locking: Fix qspinlock/x86 inline asm error
authorGuo Jin <guoj17@chinatelecom.cn>
Tue, 8 Nov 2022 06:01:26 +0000 (14:01 +0800)
committerPeter Zijlstra <peterz@infradead.org>
Wed, 16 Nov 2022 09:18:09 +0000 (10:18 +0100)
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@chinatelecom.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20221108060126.2505-1-guoj17@chinatelecom.cn
arch/x86/include/asm/qspinlock_paravirt.h

index 60ece59..dbb38a6 100644 (file)
@@ -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;"