drivers/intel/fsp: Work around multi-socket Xeon-SP pipe init bug

Starting with Intel CPX there is a bug in the reference code during
the Pipe init. This code synchronises the CAR between sockets in FSP-M.
This code implicitly assumes that the FSP heap is right above the
RC heap, where both of them are located at the bottom part of CAR.

Work around this issue by making that implicit assumption done in FSP
explicit in the coreboot linker script and allocation.

TEST=intel/archercity CRB

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Signed-off-by: Shuo Liu <shuo.liu@intel.com>

Change-Id: I38a4f4b7470556e528a1672044c31f8bd92887d4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80579
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Shuo Liu <shuo.liu@intel.com>

src/arch/x86/car.ld

@@ -9,6 +9,10 @@
 .car.data . (NOLOAD) : {
 	_car_region_start = . ;
 	. += CONFIG_FSP_M_RC_HEAP_SIZE;
+#if CONFIG(FSP_SPEC_VIOLATION_XEON_SP_HEAP_WORKAROUND)
+	REGION(fspm_heap, ., CONFIG_FSP_TEMP_RAM_SIZE, 16)
+#endif
+
 #if CONFIG(PAGING_IN_CACHE_AS_RAM)
 	/* Page table pre-allocation. CONFIG_DCACHE_RAM_BASE should be 4KiB
 	 * aligned when using this option. */
@@ -107,7 +111,7 @@ _car_region_end = . + CONFIG_DCACHE_RAM_SIZE - (. - _car_region_start)
 
 . = _car_region_start;
 .car.fspm_rc_heap . (NOLOAD) : {
-. += CONFIG_FSP_M_RC_HEAP_SIZE;
+	. += CONFIG_FSP_M_RC_HEAP_SIZE;
 }
 
 . = _car_region_end;

src/drivers/intel/fsp2_0/Kconfig

@@ -221,6 +221,17 @@ config FSP_USES_CB_STACK
 	  without reinitializing stack pointer. This feature is
 	  supported Icelake onwards.
 
+config FSP_SPEC_VIOLATION_XEON_SP_HEAP_WORKAROUND
+	bool
+	help
+	 Starting with Intel CPX there is a bug in there reference code during
+	 the pipe init. This code synchronises the CAR between sockets in FSP-M.
+	 This code implicitly assumes that the FSP heap is right above the
+	 RC heap, where both of them are located at the bottom part of CAR.
+	 Select this to have an explicit handling of the FSP StackBase to work
+	 around this issue. This is needed on multi-socket Xeon-SP systems.
+	 This will place the FSP heap right above the FSP-M RC heap.
+
 config FSP_TEMP_RAM_SIZE
 	hex
 	help

src/drivers/intel/fsp2_0/memory_init.c

@@ -170,7 +170,13 @@ static enum cb_err fsp_fill_common_arch_params(FSPM_ARCH_UPD *arch_upd,
 		[FSP_BOOT_IN_RECOVERY_MODE] = "boot in recovery mode",
 	};
 
-	if (CONFIG(FSP_USES_CB_STACK) || !ENV_CACHE_AS_RAM) {
+	if (CONFIG(FSP_USES_CB_STACK) && ENV_RAMINIT
+	    && CONFIG(FSP_SPEC_VIOLATION_XEON_SP_HEAP_WORKAROUND)) {
+		extern char _fspm_heap[];
+		extern char _efspm_heap[];
+		arch_upd->StackBase = (uintptr_t)_fspm_heap;
+		arch_upd->StackSize = (size_t)(_efspm_heap - _fspm_heap);
+	} else if (CONFIG(FSP_USES_CB_STACK) || !ENV_CACHE_AS_RAM) {
 		arch_upd->StackBase = (uintptr_t)temp_ram;
 		arch_upd->StackSize = sizeof(temp_ram);
 	} else if (setup_fsp_stack_frame(arch_upd, memmap)) {

src/soc/intel/xeon_sp/cpx/Kconfig

@@ -7,6 +7,7 @@ config SOC_INTEL_COOPERLAKE_SP
 	select CACHE_MRC_SETTINGS
 	select NO_FSP_TEMP_RAM_EXIT
 	select HAVE_INTEL_FSP_REPO
+	select FSP_SPEC_VIOLATION_XEON_SP_HEAP_WORKAROUND
 	help
 	  Intel Cooper Lake-SP support
 

src/soc/intel/xeon_sp/spr/Kconfig

@@ -13,6 +13,7 @@ config SOC_INTEL_SAPPHIRERAPIDS_SP
 	select SOC_INTEL_CSE_SERVER_SKU
 	select XEON_SP_COMMON_BASE
 	select HAVE_IOAT_DOMAINS
+	select FSP_SPEC_VIOLATION_XEON_SP_HEAP_WORKAROUND
 	help
 	  Intel Sapphire Rapids-SP support