New mechanism to define SRAM/memory map with automatic bounds checking

This patch creates a new mechanism to define the static memory layout
(primarily in SRAM) for a given board, superseding the brittle mass of
Kconfigs that we were using before. The core part is a memlayout.ld file
in the mainboard directory (although boards are expected to just include
the SoC default in most cases), which is the primary linker script for
all stages (though not rmodules for now). It uses preprocessor macros
from <memlayout.h> to form a different valid linker script for all
stages while looking like a declarative, boilerplate-free map of memory
addresses to the programmer. Linker asserts will automatically guarantee
that the defined regions cannot overlap. Stages are defined with a
maximum size that will be enforced by the linker. The file serves to
both define and document the memory layout, so that the documentation
cannot go missing or out of date.

The mechanism is implemented for all boards in the ARM, ARM64 and MIPS
architectures, and should be extended onto all systems using SRAM in the
future. The CAR/XIP environment on x86 has very different requirements
and the layout is generally not as static, so it will stay like it is
and be unaffected by this patch (save for aligning some symbol names for
consistency and sharing the new common ramstage linker script include).

BUG=None
TEST=Booted normally and in recovery mode, checked suspend/resume and
the CBMEM console on Falco, Blaze (both normal and vboot2), Pinky and
Pit. Compiled Ryu, Storm and Urara, manually compared the disassemblies
with ToT and looked for red flags.

Change-Id: Ifd2276417f2036cbe9c056f17e42f051bcd20e81
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: f1e2028e7ebceeb2d71ff366150a37564595e614
Original-Change-Id: I005506add4e8fcdb74db6d5e6cb2d4cb1bd3cda5
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/213370
Reviewed-on: http://review.coreboot.org/9283
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Tauner <stefan.tauner@gmx.at>
Reviewed-by: Aaron Durbin <adurbin@google.com>

7 files changed, 44 insertions, 259 deletions

diff --git a/src/arch/riscv/Makefile.inc b/src/arch/riscv/Makefile.inc
index 643facff8e..7f55e1fa3e 100644
--- a/src/arch/riscv/Makefile.inc
+++ b/src/arch/riscv/Makefile.inc
@@ -38,12 +38,10 @@ bootblock-y += \
 	$(top)/src/lib/memmove.c \
 	$(top)/src/lib/memset.c
 
-bootblock-y += bootblock.ld
-
-$(objcbfs)/bootblock.debug: $(obj)/arch/riscv/bootblock.bootblock.ld $$(bootblock-objs)
+$(objcbfs)/bootblock.debug: $$(bootblock-objs)
 	@printf "    LINK       $(subst $(obj)/,,$(@))\n"
 	$(LD_bootblock) --gc-sections -static -o $@ -L$(obj) \
-		-T $(obj)/arch/riscv/bootblock.bootblock.ld --start-group $(bootblock-objs) \
+		-T $(obj)/mainboard/$(MAINBOARDDIR)/memlayout.bootblock.ld --start-group $(filter-out %.ld,$(bootblock-objs)) \
 		$(LIBGCC_FILE_NAME_bootblock) --end-group
 
 endif
@@ -65,13 +63,11 @@ romstage-y += \
 
 romstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
 
-romstage-y += romstage.ld
-
 # Build the romstage
 
-$(objcbfs)/romstage.debug: $$(romstage-objs) $(obj)/arch/riscv/romstage.romstage.ld
+$(objcbfs)/romstage.debug: $$(romstage-objs)
 	@printf "    LINK       $(subst $(obj)/,,$(@))\n"
-	$(LD_romstage) --gc-sections -static -o $@ -L$(obj) -T $(obj)/arch/riscv/romstage.romstage.ld --start-group $(romstage-objs) --end-group
+	$(LD_romstage) --gc-sections -static -o $@ -L$(obj) -T $(obj)/mainboard/$(MAINBOARDDIR)/memlayout.romstage.ld --start-group $(filter-out %.ld,$(romstage-objs)) --end-group
 
 romstage-c-ccopts += $(riscv_flags)
 romstage-S-ccopts += $(riscv_asm_flags)
@@ -103,15 +99,13 @@ $(eval $(call create_class_compiler,rmodules,riscv))
 
 ramstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
 
-ramstage-y += ramstage.ld
-
 ramstage-srcs += src/mainboard/$(MAINBOARDDIR)/mainboard.c
 
 # Build the ramstage
 
-$(objcbfs)/ramstage.debug: $$(ramstage-objs) $(obj)/arch/riscv/ramstage.ramstage.ld
+$(objcbfs)/ramstage.debug: $$(ramstage-objs)
 	@printf "    CC         $(subst $(obj)/,,$(@))\n"
-	$(LD_ramstage) --gc-sections -static -o $@ -L$(obj) -T $(obj)/arch/riscv/ramstage.ramstage.ld --start-group $(ramstage-objs) --end-group
+	$(LD_ramstage) --gc-sections -static -o $@ -L$(obj) -T $(obj)/mainboard/$(MAINBOARDDIR)/memlayout.ramstage.ld --start-group $(filter-out %.ld,$(ramstage-objs)) --end-group
 
 ramstage-c-ccopts += $(riscv_flags)
 ramstage-S-ccopts += $(riscv_asm_flags)
diff --git a/src/arch/riscv/bootblock.S b/src/arch/riscv/bootblock.S
index 00962c4c19..1461a9cbc5 100644
--- a/src/arch/riscv/bootblock.S
+++ b/src/arch/riscv/bootblock.S
@@ -21,7 +21,7 @@
 // See LICENSE for license details. relating to the _start code in this file.
 #include <arch/encoding.h>
 
