Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752809AbbDFOLX (ORCPT ); Mon, 6 Apr 2015 10:11:23 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:22759 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751195AbbDFOLW (ORCPT ); Mon, 6 Apr 2015 10:11:22 -0400 Date: Mon, 6 Apr 2015 10:10:51 -0400 From: Konrad Rzeszutek Wilk To: Andy Lutomirski Cc: Andy Lutomirski , Boris Ostrovsky , Linux Kernel Mailing List , X86 ML , Ingo Molnar , Denys Vlasenko , Linus Torvalds , Denys Vlasenko , "H. Peter Anvin" , Borislav Petkov , xen-devel@lists.xenproject.org Subject: Re: [PATCH] x86, paravirt, xen: Remove the 64-bit irq_enable_sysexit pvop Message-ID: <20150406141051.GF12596@l.oracle.com> References: <8a03355698fe5b94194e9e7360f19f91c1b2cf1f.1428100853.git.luto@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7316 Lines: 187 On Fri, Apr 03, 2015 at 03:52:30PM -0700, Andy Lutomirski wrote: > [cc: Boris and Konrad. Whoops] > > On Fri, Apr 3, 2015 at 3:51 PM, Andy Lutomirski wrote: > > We don't use irq_enable_sysexit on 64-bit kernels any more. Remove Is there an commit (or name of patch) that explains why 32-bit-user-space-on-64-bit kernels is unsavory? Thank you! > > all the paravirt and Xen machinery to support it on 64-bit kernels. > > > > Signed-off-by: Andy Lutomirski > > --- > > > > I haven't actually tested this on Xen, but it builds for me. > > > > arch/x86/ia32/ia32entry.S | 6 ------ > > arch/x86/include/asm/paravirt_types.h | 7 ++++--- > > arch/x86/kernel/asm-offsets.c | 2 ++ > > arch/x86/kernel/paravirt.c | 4 +++- > > arch/x86/kernel/paravirt_patch_64.c | 1 - > > arch/x86/xen/enlighten.c | 3 ++- > > arch/x86/xen/xen-asm_64.S | 16 ---------------- > > arch/x86/xen/xen-ops.h | 2 ++ > > 8 files changed, 13 insertions(+), 28 deletions(-) > > > > diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S > > index 5d8f987a340d..eb1eb7b70f4b 100644 > > --- a/arch/x86/ia32/ia32entry.S > > +++ b/arch/x86/ia32/ia32entry.S > > @@ -77,12 +77,6 @@ ENTRY(native_usergs_sysret32) > > swapgs > > sysretl > > ENDPROC(native_usergs_sysret32) > > - > > -ENTRY(native_irq_enable_sysexit) > > - swapgs > > - sti > > - sysexit > > -ENDPROC(native_irq_enable_sysexit) > > #endif > > > > /* > > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h > > index 7549b8b369e4..38a0ff9ef06e 100644 > > --- a/arch/x86/include/asm/paravirt_types.h > > +++ b/arch/x86/include/asm/paravirt_types.h > > @@ -160,13 +160,14 @@ struct pv_cpu_ops { > > u64 (*read_pmc)(int counter); > > unsigned long long (*read_tscp)(unsigned int *aux); > > > > +#ifdef CONFIG_X86_32 > > /* > > * Atomically enable interrupts and return to userspace. This > > - * is only ever used to return to 32-bit processes; in a > > - * 64-bit kernel, it's used for 32-on-64 compat processes, but > > - * never native 64-bit processes. (Jump, not call.) > > + * is only used in 32-bit kernels. 64-bit kernels use > > + * usergs_sysret32 instead. > > */ > > void (*irq_enable_sysexit)(void); > > +#endif > > > > /* > > * Switch to usermode gs and return to 64-bit usermode using > > diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c > > index 9f6b9341950f..2d27ebf0aed8 100644 > > --- a/arch/x86/kernel/asm-offsets.c > > +++ b/arch/x86/kernel/asm-offsets.c > > @@ -49,7 +49,9 @@ void common(void) { > > OFFSET(PV_IRQ_irq_disable, pv_irq_ops, irq_disable); > > OFFSET(PV_IRQ_irq_enable, pv_irq_ops, irq_enable); > > OFFSET(PV_CPU_iret, pv_cpu_ops, iret); > > +#ifdef CONFIG_X86_32 > > OFFSET(PV_CPU_irq_enable_sysexit, pv_cpu_ops, irq_enable_sysexit); > > +#endif > > OFFSET(PV_CPU_read_cr0, pv_cpu_ops, read_cr0); > > OFFSET(PV_MMU_read_cr2, pv_mmu_ops, read_cr2); > > #endif > > diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c > > index 548d25f00c90..7563114d9c3a 100644 > > --- a/arch/x86/kernel/paravirt.c > > +++ b/arch/x86/kernel/paravirt.c > > @@ -154,7 +154,9 @@ unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf, > > ret = paravirt_patch_ident_64(insnbuf, len); > > > > else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || > > +#ifdef CONFIG_X86_32 > > type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) || > > +#endif > > type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) || > > type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) > > /* If operation requires a jmp, then jmp */ > > @@ -371,7 +373,7 @@ __visible struct pv_cpu_ops pv_cpu_ops = { > > > > .load_sp0 = native_load_sp0, > > > > -#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) > > +#if defined(CONFIG_X86_32) > > .irq_enable_sysexit = native_irq_enable_sysexit, > > #endif > > #ifdef CONFIG_X86_64 > > diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c > > index a1da6737ba5b..0de21c62c348 100644 > > --- a/arch/x86/kernel/paravirt_patch_64.c > > +++ b/arch/x86/kernel/paravirt_patch_64.c > > @@ -49,7 +49,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf, > > PATCH_SITE(pv_irq_ops, save_fl); > > PATCH_SITE(pv_irq_ops, irq_enable); > > PATCH_SITE(pv_irq_ops, irq_disable); > > - PATCH_SITE(pv_cpu_ops, irq_enable_sysexit); > > PATCH_SITE(pv_cpu_ops, usergs_sysret32); > > PATCH_SITE(pv_cpu_ops, usergs_sysret64); > > PATCH_SITE(pv_cpu_ops, swapgs); > > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c > > index 81665c9f2132..3797b6b31f95 100644 > > --- a/arch/x86/xen/enlighten.c > > +++ b/arch/x86/xen/enlighten.c > > @@ -1267,10 +1267,11 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { > > .read_tscp = native_read_tscp, > > > > .iret = xen_iret, > > - .irq_enable_sysexit = xen_sysexit, > > #ifdef CONFIG_X86_64 > > .usergs_sysret32 = xen_sysret32, > > .usergs_sysret64 = xen_sysret64, > > +#else > > + .irq_enable_sysexit = xen_sysexit, > > #endif > > > > .load_tr_desc = paravirt_nop, > > diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S > > index 985fc3ee0973..a2cabb8bd6bf 100644 > > --- a/arch/x86/xen/xen-asm_64.S > > +++ b/arch/x86/xen/xen-asm_64.S > > @@ -47,22 +47,6 @@ ENTRY(xen_iret) > > ENDPATCH(xen_iret) > > RELOC(xen_iret, 1b+1) > > > > -/* > > - * sysexit is not used for 64-bit processes, so it's only ever used to > > - * return to 32-bit compat userspace. > > - */ > > -ENTRY(xen_sysexit) > > - pushq $__USER32_DS > > - pushq %rcx > > - pushq $X86_EFLAGS_IF > > - pushq $__USER32_CS > > - pushq %rdx > > - > > - pushq $0 > > -1: jmp hypercall_iret > > -ENDPATCH(xen_sysexit) > > -RELOC(xen_sysexit, 1b+1) > > - > > ENTRY(xen_sysret64) > > /* > > * We're already on the usermode stack at this point, but > > diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h > > index 9e195c683549..c20fe29e65f4 100644 > > --- a/arch/x86/xen/xen-ops.h > > +++ b/arch/x86/xen/xen-ops.h > > @@ -134,7 +134,9 @@ DECL_ASM(void, xen_restore_fl_direct, unsigned long); > > > > /* These are not functions, and cannot be called normally */ > > __visible void xen_iret(void); > > +#ifdef CONFIG_X86_32 > > __visible void xen_sysexit(void); > > +#endif > > __visible void xen_sysret32(void); > > __visible void xen_sysret64(void); > > __visible void xen_adjust_exception_frame(void); > > -- > > 2.3.0 > > > > > > -- > Andy Lutomirski > AMA Capital Management, LLC -- 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/