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https://github.com/brain-hackers/u-boot-brain
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0797f7f0b7
Tegra U-Boot ensures that board_get_usable_ram_top() never returns a value
over 4GB, since some peripherals can't access such addresses. However, on
systems with more than 2GB of RAM, RAM bank 1 does describe this extra
RAM, so that Linux (or whatever OS) can use it, subject to DMA
limitations. Since board_get_usable_ram_top() points at the top of RAM
bank 0, the memory locations describes by RAM bank 1 are not mapped by
U-Boot's MMU configuration, and so cannot be used for anything.
For some completely inexplicable reason, U-Boot's EFI support ignores the
value returned by board_get_usable_ram_top(), and EFI memory allocation
routines will return values above U-Boot's RAM top. This causes U-Boot to
crash when it accesses that RAM, since it isn't mapped by the MMU. One
use-case where this happens is TFTP download of a file on Jetson TX1
(p2371-2180).
This change explicitly tells the EFI code that this extra RAM should not
be used, thus avoiding the crash.
A previous attempt to make EFI honor board_get_usable_ram_top() was
rejected. So, this patch will need to be replicated for any board that
implements board_get_usable_ram_top().
Fixes:
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| .. | ||
| cpu | ||
| dts | ||
| include | ||
| lib | ||
| mach-aspeed | ||
| mach-at91 | ||
| mach-bcm283x | ||
| mach-bcmstb | ||
| mach-davinci | ||
| mach-exynos | ||
| mach-highbank | ||
| mach-imx | ||
| mach-integrator | ||
| mach-k3 | ||
| mach-keystone | ||
| mach-kirkwood | ||
| mach-meson | ||
| mach-mvebu | ||
| mach-omap2 | ||
| mach-orion5x | ||
| mach-owl | ||
| mach-qemu | ||
| mach-rmobile | ||
| mach-rockchip | ||
| mach-s5pc1xx | ||
| mach-snapdragon | ||
| mach-socfpga | ||
| mach-sti | ||
| mach-stm32 | ||
| mach-stm32mp | ||
| mach-sunxi | ||
| mach-tegra | ||
| mach-uniphier | ||
| mach-versatile | ||
| mach-zynq | ||
| mach-zynqmp-r5 | ||
| thumb1/include/asm/proc-armv | ||
| config.mk | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||