efi: Add a flags parameter to efi_memory_map

In preparation for garbage collecting dynamically allocated EFI memory
maps, where the allocation method of memblock vs slab needs to be
recalled, convert the existing 'late' flag into a 'flags' bitmask.

Arrange for the flag to be passed via 'struct efi_memory_map_data'. This
structure grows additional flags in follow-on changes.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200113172245.27925-11-ardb@kernel.org

drivers/firmware/efi/memmap.c

@@ -52,21 +52,20 @@ phys_addr_t __init efi_memmap_alloc(unsigned int num_entries)
 /**
  * __efi_memmap_init - Common code for mapping the EFI memory map
  * @data: EFI memory map data
- * @late: Use early or late mapping function?
  *
  * This function takes care of figuring out which function to use to
  * map the EFI memory map in efi.memmap based on how far into the boot
  * we are.
  *
- * During bootup @late should be %false since we only have access to
- * the early_memremap*() functions as the vmalloc space isn't setup.
- * Once the kernel is fully booted we can fallback to the more robust
- * memremap*() API.
+ * During bootup EFI_MEMMAP_LATE in data->flags should be clear since we
+ * only have access to the early_memremap*() functions as the vmalloc
+ * space isn't setup.  Once the kernel is fully booted we can fallback
+ * to the more robust memremap*() API.
  *
  * Returns zero on success, a negative error code on failure.
  */
 static int __init
-__efi_memmap_init(struct efi_memory_map_data *data, bool late)
+__efi_memmap_init(struct efi_memory_map_data *data)
 {
 	struct efi_memory_map map;
 	phys_addr_t phys_map;
@@ -76,7 +75,7 @@ __efi_memmap_init(struct efi_memory_map_data *data, bool late)
 
 	phys_map = data->phys_map;
 
-	if (late)
+	if (data->flags & EFI_MEMMAP_LATE)
 		map.map = memremap(phys_map, data->size, MEMREMAP_WB);
 	else
 		map.map = early_memremap(phys_map, data->size);
@@ -92,7 +91,7 @@ __efi_memmap_init(struct efi_memory_map_data *data, bool late)
 
 	map.desc_version = data->desc_version;
 	map.desc_size = data->desc_size;
-	map.late = late;
+	map.flags = data->flags;
 
 	set_bit(EFI_MEMMAP, &efi.flags);
 
@@ -111,9 +110,10 @@ __efi_memmap_init(struct efi_memory_map_data *data, bool late)
 int __init efi_memmap_init_early(struct efi_memory_map_data *data)
 {
 	/* Cannot go backwards */
-	WARN_ON(efi.memmap.late);
+	WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
 
-	return __efi_memmap_init(data, false);
+	data->flags = 0;
+	return __efi_memmap_init(data);
 }
 
 void __init efi_memmap_unmap(void)
@@ -121,7 +121,7 @@ void __init efi_memmap_unmap(void)
 	if (!efi_enabled(EFI_MEMMAP))
 		return;
 
-	if (!efi.memmap.late) {
+	if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) {
 		unsigned long size;
 
 		size = efi.memmap.desc_size * efi.memmap.nr_map;
@@ -162,13 +162,14 @@ int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
 	struct efi_memory_map_data data = {
 		.phys_map = addr,
 		.size = size,
+		.flags = EFI_MEMMAP_LATE,
 	};
 
 	/* Did we forget to unmap the early EFI memmap? */
 	WARN_ON(efi.memmap.map);
 
 	/* Were we already called? */
-	WARN_ON(efi.memmap.late);
+	WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
 
 	/*
 	 * It makes no sense to allow callers to register different
@@ -178,7 +179,7 @@ int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
 	data.desc_version = efi.memmap.desc_version;
 	data.desc_size = efi.memmap.desc_size;
 
-	return __efi_memmap_init(&data, true);
+	return __efi_memmap_init(&data);
 }
 
 /**
@@ -195,6 +196,7 @@ int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
 int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map)
 {
 	struct efi_memory_map_data data;
+	unsigned long flags;
 
 	efi_memmap_unmap();
 
@@ -202,8 +204,9 @@ int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map)
 	data.size = efi.memmap.desc_size * nr_map;
 	data.desc_version = efi.memmap.desc_version;
 	data.desc_size = efi.memmap.desc_size;
+	data.flags = efi.memmap.flags & EFI_MEMMAP_LATE;
 
-	return __efi_memmap_init(&data, efi.memmap.late);
+	return __efi_memmap_init(&data);
 }
 
 /**

include/linux/efi.h

@@ -767,6 +767,7 @@ struct efi_memory_map_data {
 	unsigned long size;
 	unsigned long desc_version;
 	unsigned long desc_size;
+	unsigned long flags;
 };
 
 struct efi_memory_map {
@@ -776,7 +777,8 @@ struct efi_memory_map {
 	int nr_map;
 	unsigned long desc_version;
 	unsigned long desc_size;
-	bool late;
+#define EFI_MEMMAP_LATE (1UL << 0)
+	unsigned long flags;
 };
 
 struct efi_mem_range {