Re: [PATCH v3 06/18] arm64: Do not enable uaccess for invalidate_icache_range

Catalin Marinas
2021-05-25T11:20:45Z

On Thu, May 20, 2021 at 01:43:54PM +0100, Fuad Tabba wrote:
> invalidate_icache_range() works on the kernel linear map, and
> doesn't need uaccess. Remove the code that toggles
> uaccess_ttbr0_enable, as well as the code that emits an entry
> into the exception table (via the macro
> invalidate_icache_by_line).
>
> Changes return type of invalidate_icache_range() from int (which
> used to indicate a fault) to void, since it doesn't need uaccess
> and won't fault. Note that return value was never checked by any
> of the callers.
>
> No functional change intended.
> Possible performance impact due to the reduced number of
> instructions.
>
> Reported-by: Catalin Marinas <catalin.marinas@arm.com>
> Reported-by: Will Deacon <will@kernel.org>
> Link: https://lore.kernel.org/linux-arch/20200511110014.lb9PEahJ4hVOYrbwIb_qUHXyNy9KQzNFdb_I3YlzY6A@z/
> Signed-off-by: Fuad Tabba <tabba@google.com>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>