ACPI S3: Remove HIGH_MEMORY_SAVE where possible

Add implementation to use actual requirements of ramstage size
for S3 resume backup in CBMEM. The backup covers complete pages of 4 KiB.

Only the required amount of low memory is backed up when ACPI_TINY_LOWMEM_BACKUP
is selected for the platform. Enable this option for AGESA and binaryPI, other
platforms (without RELOCATABLE_RAMSTAGE) currently keep their romstage ramstack
in low memory for s3 resume path.

Change-Id: Ide7ce013f3727c2928cdb00fbcc7e7e84e859ff1
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/15255
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>

src/Kconfig

@@ -539,6 +539,19 @@ config HAVE_ACPI_RESUME
 	bool
 	default n
 
+config ACPI_TINY_LOWMEM_BACKUP
+	bool
+	default n
+	help
+	  On S3 resume path, backup only the region of low memory ramstage
+	  will occupy. Requires platform places romstage ramstack in CBMEM.
+
+config ACPI_HUGE_LOWMEM_BACKUP
+	bool
+	default !ACPI_TINY_LOWMEM_BACKUP
+	help
+	  On S3 resume path, backup low memory from RAMBASE..RAMTOP in CBMEM.
+
 config RESUME_PATH_SAME_AS_BOOT
 	bool
 	default y if ARCH_X86

src/arch/x86/acpi_s3.c

@@ -19,8 +19,10 @@
 #include <cbmem.h>
 #include <cpu/cpu.h>
 #include <timestamp.h>
+#include <program_loading.h>
 #include <romstage_handoff.h>
 #include <rules.h>
+#include <symbols.h>
 
 #if ENV_RAMSTAGE
 
@@ -79,30 +81,125 @@ void acpi_fail_wakeup(void)
 }
 #endif /* ENV_RAMSTAGE */
 
-void acpi_prepare_for_resume(void)
+struct resume_backup {
+	uint64_t cbmem;
+	uint64_t lowmem;
+	uint64_t size;
+	uint8_t valid;
+};
+
+#define BACKUP_PAGE_SZ 4096
+
+static int backup_create_or_update(struct resume_backup *backup_mem,
+				uintptr_t base, size_t size)
 {
-	if (!HIGH_MEMORY_SAVE)
+	uintptr_t top;
+
+	if (IS_ENABLED(CONFIG_ACPI_HUGE_LOWMEM_BACKUP)) {
+		base = CONFIG_RAMBASE;
+		size = HIGH_MEMORY_SAVE;
+	}
+
+	/* Align backup region to complete pages. */
+	top = ALIGN_UP(base + size, BACKUP_PAGE_SZ);
+	base = ALIGN_DOWN(base, BACKUP_PAGE_SZ);
+	size = top - base;
+
+	/* Cannot extend existing region, should not happen. */
+	if (backup_mem && (backup_mem->size < size))
+		return -1;
+
+	/* Allocate backup with room for header. */
+	if (!backup_mem) {
+		size_t header_sz = ALIGN_UP(sizeof(*backup_mem), BACKUP_PAGE_SZ);
+		backup_mem = cbmem_add(CBMEM_ID_RESUME, header_sz + size);
+		if (!backup_mem)
+			return -1;
+
+		/* Container starts from boundary after header. */
+		backup_mem->cbmem = (uintptr_t)backup_mem + header_sz;
+	}
+
+	backup_mem->valid = 0;
+	backup_mem->lowmem = base;
+	backup_mem->size = size;
+	return 0;
+}
+
+void *acpi_backup_container(uintptr_t base, size_t size)
+{
+	struct resume_backup *backup_mem = cbmem_find(CBMEM_ID_RESUME);
+	if (!backup_mem)
+		return NULL;
+
+	if (!IS_ALIGNED(base, BACKUP_PAGE_SZ) || !IS_ALIGNED(size, BACKUP_PAGE_SZ))
+		return NULL;
+
+	if (backup_create_or_update(backup_mem, base, size) < 0)
+		return NULL;
+
+	backup_mem->valid = 1;
+	return (void*)(uintptr_t)backup_mem->cbmem;
+}
+
+void backup_ramstage_section(uintptr_t base, size_t size)
+{
+	struct resume_backup *backup_mem = cbmem_find(CBMEM_ID_RESUME);
+
+	/* For first boot we exit here as CBMEM_ID_RESUME is only
+	 * created late in ramstage with acpi_prepare_resume_backup().
+	 */
+	if (!backup_mem)
+		return;
+
+	/* Check that the backup is not done twice. */
+	if (backup_mem->valid)
+		return;
+
+	/* When we are called from ramstage loader, update header with
+	 * properties of the ramstage we will load.
+	 */
+	if (backup_create_or_update(backup_mem, base, size) < 0)
 		return;
 
