arm64: scs: Remove redundant save/restore of SCS SP on entry to/from EL0

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When returning to userspace, the SCS is empty and so the SCS SP just
points to the base address of the SCS page.

Rather than saving and restoring this address in the current task, we
can simply restore the SCS SP to point at the base of the stack on entry
to EL1 from EL0.

Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

...

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Will Deacon 2026-03-13 12:32:19 +00:00 • committed by Catalin Marinas

parent 6712fcde00

commit 3ce8f5860f

2 changed files with 9 additions and 3 deletions

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8

arch/arm64/include/asm/scs.h

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4

arch/arm64/kernel/entry.S

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