[PATCH v3] cmd: move ELF load and boot to lib/elf.c

[Maxim Moskalets]

From: Maxim Moskalets <maximmosk4 at gmail.com>

Loading and running the ELF image is the responsibility of the
library and should not be associated with the command line interface.

It is also required to run ELF images from FIT with the bootm command
so as not to depend on the command line interface.

Signed-off-by: Maxim Moskalets <maximmosk4 at gmail.com>
---
 cmd/elf.c     | 53 ++++++++++++++++----------------------------------
 include/elf.h | 10 ++++++++++
 lib/elf.c     | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+), 36 deletions(-)

diff --git a/cmd/elf.c b/cmd/elf.c
index a02361f9f5..9e1df73aff 100644
--- a/cmd/elf.c
+++ b/cmd/elf.c
@@ -19,21 +19,6 @@
 #include <linux/linkage.h>
 #endif
 
-/* Allow ports to override the default behavior */
-static unsigned long do_bootelf_exec(ulong (*entry)(int, char * const[]),
-				     int argc, char *const argv[])
-{
-	unsigned long ret;
-
-	/*
-	 * pass address parameter as argv[0] (aka command name),
-	 * and all remaining args
-	 */
-	ret = entry(argc, argv);
-
-	return ret;
-}
-
 /* Interpreter command to boot an arbitrary ELF image from memory */
 int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
@@ -43,8 +28,8 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 #endif
 	unsigned long addr; /* Address of the ELF image */
 	unsigned long rc; /* Return value from user code */
-	char *sload = NULL;
-	int rcode = 0;
+	int rcode = CMD_RET_SUCCESS;
+	Bootelf_flags flags = {0};
 
 	/* Consume 'bootelf' */
 	argc--; argv++;
@@ -52,7 +37,10 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	/* Check for [-p|-s] flag. */
 	if (argc >= 1 && (argv[0][0] == '-' && \
 				(argv[0][1] == 'p' || argv[0][1] == 's'))) {
-		sload = argv[0];
+		if (argv[0][1] == 'p')
+			flags.phdr = 1;
+		log_debug("Using ELF header format %s\n",
+				flags.phdr ? "phdr" : "shdr");
 		/* Consume flag. */
 		argc--; argv++;
 	}
@@ -75,17 +63,9 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	} else
 		addr = image_load_addr;
 
-	if (!valid_elf_image(addr))
-		return 1;
-
-	if (sload && sload[1] == 'p')
-		addr = load_elf_image_phdr(addr);
-	else
-		addr = load_elf_image_shdr(addr);
-
 #if CONFIG_IS_ENABLED(CMD_ELF_FDT_SETUP)
 	if (fdt_addr) {
-		printf("## Setting up FDT at 0x%08lx ...\n", fdt_addr);
+		log_debug("Setting up FDT at 0x%08lx ...\n", fdt_addr);
 		flush();
 
 		if (image_setup_libfdt(&img, (void *)fdt_addr, NULL))
@@ -93,21 +73,22 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	}
 #endif
 
-	if (!env_get_autostart())
-		return rcode;
-
-	printf("## Starting application at 0x%08lx ...\n", addr);
-	flush();
+	if (env_get_autostart()) {
+		flags.autostart = 1;
+		log_debug("Starting application at 0x%08lx ...\n", addr);
+		flush();
+	}
 
 	/*
 	 * pass address parameter as argv[0] (aka command name),
-	 * and all remaining args
+	 * and all remaining arguments
 	 */
-	rc = do_bootelf_exec((void *)addr, argc, argv);
+	rc = bootelf(addr, flags, argc, argv);
 	if (rc != 0)
-		rcode = 1;
+		rcode = CMD_RET_FAILURE;
 
-	printf("## Application terminated, rc = 0x%lx\n", rc);
+	if (flags.autostart && rc && (ENOEXEC == errno))
+		log_err("Invalid ELF image\n");
 
 	return rcode;
 }
diff --git a/include/elf.h b/include/elf.h
index a4ba74d8ab..b88e6cf403 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -12,6 +12,12 @@
 #ifndef __ASSEMBLY__
 #include "compiler.h"
 
+/* Flag param bits for bootelf() function */
+typedef struct {
+	unsigned phdr      : 1; /* load via program (not section) headers */
+	unsigned autostart : 1; /* Start ELF after loading */
+} Bootelf_flags;
+
 /* This version doesn't work for 64-bit ABIs - Erik */
 
 /* These typedefs need to be handled better */
@@ -700,6 +706,10 @@ unsigned long elf_hash(const unsigned char *name);
 #define R_RISCV_RELATIVE	3
 
 #ifndef __ASSEMBLY__
+unsigned long bootelf_exec(ulong (*entry)(int, char * const[]),
+			   int argc, char *const argv[]);
+unsigned long bootelf(unsigned long addr, Bootelf_flags flags,
+		      int argc, char *const argv[]);
 int valid_elf_image(unsigned long addr);
 unsigned long load_elf64_image_phdr(unsigned long addr);
 unsigned long load_elf64_image_shdr(unsigned long addr);
diff --git a/lib/elf.c b/lib/elf.c
index 9a794f9cba..dc13935e10 100644
--- a/lib/elf.c
+++ b/lib/elf.c
@@ -7,6 +7,7 @@
 #include <cpu_func.h>
 #include <elf.h>
 #include <env.h>
+#include <errno.h>
 #include <net.h>
 #include <vxworks.h>
 #ifdef CONFIG_X86
@@ -15,6 +16,59 @@
 #include <linux/linkage.h>
 #endif
 
+/**
+ * bootelf_exec() - start the ELF image execution.
+ *
+ * @entry: address of entry point of ELF.
+ *
+ * May by used to allow ports to override the default behavior.
+ */
+unsigned long bootelf_exec(ulong (*entry)(int, char * const[]),
+			   int argc, char *const argv[])
+{
+	return entry(argc, argv);
+}
+
+/**
+ * bootelf() - Boot ELF from memory.
+ *
+ * @addr:  Loading address of ELF in memory.
+ * @flags: Bits like ELF_PHDR to control boot details.
+ * @argc: May be used to pass command line arguments (maybe unused).
+ *	  Necessary for backward compatibility with the CLI command.
+ *	  If unused, must be 0.
+ * @argv: see @argc. If unused, must be NULL.
+ * Return: Number returned by ELF application.
+ *
+ * Sets errno = ENOEXEC if the ELF image is not valid.
+ */
+unsigned long bootelf(unsigned long addr, Bootelf_flags flags,
+		      int argc, char *const argv[])
+{
+	unsigned long entry_addr;
+	char *args[] = {"", NULL};
+
+	errno = 0;
+
+	if (!valid_elf_image(addr)) {
+		errno = ENOEXEC;
+		return 1;
+	}
+
+	entry_addr = flags.phdr ? load_elf_image_phdr(addr)
+					    : load_elf_image_shdr(addr);
+
+	if (!flags.autostart)
+		return 0;
+
+	if (!argc && !argv) {
+		argc = 1;
+		argv = args;
+	}
+
+	return bootelf_exec((void *)entry_addr, argc, argv);
+}
+
 /*
  * A very simple ELF64 loader, assumes the image is valid, returns the
  * entry point address.
-- 
2.39.2