-.section ".start", "ax", %progbits
+.section ".text._start", "ax", %progbits
 // Maybe there's a better way.
 .space 0x2000
 .globl _start
diff --git a/src/arch/riscv/bootblock.ld b/src/arch/riscv/include/arch/header.ld
index e5cb851b39..3c42099905 100644
--- a/src/arch/riscv/bootblock.ld
+++ b/src/arch/riscv/include/arch/header.ld
@@ -1,8 +1,7 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright (C) 2006 Advanced Micro Devices, Inc.
- * Copyright (C) 2008-2010 coresystems GmbH
+ * Copyright 2014 Google Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -19,7 +18,6 @@
  */
 
 /* We use ELF as output format. So that we can debug the code in some form. */
-OUTPUT_FORMAT("elf64-littleriscv", "elf64-littleriscv", "elf64-littleriscv")
 OUTPUT_ARCH(riscv)
 
 PHDRS
@@ -27,30 +25,9 @@ PHDRS
 	to_load PT_LOAD;
 }
 
+#ifdef __BOOTBLOCK__
 ENTRY(_start)
-SECTIONS
-{
-	. = CONFIG_BOOTBLOCK_BASE;
-
-	.bootblock . : {
-		*(.start);
-		KEEP(*(.id));
-		*(.text);
-		*(.text.*);
-		*(.rodata);
-		*(.rodata.*);
-		*(.data);
-		*(.data.*);
-		*(.bss);
-		*(.bss.*);
-		*(.sbss);
-		*(.sbss.*);
-	} : to_load = 0xff
+#else
+ENTRY(stage_entry)
+#endif
 
-	/DISCARD/ : {
-		*(.comment)
-		*(.note)
-		*(.comment.*)
-		*(.note.*)
-	}
-}
diff --git a/src/arch/riscv/include/arch/memlayout.h b/src/arch/riscv/include/arch/memlayout.h
new file mode 100644
index 0000000000..b6f4cba214
--- /dev/null
+++ b/src/arch/riscv/include/arch/memlayout.h
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/* This file contains macro definitions for memlayout.ld linker scripts. */
+
+#ifndef __ARCH_MEMLAYOUT_H
+#define __ARCH_MEMLAYOUT_H
+
+/* TODO: Double-check that that's the correct alignment for our ABI. */
+#define STACK(addr, size) REGION(stack, addr, size, 8)
+
+/* TODO: Need to add DMA_COHERENT region like on ARM? */
+
+#endif /* __ARCH_MEMLAYOUT_H */
+
diff --git a/src/arch/riscv/include/arch/stages.h b/src/arch/riscv/include/arch/stages.h
index 2d1192ae35..3b8543da7f 100644
--- a/src/arch/riscv/include/arch/stages.h
+++ b/src/arch/riscv/include/arch/stages.h
@@ -22,7 +22,7 @@
 
 extern void main(void);
 
-void stage_entry(void) __attribute__((section(".text.stage_entry.riscv")));
+void stage_entry(void) __attribute__((section(".text.stage_entry")));
 void stage_exit(void *);
 void jmp_to_elf_entry(void *entry, unsigned long buffer, unsigned long size);
 
