From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, dwmw@amazon.co.uk, pjt@google.com,
luto@kernel.org, peterz@infradead.org, thomas.lendacky@amd.com,
tim.c.chen@linux.intel.com, gregkh@linux-foundation.org,
dave.hansen@intel.com, jikos@kernel.org,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v1 1/8] x86/entry/clearregs: Remove partial stack frame in fast system call
Date: Wed, 10 Jan 2018 20:09:16 -0600 [thread overview]
Message-ID: <20180111020916.2pionyjrik6pdwzb@treble> (raw)
In-Reply-To: <20180110010328.22163-2-andi@firstfloor.org>
On Tue, Jan 09, 2018 at 05:03:21PM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> Remove the partial stack frame in the 64bit syscall fast path.
> In the next patch we want to clear the extra registers, which requires
> to always save all registers. So remove the partial stack frame
> in the syscall fast path and always save everything.
>
> This actually simplifies the code because the ptregs stubs
> are not needed anymore.
>
> arch/x86/entry/entry_64.S | 57 ++++-----------------------------------------------------
> arch/x86/entry/syscall_64.c | 2 +-
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
> arch/x86/entry/entry_64.S | 57 ++++-----------------------------------------
> arch/x86/entry/syscall_64.c | 2 +-
> 2 files changed, 5 insertions(+), 54 deletions(-)
>
> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
> index 58dbf7a12a05..bbdfbdd817d6 100644
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -234,7 +234,9 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
> pushq %r9 /* pt_regs->r9 */
> pushq %r10 /* pt_regs->r10 */
> pushq %r11 /* pt_regs->r11 */
> - sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */
> + sub $(6*8), %rsp
> + SAVE_EXTRA_REGS
> +
> UNWIND_HINT_REGS extra=0
Now that the extra regs are being saved, the "extra=0" can be removed
from the unwind hint.
--
Josh
next prev parent reply other threads:[~2018-01-11 2:09 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 1:03 x86/clearregs: Register sanitizing at kernel entry for speculation hygiene Andi Kleen
2018-01-10 1:03 ` [PATCH v1 1/8] x86/entry/clearregs: Remove partial stack frame in fast system call Andi Kleen
2018-01-10 2:46 ` Brian Gerst
2018-01-11 0:16 ` Andi Kleen
2018-01-11 0:54 ` Brian Gerst
2018-01-11 1:02 ` Andi Kleen
2018-01-11 0:55 ` Andy Lutomirski
2018-01-11 1:01 ` Andi Kleen
2018-01-11 1:01 ` Brian Gerst
2018-01-11 1:22 ` Andy Lutomirski
2018-01-11 1:47 ` Andi Kleen
2018-01-11 18:44 ` Andi Kleen
2018-01-11 2:09 ` Josh Poimboeuf [this message]
2018-01-12 3:22 ` Josh Poimboeuf
2018-01-10 1:03 ` [PATCH v1 2/8] x86/entry/clearregs: Add infrastructure to clear registers Andi Kleen
2018-01-11 19:58 ` Konrad Rzeszutek Wilk
2018-01-11 20:10 ` Andi Kleen
2018-01-10 1:03 ` [PATCH v1 3/8] x86/entry/clearregs: Clear registers for 64bit SYSCALL Andi Kleen
2018-01-11 3:35 ` Brian Gerst
2018-01-11 18:47 ` Andi Kleen
2018-01-12 3:45 ` Josh Poimboeuf
2018-01-10 1:03 ` [PATCH v1 4/8] x86/entry/retpoline: Clear extra registers for compat syscalls Andi Kleen
2018-01-10 1:03 ` [PATCH v1 5/8] x86/entry/clearregs: Clear registers for 64bit exceptions/interrupts Andi Kleen
2018-01-10 1:23 ` Andy Lutomirski
2018-01-10 1:03 ` [PATCH v1 6/8] x86/entry/clearregs: Add number of arguments to syscall tables Andi Kleen
2018-01-10 1:26 ` Andy Lutomirski
2018-01-10 4:37 ` Andi Kleen
2018-01-10 20:05 ` Andy Lutomirski
2018-01-10 1:03 ` [PATCH v1 7/8] x86/entry/clearregs: Add 64bit stubs to clear unused arguments regs Andi Kleen
2018-01-10 1:03 ` [PATCH v1 8/8] x86/entry/clearregs: Clear registers for 32bit kernel Andi Kleen
2018-01-10 1:24 ` Andy Lutomirski
2018-01-10 1:16 ` x86/clearregs: Register sanitizing at kernel entry for speculation hygiene Andy Lutomirski
2018-01-10 1:34 ` Andi Kleen
2018-01-10 1:39 ` Andy Lutomirski
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