efi/libstub: Use __free() helper for pool deallocations

Annotate some local buffer allocations as __free(efi_pool) and simplify
the associated error handling accordingly. This removes a couple of
gotos and simplifies the code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Author: ardbiesheuvel

drivers/firmware/efi/libstub/efi-stub-helper.c

@@ -47,9 +47,10 @@ bool __pure __efi_soft_reserve_enabled(void)
  */
 efi_status_t efi_parse_options(char const *cmdline)
 {
-	size_t len;
+	char *buf __free(efi_pool) = NULL;
 	efi_status_t status;
-	char *str, *buf;
+	size_t len;
+	char *str;
 
 	if (!cmdline)
 		return EFI_SUCCESS;
@@ -102,7 +103,6 @@ efi_status_t efi_parse_options(char const *cmdline)
 			efi_parse_option_graphics(val + strlen("efifb:"));
 		}
 	}
-	efi_bs_call(free_pool, buf);
 	return EFI_SUCCESS;
 }
 
@@ -250,7 +250,7 @@ static efi_status_t efi_measure_tagged_event(unsigned long load_addr,
 						  u64, const union efistub_event *);
 		struct { u32 hash_log_extend_event; } mixed_mode;
 	} method;
-	struct efistub_measured_event *evt;
+	struct efistub_measured_event *evt __free(efi_pool) = NULL;
 	int size = struct_size(evt, tagged_event.tagged_event_data,
 			       events[event].event_data_len);
 	efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID;
@@ -312,7 +312,6 @@ static efi_status_t efi_measure_tagged_event(unsigned long load_addr,
 
 	status = efi_fn_call(&method, hash_log_extend_event, protocol, 0,
 			     load_addr, load_size, &evt->event_data);
-	efi_bs_call(free_pool, evt);
 
 	if (status == EFI_SUCCESS)
 		return EFI_SUCCESS;

drivers/firmware/efi/libstub/efi-stub.c

@@ -104,8 +104,8 @@ static u32 get_supported_rt_services(void)
 
 efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr)
 {
+	char *cmdline __free(efi_pool) = NULL;
 	efi_status_t status;
-	char *cmdline;
 
 	/*
 	 * Get the command line from EFI, using the LOADED_IMAGE
@@ -120,25 +120,24 @@ efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr)
 
 	if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {
 		status = efi_parse_options(cmdline);
-		if (status != EFI_SUCCESS)
-			goto fail_free_cmdline;
+		if (status != EFI_SUCCESS) {
+			efi_err("Failed to parse EFI load options\n");
+			return status;
+		}
 	}
 
 	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
 	    IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
 	    cmdline[0] == 0) {
 		status = efi_parse_options(CONFIG_CMDLINE);
-		if (status != EFI_SUCCESS)
-			goto fail_free_cmdline;
+		if (status != EFI_SUCCESS) {
+			efi_err("Failed to parse built-in command line\n");
+			return status;
+		}
 	}
 
-	*cmdline_ptr = cmdline;
+	*cmdline_ptr = no_free_ptr(cmdline);
 	return EFI_SUCCESS;
-
-fail_free_cmdline:
-	efi_err("Failed to parse options\n");
-	efi_bs_call(free_pool, cmdline);
-	return status;
 }
 
 efi_status_t efi_stub_common(efi_handle_t handle,

drivers/firmware/efi/libstub/x86-stub.c

@@ -42,7 +42,7 @@ union sev_memory_acceptance_protocol {
 static efi_status_t
 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
 {
-	struct pci_setup_rom *rom = NULL;
+	struct pci_setup_rom *rom __free(efi_pool) = NULL;
 	efi_status_t status;
 	unsigned long size;
 	uint64_t romsize;
@@ -75,36 +75,32 @@ preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
 	rom->data.len	= size - sizeof(struct setup_data);
 	rom->data.next	= 0;
 	rom->pcilen	= romsize;
-	*__rom = rom;
 
 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
 				PCI_VENDOR_ID, 1, &rom->vendor);
 
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to read rom->vendor\n");
-		goto free_struct;
+		return status;
 	}
 
 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
 				PCI_DEVICE_ID, 1, &rom->devid);
 
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to read rom->devid\n");
-		goto free_struct;
+		return status;
 	}
 
 	status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
 				&rom->device, &rom->function);
 
 	if (status != EFI_SUCCESS)
-		goto free_struct;
+		return status;
 
 	memcpy(rom->romdata, romimage, romsize);
-	return status;
-
-free_struct:
-	efi_bs_call(free_pool, rom);
-	return status;
+	*__rom = no_free_ptr(rom);
+	return EFI_SUCCESS;
 }
 
 /*