drivers/intel/fsp2_0: use FSP to allocate APEI BERT memory region

APEI (ACPI Platform Error Interface) defines BERT (Boot Error Record
Table) memory region:
* Bootloader (firmware) generates UEFI CPER (Common Platform Error
Record) records, and populates BERT region.
* OS parses ACPI BERT table, finds the BERT region address, inteprets
the data and processes it accordingly.

When CONFIG_ACPI_BERT is defined, update FSP UPD BootLoaderTolumSize,
so FSP allocates memory region for it. The APEI BERT region is placed
on top of CBMEM, for the size of CONFIG_ACPI_BERT_SIZE.

Apart from APEI BERT region, we also have plan to add APEI HEST region
which holds OS runtime hardware error record, based on firmware
first hardware error handling model. HEST region will be reserved
same way as BERT region.

Note that CBMEM region can not be used for such purpose, the OS
(bert/hest) drivers are not able to access data held in CBMEM region,
as CBMEM is set as type 16 (configuration table).

An option considered was to reserve the BERT region under CBMEM.
However, we do not know the size of CBMEM till acpi tables are set up.
On the other hand, BERT region needs to be filled up before ACPI BERT
table is finalized.

Change-Id: Ie72240e4c5fa01fcf937d33678c40f9ca826487a
Signed-off-by: Jonathan Zhang <jonzhang@fb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45391
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/drivers/intel/fsp2_0/cbmem.c

@@ -6,7 +6,14 @@
 void *cbmem_top_chipset(void)
 {
 	struct range_entry tolum;
+	uint8_t *tolum_base;
 
 	fsp_find_bootloader_tolum(&tolum);
-	return (void *)(uintptr_t)range_entry_end(&tolum);
+	tolum_base = (uint8_t *)(uintptr_t)range_entry_base(&tolum);
+
+	/*
+	 * The TOLUM range may have other memory regions (such as APEI
+	 * BERT region on top of CBMEM (IMD root and IMD small) region.
+	 */
+	return tolum_base + cbmem_overhead_size();
 }

src/drivers/intel/fsp2_0/hob_verify.c

@@ -43,9 +43,16 @@ void fsp_verify_memory_init_hobs(void)
 		die("Space between FSP reserved region and BIOS TOLUM!\n");
 	}
 
-	if (range_entry_end(&tolum) != (uintptr_t)cbmem_top()) {
+	if (!CONFIG(ACPI_BERT) && range_entry_end(&tolum) != (uintptr_t)cbmem_top()) {
 		printk(BIOS_CRIT, "TOLUM end: 0x%08llx != %p: cbmem_top\n",
 			range_entry_end(&tolum), cbmem_top());
 		die("Space between cbmem_top and BIOS TOLUM!\n");
 	}
+
+	if (CONFIG(ACPI_BERT) &&
+		range_entry_end(&tolum) != (uintptr_t)cbmem_top() + CONFIG_ACPI_BERT_SIZE) {
+		printk(BIOS_CRIT, "TOLUM end: 0x%08llx != %p: cbmem_top + 0x%x: BERT\n",
+			range_entry_end(&tolum), cbmem_top(), CONFIG_ACPI_BERT_SIZE);
+		die("Space between cbmem_top and APEI BERT!\n");
+	}
 }

src/drivers/intel/fsp2_0/memory_init.c

@@ -276,6 +276,21 @@ static void do_fsp_memory_init(const struct fspm_context *context, bool s3wake)
 	/* Reserve enough memory under TOLUD to save CBMEM header */
 	arch_upd->BootLoaderTolumSize = cbmem_overhead_size();
 
+	/*
+	 * If ACPI APEI BERT region size is defined, reserve memory for it.
+	 * +------------------------+ range_entry_top(tolum)
+	 * | Other reserved regions |
+	 * | APEI BERT region       |
+	 * +------------------------+ cbmem_top()
+	 * | CBMEM IMD ROOT         |
+	 * | CBMEM IMD SMALL        |
+	 * +------------------------+ range_entry_base(tolum), TOLUM
+	 * | CBMEM FSP MEMORY       |
+	 * | Other CBMEM regions... |
+	 */
+	if (CONFIG(ACPI_BERT))
+		arch_upd->BootLoaderTolumSize += CONFIG_ACPI_BERT_SIZE;
+
 	/* Fill common settings on behalf of chipset. */
 	if (fsp_fill_common_arch_params(arch_upd, s3wake, fsp_version,
 					memmap) != CB_SUCCESS)