mirror of
https://git.proxmox.com/git/grub2
synced 2025-05-28 07:03:27 +00:00
cc6c3ac1bf
Avoid clobbering %ebx/%rbx in inline assembly with Apple's CC * efiemu/runtime/efiemu.c (write_cmos): use %cl instead of %bl as temporary storage * include/grub/i386/tsc.h (grub_get_tsc): restore %rbx/%ebx when using Apple's CC (grub_cpu_is_tsc_supported): likewise * loader/i386/xnu.c (guessfsb): restore %rbx/%ebx in inline assembly
142 lines
4.0 KiB
C
142 lines
4.0 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2008 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 KERNEL_CPU_TSC_HEADER
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#define KERNEL_CPU_TSC_HEADER 1
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#include <grub/types.h>
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/* Read the TSC value, which increments with each CPU clock cycle. */
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static __inline grub_uint64_t
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grub_get_tsc (void)
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{
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grub_uint32_t lo, hi;
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/* The CPUID instruction is a 'serializing' instruction, and
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avoids out-of-order execution of the RDTSC instruction. */
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#ifdef APPLE_CC
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__asm__ __volatile__ ("xorl %%eax, %%eax\n\t"
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#ifdef __x86_64__
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"push %%rbx\n"
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#else
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"push %%ebx\n"
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#endif
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"cpuid\n"
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#ifdef __x86_64__
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"pop %%rbx\n"
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#else
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"pop %%ebx\n"
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#endif
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:::"%rax", "%rcx", "%rdx");
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#else
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__asm__ __volatile__ ("xorl %%eax, %%eax\n\t"
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"cpuid":::"%rax", "%rbx", "%rcx", "%rdx");
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#endif
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/* Read TSC value. We cannot use "=A", since this would use
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%rax on x86_64. */
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__asm__ __volatile__ ("rdtsc":"=a" (lo), "=d" (hi));
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return (((grub_uint64_t) hi) << 32) | lo;
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}
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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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static __inline int
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grub_cpu_is_tsc_supported (void)
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{
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if (! grub_cpu_is_cpuid_supported ())
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return 0;
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grub_uint32_t features;
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#ifdef APPLE_CC
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__asm__ ("movl $1, %%eax\n\t"
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#ifdef __x86_64__
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"push %%rbx\n"
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#else
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"push %%ebx\n"
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#endif
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"cpuid\n"
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#ifdef __x86_64__
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"pop %%rbx\n"
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#else
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"pop %%ebx\n"
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#endif
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: "=d" (features)
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: /* No inputs. */
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: /* Clobbered: */ "%rax", "%rcx");
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#else
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__asm__ ("movl $1, %%eax\n\t"
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"cpuid\n"
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: "=d" (features)
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: /* No inputs. */
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: /* Clobbered: */ "%rax", "%rbx", "%rcx");
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#endif
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return (features & (1 << 4)) != 0;
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}
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void grub_tsc_init (void);
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grub_uint64_t grub_tsc_get_time_ms (void);
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#endif /* ! KERNEL_CPU_TSC_HEADER */
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