Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757146AbXKSWJU (ORCPT ); Mon, 19 Nov 2007 17:09:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756741AbXKSWG4 (ORCPT ); Mon, 19 Nov 2007 17:06:56 -0500 Received: from mx1.redhat.com ([66.187.233.31]:49358 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756730AbXKSWGy (ORCPT ); Mon, 19 Nov 2007 17:06:54 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Andrew Morton , Linus Torvalds , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org X-Fcc: ~/Mail/linus Subject: [PATCH 13/18] x86 vDSO: ia32 sysenter_return In-Reply-To: Roland McGrath's message of Monday, 19 November 2007 13:59:43 -0800 <20071119215944.01B7C26F8BE@magilla.localdomain> References: <20071119215944.01B7C26F8BE@magilla.localdomain> Emacs: because idle RAM is the Devil's playground. Message-Id: <20071119220622.C5ED026F8BE@magilla.localdomain> Date: Mon, 19 Nov 2007 14:06:22 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3549 Lines: 102 This changes the 64-bit kernel's support for the 32-bit sysenter instruction to use stored fields rather than constants for the user-mode return address, as the 32-bit kernel does. This adds a sysenter_return field to struct thread_info, as 32-bit has. There is no observable effect from this yet. It makes the assembly code independent of the 32-bit vDSO mapping address, paving the way for making the vDSO address vary as it does on the 32-bit kernel. Signed-off-by: Roland McGrath --- arch/x86/ia32/ia32entry.S | 7 +++---- arch/x86/ia32/syscall32.c | 4 ++++ arch/x86/kernel/asm-offsets_64.c | 1 + include/asm-x86/thread_info_64.h | 3 +++ 4 files changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index df588f0..2499a32 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -12,7 +12,6 @@ #include #include #include -#include #include #include @@ -104,7 +103,7 @@ ENTRY(ia32_sysenter_target) pushfq CFI_ADJUST_CFA_OFFSET 8 /*CFI_REL_OFFSET rflags,0*/ - movl $VSYSCALL32_SYSEXIT, %r10d + movl 8*3-THREAD_SIZE+threadinfo_sysenter_return(%rsp), %r10d CFI_REGISTER rip,r10 pushq $__USER32_CS CFI_ADJUST_CFA_OFFSET 8 @@ -142,6 +141,8 @@ sysenter_do_call: andl $~TS_COMPAT,threadinfo_status(%r10) /* clear IF, that popfq doesn't enable interrupts early */ andl $~0x200,EFLAGS-R11(%rsp) + movl RIP-R11(%rsp),%edx /* User %eip */ + CFI_REGISTER rip,rdx RESTORE_ARGS 1,24,1,1,1,1 popfq CFI_ADJUST_CFA_OFFSET -8 @@ -149,8 +150,6 @@ sysenter_do_call: popq %rcx /* User %esp */ CFI_ADJUST_CFA_OFFSET -8 CFI_REGISTER rsp,rcx - movl $VSYSCALL32_SYSEXIT,%edx /* User %eip */ - CFI_REGISTER rip,rdx TRACE_IRQS_ON swapgs sti /* sti only takes effect after the next instruction */ diff --git a/arch/x86/ia32/syscall32.c b/arch/x86/ia32/syscall32.c index 15013ba..2c9c145 100644 --- a/arch/x86/ia32/syscall32.c +++ b/arch/x86/ia32/syscall32.c @@ -45,6 +45,10 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack) VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| VM_ALWAYSDUMP, syscall32_pages); + if (ret == 0) { + current->mm->context.vdso = (void __user *)VSYSCALL32_BASE; + current_thread_info()->sysenter_return = VSYSCALL32_SYSEXIT; + } up_write(&mm->mmap_sem); return ret; } diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c index d1b6ed9..1f9b0b5 100644 --- a/arch/x86/kernel/asm-offsets_64.c +++ b/arch/x86/kernel/asm-offsets_64.c @@ -47,6 +47,7 @@ int main(void) ENTRY(addr_limit); ENTRY(preempt_count); ENTRY(status); + ENTRY(sysenter_return); BLANK(); #undef ENTRY #define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry)) diff --git a/include/asm-x86/thread_info_64.h b/include/asm-x86/thread_info_64.h index beae2bf..f81638e 100644 --- a/include/asm-x86/thread_info_64.h +++ b/include/asm-x86/thread_info_64.h @@ -33,6 +33,9 @@ struct thread_info { mm_segment_t addr_limit; struct restart_block restart_block; +#ifdef CONFIG_IA32_EMULATION + void __user *sysenter_return; +#endif }; #endif - 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/