From 9f6ded879600969b36b64e6b0da04167a97622d5 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Mon, 11 Oct 2021 11:13:45 +0800
Subject: [PATCH] arm64: assembler: remove conditional NEON yield macros

mainline inclusion
from mainline-v5.13-rc1
commit 27248fe1abb2
category: bugfix
bugzilla: 172149 https://gitee.com/openeuler/kernel/issues/I4CZ7H
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=27248fe1abb2

-----------------------------------------------

The users of the conditional NEON yield macros have all been switched to
the simplified cond_yield macro, and so the NEON specific ones can be
removed.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210302090118.30666-2-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Wei Li <liwei391@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
---
 arch/arm64/include/asm/assembler.h | 70 ------------------------------
 1 file changed, 70 deletions(-)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index f1838bd93a40..2746aaa61438 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -675,76 +675,6 @@ USER(\label, ic	ivau, \tmp2)			// invalidate I line PoU
 	.endif
 	.endm
 
-/*
- * Check whether to yield to another runnable task from kernel mode NEON code
- * (which runs with preemption disabled).
- *
- * if_will_cond_yield_neon
- *        // pre-yield patchup code
- * do_cond_yield_neon
- *        // post-yield patchup code
- * endif_yield_neon    <label>
- *
- * where <label> is optional, and marks the point where execution will resume
- * after a yield has been performed. If omitted, execution resumes right after
- * the endif_yield_neon invocation. Note that the entire sequence, including
- * the provided patchup code, will be omitted from the image if
- * CONFIG_PREEMPTION is not defined.
- *
- * As a convenience, in the case where no patchup code is required, the above
- * sequence may be abbreviated to
- *
- * cond_yield_neon <label>
- *
- * Note that the patchup code does not support assembler directives that change
- * the output section, any use of such directives is undefined.
- *
- * The yield itself consists of the following:
- * - Check whether the preempt count is exactly 1 and a reschedule is also
- *   needed. If so, calling of preempt_enable() in kernel_neon_end() will
- *   trigger a reschedule. If it is not the case, yielding is pointless.
- * - Disable and re-enable kernel mode NEON, and branch to the yield fixup
- *   code.
- *
- * This macro sequence may clobber all CPU state that is not guaranteed by the
- * AAPCS to be preserved across an ordinary function call.
- */
-
-	.macro		cond_yield_neon, lbl
-	if_will_cond_yield_neon
-	do_cond_yield_neon
-	endif_yield_neon	\lbl
-	.endm
-
-	.macro		if_will_cond_yield_neon
-#ifdef CONFIG_PREEMPTION
-	get_current_task	x0
-	ldr		x0, [x0, #TSK_TI_PREEMPT]
-	sub		x0, x0, #PREEMPT_DISABLE_OFFSET
-	cbz		x0, .Lyield_\@
-	/* fall through to endif_yield_neon */
-	.subsection	1
-.Lyield_\@ :
-#else
-	.section	".discard.cond_yield_neon", "ax"
-#endif
-	.endm
-
-	.macro		do_cond_yield_neon
-	bl		kernel_neon_end
-	bl		kernel_neon_begin
-	.endm
-
-	.macro		endif_yield_neon, lbl
-	.ifnb		\lbl
-	b		\lbl
-	.else
-	b		.Lyield_out_\@
-	.endif
-	.previous
-.Lyield_out_\@ :
-	.endm
-
 	/*
 	 * Check whether preempt-disabled code should yield as soon as it
 	 * is able. This is the case if re-enabling preemption a single
-- 
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