sparc: fix accurate exception reporting in copy_to_user for Niagara 4

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[ Upstream commit 5a746c1a2c ]

The referenced commit introduced exception handlers on user-space memory
references in copy_from_user and copy_to_user. These handlers return from
the respective function and calculate the remaining bytes left to copy
using the current register contents. This commit fixes a bad calculation.
This will fix the return value of copy_to_user in a specific faulting case.
The behaviour of memcpy stays unchanged.

Fixes: 9570770480 ("sparc64: Convert NG4copy_{from,to}_user to accurate exception reporting.")
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> # on Oracle SPARC T4-1
Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Link: https://lore.kernel.org/r/20250905-memcpy_series-v4-4-1ca72dda195b@mkarcher.dialup.fu-berlin.de
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Michael Karcher 2025-09-05 00:03:33 +02:00 • committed by Greg Kroah-Hartman

parent a365ee556e

commit f4ca41f739

1 changed files with 1 additions and 1 deletions

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arch/sparc/lib/NG4memcpy.S

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