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Message-Id: <20170906224501.11816-1-miguel.bernal.marin@linux.intel.com>
Date: Wed, 6 Sep 2017 17:44:58 -0500
From: Miguel Bernal Marin <miguel.bernal.marin@...ux.intel.com>
To: Josh Poimboeuf <jpoimboe@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
"H . Peter Anvin" <hpa@...or.com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org
Subject: [PATCH v2 0/3] locking/rwsem/x86: Add stack frame dependency for some inline asm
Some warning were showed by objtool using gcc 7.2.0
kernel/locking/rwsem.o: warning: objtool: up_read()+0x11: call without frame pointer save/setup
kernel/locking/rwsem.o: warning: objtool: up_write()+0x17: call without frame pointer save/setup
kernel/locking/rwsem.o: warning: objtool: downgrade_write()+0x22: call without frame pointer save/setup
which means gcc placed an inline asm function and its call instruction before
the frame pointer setup.
This series forces a stack frame to be created before the call instruction
by listing the stack pointer as an output operand in the inline asm statement.
Changes in v2:
- Update first parameter from _ASM_ADD to '%3' at __downgrade_write()
Miguel Bernal Marin (3):
locking/rwsem/x86: Add stack frame dependency for __up_read()
locking/rwsem/x86: Add stack frame dependency for __up_write()
locking/rwsem/x86: Add stack frame dependency for __downgrade_write()
arch/x86/include/asm/rwsem.h | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
--
2.14.1
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