[PATCH v3 9/9] efi: libstub: Simplify interfaces for primary_display

@@ -14,10 +14,29 @@ static void *kernel_image_addr(void *addr)
 	return addr + kernel_image_offset;
 }
 
-struct sysfb_display_info *alloc_primary_display(void)
+/*
+ * There are two ways of populating the core kernel's sysfb_primary_display
+ * via the stub:
+ *
+ *   - using a configuration table, which relies on the EFI init code to
+ *     locate the table and copy the contents; or
+ *
+ *   - by linking directly to the core kernel's copy of the global symbol.
+ *
+ * The latter is preferred because it makes the EFIFB earlycon available very
+ * early, but it only works if the EFI stub is part of the core kernel image
+ * itself. The zboot decompressor can only use the configuration table
+ * approach.
+ */
+
+struct sysfb_display_info *lookup_primary_display(bool *needs_free)
 {
+	*needs_free = true;
+
 	if (IS_ENABLED(CONFIG_ARM))
-		return __alloc_primary_display();
+		return alloc_primary_display();
+
+	*needs_free = false;
 
 	if (IS_ENABLED(CONFIG_X86) ||
 	    IS_ENABLED(CONFIG_EFI_EARLYCON) ||

@@ -51,14 +51,14 @@ static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0);
 void __weak free_primary_display(struct sysfb_display_info *dpy)
 { }
 
-static struct sysfb_display_info *setup_primary_display(void)
+static struct sysfb_display_info *setup_primary_display(bool *dpy_needs_free)
 {
 	struct sysfb_display_info *dpy;
 	struct screen_info *screen = NULL;
 	struct edid_info *edid = NULL;
 	efi_status_t status;
 
-	dpy = alloc_primary_display();
+	dpy = lookup_primary_display(dpy_needs_free);
 	if (!dpy)
 		return NULL;
 	screen = &dpy->screen;

@@ -68,15 +68,22 @@ static struct sysfb_display_info *setup_primary_display(void)
 
 	status = efi_setup_graphics(screen, edid);
 	if (status != EFI_SUCCESS)
-		goto err_free_primary_display;
+		goto err___free_primary_display;
 
 	return dpy;
 
-err_free_primary_display:
-	free_primary_display(dpy);
+err___free_primary_display:
+	if (*dpy_needs_free)
+		free_primary_display(dpy);
 	return NULL;
 }
 
+static void release_primary_display(struct sysfb_display_info *dpy, bool dpy_needs_free)
+{
+	if (dpy && dpy_needs_free)
+		free_primary_display(dpy);
+}
+
 static void install_memreserve_table(void)
 {
 	struct linux_efi_memreserve *rsv;

@@ -156,13 +163,14 @@ efi_status_t efi_stub_common(efi_handle_t handle,
 			     char *cmdline_ptr)
 {
 	struct sysfb_display_info *dpy;
+	bool dpy_needs_free;
 	efi_status_t status;
 
 	status = check_platform_features();
 	if (status != EFI_SUCCESS)
 		return status;
 
-	dpy = setup_primary_display();
+	dpy = setup_primary_display(&dpy_needs_free);
 
 	efi_retrieve_eventlog();
 

@@ -182,7 +190,7 @@ efi_status_t efi_stub_common(efi_handle_t handle,
 
 	status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr);
 
-	free_primary_display(dpy);
+	release_primary_display(dpy, dpy_needs_free);
 
 	return status;
 }

@@ -1176,8 +1176,8 @@ efi_enable_reset_attack_mitigation(void) { }
 
 void efi_retrieve_eventlog(void);
 
+struct sysfb_display_info *lookup_primary_display(bool *needs_free);
 struct sysfb_display_info *alloc_primary_display(void);
-struct sysfb_display_info *__alloc_primary_display(void);
 void free_primary_display(struct sysfb_display_info *dpy);
 
 void efi_cache_sync_image(unsigned long image_base,

@@ -7,24 +7,9 @@
 
 #include "efistub.h"
 
-/*
- * There are two ways of populating the core kernel's sysfb_primary_display
- * via the stub:
- *
- *   - using a configuration table, which relies on the EFI init code to
- *     locate the table and copy the contents; or
- *
- *   - by linking directly to the core kernel's copy of the global symbol.
- *
- * The latter is preferred because it makes the EFIFB earlycon available very
- * early, but it only works if the EFI stub is part of the core kernel image
- * itself. The zboot decompressor can only use the configuration table
- * approach.
- */
-
 static efi_guid_t primary_display_guid = LINUX_EFI_PRIMARY_DISPLAY_TABLE_GUID;
 
-struct sysfb_display_info *__alloc_primary_display(void)
+struct sysfb_display_info *alloc_primary_display(void)
 {
 	struct sysfb_display_info *dpy;
 	efi_status_t status;

@@ -26,9 +26,11 @@ void __weak efi_cache_sync_image(unsigned long image_base,
 	// executable code loaded into memory to be safe for execution.
 }
 
-struct sysfb_display_info *alloc_primary_display(void)
+struct sysfb_display_info *lookup_primary_display(bool *needs_free)
 {
-	return __alloc_primary_display();
+	*needs_free = true;
+
+	return alloc_primary_display();
 }
 
 asmlinkage efi_status_t __efiapi