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From:   Michal Suchanek <msuchanek@suse.de>
To:     linuxppc-dev@lists.ozlabs.org
Cc:     Kate Stewart <kstewart@linuxfoundation.org>,
        Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
        Paul Mackerras <paulus@samba.org>,
        Michael Neuling <mikey@neuling.org>,
        "Bryant G. Ly" <bryantly@linux.vnet.ibm.com>,
        Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
        "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
        Daniel Axtens <dja@axtens.net>,
        Nicholas Piggin <npiggin@gmail.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        David Gibson <david@gibson.dropbear.id.au>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@kaod.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
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        Joe Perches <joe@perches.com>,
        Oliver O'Halloran <oohall@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Tobin C. Harding" <me@tobin.cc>,
        Michal Suchanek <msuchanek@suse.de>
Subject: [PATCH RFC rebase 3/9] powerpc/64: Use barrier_nospec in syscall entry
Date:   Thu, 15 Mar 2018 20:15:52 +0100
Message-Id: <b8253774e223530c808eed65d116deecc46ad36b.1521141122.git.msuchanek@suse.de>
In-Reply-To: <cover.1521141122.git.msuchanek@suse.de>
References: <20180313200108.GA4082@hirez.programming.kicks-ass.net>
 <cover.1521141122.git.msuchanek@suse.de>
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Precedence: bulk

On powerpc syscall entry is done in assembly so patch in an explicit
barrier_nospec.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/entry_64.S | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 2cb5109a7ea3..7bfc4cf48af2 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -36,6 +36,7 @@
 #include <asm/context_tracking.h>
 #include <asm/tm.h>
 #include <asm/ppc-opcode.h>
+#include <asm/barrier.h>
 #include <asm/export.h>
 #ifdef CONFIG_PPC_BOOK3S
 #include <asm/exception-64s.h>
@@ -159,6 +160,7 @@ system_call:			/* label this so stack traces look sane */
 	andi.	r11,r10,_TIF_SYSCALL_DOTRACE
 	bne	.Lsyscall_dotrace		/* does not return */
 	cmpldi	0,r0,NR_syscalls
+	barrier_nospec
 	bge-	.Lsyscall_enosys
 
 .Lsyscall:
@@ -319,6 +321,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	ld	r10,TI_FLAGS(r10)
 
 	cmpldi	r0,NR_syscalls
+	barrier_nospec
 	blt+	.Lsyscall
 
 	/* Return code is already in r3 thanks to do_syscall_trace_enter() */
-- 
2.13.6