126 lines
2.7 KiB
C
126 lines
2.7 KiB
C
/* ----------------------------------------------------------------------- *
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*
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* Copyright 2008 H. Peter Anvin - All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston MA 02110-1301, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* ifcpu64.c
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*
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* Run one command if the CPU has 64-bit support, and another if it doesn't.
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* Eventually this and other features should get folded into some kind
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* of scripting engine.
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*
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* Usage:
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*
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* label boot_kernel
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* com32 ifcpu64.c32
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* append boot_kernel_64 [-- boot_kernel_32pae] -- boot_kernel_32
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* label boot_kernel_32
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* kernel vmlinuz_32
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* append ...
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* label boot_kernel_64
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* kernel vmlinuz_64
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* append ...
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*/
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#include <alloca.h>
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#include <stdlib.h>
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#include <string.h>
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#include <cpuid.h>
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#include <syslinux/boot.h>
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static bool __constfunc cpu_has_cpuid(void)
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{
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return cpu_has_eflag(X86_EFLAGS_ID);
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}
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static bool __constfunc cpu_has_level(uint32_t level)
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{
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uint32_t group;
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uint32_t limit;
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if (!cpu_has_cpuid())
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return false;
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group = level & 0xffff0000;
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limit = cpuid_eax(group);
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if ((limit & 0xffff0000) != group)
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return false;
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if (level > limit)
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return false;
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return true;
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}
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/* This only supports feature groups 0 and 1, corresponding to the
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Intel and AMD EDX bit vectors. We can add more later if need be. */
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static bool __constfunc cpu_has_feature(int x)
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{
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uint32_t level = ((x & 1) << 31) | 1;
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return cpu_has_level(level) && ((cpuid_edx(level) >> (x & 31) & 1));
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}
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/* XXX: this really should be librarized */
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static void boot_args(char **args)
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{
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int len = 0, a = 0;
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char **pp;
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const char *p;
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char c, *q, *str;
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for (pp = args; *pp; pp++)
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len += strlen(*pp) + 1;
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q = str = alloca(len);
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for (pp = args; *pp; pp++) {
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p = *pp;
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while ((c = *p++))
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*q++ = c;
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*q++ = ' ';
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a = 1;
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}
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q -= a;
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*q = '\0';
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if (!str[0])
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syslinux_run_default();
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else
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syslinux_run_command(str);
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}
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int main(int argc, char *argv[])
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{
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char **args[3];
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int i;
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int n;
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args[0] = &argv[1];
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n = 1;
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for (i = 1; i < argc; i++) {
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if (!strcmp(argv[i], "--")) {
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argv[i] = NULL;
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args[n++] = &argv[i + 1];
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}
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if (n >= 3)
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break;
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}
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while (n < 3) {
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args[n] = args[n - 1];
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n++;
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}
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boot_args(cpu_has_feature(X86_FEATURE_LM) ? args[0] :
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cpu_has_feature(X86_FEATURE_PAE) ? args[1] : args[2]);
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return -1;
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}
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