1 files changed, 48 insertions, 15 deletions

diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
index 101eb944f13c..9e5f3c722c33 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -18,6 +18,20 @@
  * Note: efi_info is commonly left uninitialized, but that field has a
  * private magic, so it is better to leave it unchanged.
  */
+
+#define sizeof_mbr(type, member) ({ sizeof(((type *)0)->member); })
+
+#define BOOT_PARAM_PRESERVE(struct_member)                              \
+        {                                                               \
+                .start = offsetof(struct boot_params, struct_member),   \
+                .len   = sizeof_mbr(struct boot_params, struct_member), \
+        }
+
+struct boot_params_to_save {
+        unsigned int start;
+        unsigned int len;
+};
+
 static void sanitize_boot_params(struct boot_params *boot_params)
 {
         /* 
@@ -35,21 +49,40 @@ static void sanitize_boot_params(struct boot_params *boot_params)
          * problems again.
          */
         if (boot_params->sentinel) {
-                /* fields in boot_params are left uninitialized, clear them */
-                boot_params->acpi_rsdp_addr = 0;
-                memset(&boot_params->ext_ramdisk_image, 0,
-                       (char *)&boot_params->efi_info -
-                        (char *)&boot_params->ext_ramdisk_image);
-                memset(&boot_params->kbd_status, 0,
-                       (char *)&boot_params->hdr -
-                       (char *)&boot_params->kbd_status);
-                memset(&boot_params->_pad7[0], 0,
-                       (char *)&boot_params->edd_mbr_sig_buffer[0] -
-                        (char *)&boot_params->_pad7[0]);
-                memset(&boot_params->_pad8[0], 0,
-                       (char *)&boot_params->eddbuf[0] -
-                        (char *)&boot_params->_pad8[0]);
-                memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
+                static struct boot_params scratch;
+                char *bp_base = (char *)boot_params;
+                char *save_base = (char *)&scratch;
+                int i;
+
+                const struct boot_params_to_save to_save[] = {
+                        BOOT_PARAM_PRESERVE(screen_info),
+                        BOOT_PARAM_PRESERVE(apm_bios_info),
+                        BOOT_PARAM_PRESERVE(tboot_addr),
+                        BOOT_PARAM_PRESERVE(ist_info),
+                        BOOT_PARAM_PRESERVE(hd0_info),
+                        BOOT_PARAM_PRESERVE(hd1_info),
+                        BOOT_PARAM_PRESERVE(sys_desc_table),
+                        BOOT_PARAM_PRESERVE(olpc_ofw_header),
+                        BOOT_PARAM_PRESERVE(efi_info),
+                        BOOT_PARAM_PRESERVE(alt_mem_k),
+                        BOOT_PARAM_PRESERVE(scratch),
+                        BOOT_PARAM_PRESERVE(e820_entries),
+                        BOOT_PARAM_PRESERVE(eddbuf_entries),
+                        BOOT_PARAM_PRESERVE(edd_mbr_sig_buf_entries),
+                        BOOT_PARAM_PRESERVE(edd_mbr_sig_buffer),
+                        BOOT_PARAM_PRESERVE(hdr),
+                        BOOT_PARAM_PRESERVE(e820_table),
+                        BOOT_PARAM_PRESERVE(eddbuf),
+                };
+
+                memset(&scratch, 0, sizeof(scratch));
+
+                for (i = 0; i < ARRAY_SIZE(to_save); i++) {
+                        memcpy(save_base + to_save[i].start,
+                               bp_base + to_save[i].start, to_save[i].len);
+                }
+
+                memcpy(boot_params, save_base, sizeof(*boot_params));
         }
 }