Re: [PATCH v1 01/13] arm64: mm: Re-implement the __tlbi_level macro as a C function

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Tue, 16 Dec 2025 14:45:46 +0000
Ryan Roberts <ryan.roberts@arm.com> wrote:

> As part of efforts to reduce our reliance on complex preprocessor macros
> for TLB invalidation routines, convert the __tlbi_level macro to a C
> function for by-level TLB invalidation.
> 
> Each specific tlbi level op is implemented as a C function and the
> appropriate function pointer is passed to __tlbi_level(). Since
> everything is declared inline and is statically resolvable, the compiler
> will convert the indirect function call to a direct inline execution.
> 
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
> ---

> +static __always_inline void __tlbi_level(tlbi_op op, u64 addr, u32 level)
> +{
> +	u64 arg = addr;
> +
> +	if (alternative_has_cap_unlikely(ARM64_HAS_ARMv8_4_TTL) && level <= 3) {
> +		u64 ttl = level | (get_trans_granule() << 2);
> +
> +		arg &= ~TLBI_TTL_MASK;
> +		arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);

Probably don't care, but I think you could do
		FIELD_MODIFY(TLBI_TTL_MASK, &arg, ttl);
instead of those two lines. Code generation hopefully similar?
So depends on which macros you find more readable.

> +	}
> +
> +	op(arg);
> +}
>  
>  #define __tlbi_user_level(op, arg, level) do {				\
>  	if (arm64_kernel_unmapped_at_el0())				\