cbmem: dynamic cbmem support

This patch adds a parallel implementation of cbmem that supports
dynamic sizing. The original implementation relied on reserving
a fixed-size block of memory for adding cbmem entries. In order to
allow for more flexibility for adding cbmem allocations the dynamic
cbmem infrastructure was developed as an alternative to the fixed block
approach. Also, the amount of memory to reserve for cbmem allocations
does not need to be known prior to the first allocation.

The dynamic cbmem code implements the same API as the existing cbmem
code except for cbmem_init() and cbmem_reinit(). The add and find
routines behave the same way. The dynamic cbmem infrastructure
uses a top down allocator that starts allocating from a board/chipset
defined function cbmem_top(). A root pointer lives just below
cbmem_top(). In turn that pointer points to the root block which
contains the entries for all the large alloctations. The corresponding
block for each large allocation falls just below the previous entry.

It should be noted that this implementation rounds all allocations
up to a 4096 byte granularity. Though a packing allocator could
be written for small allocations it was deemed OK to just fragment
the memory as there shouldn't be that many small allocations. The
result is less code with a tradeoff of some wasted memory.

           +----------------------+ <- cbmem_top()
  |   +----|   root pointer       |
  |   |    +----------------------+
  |   |    |                      |--------+
  |   +--->|   root block         |-----+  |
  |        +----------------------+     |  |
  |        |                      |     |  |
  |        |                      |     |  |
  |        |   alloc N            |<----+  |
  |        +----------------------+        |
  |        |                      |        |
  |        |                      |        |
 \|/       |   alloc N + 1        |<-------+
  v        +----------------------+

In addition to preserving the previous cbmem API, the dynamic
cbmem API allows for removing blocks from cbmem. This allows for
the boot process to allocate memory that can be discarded after
it's been used for performing more complex boot tasks in romstage.

In order to plumb this support in there were some issues to work
around regarding writing of coreboot tables. There were a few
assumptions to how cbmem was layed out which dictated some ifdef
guarding and other runtime checks so as not to incorrectly
tag the e820 and coreboot memory tables.

The example shown below is using dynamic cbmem infrastructure.
The reserved memory for cbmem is less than 512KiB.

coreboot memory table:
 0. 0000000000000000-0000000000000fff: CONFIGURATION TABLES
 1. 0000000000001000-000000000002ffff: RAM
 2. 0000000000030000-000000000003ffff: RESERVED
 3. 0000000000040000-000000000009ffff: RAM
 4. 00000000000a0000-00000000000fffff: RESERVED
 5. 0000000000100000-0000000000efffff: RAM
 6. 0000000000f00000-0000000000ffffff: RESERVED
 7. 0000000001000000-000000007bf80fff: RAM
 8. 000000007bf81000-000000007bffffff: CONFIGURATION TABLES
 9. 000000007c000000-000000007e9fffff: RESERVED
10. 00000000f0000000-00000000f3ffffff: RESERVED
11. 00000000fed10000-00000000fed19fff: RESERVED
12. 00000000fed84000-00000000fed84fff: RESERVED
13. 0000000100000000-00000001005fffff: RAM
Wrote coreboot table at: 7bf81000, 0x39c bytes, checksum f5bf
coreboot table: 948 bytes.
CBMEM ROOT  0. 7bfff000 00001000
MRC DATA    1. 7bffe000 00001000
ROMSTAGE    2. 7bffd000 00001000
TIME STAMP  3. 7bffc000 00001000
ROMSTG STCK 4. 7bff7000 00005000
CONSOLE     5. 7bfe7000 00010000
VBOOT       6. 7bfe6000 00001000
RAMSTAGE    7. 7bf98000 0004e000
GDT         8. 7bf97000 00001000
ACPI        9. 7bf8b000 0000c000
ACPI GNVS  10. 7bf8a000 00001000
SMBIOS     11. 7bf89000 00001000
COREBOOT   12. 7bf81000 00008000

