84 lines
2.8 KiB
C
84 lines
2.8 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2009 Free Software Foundation, Inc.
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*
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* GRUB 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, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef GRUB_CPU_CPUID_HEADER
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#define GRUB_CPU_CPUID_HEADER 1
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extern unsigned char grub_cpuid_has_longmode;
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#ifdef __x86_64__
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static __inline int
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grub_cpu_is_cpuid_supported (void)
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{
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grub_uint64_t id_supported;
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__asm__ ("pushfq\n\t"
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"popq %%rax /* Get EFLAGS into EAX */\n\t"
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"movq %%rax, %%rcx /* Save original flags in ECX */\n\t"
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"xorq $0x200000, %%rax /* Flip ID bit in EFLAGS */\n\t"
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"pushq %%rax /* Store modified EFLAGS on stack */\n\t"
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"popfq /* Replace current EFLAGS */\n\t"
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"pushfq /* Read back the EFLAGS */\n\t"
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"popq %%rax /* Get EFLAGS into EAX */\n\t"
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"xorq %%rcx, %%rax /* Check if flag could be modified */\n\t"
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: "=a" (id_supported)
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: /* No inputs. */
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: /* Clobbered: */ "%rcx");
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return id_supported != 0;
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}
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#else
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static __inline int
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grub_cpu_is_cpuid_supported (void)
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{
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grub_uint32_t id_supported;
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__asm__ ("pushfl\n\t"
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"popl %%eax /* Get EFLAGS into EAX */\n\t"
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"movl %%eax, %%ecx /* Save original flags in ECX */\n\t"
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"xorl $0x200000, %%eax /* Flip ID bit in EFLAGS */\n\t"
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"pushl %%eax /* Store modified EFLAGS on stack */\n\t"
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"popfl /* Replace current EFLAGS */\n\t"
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"pushfl /* Read back the EFLAGS */\n\t"
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"popl %%eax /* Get EFLAGS into EAX */\n\t"
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"xorl %%ecx, %%eax /* Check if flag could be modified */\n\t"
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: "=a" (id_supported)
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: /* No inputs. */
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: /* Clobbered: */ "%rcx");
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return id_supported != 0;
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}
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#endif
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#ifdef __PIC__
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#define grub_cpuid(num,a,b,c,d) \
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asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1" \
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: "=a" (a), "=r" (b), "=c" (c), "=d" (d) \
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: "0" (num))
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#else
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#define grub_cpuid(num,a,b,c,d) \
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asm volatile ("cpuid" \
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: "=a" (a), "=b" (b), "=c" (c), "=d" (d) \
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: "0" (num))
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#endif
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#endif
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