rmodules: use rmodtool to create rmodules

Start using the rmodtool for generating rmodules.
rmodule_link() has been changed to create 2 rules:
one for the passed in <name>, the other for creating
<name>.rmod which is an ELF file in the format of
an rmodule.

Since the header is not compiled and linked together
with an rmodule there needs to be a way of marking
which symbol is the entry point. __rmodule_entry is
the symbol used for knowing the entry point. There
was a little churn in SMM modules to ensure an
rmodule entry point symbol takes a single argument.

Change-Id: Ie452ed866f6596bf13f137f5b832faa39f48d26e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5379
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)

3 files changed, 33 insertions, 131 deletions

diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index acd334e25d..93babd3c1f 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -133,17 +133,21 @@ ramstage-y += rmodule.c
 romstage-$(CONFIG_RELOCATABLE_RAMSTAGE) += rmodule.c
 
 RMODULE_LDSCRIPT := $(src)/lib/rmodule.ld
-RMODULE_LDFLAGS  := -nostartfiles -shared -z defs -nostdlib -Bsymbolic -T $(RMODULE_LDSCRIPT)
+RMODULE_LDFLAGS  := -nostartfiles -Wl,--emit-relocs -Wl,-z,defs -Wl,-Bsymbolic -Wl,-T,$(RMODULE_LDSCRIPT)
 
 # rmodule_link_rules is a function that should be called with:
 # (1) the object name to link
 # (2) the dependencies
 # (3) heap size of the relocatable module
-# It will create the necessary Make rules.
+# It will create the necessary Make rules to create a rmodule. The resulting
+# rmdoule is named $(1).rmod
 define rmodule_link
-$(strip $(1)): $(strip $(2)) $$(RMODULE_LDSCRIPT) $$(obj)/ldoptions
-	$$(LD) $$(RMODULE_LDFLAGS) --defsym=__heap_size=$(strip $(3)) -o $$@ $(strip $(2))
+$(strip $(1)): $(strip $(2)) $$(RMODULE_LDSCRIPT) $$(obj)/ldoptions $$(RMODTOOL)
+	$$(CC) $$(CFLAGS) $$(RMODULE_LDFLAGS) -Wl,--defsym=__heap_size=$(strip $(3)) -o $$@ -Wl,--start-group $(strip $(2)) $$(LIBGCC_FILE_NAME) -Wl,--end-group
 	$$(NM) -n $$@ > $$(basename $$@).map
+
+$(strip $(1)).rmod: $(strip $(1))
+	$$(RMODTOOL) -i $$^ -o $$@
 endef
 
 endif
diff --git a/src/lib/rmodule.c b/src/lib/rmodule.c
index 2cb70b8f33..a73e667fef 100644
--- a/src/lib/rmodule.c
+++ b/src/lib/rmodule.c
@@ -26,44 +26,6 @@
 /* Change this define to get more verbose debugging for module loading. */
 #define PK_ADJ_LEVEL BIOS_NEVER
 
-#if CONFIG_ARCH_X86
-/*
- * On X86, the only relocations currently allowed are R_386_RELATIVE which
- * have '0' for the symbol info in the relocation metadata (in r_info).
- * The reason is that the module is fully linked and just has the relocations'
- * locations.
- */
-typedef struct {
-	uint32_t r_offset;
-	uint32_t r_info;
-} Elf32_Rel;
-
-#define R_386_RELATIVE 8
-
-#define RELOCTION_ENTRY_SIZE sizeof(Elf32_Rel)
-static inline int rmodule_reloc_offset(const void *reloc)
-{
-	const Elf32_Rel *rel = reloc;
-	return rel->r_offset;
-}
-
-static inline int rmodule_reloc_valid(const void *reloc)
-{
-	const Elf32_Rel *rel = reloc;
-	return (rel->r_info == R_386_RELATIVE);
-}
-
-static inline void *remodule_next_reloc(const void *reloc)
-{
-	const Elf32_Rel *rel = reloc;
-	rel++;
-	return (void *)rel;
-}
-
-#else
-#error Arch needs to add relocation information support for RMODULE
-#endif
-
 static inline int rmodule_is_loaded(const struct rmodule *module)
 {
 	return module->location != NULL;
@@ -71,7 +33,7 @@ static inline int rmodule_is_loaded(const struct rmodule *module)
 
