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| author | Stephen Warren <swarren@nvidia.com> | 2018-08-30 15:43:44 -0600 |
|---|---|---|
| committer | Alexander Graf <agraf@suse.de> | 2018-09-23 21:55:29 +0200 |
| commit | 0797f7f0b7e1d7853e2842ddc235ffef139fa792 (patch) | |
| tree | 88c5bd96b35f8801385dedadc50848754daa4c83 /arch | |
| parent | 9b5e6396bff5ede22f880c38915da5538e8bd117 (diff) | |
| download | u-boot-0797f7f0b7e1d7853e2842ddc235ffef139fa792.zip u-boot-0797f7f0b7e1d7853e2842ddc235ffef139fa792.tar.gz u-boot-0797f7f0b7e1d7853e2842ddc235ffef139fa792.tar.bz2 | |
ARM: tegra: reserve unmapped RAM so EFI doesn't use it
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: aa909462d018 ("efi_loader: efi_allocate_pages is too restrictive")
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/mach-tegra/board2.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/board2.c b/arch/arm/mach-tegra/board2.c index 421a71b..12257a4 100644 --- a/arch/arm/mach-tegra/board2.c +++ b/arch/arm/mach-tegra/board2.c @@ -6,6 +6,7 @@ #include <common.h> #include <dm.h> +#include <efi_loader.h> #include <errno.h> #include <ns16550.h> #include <usb.h> @@ -210,6 +211,19 @@ int board_early_init_f(void) int board_late_init(void) { +#if CONFIG_IS_ENABLED(EFI_LOADER) + if (gd->bd->bi_dram[1].start) { + /* + * Only bank 0 is below board_get_usable_ram_top(), so all of + * bank 1 is not mapped by the U-Boot MMU configuration, and so + * we must prevent EFI from using it. + */ + efi_add_memory_map(gd->bd->bi_dram[1].start, + gd->bd->bi_dram[1].size >> EFI_PAGE_SHIFT, + EFI_BOOT_SERVICES_DATA, false); + } +#endif + #if defined(CONFIG_TEGRA_SUPPORT_NON_SECURE) if (tegra_cpu_is_non_secure()) { printf("CPU is in NS mode\n"); |