Messages in this thread Patch in this message | | | From | Matteo Croce <> | Date | Sat, 28 Aug 2010 00:16:59 +0200 | Subject | Re: AMD Geode NOPL emulation for kernel 2.6.36-rc2 |
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On Fri, Aug 27, 2010 at 11:32 PM, Matteo Croce <matteo@openwrt.org> 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 <tmb@mandriva.org> wrote: >> 27.08.2010 23:15, Matteo Croce skrev: >>> >>> On Fri, Aug 27, 2010 at 8:48 PM, H. Peter Anvin<hpa@zytor.com> 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 <asm/processor.h> +#include <asm/traps.h> +#include <asm/uaccess.h> + +/* 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 <willy@meta-x.org> + * Matteo Croce <technoboy85@gmail.com> + */ + +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/
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