x86/mm: Insure that boot memory areas are mapped properly

[mirror_ubuntu-bionic-kernel.git] / arch / x86 / kernel / head64.c

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 5cd0b72a02834ca1f56efae4c4681220a56a0572..0cdb53bf4c4ba4f939a2144f0abf09f47aecae56 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -34,7 +34,6 @@
 /*
  * Manage page tables very early on.
  */
-extern pgd_t early_top_pgt[PTRS_PER_PGD];
 extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
 static unsigned int __initdata next_early_pgt;
 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
@@ -181,13 +180,13 @@ static void __init reset_early_page_tables(void)
 }
 
 /* Create a new PMD entry */
-int __init early_make_pgtable(unsigned long address)
+int __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
 {
        unsigned long physaddr = address - __PAGE_OFFSET;
        pgdval_t pgd, *pgd_p;
        p4dval_t p4d, *p4d_p;
        pudval_t pud, *pud_p;
-       pmdval_t pmd, *pmd_p;
+       pmdval_t *pmd_p;
 
        /* Invalid address or early pgt is done ?  */
        if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
@@ -246,12 +245,21 @@ again:
                memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
                *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;
 }
 
+int __init early_make_pgtable(unsigned long address)
+{
+       unsigned long physaddr = address - __PAGE_OFFSET;
+       pmdval_t pmd;
+
+       pmd = (physaddr & PMD_MASK) + early_pmd_flags;
+
+       return __early_make_pgtable(address, pmd);
+}
+
 /* Don't add a printk in there. printk relies on the PDA which is not initialized 
    yet. */
 static void __init clear_bss(void)
@@ -274,6 +282,12 @@ static void __init copy_bootdata(char *real_mode_data)
        char * command_line;
        unsigned long cmd_line_ptr;
 
+       /*
+        * If SME is active, this will create decrypted mappings of the
+        * boot data in advance of the copy operations.
+        */
+       sme_map_bootdata(real_mode_data);
+
        memcpy(&boot_params, real_mode_data, sizeof boot_params);
        sanitize_boot_params(&boot_params);
        cmd_line_ptr = get_cmd_line_ptr();
@@ -281,6 +295,14 @@ static void __init copy_bootdata(char *real_mode_data)
                command_line = __va(cmd_line_ptr);
                memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
        }
+
+       /*
+        * The old boot data is no longer needed and won't be reserved,
+        * freeing up that memory for use by the system. If SME is active,
+        * we need to remove the mappings that were created so that the
+        * memory doesn't remain mapped as decrypted.
+        */
+       sme_unmap_bootdata(real_mode_data);
 }
 
 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)