And the corresponding e820 entries:
BIOS-e820: [mem 0x0000000000000000-0x0000000000000fff] type 16
BIOS-e820: [mem 0x0000000000001000-0x000000000002ffff] usable
BIOS-e820: [mem 0x0000000000030000-0x000000000003ffff] reserved
BIOS-e820: [mem 0x0000000000040000-0x000000000009ffff] usable
BIOS-e820: [mem 0x00000000000a0000-0x00000000000fffff] reserved
BIOS-e820: [mem 0x0000000000100000-0x0000000000efffff] usable
BIOS-e820: [mem 0x0000000000f00000-0x0000000000ffffff] reserved
BIOS-e820: [mem 0x0000000001000000-0x000000007bf80fff] usable
BIOS-e820: [mem 0x000000007bf81000-0x000000007bffffff] type 16
BIOS-e820: [mem 0x000000007c000000-0x000000007e9fffff] reserved
BIOS-e820: [mem 0x00000000f0000000-0x00000000f3ffffff] reserved
BIOS-e820: [mem 0x00000000fed10000-0x00000000fed19fff] reserved
BIOS-e820: [mem 0x00000000fed84000-0x00000000fed84fff] reserved
BIOS-e820: [mem 0x0000000100000000-0x00000001005fffff] usable

Change-Id: Ie3bca52211800a8652a77ca684140cfc9b3b9a6b
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2848
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

2 files changed, 19 insertions, 7 deletions

diff --git a/src/arch/x86/boot/coreboot_table.c b/src/arch/x86/boot/coreboot_table.c
index 463f723097..617fab29cc 100644
--- a/src/arch/x86/boot/coreboot_table.c
+++ b/src/arch/x86/boot/coreboot_table.c
@@ -355,6 +355,9 @@ static void lb_memory_range(struct lb_memory *mem,
 
 static void lb_reserve_table_memory(struct lb_header *head)
 {
+/* Dynamic cbmem has already reserved the memory where the coreboot tables
+ * reside. Therefore, there is nothing to fix up. */
+#if !CONFIG_DYNAMIC_CBMEM
 	struct lb_record *last_rec;
 	struct lb_memory *mem;
 	uint64_t start;
@@ -383,6 +386,7 @@ static void lb_reserve_table_memory(struct lb_header *head)
 			mem->map[i].size = pack_lb64(map_end - end);
 		}
 	}
+#endif
 }
 
 static unsigned long lb_table_fini(struct lb_header *head, int fixup)
@@ -507,7 +511,7 @@ static void lb_remove_memory_range(struct lb_memory *mem,
 	}
 }
 
-static void lb_add_memory_range(struct lb_memory *mem,
+void lb_add_memory_range(struct lb_memory *mem,
 	uint32_t type, uint64_t start, uint64_t size)
 {
 	lb_remove_memory_range(mem, start, size);
@@ -664,14 +668,20 @@ unsigned long write_coreboot_table(
 	lb_add_memory_range(mem, LB_MEM_TABLE,
 		low_table_start, low_table_end - low_table_start);
 
-	/* Record the pirq table, acpi tables, and maybe the mptable */
-	lb_add_memory_range(mem, LB_MEM_TABLE,
-		rom_table_start, rom_table_end-rom_table_start);
-
-	printk(BIOS_DEBUG, "Adding high table area\n");
-	// should this be LB_MEM_ACPI?
+	/* Record the pirq table, acpi tables, and maybe the mptable. However,
+	 * these only need to be added when the rom_table is sitting below
+	 * 1MiB. If it isn't that means high tables are being written.
+	 * The code below handles high tables correctly. */
+	if (rom_table_end <= (1 << 20))
+		lb_add_memory_range(mem, LB_MEM_TABLE,
+			rom_table_start, rom_table_end-rom_table_start);
+
+#if CONFIG_DYNAMIC_CBMEM
+	cbmem_add_lb_mem(mem);
+#else /* CONFIG_DYNAMIC_CBMEM */
 	lb_add_memory_range(mem, LB_MEM_TABLE,
 		high_tables_base, high_tables_size);
+#endif /* CONFIG_DYNAMIC_CBMEM */
 
 	/* Add reserved regions */
 	add_lb_reserved(mem);
diff --git a/src/arch/x86/boot/tables.c b/src/arch/x86/boot/tables.c
index 294a10c46c..d842e73f6e 100644
--- a/src/arch/x86/boot/tables.c
+++ b/src/arch/x86/boot/tables.c
@@ -53,6 +53,7 @@ struct lb_memory *write_tables(void)
 	 */
 	unsigned long high_table_pointer;
 
+#if !CONFIG_DYNAMIC_CBMEM
 	if (!high_tables_base) {
 		printk(BIOS_ERR, "ERROR: High Tables Base is not set.\n");
 		// Are there any boards without?
@@ -60,6 +61,7 @@ struct lb_memory *write_tables(void)
 	}
 
 	printk(BIOS_DEBUG, "High Tables Base is %llx.\n", high_tables_base);
+#endif
 
 	rom_table_start = 0xf0000;
 	rom_table_end =   0xf0000;