lib/stage_cache: Refactor Kconfig options

Add explicit CBMEM_STAGE_CACHE option. Rename
CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM to TSEG_STAGE_CACHE.

Platforms with SMM_TSEG=y always need to implement
stage_cache_external_region(). It is allowed to return with a
region of size 0 to effectively disable the cache.

There are no provisions in Kconfig to degrade from
TSEG_STAGE_CACHE to CBMEM_STAGE_CACHE.

As a security measure CBMEM_STAGE_CACHE default is changed to
disabled. AGESA platforms without TSEG will experience slower
S3 resume speed unless they explicitly select the option.

Change-Id: Ibbdc701ea85b5a3208ca4e98c428b05b6d4e5340
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34664
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/Kconfig

@@ -250,12 +250,28 @@ config RELOCATABLE_RAMSTAGE
 	 wake. When selecting this option the romstage is responsible for
 	 determing a stack location to use for loading the ramstage.
 
-config CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
-	depends on RELOCATABLE_RAMSTAGE
+config TSEG_STAGE_CACHE
 	bool
+	default y
+	depends on !NO_STAGE_CACHE && SMM_TSEG
 	help
-	 The relocated ramstage is saved in an area specified by the
-	 by the board and/or chipset.
+	  The option enables stage cache support for platform. Platform
+	  can stash copies of postcar, ramstage and raw runtime data
+	  inside SMM TSEG, to be restored on S3 resume path.
+
+config CBMEM_STAGE_CACHE
+	bool "Cache stages in CBMEM"
+	depends on !NO_STAGE_CACHE && !TSEG_STAGE_CACHE
+	help
+	  The option enables stage cache support for platform. Platform
+	  can stash copies of postcar, ramstage and raw runtime data
+	  inside CBMEM.
+
+	  While the approach is faster than reloading stages from boot media
+	  it is also a possible attack scenario via which OS can possibly
+	  circumvent SMM locks and SPI write protections.
+
+	  If unsure, select 'N'
 
 config UPDATE_IMAGE
 	bool "Update existing coreboot.rom image"
@@ -1143,7 +1159,7 @@ config RELOCATABLE_MODULES
 
 config NO_STAGE_CACHE
 	bool
-	default y if !HAVE_ACPI_RESUME
+	default y if !HAVE_ACPI_RESUME || !RELOCATABLE_RAMSTAGE
 	help
 	  Do not save any component in stage cache for resume path. On resume,
 	  all components would be read back from CBFS again.

src/cpu/intel/model_2065x/Kconfig

@@ -21,7 +21,6 @@ config CPU_SPECIFIC_OPTIONS
 	select CPU_INTEL_COMMON
 	select NO_FIXED_XIP_ROM_SIZE
 	select PARALLEL_MP
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 
 config BOOTBLOCK_CPU_INIT
 	string

src/cpu/intel/model_206ax/Kconfig

@@ -19,7 +19,6 @@ config CPU_SPECIFIC_OPTIONS
 	#select AP_IN_SIPI_WAIT
 	select TSC_SYNC_MFENCE
 	select CPU_INTEL_COMMON
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select PARALLEL_MP
 	select NO_FIXED_XIP_ROM_SIZE
 

src/cpu/intel/smm/gen1/smmrelocate.c

@@ -121,7 +121,7 @@ static void fill_in_relocation_params(struct smm_relocation_params *params)
 	}
 
 	/* Adjust available SMM handler memory size. */
-	if (CONFIG(CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM)) {
+	if (CONFIG(TSEG_STAGE_CACHE)) {
 		ASSERT(params->smram_size > CONFIG_SMM_RESERVED_SIZE);
 		params->smram_size -= CONFIG_SMM_RESERVED_SIZE;
 	}

src/include/stage_cache.h

@@ -32,8 +32,7 @@ enum {
 	STAGE_S3_DATA,
 };
 
