On 24.03.2013 18:01, Leif Lindholm wrote:
>
> 0004-arm-uboot-support.patch
>
>
> === modified file 'Makefile.util.def'
> --- Makefile.util.def 2013-03-24 13:03:12 +0000
> +++ Makefile.util.def 2013-03-24 13:03:31 +0000
> @@ -467,6 +467,7 @@
> enable = mips_loongson;
> enable = ia64_efi;
> enable = powerpc_ieee1275;
> + enable = arm_uboot;
> };
>
> script = {
>
> === modified file 'grub-core/Makefile.am'
> --- grub-core/Makefile.am 2013-03-20 16:13:31 +0000
> +++ grub-core/Makefile.am 2013-03-24 13:03:31 +0000
> @@ -211,6 +211,13 @@
> KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/lib/arg.h
> endif
>
> +if COND_arm_uboot
> +KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/uboot/uboot.h
> +KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/uboot/disk.h
> +KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/extcmd.h
> +KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/lib/arg.h
> +endif
> +
> if COND_emu
> KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/datetime.h
> KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/emu/misc.h
>
> === modified file 'grub-core/Makefile.core.def'
> --- grub-core/Makefile.core.def 2013-03-24 13:03:12 +0000
> +++ grub-core/Makefile.core.def 2013-03-24 13:03:31 +0000
> @@ -79,6 +79,7 @@
> mips_startup = kern/mips/startup.S;
> sparc64_ieee1275_startup = kern/sparc64/ieee1275/crt0.S;
> powerpc_ieee1275_startup = kern/powerpc/ieee1275/startup.S;
> + arm_uboot_startup = kern/arm/uboot/startup.S;
>
> common = kern/command.c;
> common = kern/corecmd.c;
>
> === added directory 'grub-core/kern/arm/uboot'
> === added file 'grub-core/kern/arm/uboot/startup.S'
> --- grub-core/kern/arm/uboot/startup.S 1970-01-01 00:00:00 +0000
> +++ grub-core/kern/arm/uboot/startup.S 2013-03-24 13:03:31 +0000
> @@ -0,0 +1,176 @@
> +/*
> + * GRUB -- GRand Unified Bootloader
> + * Copyright (C) 2013 Free Software Foundation, Inc.
> + *
> + * GRUB is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * GRUB is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <grub/offsets.h>
> +#include <grub/symbol.h>
> +#include <grub/machine/kernel.h>
> +
> +/*
> + * GRUB is called from U-Boot as a Linux Kernel type image, which
> + * means among other things that it always enters in ARM state.
> + *
> + *
> + * Overview of GRUB image layout:
> + *
> + * _start:
> + * Entry point (1 ARM branch instruction, to "codestart")
> + * grub_total_module_size:
> + * Data field: Size of included module blob
> + * (when generated by grub-mkimage)
> + * codestart:
> + * Remainder of statically-linked executable code and data.
> + * __bss_start:
> + * Start of included module blob.
> + * Also where global/static variables are located.
> + * _end:
> + * End of bss region (but not necessarily module blob).
> + * <overflow>:
> + * Any part of the module blob that extends beyond _end.
> + * <modules>:
> + * Loadable modules, post relocation.
> + * <stack>:
> + * <heap>:
> + */
> +
> + .text
> + .arm
> +FUNCTION(_start)
> + b codestart
> +
> + @ Size of final image integrated module blob - set by grub-mkimage
> + . = _start + GRUB_KERNEL_MACHINE_TOTAL_MODULE_SIZE
> +VARIABLE(grub_total_module_size)
> + .long 0
> +
> +FUNCTION(codestart)
> + @ Store context: Machine ID, atags/dtb, ...
> + @ U-Boot API signature is stored on the U-Boot heap
> + @ Stack pointer used as start address for signature probing
> + mov r12, sp
> + ldr sp, =entry_state
> + push {r4-r12,lr} @ store U-Boot context (sp in r12)
> +
> + @ Put kernel parameters aside until we can store them (further down)
> + mov r4, r1 @ machine type
> + mov r5, r2 @ boot data
> +
> + @ Modules have been stored as a blob in BSS,
> + @ they need to be manually relocated to _end or
> + @ (__bss_start + grub_total_module_size), whichever greater.
> + bl uboot_get_real_bss_start @ r0 = src
> + ldr r1, =EXT_C(_end) @ dst = End of BSS
> + ldr r2, grub_total_module_size @ blob size
> + add r3, r0, r2 @ blob end
> + cmp r1, r3 @ _end < blob end?
> + movlt r1, r3 @ dst = blob end + blob size
> +
> +1: ldr r3, [r0], #4 @ r3 = *src++
> + str r3, [r1], #4 @ *dst++ = r3
> + subs r2, #4 @ remaining -= 4
> + bne 1b @ while remaining != 0
> +
> + @ Set up a new stack, beyond the end of copied modules.
> + ldr r3, =GRUB_KERNEL_MACHINE_STACK_SIZE
> + add r3, r1, r3 @ Place stack beyond end of modules
> + and sp, r3, #~0x7 @ Ensure 8-byte alignment
> +
> + @ Since we _are_ the C run-time, we need to manually zero the BSS
> + @ region before continuing
> + bl uboot_get_real_bss_start @ zero from hereThis start is wrong. Even if modules start later due to alignment, BSS starts at __bss_start. Additional problem is that both __bss_start and _end may be unaligned unless special care is taken (like putting a dummy uint32_t at the beginning of BSS by putting it at the end of startup.S or using ld options) > + ldr r1, =EXT_C(_end) @ to here > + mov r2, #0 > +1: str r2, [r0], #4 > + cmp r0, r1 > + bne 1b > + > + @ Global variables now accessible - store kernel parameters in memory > + ldr r12, =EXT_C(uboot_machine_type) > + str r4, [r12] > + ldr r12, =EXT_C(uboot_boot_data) > + str r5, [r12] > + Instead of temporary stashing the values to registers you can just init those values in C code to e.g. 0x55aa55aa so they'll be in .data and so accessible from the very beginning. > + b EXT_C(grub_main) > + > + /* > + * __bss_start does not actually point to the start of the runtime > + * BSS, but rather to the next byte following the preceding data. > + */ Only modules are aligned. BSS itself is still at _bss. > +FUNCTION (uboot_get_real_bss_start) > + ldr r0, =EXT_C(__bss_start) @ src > + tst r0, #(GRUB_KERNEL_MACHINE_MOD_ALIGN - 1) > + beq 1f > + mvn r1, #(GRUB_KERNEL_MACHINE_MOD_ALIGN - 1) > + and r0, r0, r1 > + add r0, r0, #(GRUB_KERNEL_MACHINE_MOD_ALIGN) Can be trivially simplified to: mvn r1, #(GRUB_KERNEL_MACHINE_MOD_ALIGN - 1) add r0, r0, r1 and r0, r0, r1 which can be then inlined. Also it's more reliable to save grub_modbase as soon as we computed it in asm part (and use 0x55aa55aa trick to make it accessible early)
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