ep,
ES_TO_AARCH32);
else
armv8_switch_to_el2((u64)images->ft_addr, 0, 0, 0,
images->ep,
ES_TO_AARCH64);
#endif
}
#else
unsigned long machid = gd->bd->bi_arch_number;
char *s;
void (*kernel_entry)(int zero, int arch, uint params);
unsigned long r2;
int fake = (flag & BOOTM_STATE_OS_FAKE_GO);
kernel_entry = (void (*)(int, int, uint))images->ep;
#ifdef CONFIG_CPU_V7M
ulong addr = (ulong)kernel_entry | 1;
kernel_entry = (void *)addr;
#endif
s = env_get("machid");
if (s) {
if (strict_strtoul(s, 16, &machid) < 0) {
debug("strict_strtoul failed!\n");
return;
}
printf("Using machid 0x%lx from environment\n", machid);
}
debug("## Transferring control to Linux (at address %08lx)" \
"...\n", (ulong) kernel_entry);
bootstage_mark(BOOTSTAGE_ID_RUN_OS);
announce_and_cleanup(fake);
printf("\nat announce_and_cleanup 1 ...\n\n");
printf("point-1\n");
if (IMAGE_ENABLE_OF_LIBFDT && images->ft_len){
printf("point-1.1\n");
r2 = (unsigned long)images->ft_addr;
}
else{
printf("point-1.2\n");
r2 = gd->bd->bi_boot_params;
printf("print1.3\n");
}
printf("point-2 the fake value is %d \n", fake);
if (!fake) {
#ifdef CONFIG_ARMV7_NONSEC
if (armv7_boot_nonsec()) {
printf("point-3\n");
armv7_init_nonsec();
printf("point-4\n");
secure_ram_addr(_do_nonsec_entry)(kernel_entry,
0, machid, r2);
printf("point-5\n");
} else
#endif
printf("\n before kernel_entry ..at the address of %lx the machid is %lx and r2 is %lx.\n\n", kernel_entry, machid, r2);
kernel_entry(0, machid, r2);
printf("point-6\n");
}
#endif
printf("\n at end of kernel_entry ...\n\n");
}
- 在 linux-ti-staging-rt/init/main.c 中
asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
{
printk("I am the first statement in start_kernel in main.c" );
char *command_line;
char *after_dashes;
set_task_stack_end_magic(&init_task);
smp_setup_processor_id();
debug_objects_early_init();
cgroup_init_early();
local_irq_disable();
early_boot_irqs_disabled = true;
- 在 linux-ti-staging-rt/arch/arm/kernel/setup.c 中
void __init smp_setup_processor_id(void)
{
int i;
pr_info("at the start of smp_setup_processor_id");
u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
u32 cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
cpu_logical_map(0) = cpu;
for (i = 1; i < nr_cpu_ids; ++i)
cpu_logical_map(i) = i == cpu ? 0 : i;
/*
* clear __my_cpu_offset on boot CPU to avoid hang caused by
* using percpu variable early, for example, lockdep will
* access percpu variable inside lock_release
*/
set_my_cpu_offset(0);
pr_info("Booting Linux on physical CPU 0x%x\n", mpidr);
}
从记录上述代码更改的日志和映射中、我们可以观察到 u-boot 从
kernel_entry (0、machid、r2)；
传递到内核、内核的第一个日志位于
asmlink_visible void _init ___ no_cleane_address start_kernel (void)函数
{
printk ("我是 main.c 中 start_kernel 中的第一个语句");
……
在这两点之间、会消耗4至5秒的时间。
这段时间有什么用?
如何缩短这段时间来实现 我们的最终目标？ 因为我们的最终目标是在加载内核之前需要10秒和6秒。