-#if CONFIG(CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM) \
-		|| CONFIG(RELOCATABLE_RAMSTAGE)
+#if CONFIG(TSEG_STAGE_CACHE) || CONFIG(CBMEM_STAGE_CACHE)
 /* Cache the loaded stage provided according to the parameters. */
 void stage_cache_add(int stage_id, const struct prog *stage);
 /* Load the cached stage at given location returning the stage entry point. */

src/lib/Makefile.inc

@@ -176,16 +176,13 @@ verstage-$(CONFIG_REG_SCRIPT) += reg_script.c
 romstage-$(CONFIG_REG_SCRIPT) += reg_script.c
 ramstage-$(CONFIG_REG_SCRIPT) += reg_script.c
 
-ifeq ($(CONFIG_CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM),y)
-ramstage-y += ext_stage_cache.c
-romstage-y += ext_stage_cache.c
-postcar-y += ext_stage_cache.c
-else
-ramstage-$(CONFIG_RELOCATABLE_RAMSTAGE) += cbmem_stage_cache.c
-romstage-$(CONFIG_RELOCATABLE_RAMSTAGE) += cbmem_stage_cache.c
-postcar-$(CONFIG_RELOCATABLE_RAMSTAGE) += cbmem_stage_cache.c
-endif
+ramstage-$(CONFIG_TSEG_STAGE_CACHE) += ext_stage_cache.c
+romstage-$(CONFIG_TSEG_STAGE_CACHE) += ext_stage_cache.c
+postcar-$(CONFIG_TSEG_STAGE_CACHE) += ext_stage_cache.c
 
+ramstage-$(CONFIG_CBMEM_STAGE_CACHE) += cbmem_stage_cache.c
+romstage-$(CONFIG_CBMEM_STAGE_CACHE) += cbmem_stage_cache.c
+postcar-$(CONFIG_CBMEM_STAGE_CACHE) += cbmem_stage_cache.c
 
 romstage-y += boot_device.c
 ramstage-y += boot_device.c

src/northbridge/intel/gm45/Kconfig

@@ -29,7 +29,6 @@ config NORTHBRIDGE_SPECIFIC_OPTIONS # dummy
 	select POSTCAR_STAGE
 	select POSTCAR_CONSOLE
 	select PARALLEL_MP
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 
 config CBFS_SIZE
 	hex

src/northbridge/intel/haswell/Kconfig

@@ -19,7 +19,6 @@ config NORTHBRIDGE_INTEL_HASWELL
 	select CACHE_MRC_SETTINGS
 	select INTEL_DDI
 	select INTEL_GMA_ACPI
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select POSTCAR_STAGE
 	select POSTCAR_CONSOLE
 	select C_ENVIRONMENT_BOOTBLOCK

src/northbridge/intel/i945/Kconfig

@@ -30,7 +30,6 @@ config NORTHBRIDGE_SPECIFIC_OPTIONS # dummy
 	select POSTCAR_STAGE
 	select POSTCAR_CONSOLE
 	select PARALLEL_MP
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 
 config NORTHBRIDGE_INTEL_SUBTYPE_I945GC
 	def_bool n

src/northbridge/intel/pineview/Kconfig

@@ -31,7 +31,6 @@ config NORTHBRIDGE_SPECIFIC_OPTIONS # dummy
 	select POSTCAR_STAGE
 	select POSTCAR_CONSOLE
 	select PARALLEL_MP
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select C_ENVIRONMENT_BOOTBLOCK
 
 config BOOTBLOCK_NORTHBRIDGE_INIT

src/northbridge/intel/x4x/Kconfig

@@ -29,7 +29,6 @@ config NORTHBRIDGE_SPECIFIC_OPTIONS # dummy
 	select POSTCAR_STAGE
 	select POSTCAR_CONSOLE
 	select PARALLEL_MP
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 
 config CBFS_SIZE
 	hex

