[PATCH v2 16/21] ARM: link ELF image into PBL

[Sascha Hauer <s.hauer@pengutronix.de>]

Instead of linking the raw binary barebox proper image into the PBL link
the ELF image into the PBL. With this barebox proper starts with a properly
linked and fully initialized C environment, so the calls to
relocate_to_adr() and setup_c() can be removed from barebox proper.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/Kconfig          |  2 ++
 arch/arm/cpu/start.c      | 11 +++--------
 arch/arm/cpu/uncompress.c | 26 +++++++++++++++++++-------
 3 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5123e9b1402c56db94df6a7a33ae993c61d51fbc..c53c58844a9411e3777711db2900b0e01cf55eec 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -18,6 +18,8 @@ config ARM
 	select HW_HAS_PCI
 	select ARCH_HAS_DMA_WRITE_COMBINE
 	select HAVE_EFI_LOADER if MMU # for payload unaligned accesses
+	select ELF
+	select PBL_IMAGE_ELF
 	default y
 
 config ARCH_LINUX_NAME
diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
index f7d4507e71588ba5e241b24b952d55e2a4b0f794..f7062380cd5d265b3326f247a99b1847e16d64f0 100644
--- a/arch/arm/cpu/start.c
+++ b/arch/arm/cpu/start.c
@@ -127,8 +127,9 @@ static int barebox_memory_areas_init(void)
 }
 device_initcall(barebox_memory_areas_init);
 
-__noreturn __prereloc void barebox_non_pbl_start(unsigned long membase,
-		unsigned long memsize, struct handoff_data *hd)
+__noreturn void barebox_non_pbl_start(unsigned long membase,
+				      unsigned long memsize,
+				      struct handoff_data *hd)
 {
 	unsigned long endmem = membase + memsize;
 	unsigned long malloc_start, malloc_end;
@@ -139,12 +140,6 @@ __noreturn __prereloc void barebox_non_pbl_start(unsigned long membase,
 	if (IS_ENABLED(CONFIG_CPU_V7))
 		armv7_hyp_install();
 
-	relocate_to_adr(barebox_base);
-
-	setup_c();
-
-	barrier();
-
 	pbl_barebox_break();
 
 	pr_debug("memory at 0x%08lx, size 0x%08lx\n", membase, memsize);
diff --git a/arch/arm/cpu/uncompress.c b/arch/arm/cpu/uncompress.c
index b9fc1d04db96e77c8fcd7fd1930798ea1d9294d7..8cc7102290986e71d2f3a2f34df1a9f946c56ced 100644
--- a/arch/arm/cpu/uncompress.c
+++ b/arch/arm/cpu/uncompress.c
@@ -20,6 +20,7 @@
 #include <asm/mmu.h>
 #include <asm/unaligned.h>
 #include <compressed-dtb.h>
+#include <elf.h>
 
 #include <debug_ll.h>
 
@@ -41,6 +42,8 @@ void __noreturn barebox_pbl_start(unsigned long membase, unsigned long memsize,
 	void *pg_start, *pg_end;
 	unsigned long pc = get_pc();
 	void *handoff_data;
+	struct elf_image elf;
+	int ret;
 
 	/* piggy data is not relocated, so determine the bounds now */
 	pg_start = runtime_address(input_data);
@@ -85,21 +88,30 @@ void __noreturn barebox_pbl_start(unsigned long membase, unsigned long memsize,
 	else if (IS_ENABLED(CONFIG_ARMV7R_MPU))
 		set_cr(get_cr() | CR_C);
 
-	pr_debug("uncompressing barebox binary at 0x%p (size 0x%08x) to 0x%08lx (uncompressed size: 0x%08x)\n",
+	pr_debug("uncompressing barebox ELF at 0x%p (size 0x%08x) to 0x%08lx (uncompressed size: 0x%08x)\n",
 			pg_start, pg_len, barebox_base, uncompressed_len);
 
 	pbl_barebox_uncompress((void*)barebox_base, pg_start, pg_len);
 
+	pr_debug("relocating ELF in place\n");
+
+	ret = elf_open_binary_into(&elf, (void *)barebox_base);
+	if (ret)
+		panic("Failed to open ELF binary: %d\n", ret);
+
+	ret = elf_load_inplace(&elf);
+	if (ret)
+		panic("Failed to relocate ELF: %d\n", ret);
+
+	pr_debug("ELF entry point: 0x%llx\n", elf.entry);
+
+	barebox = (void *)(unsigned long)elf.entry;
+
 	handoff_data_move(handoff_data);
 
 	sync_caches_for_execution();
 
-	if (IS_ENABLED(CONFIG_THUMB2_BAREBOX))
-		barebox = (void *)(barebox_base + 1);
-	else
-		barebox = (void *)barebox_base;
-
-	pr_debug("jumping to uncompressed image at 0x%p\n", barebox);
+	pr_debug("jumping to ELF entry point at 0x%p\n", barebox);
 
 	if (IS_ENABLED(CONFIG_CPU_V7) && boot_cpu_mode() == HYP_MODE)
 		armv7_switch_to_hyp();

-- 
2.47.3