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From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: barebox@lists.infradead.org
Subject: Re: [PATCH 059/112] efi: payload: init: restrict barebox mem to first 1G only on x86
Date: Mon, 8 Jan 2024 08:22:31 +0100	[thread overview]
Message-ID: <dec08c7e-8128-45b9-918d-9eaf15e61ec7@pengutronix.de> (raw)
In-Reply-To: <ZZgY_jrnN-bmpIAu@pengutronix.de>

On 05.01.24 15:58, Michael Olbrich wrote:
> On Fri, Jan 05, 2024 at 11:41:09AM +0100, Ahmad Fatoum wrote:
>> On 05.01.24 10:31, Michael Olbrich wrote:
>>> On Fri, Jan 05, 2024 at 10:14:33AM +0100, Ahmad Fatoum wrote:
>>>> On 04.01.24 19:10, Michael Olbrich wrote:
>>>>> On Thu, Jan 04, 2024 at 12:17:12PM +0100, Ahmad Fatoum wrote:
>>>>>> On 03.01.24 19:58, Michael Olbrich wrote:
>>>>>>> On Wed, Jan 03, 2024 at 07:12:19PM +0100, Ahmad Fatoum wrote:
>>>>>>>> When run as EFI payload, barebox will not have full access to DRAM and will
>>>>>>>> have to ask the EFI firmware for memory. It does so once at the beginning
>>>>>>>> and since commit 356aaef5a37d ("efi: improve malloc pool allocation"),
>>>>>>>> the buffer was always placed beneath the 1G boundary.
>>>>>>>>
>>>>>>>> Aforementioned commit didn't elaborate why a maximum of 1G in particular
>>>>>>>> was chosen. Anyways, non-PC architectures have different memory maps, so
>>>>>>>> a 1G limit doesn't make sense there. Therefore restrict the limit to
>>>>>>>> ARCH_X86. On non-x86, we allow the memory pages to be located anywhere.
>>>>>>>
>>>>>>> The 1G is somewhat arbitrary but if you don't restrict the memory to 32bit,
>>>>>>> then loading the kernel may fail: The addresses in "struct
>>>>>>> linux_kernel_header" are only 32bit. So if you impose no restrictions at
>>>>>>> all, then this memory cannot be used for the kernel and initrd.
>>>>>>
>>>>>> The limit for x86 remains at 1G. It's only for other architectures, that we
>>>>>> remove the limit. I suspect that other architectures won't have this kind
>>>>>> of problems though , because they would boot the kernel image via EFI load
>>>>>> and start image boot services, where the EFI firmware takes care to layout
>>>>>> the boot artifacts.
>>>>>>
>>>>>> Once we have that in place, we could even use it on x86 instead of
>>>>>> using struct linux_kernel_header, but I haven't investigated this yet.
>>>>>
>>>>> How do you load the initrd via EFI? As far as I know, that only works as a
>>>>> filename in the EFI boot partition.
>>>>
>>>> This seems to be relaxed in newer kernels, see
>>>> https://lore.kernel.org/linux-efi/20200207202637.GA3464906@rani.riverdale.lan/T/
>>>
>>> It's not quite clear to me how that works, but from what I can tell,
>>> requires support from the firmware and barebox needs to use it. So that
>>> does not help here.
>>> You need to either disable the legacy handler to avoid arbitrary failures
>>> or explicitly allocate the initrd memory from efi with the restriction to
>>> <4G.
>>
>> The legacy handler wouldn't apply to other architectures:
>>
>>   - The Kernel images for ARM64 and RISC-V have different more-specific filetypes
>>     than filetype_exe
> 
> Ah, now I get it. I forgot that that code is x86 specific. So how do you
> boot Linux from EFI anyways on other architectures?

We don't yet.

> I don't see any filetypes for EFI binaries for other architectures. I'm not
> sure how that works but would expect to find some code that hands over
> efi_sys_table? Or what am I missing?

Only binfmt handler is registered for normal EFI start. initrd/DT will have
to follow later.

