From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E677C0651F for ; Thu, 4 Jul 2019 20:03:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 19277218A0 for ; Thu, 4 Jul 2019 20:03:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="3jcax4SS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727351AbfGDUDj (ORCPT ); Thu, 4 Jul 2019 16:03:39 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55192 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725865AbfGDUDg (ORCPT ); Thu, 4 Jul 2019 16:03:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=r8dg4oq4U1ca5BCTpc4fQOmKzJ5WSELVXrVdsnIl7C0=; b=3jcax4SSdg/NjcPmn6NkfQbI7m fs4sagnlGDRU3Jqgl/1XICOmxUXu4gXiPjJDTJUozJ/Ur7drDtHk/HpiwW8f/W61KFcIV5Puncwos 8g7SqhdU55NBxXOIEAc7B85mqgTUSzXLjS6I4RKdRA8xWNBpksO83UtwBXhJPBYjl5gB5l2XjiAyj 6QGZ0GmgK1ZVHhfVRtdCI+rU96+iYsl58sCyHS8pxRdBNNlmE2sttYkZJ+qkiMoYpbfvckgZulSvH gFoSI+YzfntXQvP1nS2lIMz8NljlHxxMXH113K/HeFzg1zNHtRZOa2GrfQB0scO//aVSWja5coWFQ ARVD71Gg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hj7wZ-0005eZ-NC; Thu, 04 Jul 2019 20:03:00 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 3D8A52059DEA2; Thu, 4 Jul 2019 22:02:58 +0200 (CEST) Message-Id: <20190704200050.306303504@infradead.org> User-Agent: quilt/0.65 Date: Thu, 04 Jul 2019 21:55:56 +0200 From: Peter Zijlstra To: tglx@linutronix.de, bp@alien8.de, mingo@kernel.org, rostedt@goodmis.org, luto@kernel.org, torvalds@linux-foundation.org Cc: hpa@zytor.com, dave.hansen@linux.intel.com, jgross@suse.com, linux-kernel@vger.kernel.org, zhe.he@windriver.com, joel@joelfernandes.org, devel@etsukata.com, peterz@infradead.org Subject: [PATCH v2 1/7] x86/paravirt: Make read_cr2() CALLEE_SAVE References: <20190704195555.580363209@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The one paravirt read_cr2() implementation (Xen) is actually quite trivial and doesn't need to clobber anything other than the return register. By making read_cr2() CALLEE_SAVE we avoid all the PUSH/POP nonsense and allow more convenient use from assembly. Reviewed-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/entry/calling.h | 6 ++++++ arch/x86/include/asm/paravirt.h | 22 +++++++++++++--------- arch/x86/include/asm/paravirt_types.h | 2 +- arch/x86/kernel/asm-offsets.c | 1 + arch/x86/kernel/head_64.S | 4 +--- arch/x86/kernel/paravirt.c | 2 +- arch/x86/xen/enlighten_pv.c | 3 ++- arch/x86/xen/mmu_pv.c | 12 +----------- arch/x86/xen/xen-asm.S | 17 +++++++++++++++++ arch/x86/xen/xen-ops.h | 3 +++ 10 files changed, 46 insertions(+), 26 deletions(-) --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -383,3 +383,9 @@ For 32-bit we have the following convent .Lafter_call_\@: #endif .endm + +#ifdef CONFIG_PARAVIRT_XXL +#define GET_CR2_INTO(reg) GET_CR2_INTO_AX ; _ASM_MOV %_ASM_AX, reg +#else +#define GET_CR2_INTO(reg) _ASM_MOV %cr2, reg +#endif --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -116,7 +116,7 @@ static inline void write_cr0(unsigned lo static inline unsigned long read_cr2(void) { - return PVOP_CALL0(unsigned long, mmu.read_cr2); + return PVOP_CALLEE0(unsigned long, mmu.read_cr2); } static inline void write_cr2(unsigned long x) @@ -909,13 +909,7 @@ extern void default_banner(void); ANNOTATE_RETPOLINE_SAFE; \ call PARA_INDIRECT(pv_ops+PV_CPU_swapgs); \ ) -#endif - -#define GET_CR2_INTO_RAX \ - ANNOTATE_RETPOLINE_SAFE; \ - call PARA_INDIRECT(pv_ops+PV_MMU_read_cr2); -#ifdef CONFIG_PARAVIRT_XXL #define USERGS_SYSRET64 \ PARA_SITE(PARA_PATCH(PV_CPU_usergs_sysret64), \ ANNOTATE_RETPOLINE_SAFE; \ @@ -929,9 +923,19 @@ extern void default_banner(void); call PARA_INDIRECT(pv_ops+PV_IRQ_save_fl); \ PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);) #endif -#endif +#endif /* CONFIG_PARAVIRT_XXL */ +#endif /* CONFIG_X86_64 */ + +#ifdef CONFIG_PARAVIRT_XXL + +#define GET_CR2_INTO_AX \ + PARA_SITE(PARA_PATCH(PV_MMU_read_cr2), \ + ANNOTATE_RETPOLINE_SAFE; \ + call PARA_INDIRECT(pv_ops+PV_MMU_read_cr2); \ + ) + +#endif /* CONFIG_PARAVIRT_XXL */ -#endif /* CONFIG_X86_32 */ #endif /* __ASSEMBLY__ */ #else /* CONFIG_PARAVIRT */ --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -220,7 +220,7 @@ struct pv_mmu_ops { void (*exit_mmap)(struct mm_struct *mm); #ifdef CONFIG_PARAVIRT_XXL - unsigned long (*read_cr2)(void); + struct paravirt_callee_save read_cr2; void (*write_cr2)(unsigned long); unsigned long (*read_cr3)(void); --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -76,6 +76,7 @@ static void __used common(void) BLANK(); OFFSET(XEN_vcpu_info_mask, vcpu_info, evtchn_upcall_mask); OFFSET(XEN_vcpu_info_pending, vcpu_info, evtchn_upcall_pending); + OFFSET(XEN_vcpu_info_arch_cr2, vcpu_info, arch.cr2); #endif BLANK(); --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -29,9 +29,7 @@ #ifdef CONFIG_PARAVIRT_XXL #include #include -#define GET_CR2_INTO(reg) GET_CR2_INTO_RAX ; movq %rax, reg #else -#define GET_CR2_INTO(reg) movq %cr2, reg #define INTERRUPT_RETURN iretq #endif @@ -323,7 +321,7 @@ END(early_idt_handler_array) cmpq $14,%rsi /* Page fault? */ jnz 10f - GET_CR2_INTO(%rdi) /* Can clobber any volatile register if pv */ + GET_CR2_INTO(%rdi) /* can clobber %rax if pv */ call early_make_pgtable andl %eax,%eax jz 20f /* All good */ --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -370,7 +370,7 @@ struct paravirt_patch_template pv_ops = .mmu.exit_mmap = paravirt_nop, #ifdef CONFIG_PARAVIRT_XXL - .mmu.read_cr2 = native_read_cr2, + .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(native_read_cr2), .mmu.write_cr2 = native_write_cr2, .mmu.read_cr3 = __native_read_cr3, .mmu.write_cr3 = native_write_cr3, --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -998,7 +998,8 @@ void __init xen_setup_vcpu_info_placemen __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); pv_ops.irq.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); - pv_ops.mmu.read_cr2 = xen_read_cr2_direct; + pv_ops.mmu.read_cr2 = + __PV_IS_CALLEE_SAVE(xen_read_cr2_direct); } } --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1307,16 +1307,6 @@ static void xen_write_cr2(unsigned long this_cpu_read(xen_vcpu)->arch.cr2 = cr2; } -static unsigned long xen_read_cr2(void) -{ - return this_cpu_read(xen_vcpu)->arch.cr2; -} - -unsigned long xen_read_cr2_direct(void) -{ - return this_cpu_read(xen_vcpu_info.arch.cr2); -} - static noinline void xen_flush_tlb(void) { struct mmuext_op *op; @@ -2397,7 +2387,7 @@ static void xen_leave_lazy_mmu(void) } static const struct pv_mmu_ops xen_mmu_ops __initconst = { - .read_cr2 = xen_read_cr2, + .read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2), .write_cr2 = xen_write_cr2, .read_cr3 = xen_read_cr3, --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -10,6 +10,7 @@ #include #include #include +#include #include @@ -135,3 +136,19 @@ ENTRY(check_events) FRAME_END ret ENDPROC(check_events) + +ENTRY(xen_read_cr2) + FRAME_BEGIN + _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX + _ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX + FRAME_END + ret + ENDPROC(xen_read_cr2); + +ENTRY(xen_read_cr2_direct) + FRAME_BEGIN + _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX + FRAME_END + ret + ENDPROC(xen_read_cr2_direct); + --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -134,6 +134,9 @@ __visible void xen_irq_disable_direct(vo __visible unsigned long xen_save_fl_direct(void); __visible void xen_restore_fl_direct(unsigned long); +__visible unsigned long xen_read_cr2(void); +__visible unsigned long xen_read_cr2_direct(void); + /* These are not functions, and cannot be called normally */ __visible void xen_iret(void); __visible void xen_sysret32(void);