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ARM: 8790/1: signal: always use __copy_to_user to save iwmmxt context

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Commit 73839798af7ebc6c8d0c9271ebbbc148700e521f upstream.

When setting a dummy iwmmxt context, create a local instance and
use __copy_to_user both cases whether iwmmxt is being used or not.
This has the benefit of disabling/enabling PAN once for the whole copy
intead of once per write.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Julien Thierry 2019-02-13 21:10:07 -05:00 committed by Greg Kroah-Hartman
parent 56a0f2f329
commit a26e4c1f48
1 changed files with 6 additions and 4 deletions
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10
arch/arm/kernel/signal.c
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@ -76,8 +76,6 @@ static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
kframe->magic = IWMMXT_MAGIC;
kframe->size = IWMMXT_STORAGE_SIZE;
iwmmxt_task_copy(current_thread_info(), &kframe->storage);
err = __copy_to_user(frame, kframe, sizeof(*frame));
} else {
/*
* For bug-compatibility with older kernels, some space
@ -85,10 +83,14 @@ static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
* Set the magic and size appropriately so that properly
* written userspace can skip it reliably:
*/
__put_user_error(DUMMY_MAGIC, &frame->magic, err);
__put_user_error(IWMMXT_STORAGE_SIZE, &frame->size, err);
*kframe = (struct iwmmxt_sigframe) {
.magic = DUMMY_MAGIC,
.size = IWMMXT_STORAGE_SIZE,
};
}
err = __copy_to_user(frame, kframe, sizeof(*kframe));
return err;
}