diff options
Diffstat (limited to 'arch/x86/realmode/init.c')
| -rw-r--r-- | arch/x86/realmode/init.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c index 4a3da7592b99..c5e29db02a46 100644 --- a/arch/x86/realmode/init.c +++ b/arch/x86/realmode/init.c @@ -17,6 +17,32 @@ 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; @@ -72,6 +98,7 @@ static void __init setup_real_mode(void) #ifdef CONFIG_X86_64 u64 *trampoline_pgd; u64 efer; + int i; #endif base = (unsigned char *)real_mode_header; @@ -128,8 +155,17 @@ static void __init setup_real_mode(void) trampoline_header->flags = 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; - trampoline_pgd[511] = init_top_pgt[511].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); |