> And if you boot a non-EFI binary shouldn't you call RS->exit_boot_services()
> before actually starting the kernel?

Possibly. I remember that booting a kernel without EFI stub failed, but haven't
investigated why this was the case.

> And we should move setting LoaderTimeExecUSec into some kind of barebox
> shutdown handler to ensure that it is set even if other bootm handlers are
> used. But that's all unrelated to this patch.

Yes. I'll keep that in mind for when the bootm handler is added.

Thanks,
Ahmad

> 
> Regards,
> Michael
> 
>>   - The Linux kernel header check will probabaly fail for every format that's not
>>     x86
>>
>> Cheers,
>> Ahmad 
>>
>>>
>>> Michael
>>>
>>>>> That was the reason for implementing
>>>>> the "legacy" boot mode. And what about the device-tree?
>>>>
>>>> There is an EFI config table for FDT (DEVICE_TREE_GUID in Linux code). barebox
>>>> as EFI loader can use it to provide its own DT. I have to check what's the cleanest
>>>> way for barebox as EFI payload to provide a different DT, but I hope there is a way
>>>> without barebox as EFI payload having to manipulate the device tree itself.
>>>>
>>>> Cheers,
>>>> Ahmad
>>>>
>>>>>
>>>>> Michael
>>>>>
>>>>>>>> This can break PCI drivers on systems that so far assumed barebox memory
>>>>>>>> is located in the first 4G, but that's ok. That code will need to be
>>>>>>>> fixed eventually anyway.
>>>>>>>>
>>>>>>>> Cc: Michael Olbrich <m.olbrich@pengutronix.de>
>>>>>>>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
>>>>>>>> ---
>>>>>>>>  efi/payload/init.c | 2 +-
>>>>>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>>>
>>>>>>>> diff --git a/efi/payload/init.c b/efi/payload/init.c
>>>>>>>> index 4b612e61afb3..0c2f38e9c86a 100644
>>>>>>>> --- a/efi/payload/init.c
>>>>>>>> +++ b/efi/payload/init.c
>>>>>>>> @@ -292,7 +292,7 @@ void efi_main(efi_handle_t image, struct efi_system_table *sys_table)
>>>>>>>>  		BS->handle_protocol(efi_loaded_image->device_handle,
>>>>>>>>  				&efi_device_path_protocol_guid, (void **)&efi_device_path);
>>>>>>>>  
>>>>>>>> -	mem = 0x3fffffff;
>>>>>>>> +	mem = IS_ENABLED(CONFIG_X86) ? 0x3fffffff : ~0ULL;
>>>>>>>>  	for (memsize = SZ_256M; memsize >= SZ_8M; memsize /= 2) {
>>>>>>>>  		efiret  = BS->allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
>>>>>>>>  					     EFI_LOADER_DATA,
>>>>>>>> -- 
>>>>>>>> 2.39.2
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> -- 
>>>>>> Pengutronix e.K.                           |                             |
>>>>>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>>>>>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>>>>>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
>>>>>>
>>>>>>
>>>>>
>>>>
>>>> -- 
>>>> Pengutronix e.K.                           |                             |
>>>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>>>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>>>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
>>>>
>>>>
>>>
>>
>> -- 
>> Pengutronix e.K.                           |                             |
>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
>>
>>
>>
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |




  reply	other threads:[~2024-01-08  7:23 UTC|newest]

