From 24a238f7633cbebcc00b810d0ac1608233a81fbf Mon Sep 17 00:00:00 2001
From: Heinrich Schuchardt <xypron.glpk@gmx.de>
Date: Thu, 20 Jun 2019 22:00:02 +0000
Subject: [PATCH] efi_loader: clean up runtime detaching

The detaching of the runtime will have to move to ExitBootServices() to
encompass operating system that do not call SetVirtualAddressMap().

This patch changes the logic for the relocation of the pointers in the
runtime table such that the relocation becomes independent of the entries
in the detach list.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 lib/efi_loader/efi_runtime.c | 78 +++++++++++++++++++++++++-----------
 1 file changed, 55 insertions(+), 23 deletions(-)

diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index c56230cad3..702136ae0e 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -420,29 +420,53 @@ static const struct efi_runtime_detach_list_struct efi_runtime_detach_list[] = {
 	}
 };
 
-static bool efi_runtime_tobedetached(void *p)
+/**
+ * efi_is_runtime_service_pointer() - check if pointer points to runtime table
+ *
+ * @p:		pointer to check
+ * Return:	true if the pointer points to a service function pointer in the
+ *		runtime table
+ */
+static bool efi_is_runtime_service_pointer(void *p)
 {
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(efi_runtime_detach_list); i++)
-		if (efi_runtime_detach_list[i].ptr == p)
-			return true;
-
-	return false;
+	return p >= (void *)&efi_runtime_services.get_time &&
+	       p <= (void *)&efi_runtime_services.query_variable_info;
 }
 
-static void efi_runtime_detach(ulong offset)
+static __efi_runtime void efi_runtime_detach(void)
 {
 	int i;
-	ulong patchoff = offset - (ulong)gd->relocaddr;
 
+	/*
+	 * Replace boottime functions by runtime functions
+	 * TODO: move this step to ExitBootServices()
+	 */
 	for (i = 0; i < ARRAY_SIZE(efi_runtime_detach_list); i++) {
 		ulong patchto = (ulong)efi_runtime_detach_list[i].patchto;
 		ulong *p = efi_runtime_detach_list[i].ptr;
-		ulong newaddr = patchto ? (patchto + patchoff) : 0;
 
-		debug("%s: Setting %p to %lx\n", __func__, p, newaddr);
-		*p = newaddr;
+		debug("%s: Setting %p to %lx\n", __func__, p, patchto);
+		*p = patchto;
+	}
+}
+
+static __efi_runtime void efi_relocate_runtime_table(ulong offset)
+{
+	ulong patchoff;
+	void **pos;
+
+	/* Relocate the runtime services pointers */
+	patchoff = offset - gd->relocaddr;
+	for (pos = (void **)&efi_runtime_services.get_time;
+	     pos <= (void **)&efi_runtime_services.query_variable_info; ++pos) {
+		/*
+		 * The UEFI spec requires not to update VirtualAddressMap()
+		 * and ConvertPointer().
+		 */
+		if (*pos && pos !=
+		    (void **)&efi_runtime_services.set_virtual_address_map &&
+		    pos != (void **)&efi_runtime_services.convert_pointer)
+			*pos += patchoff;
 	}
 
 	/* Update CRC32 */
@@ -467,6 +491,10 @@ void efi_runtime_relocate(ulong offset, struct efi_mem_desc *map)
 
 		p = (void*)((ulong)rel->offset - base) + gd->relocaddr;
 
+		/* The runtime services are updated in efi_runtime_detach() */
+		if (map && efi_is_runtime_service_pointer(p))
+			continue;
+
 		debug("%s: rel->info=%#lx *p=%#lx rel->offset=%p\n", __func__,
 		      rel->info, *p, rel->offset);
 
@@ -490,9 +518,8 @@ void efi_runtime_relocate(ulong offset, struct efi_mem_desc *map)
 		}
 #endif
 		default:
-			if (!efi_runtime_tobedetached(p))
-				printf("%s: Unknown relocation type %llx\n",
-				       __func__, rel->info & R_MASK);
+			printf("%s: Unknown relocation type %llx\n",
+			       __func__, rel->info & R_MASK);
 			continue;
 		}
 
@@ -500,9 +527,8 @@ void efi_runtime_relocate(ulong offset, struct efi_mem_desc *map)
 		if (map && ((newaddr < map->virtual_start) ||
 		    newaddr > (map->virtual_start +
 			      (map->num_pages << EFI_PAGE_SHIFT)))) {
-			if (!efi_runtime_tobedetached(p))
-				printf("%s: Relocation at %p is out of "
-				       "range (%lx)\n", __func__, p, newaddr);
+			printf("%s: Relocation at %p is out of range (%lx)\n",
+			       __func__, p, newaddr);
 			continue;
 		}
 
@@ -607,7 +633,15 @@ static efi_status_t EFIAPI efi_set_virtual_address_map(
 		}
 	}
 
-	/* Move the actual runtime code over */
+	/*
+	 * Some runtime services are implemented in a way that we can only offer
+	 * them at boottime. Replace those function pointers.
+	 *
+	 * TODO: move this call to ExitBootServices().
+	 */
+	efi_runtime_detach();
+
+	/* Relocate the runtime. See TODO above */
 	for (i = 0; i < n; i++) {
 		struct efi_mem_desc *map;
 
@@ -616,10 +650,8 @@ static efi_status_t EFIAPI efi_set_virtual_address_map(
 			ulong new_offset = map->virtual_start -
 					   map->physical_start + gd->relocaddr;
 
+			efi_relocate_runtime_table(new_offset);
 			efi_runtime_relocate(new_offset, map);
-			/* Once we're virtual, we can no longer handle
-			   complex callbacks */
-			efi_runtime_detach(new_offset);
 			return EFI_EXIT(EFI_SUCCESS);
 		}
 	}
-- 
2.25.1