src/soc/amd/picasso/Kconfig

@@ -52,7 +52,6 @@ config CPU_SPECIFIC_OPTIONS
 	select C_ENVIRONMENT_BOOTBLOCK
 	select BOOT_DEVICE_SUPPORTS_WRITES if BOOT_DEVICE_SPI_FLASH
 	select BOOT_DEVICE_SPI_FLASH_RW_NOMMAP_EARLY if BOOT_DEVICE_SPI_FLASH
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM if HAVE_ACPI_RESUME
 	select PARALLEL_MP
 	select PARALLEL_MP_AP_WORK
 	select HAVE_SMI_HANDLER

src/soc/amd/stoneyridge/Kconfig

@@ -73,7 +73,6 @@ config CPU_SPECIFIC_OPTIONS
 	select C_ENVIRONMENT_BOOTBLOCK
 	select BOOT_DEVICE_SUPPORTS_WRITES if BOOT_DEVICE_SPI_FLASH
 	select BOOT_DEVICE_SPI_FLASH_RW_NOMMAP_EARLY if BOOT_DEVICE_SPI_FLASH
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM if HAVE_ACPI_RESUME
 	select PARALLEL_MP
 	select PARALLEL_MP_AP_WORK
 	select HAVE_SMI_HANDLER

src/soc/intel/apollolake/Kconfig

@@ -40,7 +40,6 @@ config CPU_SPECIFIC_OPTIONS
 	# Misc options
 	select C_ENVIRONMENT_BOOTBLOCK
 	select CACHE_MRC_SETTINGS
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select COLLECT_TIMESTAMPS
 	select COMMON_FADT
 	select FSP_PLATFORM_MEMORY_SETTINGS_VERSIONS

src/soc/intel/braswell/Kconfig

@@ -14,7 +14,6 @@ config CPU_SPECIFIC_OPTIONS
 	select ARCH_VERSTAGE_X86_32
 	select BOOT_DEVICE_SUPPORTS_WRITES
 	select CACHE_MRC_SETTINGS
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select COLLECT_TIMESTAMPS
 	select SUPPORT_CPU_UCODE_IN_CBFS
 	select MICROCODE_BLOB_NOT_IN_BLOB_REPO

src/soc/intel/broadwell/Kconfig

@@ -15,7 +15,6 @@ config CPU_SPECIFIC_OPTIONS
 	select BOOT_DEVICE_SUPPORTS_WRITES
 	select CACHE_MRC_SETTINGS
 	select MRC_SETTINGS_PROTECT
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select CPU_INTEL_FIRMWARE_INTERFACE_TABLE
 	select SUPPORT_CPU_UCODE_IN_CBFS
 	select HAVE_SMI_HANDLER

src/soc/intel/cannonlake/Kconfig

@@ -59,7 +59,6 @@ config CPU_SPECIFIC_OPTIONS
 	select BOOT_DEVICE_SUPPORTS_WRITES
 	select C_ENVIRONMENT_BOOTBLOCK
 	select CACHE_MRC_SETTINGS
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select COMMON_FADT
 	select CPU_INTEL_COMMON
 	select CPU_INTEL_FIRMWARE_INTERFACE_TABLE

src/soc/intel/icelake/Kconfig

@@ -16,7 +16,6 @@ config CPU_SPECIFIC_OPTIONS
 	select BOOT_DEVICE_SUPPORTS_WRITES
 	select C_ENVIRONMENT_BOOTBLOCK
 	select CACHE_MRC_SETTINGS
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select COMMON_FADT
 	select CPU_INTEL_FIRMWARE_INTERFACE_TABLE
 	select FSP_M_XIP

src/soc/intel/skylake/Kconfig

@@ -27,7 +27,6 @@ config CPU_SPECIFIC_OPTIONS
 	select BOOT_DEVICE_SPI_FLASH_RW_NOMMAP_EARLY if BOOT_DEVICE_SPI_FLASH
 	select BOOT_DEVICE_SUPPORTS_WRITES
 	select CACHE_MRC_SETTINGS
-	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select COLLECT_TIMESTAMPS
 	select COMMON_FADT
 	select CPU_INTEL_COMMON