Date: Wed, 23 Dec 2015 22:18:44 -0800 From: Tim Kientzle <tim@kientzle.com> To: Sylvain Garrigues <sylgar@gmail.com> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Booting the ELF kernel without ubldr on Raspberry Pi Message-ID: <32849B9F-C7B8-4A86-B8F1-043F62D2E64C@kientzle.com> In-Reply-To: <C6819C94-DF61-447F-AC61-FD3E061A6F76@gmail.com>
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Actually, it would be more interesting to go a step further and boot the FreeBSD kernel directly from the firmware, bypassing both U-Boot and ubldr. Warner did some work long ago to allow the FreeBSD kernel to boot from a Linux boot loader, which should make this possible. You might try looking at that code and seeing if you can get it to work. Cheers, Tim > On Dec 21, 2015, at 7:48 PM, Sylvain Garrigues <sylgar@gmail.com> wrote: > > Hello, > > I’d like to boot FreeBSD directly with u-boot, without ubldr, using an image provided by the u-boot mkimage tool. The reason is simple: mkimage can deal with compressed kernels and will therefore speed my boot time. And I want to try it anyway, as it seems possible reading http://bsdcan.org/2008/schedule/attachments/49_2008_uboot_freebsd.pdf <http://bsdcan.org/2008/schedule/attachments/49_2008_uboot_freebsd.pdf>; and various other > > Before going there and using an mkimage, I’d like to boot the kernel image just with the same bootelf version provided by the sysutils/u-boot-rpi2 port. It doesn’t display anything and crashes (I think I can see « illegal instruction » just before the board reboots). I don’t understand why, and this is my first question. > > Then I looked at the mkimage utility, although we can specify and freebsd kernel type through the -O flag, the bootm command only understands linux and NetBSD. I guess I should use linux there? > > Thanks for your help, > Sylvain > > > PS: FYI, below is: > > 1/ info about my kernel (I can see the entry point is at 0xc0100100), copied into the fat partition > > # readelf -h /root/crochet/work/obj/arm.armv6/root/crochet/src/sys/RPI2/kernel > ELF Header: > Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00 > Class: ELF32 > Data: 2's complement, little endian > Version: 1 (current) > OS/ABI: UNIX - System V > ABI Version: 0 > Type: EXEC (Executable file) > Machine: ARM > Version: 0x1 > Entry point address: 0xc0100100 > Start of program headers: 52 (bytes into file) > Start of section headers: 6235080 (bytes into file) > Flags: 0x5000202, has entry point, Version5 EABI, <unknown> > Size of this header: 52 (bytes) > Size of program headers: 32 (bytes) > Number of program headers: 6 > Size of section headers: 40 (bytes) > Number of section headers: 38 > Section header string table index: 35 > [root@clad /usr/ports/sysutils/u-boot-rpi2]# > > 2/ the interesting part of my include/configs/rpi-common.h from u-boot: > > #define CONFIG_EXTRA_ENV_SETTINGS \ > ENV_DEVICE_SETTINGS \ > "loadaddr=0x02000000\0" \ > "Fatboot=" \ > "env exists loaderdev || env set loaderdev ${fatdev}; " \ > "echo Booting from: ${fatdev} ${bootfile}; " \ > "fatload ${fatdev} ${loadaddr} ${bootfile} && bootelf ${loadaddr}; " \ > "\0" \ > "preboot=" \ > "fdt addr 0x100; " \ > "env set bootfile kernel; " \ > "env set fatdev 'mmc 0'; " \ > "\0" > #undef CONFIG_BOOTCOMMAND > #define CONFIG_BOOTCOMMAND "run Fatboot" > #undef CONFIG_PREBOOT > #define CONFIG_PREBOOT "run preboot" > _______________________________________________ > freebsd-arm@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org"help
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