 /* Calculate a loaded program address based on the blob address. */
 static inline void *rmodule_load_addr(const struct rmodule *module,
-                                      uint32_t blob_addr)
+                                      uintptr_t blob_addr)
 {
 	char *loc = module->location;
 	return &loc[blob_addr - module->header->module_link_start_address];
@@ -151,13 +113,13 @@ static void rmodule_clear_bss(struct rmodule *module)
 	memset(begin, 0, size);
 }
 
-static inline int rmodule_number_relocations(const struct rmodule *module)
+static inline size_t rmodule_number_relocations(const struct rmodule *module)
 {
-	int r;
+	size_t r;
 
 	r = module->header->relocations_end_offset;
 	r -= module->header->relocations_begin_offset;
-	r /= RELOCTION_ENTRY_SIZE;
+	r /= sizeof(uintptr_t);
 	return r;
 }
 
@@ -176,51 +138,33 @@ static void rmodule_copy_payload(const struct rmodule *module)
 	memcpy(module->location, module->payload, module->payload_size);
 }
 
-static inline uint32_t *rmodule_adjustment_location(const struct rmodule *module,
-                                               const void *reloc)
-{
-	int reloc_offset;
-
-	/* Don't relocate header field entries -- only program relocations. */
-	reloc_offset = rmodule_reloc_offset(reloc);
-	if (reloc_offset < module->header->module_link_start_address)
-		return NULL;
-
-	return rmodule_load_addr(module, reloc_offset);
-}
-
 static int rmodule_relocate(const struct rmodule *module)
 {
-	int num_relocations;
-	const void *reloc;
-	uint32_t adjustment;
+	size_t num_relocations;
+	const uintptr_t *reloc;
+	uintptr_t adjustment;
 
 	/* Each relocation needs to be adjusted relative to the beginning of
 	 * the loaded program. */
-	adjustment = (uint32_t)rmodule_load_addr(module, 0);
+	adjustment = (uintptr_t)rmodule_load_addr(module, 0);
 
 	reloc = module->relocations;
 	num_relocations = rmodule_number_relocations(module);
 
-	printk(BIOS_DEBUG, "Processing %d relocs with adjust value of 0x%08x\n",
+	printk(BIOS_DEBUG, "Processing %zu relocs. Offset value of 0x%08x\n",
 	       num_relocations, adjustment);
 
 	while (num_relocations > 0) {
-		uint32_t *adjust_loc;
-
-		if (!rmodule_reloc_valid(reloc))
-			return -1;
+		uintptr_t *adjust_loc;
 
 		/* If the adjustment location is non-NULL adjust it. */
-		adjust_loc = rmodule_adjustment_location(module, reloc);
-		if (adjust_loc != NULL) {
-			printk(PK_ADJ_LEVEL, "Adjusting %p: 0x%08x -> 0x%08x\n",
+		adjust_loc = rmodule_load_addr(module, *reloc);
+		printk(PK_ADJ_LEVEL, "Adjusting %p: 0x%08x -> 0x%08x\n",
 			       adjust_loc, *adjust_loc,
 			       *adjust_loc + adjustment);
 			*adjust_loc += adjustment;
-		}
 
-		reloc = remodule_next_reloc(reloc);
+		reloc++;
 		num_relocations--;
 	}
 
@@ -232,8 +176,8 @@ int rmodule_load_alignment(const struct rmodule *module)
 	/* The load alignment is the start of the program's linked address.
 	 * The base address where the program is loaded needs to be a multiple
 	 * of the program's starting link address. That way all data alignment
-	 * in the program is preserved. */
-	return module->header->module_link_start_address;
+	 * in the program is preserved. Default to 4KiB. */
+	return 4096;
 }
 
