From: Nicholas Piggin <npiggin@gmail.com>
To: Michal Suchanek <msuchanek@suse.de>
Cc: linuxppc-dev@lists.ozlabs.org,
"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>,
"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>,
"Cédric Le Goater" <clg@kaod.org>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Andrew Donnellan" <andrew.donnellan@au1.ibm.com>,
"Philippe Ombredanne" <pombredanne@nexb.com>,
"Joe Perches" <joe@perches.com>,
"Oliver O'Halloran" <oohall@gmail.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Tobin C. Harding" <me@tobin.cc>
Subject: Re: [PATCH RFC rebase 3/9] powerpc/64: Use barrier_nospec in syscall entry
Date: Fri, 16 Mar 2018 15:18:23 +1000 [thread overview]
Message-ID: <20180316151823.2f28d5ea@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <b8253774e223530c808eed65d116deecc46ad36b.1521141122.git.msuchanek@suse.de>
On Thu, 15 Mar 2018 20:15:52 +0100
Michal Suchanek <msuchanek@suse.de> wrote:
> On powerpc syscall entry is done in assembly so patch in an explicit
> barrier_nospec.
Same comment as Linus for this -- the barriers are before the branch here,
so is it possible the branch instruction can be speculative while the index
is used to load the syscall table?
Thanks,
Nick
>
> 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() */
next prev parent reply other threads:[~2018-03-16 5:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-13 18:32 [PATCH RFC 0/8] powerpc barrier_nospec Michal Suchanek
2018-03-13 18:32 ` [PATCH RFC 1/8] powerpc: Add barrier_nospec Michal Suchanek
2018-03-13 20:01 ` Peter Zijlstra
2018-03-15 19:15 ` [PATCH RFC rebase 0/9] powerpc barrier_nospec Michal Suchanek
2018-03-15 19:15 ` [PATCH RFC rebase 1/9] powerpc: Add barrier_nospec Michal Suchanek
2018-03-15 19:15 ` [PATCH RFC rebase 2/9] powerpc: Use barrier_nospec in copy_from_user Michal Suchanek
2018-03-15 21:37 ` Linus Torvalds
2018-03-16 13:22 ` Michael Ellerman
2018-03-15 19:15 ` [PATCH RFC rebase 3/9] powerpc/64: Use barrier_nospec in syscall entry Michal Suchanek
2018-03-16 5:18 ` Nicholas Piggin [this message]
2018-03-16 9:15 ` Michal Suchánek
2018-03-16 10:46 ` Nicholas Piggin
2018-03-16 13:28 ` Michael Ellerman
2018-03-16 17:08 ` Linus Torvalds
2018-03-15 19:15 ` [PATCH RFC rebase 4/9] powerpc/64s: Use barrier_nospec in RFI_FLUSH_SLOT Michal Suchanek
2018-03-15 19:15 ` [PATCH RFC rebase 5/9] powerpc/64s: Add support for ori barrier_nospec patching Michal Suchanek
2018-03-15 19:15 ` [PATCH RFC rebase 6/9] powerpc/64: Patch barrier_nospec in modules Michal Suchanek
2018-03-15 19:15 ` [PATCH RFC rebase 7/9] powerpc/64: barrier_nospec: Add debugfs trigger Michal Suchanek
2018-03-15 19:15 ` [PATCH RFC rebase 8/9] powerpc/64s: barrier_nospec: Add hcall triggerr Michal Suchanek
2018-03-15 19:15 ` [PATCH RFC rebase 9/9] powerpc/64: barrier_nospec: Add commandline trigger Michal Suchanek
2018-03-23 15:59 ` Diana Madalina Craciun
2018-03-16 8:08 ` [PATCH RFC rebase 0/9] powerpc barrier_nospec Greg Kroah-Hartman
2018-03-16 9:31 ` Michal Suchánek
2018-03-13 18:33 ` [PATCH RFC 2/8] powerpc: Use barrier_nospec in copy_from_user Michal Suchanek
2018-03-13 18:33 ` [PATCH RFC 3/8] powerpc/64: Use barrier_nospec in syscall entry Michal Suchanek
2018-03-13 18:33 ` [PATCH RFC 4/8] powerpc/64s: Add support for ori barrier_nospec Michal Suchanek
2018-03-13 18:33 ` [PATCH RFC 5/8] powerpc/64: Patch barrier_nospec in modules Michal Suchanek
2018-03-13 18:33 ` [PATCH RFC 6/8] powerpc/64: barrier_nospec: Add debugfs trigger Michal Suchanek
2018-03-13 18:33 ` [PATCH RFC 7/8] powerpc/64s: barrier_nospec: Add hcall triggerr Michal Suchanek
2018-03-13 18:33 ` [PATCH RFC 8/8] powerpc/64: barrier_nospec: Add commandline trigger Michal Suchanek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180316151823.2f28d5ea@roar.ozlabs.ibm.com \
--to=npiggin@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=andrew.donnellan@au1.ibm.com \
--cc=bryantly@linux.vnet.ibm.com \
--cc=clg@kaod.org \
--cc=david@gibson.dropbear.id.au \
--cc=dja@axtens.net \
--cc=gregkh@linuxfoundation.org \
--cc=joe@perches.com \
--cc=kstewart@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=maddy@linux.vnet.ibm.com \
--cc=mahesh@linux.vnet.ibm.com \
--cc=me@tobin.cc \
--cc=mhiramat@kernel.org \
--cc=mikey@neuling.org \
--cc=msuchanek@suse.de \
--cc=naveen.n.rao@linux.vnet.ibm.com \
--cc=oohall@gmail.com \
--cc=paulus@samba.org \
--cc=pombredanne@nexb.com \
--cc=sergey.senozhatsky@gmail.com \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).