[U-Boot] bootefi failures on armv7

Heinrich Schuchardt
2019-04-10T20:15:45Z

On 4/10/19 6:57 PM, Ilias Apalodimas wrote:
> Hi Alexander, Heinrich,
>
> (Resending since i was too quick on the trigger forgot to cc the public
> mailing list. Sorry for the mess)
>
> I can't get an armv7 board (STM32MP157C-DK2) to boot with bootefi on
> specific kernel/uboot configurations.
> u-boot version: U-Boot 2019.04-rc3
> kernel version: 5.0.0-rc3
>
> What works:
> - bootefi + 'dtb=' on kernel cmdline regardless of kernel config
> - bootefi + fdtcontroladdr if CONFIG_ARM_LPAE=y on my kernel config

CONFIG_ARM_LPAE=y influences the number of page table levels:

#ifdef CONFIG_ARM_LPAE
#include <asm/pgtable-3level.h>
#else
#include <asm/pgtable-2level.h>
#endif

Hence in arch/arm/mm/mmu.c, arm_pte_alloc() different values of
PTE_HWTABLE_OFF and PTE_HWTABLE_SIZE will be used.

>
> What doesn't work:
> bootefi + fdtcontroladdr if CONFIG_ARM_LPAE is not set.
>
> Once this config is selected the kernel hangs on a BUG_ON() in arm_pte_alloc()
>
> Adding a dump_stack() there throws the relevant information.
> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc3-29427-g769f1f8f9b56-dirty #127
> [ 0.000000] Hardware name: STM32 (Device Tree Support)
> [ 0.000000] [<c03123ec>] (unwind_backtrace) from [<c030ce0c>] (show_stack+0x10/0x14)
> [ 0.000000] [<c030ce0c>] (show_stack) from [<c0e27250>] (dump_stack+0x8c/0xa0)
> [ 0.000000] [<c0e27250>] (dump_stack) from [<c1507e9c>] (arm_pte_alloc+0x74/0xb8)
> [ 0.000000] [<c1507e9c>] (arm_pte_alloc) from [<c15081ec>] (__create_mapping+0x30c/0x36c)
> [ 0.000000] [<c15081ec>] (__create_mapping) from [<c15089f8>] (paging_init+0x234/0x648)
> [ 0.000000] [<c15089f8>] (paging_init) from [<c1504950>] (setup_arch+0x660/0xcac)
> [ 0.000000] [<c1504950>] (setup_arch) from [<c1500a4c>] (start_kernel+0x70/0x458)
> [ 0.000000] [<c1500a4c>] (start_kernel) from [<00000000>] ( (null))
>
> Kernel's EFI map:
> [ 0.000000] efi: 0x0000c0000000-0x0000c1ffffff [Boot Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2000000-0x0000c2860fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2861000-0x0000c7cfffff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7d00000-0x0000c7efffff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7f00000-0x0000c7f0bfff [Runtime Data |RUN| | | | | | | |WB| | | ]

So this seems to be the allocation for the devicetree starting at 127
MiB from RAM start. You seem not to be using the Linux device tree:
Linux 5.0 has 25004 bytes in arch/arm/boot/dts/stm32mp157c-ed1.dtb. So
this fits into 7 pages + 3 pages we add to it. But here 12 pages are
allocated.

Up to this point I cannot see where U-Boot is doing anything
incorrectly. I would not want to change the 127 MiB value to some other
value that might fail on other boards.

Maybe you could contact the Linux mm maintainers to get an understanding
what implicit assumptions the Linux kernel makes when building page
tables or how to debug the problem.

