Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753578Ab0H0WT2 (ORCPT ); Fri, 27 Aug 2010 18:19:28 -0400 Received: from mail-iw0-f174.google.com ([209.85.214.174]:50390 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753455Ab0H0WT1 convert rfc822-to-8bit (ORCPT ); Fri, 27 Aug 2010 18:19:27 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:cc:content-type :content-transfer-encoding; b=g8eg8+Amh4aFVpy/nYlr8p7K53IEw6OFnkF4YN484RAHFWIoc4xJM9LBxEIGeQOwXj qkz5rvtyl/Qn+el4NzdcMDkQJ1USTnrBHZYP5hj2c/5GsGQ5twfV052K9iOJSt+zB/8A Zea5i+BZ8T0QSK+9/gPzsp4fXIaWSPmvuVdI8= MIME-Version: 1.0 In-Reply-To: References: <4C780888.9000301@zytor.com> <4C7824F2.1050709@mandriva.org> From: Matteo Croce Date: Sat, 28 Aug 2010 00:19:06 +0200 X-Google-Sender-Auth: N8cQt2dojOXw4U4f_EJTe6CdfSw Message-ID: Subject: Re: AMD Geode NOPL emulation for kernel 2.6.36-rc2 To: Thomas Backlund Cc: "H. Peter Anvin" , linux-kernel@vger.kernel.org, Alan Cox , Natale Vinto Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13513 Lines: 449 On Sat, Aug 28, 2010 at 12:16 AM, Matteo Croce wrote: > On Fri, Aug 27, 2010 at 11:32 PM, Matteo Croce wrote: >> can I ignore the return value when I expect val to be non zero? >> the doc says: "On error, the variable @x is set to zero." >> >> On Fri, Aug 27, 2010 at 10:49 PM, Thomas Backlund wrote: >>> 27.08.2010 23:15, Matteo Croce skrev: >>>> >>>> On Fri, Aug 27, 2010 at 8:48 PM, H. Peter Anvin  wrote: >>>>> >>>>> You're doing user-space references without get_user(). >>>>> >>>>>        -hpa >>>>> >>>>> -- >>>>> H. Peter Anvin, Intel Open Source Technology Center >>>>> I work for Intel.  I don't speak on their behalf. >>>>> >>>>> >>>> >>>> Here with get_user. >>>> I CC Natale which is my beta tester, he have some Alix boards running >>>> 24/24 >>>> with my patch >>>> >>>> --- a/arch/x86/kernel/Makefile  2010-08-27 19:42:01.795858001 +0200 >>>> +++ b/arch/x86/kernel/Makefile  2010-08-27 19:42:12.525858001 +0200 >>>> @@ -88,6 +88,8 @@ >>>>  obj-$(CONFIG_APB_TIMER)               += apb_timer.o >>>> >>>>  obj-$(CONFIG_K8_NB)           += k8.o >>>> +obj-$(CONFIG_GEODE_NOPL)       += nopl_emu.o >>>> +obj-$(CONFIG_GEODE_NOPL)       += nopl_emu.o >>> >>> Same line added twice... >>> >>> -- >>> Thomas >>> >> >> >> >> -- >> Matteo Croce >> OpenWrt developer >>   _______                     ________        __ >>  |       |.-----.-----.-----.|  |  |  |.----.|  |_ >>  |   -   ||  _  |  -__|     ||  |  |  ||   _||   _| >>  |_______||   __|_____|__|__||________||__|  |____| >>           |__| W I R E L E S S   F R E E D O M >>  KAMIKAZE (bleeding edge) ------------------ >>   * 10 oz Vodka       Shake well with ice and strain >>   * 10 oz Triple sec  mixture into 10 shot glasses. >>   * 10 oz lime juice  Salute! >>  --------------------------------------------------- >> > > Here is with proper checks > > --- a/arch/x86/kernel/Makefile  2010-08-27 19:42:01.795858001 +0200 > +++ b/arch/x86/kernel/Makefile  2010-08-27 19:42:12.525858001 +0200 > @@ -88,6 +88,8 @@ >  obj-$(CONFIG_APB_TIMER)                += apb_timer.o > >  obj-$(CONFIG_K8_NB)            += k8.o > +obj-$(CONFIG_GEODE_NOPL)       += nopl_emu.o > +obj-$(CONFIG_GEODE_NOPL)       += nopl_emu.o >  obj-$(CONFIG_DEBUG_RODATA_TEST)        += test_rodata.o >  