efi_loader: Change return type of efi_add_memory_map()

We currently have some inconsistent use of efi_add_memory_map()
throughout the code. In particular the return value of efi_add_memory_map()
is not interpreted the same way by various users in the codebase.

This patch does the following:

- Changes efi_add_memory_map() to return efi_status_t.
- Adds a method description to efi_add_memory_map().
- Changes efi_add_memory_map() to return EFI_SUCCESS
- Returns non-zero for error in efi_add_memory_map()
- Updates efi_allocate_pages() to new efi_add_memory_map()
- Updates efi_free_pages() to new efi_add_memory_map()
- Updates efi_carve_out_dt_rsv() to new efi_add_memory_map()
- Updates efi_add_runtime_mmio()  to new efi_add_memory_map()

Fixes: 5d00995c361c ("efi_loader: Implement memory allocation and map")
Fixes: 74c16acce30b ("efi_loader: Don't allocate from memory holes")
Suggested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Alexander Graf <agraf@csgraf.de>
Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

2 files changed, 23 insertions, 15 deletions

diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
index 2737938..4c0216b 100644
--- a/lib/efi_loader/efi_memory.c
+++ b/lib/efi_loader/efi_memory.c
@@ -223,8 +223,17 @@ static s64 efi_mem_carve_out(struct efi_mem_list *map,
 	return EFI_CARVE_LOOP_AGAIN;
 }
 
-uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
-			    bool overlap_only_ram)
+/**
+ * efi_add_memory_map() - add memory area to the memory map
+ *
+ * @start:		start address, must be a multiple of EFI_PAGE_SIZE
+ * @pages:		number of pages to add
+ * @memory_type:	type of memory added
+ * @overlap_only_ram:	the memory area must overlap existing
+ * Return:		status code
+ */
+efi_status_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
+				bool overlap_only_ram)
 {
 	struct list_head *lhandle;
 	struct efi_mem_list *newlist;
@@ -239,7 +248,7 @@ uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
 		return EFI_INVALID_PARAMETER;
 
 	if (!pages)
-		return start;
+		return EFI_SUCCESS;
 
 	++efi_memory_map_key;
 	newlist = calloc(1, sizeof(*newlist));
@@ -277,7 +286,7 @@ uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
 				 * The user requested to only have RAM overlaps,
 				 * but we hit a non-RAM region. Error out.
 				 */
-				return 0;
+				return EFI_NO_MAPPING;
 			case EFI_CARVE_NO_OVERLAP:
 				/* Just ignore this list entry */
 				break;
@@ -307,7 +316,7 @@ uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
 		 * The payload wanted to have RAM overlaps, but we overlapped
 		 * with an unallocated region. Error out.
 		 */
-		return 0;
+		return EFI_NO_MAPPING;
 	}
 
 	/* Add our new map */
@@ -326,7 +335,7 @@ uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
 		}
 	}
 
-	return start;
+	return EFI_SUCCESS;
 }
 
 /**
@@ -455,7 +464,7 @@ efi_status_t efi_allocate_pages(int type, int memory_type,
 	}
 
 	/* Reserve that map in our memory maps */
-	if (efi_add_memory_map(addr, pages, memory_type, true) != addr)
+	if (efi_add_memory_map(addr, pages, memory_type, true) != EFI_SUCCESS)
 		/* Map would overlap, bail out */
 		return  EFI_OUT_OF_RESOURCES;
 
@@ -487,7 +496,6 @@ void *efi_alloc(uint64_t len, int memory_type)
  */
 efi_status_t efi_free_pages(uint64_t memory, efi_uintn_t pages)
 {
-	uint64_t r = 0;
 	efi_status_t ret;
 
 	ret = efi_check_allocated(memory, true);
@@ -501,13 +509,13 @@ efi_status_t efi_free_pages(uint64_t memory, efi_uintn_t pages)
 		return EFI_INVALID_PARAMETER;
 	}
 
-	r = efi_add_memory_map(memory, pages, EFI_CONVENTIONAL_MEMORY, false);
+	ret = efi_add_memory_map(memory, pages, EFI_CONVENTIONAL_MEMORY, false);
 	/* Merging of adjacent free regions is missing */
 
-	if (r == memory)
-		return EFI_SUCCESS;
+	if (ret != EFI_SUCCESS)
+		return EFI_NOT_FOUND;
 
-	return EFI_NOT_FOUND;
+	return ret;
 }
 
 /**
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index 9f4ba2f..8b56ab0 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -694,10 +694,10 @@ efi_status_t efi_add_runtime_mmio(void *mmio_ptr, u64 len)
 	struct efi_runtime_mmio_list *newmmio;
 	u64 pages = (len + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT;
 	uint64_t addr = *(uintptr_t *)mmio_ptr;
-	uint64_t retaddr;
+	efi_status_t ret;
 
-	retaddr = efi_add_memory_map(addr, pages, EFI_MMAP_IO, false);
-	if (retaddr != addr)
+	ret = efi_add_memory_map(addr, pages, EFI_MMAP_IO, false);
+	if (ret != EFI_SUCCESS)
 		return EFI_OUT_OF_RESOURCES;
 
 	newmmio = calloc(1, sizeof(*newmmio));