Best regards

Heinrich

> [ 0.000000] efi: 0x0000c7f0c000-0x0000dc705fff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc706000-0x0000dc709fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc70a000-0x0000dcf6afff [Loader Code | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6b000-0x0000dcf6bfff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6c000-0x0000dcf72fff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf73000-0x0000dcf73fff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf74000-0x0000dcf75fff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf76000-0x0000dff80fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff81000-0x0000dff81fff [Runtime Code |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff82000-0x0000dfffffff [Loader Data | | | | | | | | |WB| | | ]
>
> I've found some hacky workarounds on that and i'd like some input on what's
> actually wrong
>
> - Workaround 1, add a bogus bootefi cmd
>
> instead of
> load mmc 0:5 $kernel_addr_r efi/BOOT/zImage;
> bootefi $kernel_addr_r $fdtcontroladdr
>
> doing
> bootefi $kernel_addr_r $fdtcontroladdr
> load mmc 0:5 $kernel_addr_r efi/BOOT/zImage
> bootefi $kernel_addr_r $fdtcontroladdr' works
>
> The first bootefi command will fail since there's nothing loaded on
> that address yet. What happens is that u-boot adds an extra
> memory_map, via efi_add_memory_map() and the kernel boots
>
> Kernel's EFI map:
> [ 0.000000] efi: Processing EFI memory map:
> [ 0.000000] efi: 0x0000c0000000-0x0000c1ffffff [Boot Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2000000-0x0000c2860fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2861000-0x0000c7cf3fff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7cf4000-0x0000c7ef3fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7ef4000-0x0000c7f0bfff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7f0c000-0x0000dc704fff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc705000-0x0000dc708fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc709000-0x0000dcf69fff [Loader Code | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6a000-0x0000dcf6cfff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6d000-0x0000dcf6dfff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6e000-0x0000dcf74fff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf75000-0x0000dcf75fff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf76000-0x0000dff80fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff81000-0x0000dff81fff [Runtime Code |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff82000-0x0000dfffffff [Loader Data | | | | | | | | |WB| | | ]
>
>
> - Workaround 2, copy fdt one page before the 127mb limit
>
> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
> index 3619a20e6433..a0b6156845da 100644
> --- a/cmd/bootefi.c
> +++ b/cmd/bootefi.c
> @@ -108,11 +108,13 @@ static efi_status_t copy_fdt(void **fdtp)
> * Safe fdt location is at 127 MiB.
> * On the sandbox convert from the sandbox address space.
> */
> - new_fdt_addr = (uintptr_t)map_sysmem(fdt_ram_start + 0x7f00000 +
> - fdt_size, 0);
> + //new_fdt_addr = (uintptr_t)map_sysmem(fdt_ram_start + 0x7f00000 +
> + //fdt_size, 0);
> + new_fdt_addr = (uintptr_t)map_sysmem(fdt_ram_start + 0x7f00000, fdt_size);
> ret = efi_allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
> EFI_RUNTIME_SERVICES_DATA, fdt_pages,
> &new_fdt_addr);
> + printf("FDTADDR: %llx pages %lu sz %x\n", new_fdt_addr, fdt_pages, fdt_size);
> if (ret != EFI_SUCCESS) {
> /* If we can't put it there, put it somewhere */
> new_fdt_addr = (ulong)memalign(EFI_PAGE_SIZE, fdt_size);
>
> This loads the fdt on c7ef4000 (which is more than a page). Changing
> the address from 0x7f00000 to 7EFF000, on the original code, works as
> well
>
> Kernel's EFI map (with the patch) :
> [ 0.000000] efi: Processing EFI memory map:
> [ 0.000000] efi: 0x0000c0000000-0x0000c1ffffff [Boot Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2000000-0x0000c2860fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2861000-0x0000c7cf3fff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7cf4000-0x0000c7ef3fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7ef4000-0x0000c7efffff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7f00000-0x0000dc705fff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc706000-0x0000dc709fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc70a000-0x0000dcf6afff [Loader Code | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6b000-0x0000dcf6bfff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6c000-0x0000dcf72fff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf73000-0x0000dcf73fff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf74000-0x0000dcf75fff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf76000-0x0000dff80fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff81000-0x0000dff81fff [Runtime Code |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff82000-0x0000dfffffff [Loader Data | | | | | | | | |WB| | | ]
>
> - Workaround 3, align fdt on 1mb boundries
>
> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
> index 3619a20e6433..37e849fad773 100644
> --- a/cmd/bootefi.c
> +++ b/cmd/bootefi.c
> @@ -101,7 +101,8 @@ static efi_status_t copy_fdt(void **fdtp)
> * needs to be expanded later.
> */
> fdt = *fdtp;
> - fdt_pages = efi_size_in_pages(fdt_totalsize(fdt) + 0x3000);
> + //fdt_pages = efi_size_in_pages(fdt_totalsize(fdt) + 0x3000);
> + fdt_pages = efi_size_in_pages(0x100000);
> fdt_size = fdt_pages << EFI_PAGE_SHIFT;
>
> /*
>
> Kernel's EFI map:
> [ 0.000000] efi: Processing EFI memory map:
> [ 0.000000] efi: 0x0000c0000000-0x0000c1ffffff [Boot Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2000000-0x0000c2860fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c2861000-0x0000c7cfffff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7d00000-0x0000c7efffff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c7f00000-0x0000c7ffffff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000c8000000-0x0000dc705fff [Conventional Memory| | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc706000-0x0000dc709fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dc70a000-0x0000dcf6afff [Loader Code | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6b000-0x0000dcf6bfff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf6c000-0x0000dcf72fff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf73000-0x0000dcf73fff [Runtime Data |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf74000-0x0000dcf75fff [Reserved | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dcf76000-0x0000dff80fff [Loader Data | | | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff81000-0x0000dff81fff [Runtime Code |RUN| | | | | | | |WB| | | ]
> [ 0.000000] efi: 0x0000dff82000-0x0000dfffffff [Loader Data | | | | | | | | |WB| | | ]
>
>
> Thanks
> /Ilias
>