obj-$(CONFIG_DEBUG_NX_TEST)    += test_nx.o > > --- a/arch/x86/kernel/cpu/amd.c 2010-08-27 19:42:01.855858001 +0200 > +++ b/arch/x86/kernel/cpu/amd.c 2010-08-27 19:42:12.535858001 +0200 > @@ -137,11 +137,15 @@ >                return; >        } > > +#ifdef CONFIG_GEODE_NOPL >        if (c->x86_model == 10) { > -               /* AMD Geode LX is model 10 */ > -               /* placeholder for any needed mods */ > +               /* Geode only lacks the NOPL instruction to be i686, > +                  but we can promote it to a i686 class cpu > +                  and emulate NOPLs in the exception handler*/ > +               boot_cpu_data.x86 = 6; >                return; >        } > +#endif >  } > >  static void __cpuinit amd_k7_smp_check(struct cpuinfo_x86 *c) > --- a/arch/x86/kernel/entry_32.S        2010-08-27 19:42:01.735858001 +0200 > +++ b/arch/x86/kernel/entry_32.S        2010-08-27 19:42:12.535858001 +0200 > @@ -978,7 +978,11 @@ >        RING0_INT_FRAME >        pushl $0 >        CFI_ADJUST_CFA_OFFSET 4 > +#ifdef CONFIG_GEODE_NOPL > +       pushl $do_nopl_emu > +#else >        pushl $do_invalid_op > +#endif >        CFI_ADJUST_CFA_OFFSET 4 >        jmp error_code >        CFI_ENDPROC > --- /dev/null   1970-01-01 00:00:00.000000000 +0000 > +++ b/arch/x86/kernel/nopl_emu.c        2010-08-28 00:11:52.627085002 +0200 > @@ -0,0 +1,128 @@ > +/* > + *  linux/arch/x86/kernel/nopl_emu.c > + * > + *  Copyright (C) 2002  Willy Tarreau > + *  Copyright (C) 2010  Matteo Croce > + */ > + > +#include > +#include > +#include > + > +/* This code can be used to allow the AMD Geode to hopefully correctly execute > + * some code which was originally compiled for an i686, by emulating NOPL, > + * the only missing i686 instruction in the CPU > + * > + * Willy Tarreau > + * Matteo Croce > + */ > + > +static inline int do_1f(u8 *ip) > +{ > +       u8 val1, val2; > +       int length = 3; > +       if (get_user(val1, ip)) > +               return 0; > +       switch (val1) { > +       case 0x84: > +               get_user(val1, ip + 5); > +               if (!val1) > +                       length++; > +               else > +                       return 0; > +       case 0x80: > +               get_user(val1, ip + 4); > +               get_user(val2, ip + 3); > +               if (!val1 && !val2) > +                       length += 2; > +               else > +                       return 0; > +       case 0x44: > +               get_user(val1, ip + 2); > +               if (!val1) > +                       length++; > +               else > +                       return 0; > +       case 0x40: > +               get_user(val1, ip + 1); > +               if (!val1) > +                       length++; > +               else > +                       return 0; > +       case 0x00: > +               return length; > +       } > +       return 0; > +} > + > +static inline int do_0f(u8 *ip) > +{ > +       u8 val; > +       if (get_user(val, ip)) > +               return 0; > +       if (val == 0x1f) > +               return do_1f(ip + 1); > +       return 0; > +} > + > +static inline int do_66(u8 *ip) > +{ > +       u8 val; > +       if (get_user(val, ip)) > +               return 0; > +       if (val == 0x90) > +               