arm64: Do not enable uaccess for invalidate_icache_range

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invalidate_icache_range() works on kernel addresses, 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/
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-6-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

...

This commit is contained in:

Fuad Tabba 2021-05-24 09:29:48 +01:00 • committed by Will Deacon

parent 116b7f5594

commit 7908072da5

2 changed files with 2 additions and 11 deletions

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2

arch/arm64/include/asm/cacheflush.h

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11

arch/arm64/mm/cache.S

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