On 08/04/2018 10:56 AM, Heinrich Schuchardt wrote:
On 08/02/2018 07:00 PM, Stephen Warren wrote:
On 08/01/2018 11:57 PM, Heinrich Schuchardt wrote:
On 08/01/2018 06:17 PM, Stephen Warren wrote:
On 08/01/2018 12:07 AM, Heinrich Schuchardt wrote:
On 07/31/2018 09:44 PM, Stephen Warren wrote:
From: Stephen Warren swarren@nvidia.com
Some boards define a maximum usable RAM top that's more restrictive than the ranges defined by U-Boot's memory bank definitions[1]. In this case, the unusable RAM isn't mapped in the page tables, and so the EFI code must not attempt to allocate RAM from outside the usable regions. Fix efi_find_free_memory() to detect when max_addr is unconstrained or out of range, and substitue a valid value.
In this case the board has to call efi_add_memory_map() to mark the reserved region (cf. board/raspberrypi/rpi/rpi.c) or have to mark the memory region as reserved in the device tree (see efi_carve_out_dt_rsv()).
Please, check if the tegra boards with which you had problems do so.
I don't think this makes sense; memory should be managed the same way within U-Boot no matter which part of U-Boot is consuming that memory. Memory regions are currently represented by the content of the memory bank definitions and gd->ram_top. Having different parts of the code define legal RAM usage in different ways is horribly inconsistent.
Memory banks and gd->top together cannot reflect unusable memory regions in the middle of the RAM area.
Sure this is possible. For example, a common set of memory banks for Tegra is:
bank 0: start: 0x080000000 length: 0x070000000 limit: 0x0f0000000 bank 1: start: 0x100000000 length: 0x080000000 limit: 0x180000000
gd->ram_top = 0x0f0000000 That is set so that U-Boot itself (not just the UEFI code) doesn't use RAM above 4GB due to HW peripherals that can't access such RAM. The RAM above 4GB is left in the DRAM banks so that the kernel can use it for non-DMA purposes
Hello Stephen,
this explanation makes the problem much clearer. Memory usable by the operating system but not by the firmware cannot be expressed in the device tree.
If bank 1 cannot be used by U-Boot but can be used by the operating system we should mark it as EFI_BOOT_SERVICES_DATA by calling efi_add_memory_map() in arch/arm/mach-tegra/board2.c. This will indicate to the operating system that it may use this memory after exiting boot services and the U-Boot EFI subsystem will not use this region. This call could be done in dram_init_banksize().
Could you give this a try, please.
Please revert the patch first, then we can fix this later (I sent the revert as a patch already). I'm leaving on vacation right now, so won't be able to look at this for at least 2 weeks. We need to fix the regression immediately. Equally, EFI shouldn't require boards to provide memory information to U-Boot in a different way than the rest of U-Boot as I mentioned, so even if this WAR works, it doesn't sound scalable across all boards.