linux-kernel - [tip: locking/urgent] locking: Fix qspinlock/x86 inline asm error

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Date:   Wed, 16 Nov 2022 09:21:55 -0000
From:   "tip-bot2 for Guo Jin" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Guo Jin <guoj17@...natelecom.cn>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Nathan Chancellor <nathan@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: locking/urgent] locking: Fix qspinlock/x86 inline asm error

The following commit has been merged into the locking/urgent branch of tip:

Commit-ID:     23df39fc6a36183af5e6e4f47523f1ad2cdc1d30
Gitweb:        https://git.kernel.org/tip/23df39fc6a36183af5e6e4f47523f1ad2cdc1d30
Author:        Guo Jin <guoj17@...natelecom.cn>
AuthorDate:    Tue, 08 Nov 2022 14:01:26 +08:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Wed, 16 Nov 2022 10:18:09 +01:00

locking: Fix qspinlock/x86 inline asm error

When compiling linux 6.1.0-rc3 configured with CONFIG_64BIT=y and
CONFIG_PARAVIRT_SPINLOCKS=y on x86_64 using LLVM 11.0, an error:
"<inline asm> error: changed section flags for .spinlock.text,
expected:: 0x6" occurred.

The reason is the .spinlock.text in kernel/locking/qspinlock.o
is used many times, but its flags are omitted in subsequent use.

LLVM 11.0 assembler didn't permit to
leave out flags in subsequent uses of the same sections.

So this patch adds the corresponding flags to avoid above error.

Fixes: 501f7f69bca1 ("locking: Add __lockfunc to slow path functions")
Signed-off-by: Guo Jin <guoj17@...natelecom.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Nathan Chancellor <nathan@...nel.org>
Link: https://lore.kernel.org/r/20221108060126.2505-1-guoj17@chinatelecom.cn
---
 arch/x86/include/asm/qspinlock_paravirt.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 60ece59..dbb38a6 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -37,7 +37,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
  *   rsi = lockval           (second argument)
  *   rdx = internal variable (set to 0)
  */
-asm    (".pushsection .spinlock.text;"
+asm    (".pushsection .spinlock.text, \"ax\";"
 	".globl " PV_UNLOCK ";"
 	".type " PV_UNLOCK ", @function;"
 	".align 4,0x90;"