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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223// SPDX-License-Identifier: GPL-2.0#include <linux/io.h>#include <linux/slab.h>#include <linux/memblock.h>#include <linux/cc_platform.h>#include <linux/pgtable.h>
#include <asm/set_memory.h>#include <asm/realmode.h>#include <asm/tlbflush.h>#include <asm/crash.h>#include <asm/msr.h>#include <asm/sev.h>
struct real_mode_header *real_mode_header;u32 *trampoline_cr4_features;
/* Hold the pgd entry used on booting additional CPUs */pgd_t trampoline_pgd_entry;
void load_trampoline_pgtable(void){#ifdef CONFIG_X86_32 load_cr3(initial_page_table);#else /* * This function is called before exiting to real-mode and that will * fail with CR4.PCIDE still set. */ if (boot_cpu_has(X86_FEATURE_PCID)) cr4_clear_bits(X86_CR4_PCIDE);
write_cr3(real_mode_header->trampoline_pgd);#endif
/* * The CR3 write above will not flush global TLB entries. * Stale, global entries from previous page tables may still be * present. Flush those stale entries. * * This ensures that memory accessed while running with * trampoline_pgd is *actually* mapped into trampoline_pgd. */ __flush_tlb_all();}
void __init reserve_real_mode(void){ phys_addr_t mem, limit = x86_init.resources.realmode_limit; size_t size = real_mode_size_needed();
if (!size) return;
WARN_ON(slab_is_available());
mem = memblock_phys_alloc_range(size, PAGE_SIZE, 0, limit); if (!mem) pr_info("No memory below %pa for the real-mode trampoline\n", &limit); else set_real_mode_mem(mem);
/* * Unconditionally reserve the entire first 1M, see comment in * setup_arch(). */ memblock_reserve(0, SZ_1M);
memblock_clear_kho_noprsrv(0, SZ_1M);}
static void __init sme_sev_setup_real_mode(struct trampoline_header *th){#ifdef CONFIG_AMD_MEM_ENCRYPT if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) th->flags |= TH_FLAGS_SME_ACTIVE;
if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) { /* * Skip the call to verify_cpu() in secondary_startup_64 as it * will cause #VC exceptions when the AP can't handle them yet. */ th->start = (u64) secondary_startup_64_no_verify;
if (sev_es_setup_ap_jump_table(real_mode_header)) panic("Failed to get/update SEV-ES AP Jump Table"); }#endif}
static void __init setup_real_mode(void){ u16 real_mode_seg; const u32 *rel; u32 count; unsigned char *base; unsigned long phys_base; struct trampoline_header *trampoline_header; size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);#ifdef CONFIG_X86_64 u64 *trampoline_pgd; u64 efer; int i;#endif
base = (unsigned char *)real_mode_header;
/* * If SME is active, the trampoline area will need to be in * decrypted memory in order to bring up other processors * successfully. This is not needed for SEV. */ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);
memcpy(base, real_mode_blob, size);
phys_base = __pa(base); real_mode_seg = phys_base >> 4;
rel = (u32 *) real_mode_relocs;
/* 16-bit segment relocations. */ count = *rel++; while (count--) { u16 *seg = (u16 *) (base + *rel++); *seg = real_mode_seg; }
/* 32-bit linear relocations. */ count = *rel++; while (count--) { u32 *ptr = (u32 *) (base + *rel++); *ptr += phys_base; }
/* Must be performed *after* relocation. */ trampoline_header = (struct trampoline_header *) __va(real_mode_header->trampoline_header);
#ifdef CONFIG_X86_32 trampoline_header->start = __pa_symbol(startup_32_smp); trampoline_header->gdt_limit = __BOOT_DS + 7; trampoline_header->gdt_base = __pa_symbol(boot_gdt);#else /* * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR * so we need to mask it out. */ rdmsrq(MSR_EFER, efer); trampoline_header->efer = efer & ~EFER_LMA;
trampoline_header->start = (u64) secondary_startup_64; trampoline_cr4_features = &trampoline_header->cr4; *trampoline_cr4_features = mmu_cr4_features;
trampoline_header->flags = 0;
trampoline_lock = &trampoline_header->lock; *trampoline_lock = 0;
trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
/* Map the real mode stub as virtual == physical */ trampoline_pgd[0] = trampoline_pgd_entry.pgd;
/* * Include the entirety of the kernel mapping into the trampoline * PGD. This way, all mappings present in the normal kernel page * tables are usable while running on trampoline_pgd. */ for (i = pgd_index(__PAGE_OFFSET); i < PTRS_PER_PGD; i++) trampoline_pgd[i] = init_top_pgt[i].pgd;#endif
sme_sev_setup_real_mode(trampoline_header);}
/* * reserve_real_mode() gets called very early, to guarantee the * availability of low memory. This is before the proper kernel page * tables are set up, so we cannot set page permissions in that * function. Also trampoline code will be executed by APs so we * need to mark it executable at do_pre_smp_initcalls() at least, * thus run it as a early_initcall(). */static void __init set_real_mode_permissions(void){ unsigned char *base = (unsigned char *) real_mode_header; size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
size_t ro_size = PAGE_ALIGN(real_mode_header->ro_end) - __pa(base);
size_t text_size = PAGE_ALIGN(real_mode_header->ro_end) - real_mode_header->text_start;
unsigned long text_start = (unsigned long) __va(real_mode_header->text_start);
set_memory_nx((unsigned long) base, size >> PAGE_SHIFT); set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT); set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);}
void __init init_real_mode(void){ if (!real_mode_header) panic("Real mode trampoline was not allocated");
setup_real_mode(); set_real_mode_permissions();}
static int __init do_init_real_mode(void){ x86_platform.realmode_init(); return 0;}early_initcall(do_init_real_mode);