[tip:,locking/urgent] locking: Fix qspinlock/x86 inline asm error

Message ID 166859051534.4906.7078966677789928700.tip-bot2@tip-bot2
State New
Headers
Series [tip:,locking/urgent] locking: Fix qspinlock/x86 inline asm error |

Commit Message

tip-bot2 for Thomas Gleixner Nov. 16, 2022, 9:21 a.m. UTC
  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@chinatelecom.cn>
AuthorDate:    Tue, 08 Nov 2022 14:01:26 +08:00
Committer:     Peter Zijlstra <peterz@infradead.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@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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
  

Comments

Juergen Gross Nov. 16, 2022, 9:40 a.m. UTC | #1
On 16.11.22 10:21, tip-bot2 for Guo Jin wrote:
> 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@chinatelecom.cn>
> AuthorDate:    Tue, 08 Nov 2022 14:01:26 +08:00
> Committer:     Peter Zijlstra <peterz@infradead.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@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

Wouldn't it be better to take my more generic patch [1] instead?

[1]: https://lore.kernel.org/lkml/20221109134418.6516-1-jgross@suse.com/


Juergen
  
Peter Zijlstra Nov. 16, 2022, 10:39 a.m. UTC | #2
On Wed, Nov 16, 2022 at 10:40:10AM +0100, Juergen Gross wrote:
> On 16.11.22 10:21, tip-bot2 for Guo Jin wrote:
> > 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@chinatelecom.cn>
> > AuthorDate:    Tue, 08 Nov 2022 14:01:26 +08:00
> > Committer:     Peter Zijlstra <peterz@infradead.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@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
> 
> Wouldn't it be better to take my more generic patch [1] instead?
> 
> [1]: https://lore.kernel.org/lkml/20221109134418.6516-1-jgross@suse.com/

Durr, I missed that, lemme go stare at it.
  

Patch

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;"