Thread overview: 134+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-03 18:11 [PATCH 000/112] efi: prepare for ARM64 EFI loader support Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 001/112] string: implement strcmp_ptr and streq_ptr helpers Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 002/112] commands: efiexit: flush console and shutdown barebox Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 003/112] treewide: add errno_set helper for returning positive error code in errno Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 004/112] vsprintf: guard against NULL in UUID %pU Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 005/112] common: add option to poweroff system on failure Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 006/112] boot: print error code when booting fails Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 007/112] common: efi: move directory to top-level Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 008/112] efi: payload: rename CONFIG_EFI_BOOTUP to CONFIG_EFI_PAYLOAD Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 009/112] efi: payload: image: return actual read_file() error Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 010/112] of: don't report failure to of_read_file twice Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 011/112] efi: payload: make missing state reporting less verbose Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 012/112] libfile: factor out read_file_into_buf helper Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 013/112] efi: payload: image: allocate image via loader if it exceeds malloc area Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 014/112] efi: payload: image: use assigned barebox loader type on x86 Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 015/112] efi: payload: iomem: adjust types to avoid casting Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 016/112] commands: kallsyms: add command-line interface Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 017/112] block: define BLOCKSIZE globally in block.h Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 018/112] cdev: implement setter/getter for cdev device node Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 019/112] block: virtio: assign virtio-mmio device tree node to cdevs Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 020/112] commands: stat: print DT node for cdevs if available Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 021/112] partitions: have parsers record bootable bits Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 022/112] commands: stat: display bootable partition table bit info Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 023/112] block: record block device type Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 024/112] include: add definitions for UAPI discoverable partitions spec Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 025/112] efi: payload: restrict 8250 UART at I/O port 0x3f8 registration to x86 Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 026/112] fs: fix unreaddir, so readdir returns unread dirent first Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 027/112] fs: turn creat into static inline helper Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 028/112] fs: drop unused LOOKUP_ flags Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 029/112] fs: opendir: reference mount point until closedir is called Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 030/112] fs: factor out opendir iteration Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 031/112] fs: implement fdopendir and rewinddir Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 032/112] fs: remove unused member from struct nameidata Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 033/112] fs: always check path_init for errors Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 034/112] fs: set current working dir directly when mounting root Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 035/112] fs: implement openat and friends Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 036/112] fs: implement O_PATH Ahmad Fatoum
2024-01-05 11:22   ` Sascha Hauer
2024-01-05 11:26     ` Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 037/112] fs: support different root directories Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 038/112] fs: implement O_CHROOT Ahmad Fatoum
2024-01-03 18:11 ` [PATCH 039/112] commands: introduce new findmnt command Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 040/112] fs: initialize struct nameidata::last Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 041/112] fs: support opening / Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 042/112] test: self: add dirfd tests Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 043/112] commands: stat: add option for statat Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 044/112] efi: payload: lower command line options print from error to info Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 045/112] efi: payload: init: warn if /boot FS is unknown Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 046/112] commands: time: refactor into new strjoin Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 047/112] string: reduce strjoin runtime, drop trailing separator Ahmad Fatoum
2024-01-08  7:11   ` Sascha Hauer
2024-01-08  7:18     ` Ahmad Fatoum
2024-01-08  7:43       ` Sascha Hauer
2024-01-03 18:12 ` [PATCH 048/112] test: self: add strjoin tests Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 049/112] filetype: have cdev_detect_type take a cdev Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 050/112] ARM: mmu-early: gracefully handle already enabled MMU Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 051/112] efi: don't hide structs, enums or unions behind _t Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 052/112] efi: make headers self-contained Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 053/112] efi: unify whitespace for GUIDs Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 054/112] efi: efi-guid: add more GUIDs Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 055/112] ARM64: cpu: setupc: rewrite to be fully PIC Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 056/112] ARM64: runtime-offset: make get_runtime_offset " Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 057/112] pbl: introduce CONFIG_PBL_FULLY_PIC Ahmad Fatoum
2024-01-08  7:47   ` Sascha Hauer
2024-01-22 19:15     ` Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 058/112] efi: payload: fix ARM build Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 059/112] efi: payload: init: restrict barebox mem to first 1G only on x86 Ahmad Fatoum
