linux-486/linux/patches/init.c.patch

--- arch/x86/realmode/init.c.new	2022-04-21 08:59:29.875419413 -0400
+++ arch/x86/realmode/init.c	2022-04-21 09:00:11.359752804 -0400
@@ -19,195 +19,195 @@
 
 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();
+//#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;
-	size_t size = real_mode_size_needed();
-
-	if (!size)
-		return;
-
-	WARN_ON(slab_is_available());
-
-	/* Has to be under 1M so we can execute real-mode AP code. */
-	mem = memblock_phys_alloc_range(size, PAGE_SIZE, 0, 1<<20);
-	if (!mem)
-		pr_info("No sub-1M memory is available for the trampoline\n");
-	else
-		set_real_mode_mem(mem);
-
-	/*
-	 * Unconditionally reserve the entire fisrt 1M, see comment in
-	 * setup_arch().
-	 */
-	memblock_reserve(0, SZ_1M);
-}
-
-static void 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.
-	 */
-	rdmsrl(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_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);
-}
-
-static int __init init_real_mode(void)
-{
-	if (!real_mode_header)
-		panic("Real mode trampoline was not allocated");
-
-	setup_real_mode();
-	set_real_mode_permissions();
-
-	return 0;
-}
-early_initcall(init_real_mode);
+//	phys_addr_t mem;
+//	size_t size = real_mode_size_needed();
+//
+//	if (!size)
+//		return;
+//
+//	WARN_ON(slab_is_available());
+//
+//	/* Has to be under 1M so we can execute real-mode AP code. */
+//	mem = memblock_phys_alloc_range(size, PAGE_SIZE, 0, 1<<20);
+//	if (!mem)
+//		pr_info("No sub-1M memory is available for the trampoline\n");
+//	else
+//		set_real_mode_mem(mem);
+//
+//	/*
+//	 * Unconditionally reserve the entire fisrt 1M, see comment in
+//	 * setup_arch().
+//	 */
+//	memblock_reserve(0, SZ_1M);
+}
+
+//static void 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.
+//	 */
+//	rdmsrl(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_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);
+//}
+//
+//static int __init init_real_mode(void)
+//{
+//	if (!real_mode_header)
+//		panic("Real mode trampoline was not allocated");
+//
+//	setup_real_mode();
+//	set_real_mode_permissions();
+//
+//	return 0;
+//}
+//early_initcall(init_real_mode);