diff --git a/src/arch/riscv/ramstage.ld b/src/arch/riscv/ramstage.ld
deleted file mode 100644
index 21c9638792..0000000000
--- a/src/arch/riscv/ramstage.ld
+++ /dev/null
@@ -1,134 +0,0 @@
-/*
- *	Memory map:
- *
- *	CONFIG_RAMBASE		: text segment
- *				: rodata segment
- *				: data segment
- *				: bss segment
- *				: stack
- *				: heap
- */
-/*
- * Copyright 2013 Google Inc.
- * Bootstrap code for the STPC Consumer
- * Copyright (c) 1999 by Net Insight AB. All Rights Reserved.
- */
-
-/*
- *	Written by Johan Rydberg, based on work by Daniel Kahlin.
- *      Rewritten by Eric Biederman
- *  2005.12 yhlu add ramstage cross the vga font buffer handling
- */
-
-ENTRY(stage_entry)
-
-PHDRS
-{
-	to_load PT_LOAD;
-}
-
-SECTIONS
-{
-	. = 0x100000; /*CONFIG_SYS_SDRAM_BASE;*/
-	/* First we place the code and read only data (typically const declared).
-	 * This could theoretically be placed in rom.
-	 */
-	.text : {
-		_text = .;
-		_start = .;
-		*(.text.stage_entry.riscv);
-		*(.text);
-		*(.text.*);
-		. = ALIGN(16);
-		_etext = .;
-	} : to_load
-
-	.ctors : {
-		. = ALIGN(0x100);
-		__CTOR_LIST__ = .;
-		*(.ctors);
-		LONG(0);
-		__CTOR_END__ = .;
-	}
-
-	.rodata : {
-		_rodata = .;
-		. = ALIGN(4);
-		console_drivers = .;
-		*(.rodata.console_drivers)
-		econsole_drivers = . ;
-		. = ALIGN(4);
-		pci_drivers = . ;
-		*(.rodata.pci_driver)
-		epci_drivers = . ;
-		cpu_drivers = . ;
-		*(.rodata.cpu_driver)
-		ecpu_drivers = . ;
-		_bs_init_begin = .;
-		*(.bs_init)
-		LONG(0);
-		_bs_init_end = .;
-		*(.rodata)
-		*(.rodata.*)
-		/* kevinh/Ispiri - Added an align, because the objcopy tool
-		 * incorrectly converts sections that are not long word aligned.
-		 */
-		 . = ALIGN(4);
-
-		_erodata = .;
-	}
-	/* After the code we place initialized data (typically initialized
-	 * global variables). This gets copied into ram by startup code.
-	 * __data_start and __data_end shows where in ram this should be placed,
-	 * whereas __data_loadstart and __data_loadend shows where in rom to
-	 * copy from.
-	 */
-	.data : {
-		_data = .;
-		*(.data)
-		_edata = .;
-	}
-
-	/* bss does not contain data, it is just a space that should be zero
-	 * initialized on startup. (typically uninitialized global variables)
-	 * crt0.S fills between _bss and _ebss with zeroes.
-	 */
-	_bss = .;
-	.bss . : {
-		*(.bss)
-		*(.sbss)
-		*(COMMON)
-	}
-	_ebss = .;
-	_end = .;
-
-	/* coreboot really "ends" here. Only heap and stack are placed after
-	 * this line.
-	 */
-
-        _heap = .;
-        .heap . : {
-                /* Reserve CONFIG_HEAP_SIZE bytes for the heap */
-                . = CONFIG_HEAP_SIZE ;
-                . = ALIGN(4);
-        }
-        _eheap = .;
-
-	_stack = CONFIG_STACK_BOTTOM;
-	_estack = CONFIG_STACK_TOP;
-
-	/* The ram segment. This includes all memory used by the memory
-	 * resident copy of coreboot, except the tables that are produced on
-	 * the fly, but including stack and heap.
-	 */
-	_ram_seg = _text;
-	_eram_seg = _eheap;
-
-	/* Discard the sections we don't need/want */
-
-	/DISCARD/ : {
-		*(.comment)
-		*(.note)
-		*(.note.*)
-	}
-}
diff --git a/src/arch/riscv/romstage.ld b/src/arch/riscv/romstage.ld
deleted file mode 100644
index e49d1c10aa..0000000000
--- a/src/arch/riscv/romstage.ld
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- *	Memory map:
- *
- *	CONFIG_ROMSTAGE_BASE	: text segment
- *				: rodata segment
- *				: data segment
- *				: bss segment
- *				: stack
- *				: heap
- */
-/*
- * Bootstrap code for the STPC Consumer
- * Copyright (c) 1999 by Net Insight AB. All Rights Reserved.
- */
-
-/*
- *	Written by Johan Rydberg, based on work by Daniel Kahlin.
- *      Rewritten by Eric Biederman
- *  2005.12 yhlu add ramstage cross the vga font buffer handling
- */
-
-/* We use ELF as output format. So that we can debug the code in some form. */
-OUTPUT_FORMAT("elf64-littleriscv", "elf64-littleriscv", "elf64-littleriscv")
-OUTPUT_ARCH(riscv)
-
-PHDRS
-{
-	to_load PT_LOAD;
-}
-
-ENTRY(stage_entry)
-
-SECTIONS
-{
-	. = CONFIG_ROMSTAGE_BASE;
-
-	.romtext . : {
-		_start = .;
-		*(.text.stage_entry.riscv);
-		*(.text.startup);
-		*(.text);
-		*(.text.*);
-	} : to_load
-
-	.romdata . : {
-		*(.rodata);
-		*(.rodata.*);
-		*(.machine_param);
-		*(.data);
-		*(.data.*);
-		. = ALIGN(8);
-		_erom = .;
-	}
-
-	__image_copy_end = .;
-
-	/* bss does not contain data, it is just a space that should be zero
-	 * initialized on startup. (typically uninitialized global variables)
-	 * crt0.S fills between _bss and _ebss with zeroes.
-	 */
-	.bss . : {
-		. = ALIGN(8);
-		_bss = .;
-		*(.bss)
-		*(.bss.*)
-		*(.sbss)
-		*(.sbss.*)
-		_ebss = .;
-	}
-
-	_end = .;
-
-	preram_cbmem_console = CONFIG_CONSOLE_PRERAM_BUFFER_BASE;
-
-	/* Discard the sections we don't need/want */
-	/DISCARD/ : {
-		*(.comment)
-		*(.note)
-		*(.comment.*)
-		*(.note.*)
-		*(.eh_frame);
-	}
-}