2024-01-03 18:58   ` Michael Olbrich
2024-01-04 11:17     ` Ahmad Fatoum
2024-01-04 18:10       ` Michael Olbrich
2024-01-05  9:14         ` Ahmad Fatoum
2024-01-05  9:31           ` Michael Olbrich
2024-01-05 10:41             ` Ahmad Fatoum
2024-01-05 14:58               ` Michael Olbrich
2024-01-08  7:22                 ` Ahmad Fatoum [this message]
2024-01-03 18:12 ` [PATCH 060/112] ARM: pbl: add 64K segment alignment for PE/COFF Ahmad Fatoum
2024-01-08  8:05   ` Sascha Hauer
2024-01-22 19:18     ` Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 061/112] efi: add efi_is_loader/efi_is_payload helpers Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 062/112] efi: payload: suppress EFI payload initcalls when not EFI-loaded Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 063/112] ARM: make board data definitions accessible to other architectures Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 064/112] boarddata: add barebox_boarddata_is_machine helper Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 065/112] common: add PE/COFF loader Ahmad Fatoum
2024-01-08  8:37   ` Sascha Hauer
2024-03-04 17:09     ` Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 066/112] efi: use efi_handle_t where appropriate Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 067/112] efi: block: move definitions into header file Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 068/112] efi: define efi_handle_t as opaque pointer Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 069/112] efi: constify guid_t in API Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 070/112] efi: rename efi_simple_input_interface to efi_simple_text_input_protocol Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 071/112] efi: add EFI_WARN constants Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 072/112] efi-stdio: fix wait_for_event argument Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 073/112] efi-stdio: wait for extended input key event when using extended input Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 074/112] efi: flesh out EFI definitions in header Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 075/112] efi: add efi_driver_binding_protocol Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 076/112] efi: improve usability of EFI_PAGE_* macros Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 077/112] fs: efi: move definitions into header Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 078/112] efi: fs: flesh out file system definitions Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 079/112] efi: stdio: fix efi_register_keystroke_notify prototype Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 080/112] video: mark EFI_GOP driver x86-only for now Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 081/112] filetype: add new file types for EFI-enabled Linux images Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 082/112] efi: payload: register handler for EFI-stubbed ARM64 kernel Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 083/112] efi: payload: factor C efi_main into dedicated file Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 084/112] efi: payload: early-mem: simplify error message reporting Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 085/112] efi: payload: early-mem: use EFI_PAGE_SIZE instead of PAGE_SIZE Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 086/112] ARM64: add optional EFI stub Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 087/112] efi: devicepath: improve const safety Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 088/112] efi: refactor device_path_to_partuuid for code reuse Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 089/112] efi: devicepath: implement device_path_to_str_buf variant Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 090/112] vsprintf: add %pD for printing EFI device path Ahmad Fatoum
2024-01-08  9:01   ` Sascha Hauer
2024-03-04 17:26     ` Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 091/112] lib: string: import Linux strreplace helper Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 092/112] efi: payload: dynamically determine bootloader file name Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 093/112] efi: payload: iomem: register later Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 094/112] efi: payload: protect against buggy EFI implementations Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 095/112] efi: payload: don't require efi_loaded_image->parent_handle for bootsource detection Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 096/112] commands: add cpuinfo -s option for stacktrace Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 097/112] efi: devicepath: align MemoryMapped name with spec Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 098/112] efi: devicepath: pretty print BBS BEV DeviceType Ahmad Fatoum
2024-01-03 18:12 ` [PATCH 099/112] efi: devicepath: format GUIDs as little endian Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 100/112] efi: devicepath: move END device node definitions into header Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 101/112] efi: devicepath: drop underscores in hex constants Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 102/112] efi: devicepath: namespace definitions Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 103/112] efi: devicepath: use flexible array members for trailing strings Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 104/112] efi: devicepath: drop unused macro Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 105/112] efi: devicepath: let compiler worry about unaligned unpacking Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 106/112] efi: devicepath: correct formatting of BBS Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 107/112] commands: provide efi_handle_dump in both payload and loader Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 108/112] lib: uuid: implement uuid/guid_parse Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 109/112] commands: efi_handle_dump: prepare for supporting EFI loader Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 110/112] commands: efi_handle_dump: print loaded image devpath Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 111/112] commands: efi_handle_dump: use guid_parse instead of open-coding Ahmad Fatoum
2024-01-03 18:13 ` [PATCH 112/112] commands: efi_handle_dump: don't ignore failure to parse GUID Ahmad Fatoum

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