Hi Sasha,
On Sun, Dec 29, 2024 at 08:46:21PM -0500, Sasha Levin wrote:
> commit 6b17ecf6de3064c79db2e53eca71e31c1a4da62e
> Author: Yunfeng Ye <yeyunfeng@xxxxxxxxxx>
> Date: Thu Dec 9 09:42:25 2021 +0800
>
> arm64: mm: Rename asid2idx() to ctxid2asid()
>
> [ Upstream commit a3a5b763410c7bceacf41a52071134d9dc26202a ]
>
> The commit 0c8ea531b774 ("arm64: mm: Allocate ASIDs in pairs") introduce
> the asid2idx and idx2asid macro, but these macros are not really useful
> after the commit f88f42f853a8 ("arm64: context: Free up kernel ASIDs if
> KPTI is not in use").
>
> The code "(asid & ~ASID_MASK)" can be instead by a macro, which is the
> same code with asid2idx(). So rename it to ctxid2asid() for a better
> understanding.
>
> Also we add asid2ctxid() macro, the contextid can be generated based on
> the asid and generation through this macro.
>
> Signed-off-by: Yunfeng Ye <yeyunfeng@xxxxxxxxxx>
> Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/c31516eb-6d15-94e0-421c-305fc010ea79@xxxxxxxxxx
> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Stable-dep-of: c0900d15d31c ("arm64: Ensure bits ASID[15:8] are masked out when the kernel uses 8-bit ASIDs")
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
> index cd72576ae2b7..bbc2708fe928 100644
> --- a/arch/arm64/mm/context.c
> +++ b/arch/arm64/mm/context.c
> @@ -35,8 +35,8 @@ static unsigned long *pinned_asid_map;
> #define ASID_FIRST_VERSION (1UL << asid_bits)
>
> #define NUM_USER_ASIDS ASID_FIRST_VERSION
> -#define asid2idx(asid) ((asid) & ~ASID_MASK)
> -#define idx2asid(idx) asid2idx(idx)
> +#define ctxid2asid(asid) ((asid) & ~ASID_MASK)
> +#define asid2ctxid(asid, genid) ((asid) | (genid))
Is this patch needed only to ensure that commit c0900d15d31c ("arm64:
Ensure bits ASID[15:8] are masked out when the kernel uses 8-bit ASIDs")
applies cleanly? There's no functional dependency between them, just
adjacent lines being changed by the two patches. Up to you if you prefer
to cherry-pick another patch, it is harmless. Otherwise I'm happy to
send backports for commit c0900d15d31c separately.
--
Catalin
