ARM: 8790/1: signal: always use __copy_to_user to save iwmmxt context (73839798) · Commits · 戴 / test

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>

arch/arm/kernel/signal.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -77,8 +77,6 @@ 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
		@@ -86,10 +84,14 @@ 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;
		}

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