Re: [PATCH v7 07/10] kernel/jump_label: abstract jump_entry member accessors

[Ard Biesheuvel]

On 5 January 2018 at 17:58, Catalin Marinas <catalin.marinas@xxxxxxx> wrote:
> On Tue, Jan 02, 2018 at 08:05:46PM +0000, Ard Biesheuvel wrote:
>> diff --git a/arch/arm/include/asm/jump_label.h b/arch/arm/include/asm/jump_label.h
>> index e12d7d096fc0..7b05b404063a 100644
>> --- a/arch/arm/include/asm/jump_label.h
>> +++ b/arch/arm/include/asm/jump_label.h
>> @@ -45,5 +45,32 @@ struct jump_entry {
>>       jump_label_t key;
>>  };
>>
>> +static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
>> +{
>> +     return entry->code;
>> +}
>> +
>> +static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
>> +{
>> +     return (struct static_key *)((unsigned long)entry->key & ~1UL);
>> +}
>> +
>> +static inline bool jump_entry_is_branch(const struct jump_entry *entry)
>> +{
>> +     return (unsigned long)entry->key & 1UL;
>> +}
>> +
>> +static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
>> +{
>> +     return entry->code == 0;
>> +}
>> +
>> +static inline void jump_entry_set_module_init(struct jump_entry *entry)
>> +{
>> +     entry->code = 0;
>> +}
>> +
>> +#define jump_label_swap              NULL
>
> Is there any difference between these functions on any of the
> architectures touched? Even with the relative offset, arm64 and x86
> looked the same to me (well, I may have missed some detail).
>

No, the latter two are identical everywhere, and the others are the
same modulo absolute vs relative.

The issue is that the struct definition is per-arch so the accessors
should be as well. Perhaps I should introduce two variants two
asm-generic, similar to how we have different flavors of unaligned
accessors.