Fixed MTP to work with TWRP

arch/x86/kernel/head64.c

@@ -0,0 +1,194 @@
+/*
+ *  prepare to run common code
+ *
+ *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/percpu.h>
+#include <linux/start_kernel.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+
+#include <asm/processor.h>
+#include <asm/proto.h>
+#include <asm/smp.h>
+#include <asm/setup.h>
+#include <asm/desc.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+#include <asm/kdebug.h>
+#include <asm/e820.h>
+#include <asm/bios_ebda.h>
+#include <asm/bootparam_utils.h>
+#include <asm/microcode.h>
+
+/*
+ * Manage page tables very early on.
+ */
+extern pgd_t early_level4_pgt[PTRS_PER_PGD];
+extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
+static unsigned int __initdata next_early_pgt = 2;
+pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
+
+/* Wipe all early page tables except for the kernel symbol map */
+static void __init reset_early_page_tables(void)
+{
+	unsigned long i;
+
+	for (i = 0; i < PTRS_PER_PGD-1; i++)
+		early_level4_pgt[i].pgd = 0;
+
+	next_early_pgt = 0;
+
+	write_cr3(__pa(early_level4_pgt));
+}
+
+/* Create a new PMD entry */
+int __init early_make_pgtable(unsigned long address)
+{
+	unsigned long physaddr = address - __PAGE_OFFSET;
+	unsigned long i;
+	pgdval_t pgd, *pgd_p;
+	pudval_t pud, *pud_p;
+	pmdval_t pmd, *pmd_p;
+
+	/* Invalid address or early pgt is done ?  */
+	if (physaddr >= MAXMEM || read_cr3() != __pa(early_level4_pgt))
+		return -1;
+
+again:
+	pgd_p = &early_level4_pgt[pgd_index(address)].pgd;
+	pgd = *pgd_p;
+
+	/*
+	 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
+	 * critical -- __PAGE_OFFSET would point us back into the dynamic
+	 * range and we might end up looping forever...
+	 */
+	if (pgd)
+		pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
+	else {
+		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
+			reset_early_page_tables();
+			goto again;
+		}
+
+		pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
+		for (i = 0; i < PTRS_PER_PUD; i++)
+			pud_p[i] = 0;
+		*pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
+	}
+	pud_p += pud_index(address);
+	pud = *pud_p;
+
+	if (pud)
+		pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
+	else {
+		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
+			reset_early_page_tables();
+			goto again;
+		}
+
+		pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
+		for (i = 0; i < PTRS_PER_PMD; i++)
+			pmd_p[i] = 0;
+		*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
+	}
+	pmd = (physaddr & PMD_MASK) + early_pmd_flags;
+	pmd_p[pmd_index(address)] = pmd;
+
+	return 0;
+}
+
+/* Don't add a printk in there. printk relies on the PDA which is not initialized 
+   yet. */
+static void __init clear_bss(void)
+{
+	memset(__bss_start, 0,
+	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
+}
+
+static unsigned long get_cmd_line_ptr(void)
+{
+	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+
+	cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
+
+	return cmd_line_ptr;
+}
+
+static void __init copy_bootdata(char *real_mode_data)
+{
+	char * command_line;
+	unsigned long cmd_line_ptr;
+
+	memcpy(&boot_params, real_mode_data, sizeof boot_params);
+	sanitize_boot_params(&boot_params);
+	cmd_line_ptr = get_cmd_line_ptr();
+	if (cmd_line_ptr) {
+		command_line = __va(cmd_line_ptr);
+		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
+	}
+}
+
+asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
+{
+	int i;
+
+	/*
+	 * Build-time sanity checks on the kernel image and module
+	 * area mappings. (these are purely build-time and produce no code)
+	 */
+	BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
+	BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
+	BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
+	BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
+	BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
+	BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
+	BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
+				(__START_KERNEL & PGDIR_MASK)));
+	BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
+
+	/* Kill off the identity-map trampoline */
+	reset_early_page_tables();
+
+	/* clear bss before set_intr_gate with early_idt_handler */
+	clear_bss();
+
+	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
+		set_intr_gate(i, early_idt_handlers[i]);
+	load_idt((const struct desc_ptr *)&idt_descr);
+
+	copy_bootdata(__va(real_mode_data));
+
+	/*
+	 * Load microcode early on BSP.
+	 */
+	load_ucode_bsp();
+
+	if (console_loglevel >= CONSOLE_LOGLEVEL_DEBUG)
+		early_printk("Kernel alive\n");
+
+	clear_page(init_level4_pgt);
+	/* set init_level4_pgt kernel high mapping*/
+	init_level4_pgt[511] = early_level4_pgt[511];
+
+	x86_64_start_reservations(real_mode_data);
+}
+
+void __init x86_64_start_reservations(char *real_mode_data)
+{
+	/* version is always not zero if it is copied */
+	if (!boot_params.hdr.version)
+		copy_bootdata(__va(real_mode_data));
+
+	reserve_ebda_region();
+
+	start_kernel();
+}