return 2; > +       if (val == 0x0f) { > +               int res = do_0f(ip + 1); > +               if (res) > +                       return res + 1; > +               else > +                       return 0; > +       } > +       return 0; > +} > + > +static inline int do_start(u8 *ip) > +{ > +       u8 val; > +       if (get_user(val, ip)) > +               return 0; > +       if (val == 0x0f) > +               return do_0f(ip + 1); > +       if (val == 0x66) > +               return do_66(ip + 1); > +       return 0; > +} > + > +/* [do_nopl_emu] is called by exception 6 after an invalid opcode has been > + * encountered. It will try to emulate it by doing nothing, > + * and will send a SIGILL or SIGSEGV to the process if not possible. > + * the NOPL can have variable length opcodes: > + > +bytes number   opcode > +       2       66 90 > +       3       0f 1f 00 > +       4       0f 1f 40 00 > +       5       0f 1f 44 00 00 > +       6       66 0f 1f 44 00 00 > +       7       0f 1f 80 00 00 00 00 > +       8       0f 1f 84 00 00 00 00 00 > +       9       66 0f 1f 84 00 00 00 00 00 > +*/ > +void do_nopl_emu(struct pt_regs *regs, long error_code) > +{ > +       u8 *ip = (u8 *)instruction_pointer(regs); > +       int res = do_start(ip); > + > +       if (res) { > +               int i = 0; > +               do { > +                       ip += res; > +                       i++; > +                       res = do_start(ip); > +               } while(res); > +               printk(KERN_DEBUG "geode_nopl: emulated %d instructions\n", i); > +               regs->ip = (typeof(regs->ip))ip; > +       } else > +               do_invalid_op(regs, error_code); > +} > > > -- > Matteo Croce > OpenWrt developer >   _______                     ________        __ >  |       |.-----.-----.-----.|  |  |  |.----.|  |_ >  |   -   ||  _  |  -__|     ||  |  |  ||   _||   _| >  |_______||   __|_____|__|__||________||__|  |____| >           |__| W I R E L E S S   F R E E D O M >  KAMIKAZE (bleeding edge) ------------------ >   * 10 oz Vodka       Shake well with ice and strain >   * 10 oz Triple sec  mixture into 10 shot glasses. >   * 10 oz lime juice  Salute! >  --------------------------------------------------- > Sorry still left the duplicated line --- a/arch/x86/kernel/Makefile 2010-08-27 19:42:01.795858001 +0200 +++ b/arch/x86/kernel/Makefile 2010-08-28 00:16:53.607507000 +0200 @@ -88,6 +88,7 @@ obj-$(CONFIG_APB_TIMER) += apb_timer.o obj-$(CONFIG_K8_NB) += k8.o +obj-$(CONFIG_GEODE_NOPL) += nopl_emu.o obj-$(CONFIG_DEBUG_RODATA_TEST) += test_rodata.o obj-$(CONFIG_DEBUG_NX_TEST) += test_nx.o --- a/arch/x86/kernel/cpu/amd.c 2010-08-27 19:42:01.855858001 +0200 +++ b/arch/x86/kernel/cpu/amd.c 2010-08-27 19:42:12.535858001 +0200 @@ -137,11 +137,15 @@ return; } +#ifdef CONFIG_GEODE_NOPL if (c->x86_model == 10) { - /* AMD Geode LX is model 10 */ - /* placeholder for any needed mods */ + /* Geode only lacks the NOPL instruction to be i686, + but we can promote it to a i686 class cpu + and emulate NOPLs in the exception handler*/ + boot_cpu_data.x86 = 6; return; } +#endif } static void __cpuinit amd_k7_smp_check(struct cpuinfo_x86 *c) --- a/arch/x86/kernel/entry_32.S 2010-08-27 19:42:01.735858001 +0200 +++ b/arch/x86/kernel/entry_32.S 2010-08-27 19:42:12.535858001 +0200 @@ -978,7 +978,11 @@ RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 +#ifdef CONFIG_GEODE_NOPL + pushl $do_nopl_emu +#else pushl $do_invalid_op +#endif CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ b/arch/x86/kernel/nopl_emu.c 2010-08-28 00:11:52.627085002 +0200 @@ -0,0 +1,128 @@ +/* + * linux/arch/x86/kernel/nopl_emu.c + * + * Copyright (C) 2002 Willy Tarreau + * Copyright (C) 2010 Matteo Croce + */ + +#include +#include +#include + +/* This code can be used to allow the AMD Geode to hopefully correctly execute + * some code which was originally compiled for an i686, by emulating NOPL, + * the only missing i686 instruction in the CPU + * + * Willy Tarreau + * Matteo Croce + */ + +static inline int do_1f(u8 *ip) +{ + u8 val1, val2; + int length = 3; + if (get_user(val1, ip)) + return 0; + switch (val1) { + case 0x84: + get_user(val1, ip + 5); + if (!val1) + length++; + else + return 0; + case 0x80: + get_user(val1, ip + 4); + get_user(val2, ip + 3); + if (!val1 && !val2) + length += 2; + else + return 0; + case 0x44: + get_user(val1, ip + 2); + if (!val1) + length++; + else + return 0; + case 0x40: + get_user(val1, ip + 1); + if (!val1) + length++; + else + return 0; + case 0x00: + return length; + } + return 0; +} + +static inline int do_0f(u8 *ip) +{ + u8 val; + if (get_user(val, ip)) + return 0; + if (val == 0x1f) + return do_1f(ip + 1); + return 0; +} + +static inline int do_66(u8 *ip) +{ + u8 val; + if (get_user(val, ip)) + return 0; + if (val == 0x90) + return 2; + if (val == 0x0f) { + int res = do_0f(ip + 1); + if (res) + return res + 1; + else + return 0; + } + return 0; +} + +static inline int do_start(u8 *ip) +{ + u8 val; + if (get_user(val, ip)) + return 0; + if (val == 0x0f) + return do_0f(ip + 1); + if (val == 0x66) + return do_66(ip + 1); + return 0; +} + +/* [do_nopl_emu] is called by exception 6 after an invalid opcode has been + * encountered. It will try to emulate it by doing nothing, + * and will send a SIGILL or SIGSEGV to the process if not possible. + * the NOPL can have variable length opcodes: + +bytes number opcode + 2 66 90 + 3 0f 1f 00 + 4 0f 1f 40 00 + 5 0f 1f 44 00 00 + 6 66 0f 1f 44 00 00 + 7 0f 1f 80 00 00 00 00 + 8 0f 1f 84 00 00 00 00 00 + 9 66 0f 1f 84 00 00 00 00 00 +*/ +void do_nopl_emu(struct pt_regs *regs, long error_code) +{ + u8 *ip = (u8 *)instruction_pointer(regs); + int res = do_start(ip); + + if (res) { + int i = 0; + do { + ip += res; + i++; + res = do_start(ip); + } while(res); + printk(KERN_DEBUG "geode_nopl: emulated %d instructions\n", i); + regs->ip = (typeof(regs->ip))ip; + } else + do_invalid_op(regs, error_code); +} -- Matteo Croce OpenWrt developer   _______                     ________        __  |       |.-----.-----.-----.|  |  |  |.----.|  |_  |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|  |_______||   __|_____|__|__||________||__|  |____|           |__| W I R E L E S S   F R E E D O M  KAMIKAZE (bleeding edge) ------------------   * 10 oz Vodka       Shake well with ice and strain   * 10 oz Triple sec  mixture into 10 shot glasses.   * 10 oz lime juice  Salute!  --------------------------------------------------- -- 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/