Re: [PATCH v2] efi/libstub: arm*: Pass latest memory map to the kernel

Ard Biesheuvel
2016-12-20T22:33:28Z

On 20 December 2016 at 22:32, Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On 19 December 2016 at 21:38, Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> wrote:
>> On Mon, 19 Dec, at 02:24:19PM, James Morse wrote:
>>> From: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>>
>>> As reported by James, the current libstub code involving the annotated
>>> memory map only works somewhat correctly by accident, due to the fact
>>> that a pool allocation happens to be reused immediately, retaining its
>>> former contents.
>>>
>>> Instead of juggling memory maps, which makes the code more complex than
>>> it needs to be, simply put a placholder value into the FDT, and only
>>> write the actual value after ExitBootServices() has been called.
>>>
>>> Reported-by: James Morse <james.morse-5wv7dgnIgG8@public.gmane.org>
>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>> [Update mmap-size too, remove updated_fdt()s unused params and header entry]
>>> Signed-off-by: James Morse <james.morse-5wv7dgnIgG8@public.gmane.org>
>>> ---
>>> Hi Ard,
>>>
>>> This is a v2 of your patch that updates the mmap-size too. This solves the
>>> truncated memmap problem I saw with v1 on Seattle.
>>>
>>> The original patch was CC-stable, so I think this should also have:
>>> Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
>>> Fixes: ed9cc156c42f ("efi/libstub: Use efi_exit_boot_services() in FDT")
>>>
>>>
>>> Thanks,
>>>
>>> James
>>>
>>> drivers/firmware/efi/libstub/efistub.h | 8 ----
>>> drivers/firmware/efi/libstub/fdt.c | 75 +++++++++++++++++++++-------------
>>> 2 files changed, 47 insertions(+), 36 deletions(-)
>>
>> Thanks James. I've queued this one up in the 'urgent' queue and tagged
>> it for stable. I'll send it to tip before the end of the week.
>
> Could we fold the hunk below, please?
>
> diff --git a/drivers/firmware/efi/libstub/fdt.c
> b/drivers/firmware/efi/libstub/fdt.c
> index 9b11b0559a23..90ab96845937 100644
> --- a/drivers/firmware/efi/libstub/fdt.c
> +++ b/drivers/firmware/efi/libstub/fdt.c
> @@ -149,26 +149,25 @@ static efi_status_t
> update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
> static efi_status_t update_fdt_memmap(void *fdt, u64 memmap, u32 map_size)
> {
> int node = fdt_path_offset(fdt, "/chosen");
> - efi_status_t status;
> + int err;
>
> if (node < 0)
> return EFI_LOAD_ERROR;
>
> memmap = cpu_to_fdt64(memmap);
> - status = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
> - &memmap, sizeof(memmap));
> + err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
> + &memmap, sizeof(memmap));
>
> if (status)
> return EFI_LOAD_ERROR;
>
> map_size = cpu_to_fdt32(map_size);
> - status = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
> - &map_size, sizeof(map_size));
> + err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
> + &map_size, sizeof(map_size));
>
> if (status)
> return EFI_LOAD_ERROR;
>
> -
> return EFI_SUCCESS;
> }
>
> My mistake, and harmless in practice, but sloppy nonetheless

... but with the 'if (status)' replaced as well, of course (2x)