Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754554AbbB0AIF (ORCPT ); Thu, 26 Feb 2015 19:08:05 -0500 Received: from mail-pd0-f176.google.com ([209.85.192.176]:40016 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932306AbbB0AIC (ORCPT ); Thu, 26 Feb 2015 19:08:02 -0500 From: Andy Lutomirski To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Borislav Petkov , Oleg Nesterov , Denys Vlasenko , Andy Lutomirski Subject: [RFC 3/3] x86, asm: Change the 32-bit sysenter code to use sp0 Date: Thu, 26 Feb 2015 16:07:51 -0800 Message-Id: <080a1451ccbaf01aeff7923b898ac67e92423033.1424994489.git.luto@amacapital.net> X-Mailer: git-send-email 2.1.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1605 Lines: 46 The ia32 sysenter code loaded the top of the kernel stack into rsp by loading kernel_stack and then adjusting it. It can be simplified to just read sp0 directly. This requires the addition of a new asm-offsets entry for sp0. Signed-off-by: Andy Lutomirski --- arch/x86/ia32/ia32entry.S | 3 +-- arch/x86/kernel/asm-offsets_64.c | 1 + 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index ed9746340363..719db63b35c4 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -113,8 +113,7 @@ ENTRY(ia32_sysenter_target) CFI_DEF_CFA rsp,0 CFI_REGISTER rsp,rbp SWAPGS_UNSAFE_STACK - movq PER_CPU_VAR(kernel_stack), %rsp - addq $(KERNEL_STACK_OFFSET),%rsp + movq PER_CPU_VAR(init_tss + TSS_sp0), %rsp /* * No need to follow this irqs on/off section: the syscall * disabled irqs, here we enable it straight after entry: diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c index fdcbb4d27c9f..5ce6f2da8763 100644 --- a/arch/x86/kernel/asm-offsets_64.c +++ b/arch/x86/kernel/asm-offsets_64.c @@ -81,6 +81,7 @@ int main(void) #undef ENTRY OFFSET(TSS_ist, tss_struct, x86_tss.ist); + OFFSET(TSS_sp0, tss_struct, x86_tss.sp0); BLANK(); DEFINE(__NR_syscall_max, sizeof(syscalls_64) - 1); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/