 int rmodule_load(void *base, struct rmodule *module)
diff --git a/src/lib/rmodule.ld b/src/lib/rmodule.ld
index 0cdbb2fa25..9222f3b876 100644
--- a/src/lib/rmodule.ld
+++ b/src/lib/rmodule.ld
@@ -1,19 +1,15 @@
-OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
-OUTPUT_ARCH(i386)
-
 /*
  * This linker script is used to link rmodules (relocatable modules).  It
  * links at zero so that relocation fixups are easy when placing the binaries
  * anywhere in the address space.
  *
  * NOTE:  The program's loadable sections (text, module_params, and data) are
- * packed into the flat blob using the AT directive. The rmodule loader assumes
- * the entire program resides in one contiguous address space. Therefore,
- * alignment for a given section (if required) needs to be done at the end of
- * the preceeding section. e.g. if the data section should be aligned to an 8
- * byte address the text section should have ALIGN(8) at the end of its section.
- * Otherwise there won't be a consistent mapping between the flat blob and the
- * loaded program.
+ * packed into the flat blob. The rmodule loader assumes the entire program
+ * resides in one contiguous address space. Therefore, alignment for a given
+ * section (if required) needs to be done at the end of the preceeding section.
+ * e.g. if the data section should be aligned to an 8 byte address the text
+ * section should have ALIGN(8) at the end of its section.  Otherwise there
+ * won't be a consistent mapping between the flat blob and the loaded program.
  */
 
 BASE_ADDRESS = 0x00000;
@@ -22,21 +18,9 @@ SECTIONS
 {
 	. = BASE_ADDRESS;
 
-	.header : AT (0) {
-		*(.module_header);
-		. = ALIGN(8);
-	}
-
-	/* Align the start of the module program to a large enough alignment
-	 * so that any data in the program with an alignement property is met.
-	 * Essentially, this alignment is the maximum possible data alignment
-	 * property a program can have. */
-	. = ALIGN(4096);
-	_module_link_start_addr = .;
-	_payload_begin_offset  = LOADADDR(.header) + SIZEOF(.header);
-
-	.payload : AT (_payload_begin_offset) {
+	.payload :  {
 		/* C code of the module. */
+		_ram_seg = .;
 		*(.textfirst);
 		*(.text);
 		*(.text.*);
@@ -88,9 +72,6 @@ SECTIONS
 		. = ALIGN(8);
 	}
 
-	/* _payload_end marks the end of the module's code and data. */
-	_payload_end_offset = LOADADDR(.payload) + SIZEOF(.payload);
-
 	.bss (NOLOAD) : {
 		/* C uninitialized data of the module. */
 		_bss = .;
@@ -107,38 +88,11 @@ SECTIONS
 		_heap = .;
 		. = . + __heap_size;
 		_eheap = .;
+		_eram_seg = .;
 	}
 
-	/* _module_program_size is the total memory used by the program. */
-	_module_program_size = _eheap - _module_link_start_addr;
-
-	/* coreboot's ramstage uses the _ram_seg and _eram_seg symbols
-	 * for determining its load location. Provide those to help it out.
-	 * It's a nop for any non-ramstage rmodule. */
-	_ram_seg = _module_link_start_addr;
-	_eram_seg = _module_link_start_addr + _module_program_size;
-
-	/* The relocation information is linked on top of the BSS section
-	 * because the BSS section takes no space on disk. The relocation data
-	 * resides directly after the data section in the flat binary. */
-	.relocations ADDR(.bss) : AT (_payload_end_offset) {
-		*(.rel.*);
-	}
-	_relocations_begin_offset = LOADADDR(.relocations);
-	_relocations_end_offset  = _relocations_begin_offset +
-	                           SIZEOF(.relocations);
-
 	/DISCARD/ : {
-		/* Drop unnecessary sections. Since these modules are linked
-		 * as shared objects there are dynamic sections. These sections
-		 * aren't needed so drop them. */
-		*(.comment);
-		*(.note);
-		*(.note.*);
-		*(.dynamic);
-		*(.dynsym);
-		*(.dynstr);
-		*(.gnu.hash);
+		/* Drop unnecessary sections. */
 		*(.eh_frame);
 	}
 }