Re: [PATCH 12/12] efi: make const array 'apple' static

From: Ard Biesheuvel
Date: Fri Mar 09 2018 - 02:44:24 EST


On 9 March 2018 at 07:43, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
> On 8 March 2018 at 11:05, Joe Perches <joe@xxxxxxxxxxx> wrote:
>> On Thu, 2018-03-08 at 08:00 +0000, Ard Biesheuvel wrote:
>>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>>
>>> Don't populate the const read-only array 'buf' on the stack but instead
>>> make it static. Makes the object code smaller by 64 bytes:
>>>
>>> Before:
>>> text data bss dec hex filename
>>> 9264 1 16 9281 2441 arch/x86/boot/compressed/eboot.o
>>>
>>> After:
>>> text data bss dec hex filename
>>> 9200 1 16 9217 2401 arch/x86/boot/compressed/eboot.o
>>>
>>> (gcc version 7.2.0 x86_64)
>>>
>>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>>> ---
>>> arch/x86/boot/compressed/eboot.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
>>> index 886a9115af62..f2251c1c9853 100644
>>> --- a/arch/x86/boot/compressed/eboot.c
>>> +++ b/arch/x86/boot/compressed/eboot.c
>>> @@ -423,7 +423,7 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params)
>>>
>>> static void setup_quirks(struct boot_params *boot_params)
>>> {
>>> - efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
>>> + static efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
>>
>> Perhaps
>>
>> static const efi_char16_t apple[] ...
>>
>> is better.
>>
>
> Why would that be any better? I have always found the 'const'
> placement after the type to be much clearer.
>
> const void *
> void const *
> void * const
>
> I.e., #2 and #3 are equivalent,

That would be #1 and #2, of course

> and so 'const' associates to the left
> not to the right, unless it is at the beginning.
>
> Personally, I don't mind either way, but saying it is 'better' is a stretch imo