 	/* Back up the OS-controlled memory where ramstage will be loaded. */
-	void *src = (void *)CONFIG_RAMBASE;
-	void *dest = cbmem_find(CBMEM_ID_RESUME);
-	if (dest != NULL)
-		memcpy(dest, src, HIGH_MEMORY_SAVE);
+	memcpy((void*)(uintptr_t)backup_mem->cbmem,
+		(void*)(uintptr_t)backup_mem->lowmem, (size_t)backup_mem->size);
+	backup_mem->valid = 1;
 }
 
+/* Make backup of low-memory region, relying on the base and size
+ * of the ramstage that was loaded before entry to ACPI S3.
+ *
+ * DEPRECATED
+ */
+void acpi_prepare_for_resume(void)
+{
+	struct resume_backup *backup_mem = cbmem_find(CBMEM_ID_RESUME);
+	if (!backup_mem)
+		return;
+
+	/* Back up the OS-controlled memory where ramstage will be loaded. */
+	memcpy((void*)(uintptr_t)backup_mem->cbmem,
+		(void*)(uintptr_t)backup_mem->lowmem, (size_t)backup_mem->size);
+	backup_mem->valid = 1;
+}
+
+/* Let's prepare the ACPI S3 Resume area now already, so we can rely on
+ * it being there during reboot time. If this fails, ACPI resume will
+ * be disabled. We assume that ramstage does not change while in suspend,
+ * so base and size of the currently running ramstage are used
+ * for allocation.
+ */
 void acpi_prepare_resume_backup(void)
 {
 	if (!acpi_s3_resume_allowed())
 		return;
 
-	/* Let's prepare the ACPI S3 Resume area now already, so we can rely on
-	 * it being there during reboot time. We don't need the pointer, nor
-	 * the result right now. If it fails, ACPI resume will be disabled.
-	 */
+	if (IS_ENABLED(CONFIG_RELOCATABLE_RAMSTAGE))
+		return;
 
-	if (HIGH_MEMORY_SAVE)
-		cbmem_add(CBMEM_ID_RESUME, HIGH_MEMORY_SAVE);
+	backup_create_or_update(NULL, (uintptr_t)_program, _program_size);
 }
 
 #define WAKEUP_BASE 0x600
@@ -115,17 +212,22 @@ extern unsigned int __wakeup_size;
 
 static void acpi_jump_to_wakeup(void *vector)
 {
-	uintptr_t acpi_backup_memory = 0;
+	uintptr_t source = 0, target = 0;
+	size_t size = 0;
 
 	if (!acpi_s3_resume_allowed()) {
 		printk(BIOS_WARNING, "ACPI: S3 resume not allowed.\n");
 		return;
 	}
 
-	if (HIGH_MEMORY_SAVE) {
-		acpi_backup_memory = (uintptr_t)cbmem_find(CBMEM_ID_RESUME);
-
-		if (!acpi_backup_memory) {
+	if (!IS_ENABLED(CONFIG_RELOCATABLE_RAMSTAGE)) {
+		struct resume_backup *backup_mem = cbmem_find(CBMEM_ID_RESUME);
+		if (backup_mem && backup_mem->valid) {
+			backup_mem->valid = 0;
+			target = backup_mem->lowmem;
+			source = backup_mem->cbmem;
+			size = backup_mem->size;
+		} else  {
 			printk(BIOS_WARNING, "ACPI: Backup memory missing. "
 				"No S3 resume.\n");
 			return;
@@ -137,8 +239,7 @@ static void acpi_jump_to_wakeup(void *vector)
 
 	timestamp_add_now(TS_ACPI_WAKE_JUMP);
 
-	acpi_do_wakeup((uintptr_t)vector, acpi_backup_memory, CONFIG_RAMBASE,
-		       HIGH_MEMORY_SAVE);
+	acpi_do_wakeup((uintptr_t)vector, source, target, size);
 }
 
 void __attribute__((weak)) mainboard_suspend_resume(void)

src/arch/x86/include/arch/acpi.h

@@ -25,12 +25,7 @@
 #ifndef __ASM_ACPI_H
 #define __ASM_ACPI_H
 
-#if IS_ENABLED(CONFIG_HAVE_ACPI_RESUME) && \
-	! IS_ENABLED(CONFIG_RELOCATABLE_RAMSTAGE)
 #define HIGH_MEMORY_SAVE	(CONFIG_RAMTOP - CONFIG_RAMBASE)
-#else
-#define HIGH_MEMORY_SAVE	0
-#endif
 
 #if IS_ENABLED(CONFIG_ACPI_INTEL_HARDWARE_SLEEP_VALUES)
 /*
@@ -688,6 +683,13 @@ static inline int acpi_s3_resume_allowed(void)
 	return IS_ENABLED(CONFIG_HAVE_ACPI_RESUME);
 }
 
+/* Return address in reserved memory where to backup low memory
+ * while platform resumes from S3 suspend. Caller is responsible of
+ * making a complete copy of the region base..base+size, with
+ * parameteres base and size that meet page alignment requirement.
+ */
+void *acpi_backup_container(uintptr_t base, size_t size);
+
 #if IS_ENABLED(CONFIG_HAVE_ACPI_RESUME)
 extern int acpi_slp_type;
 

src/cpu/amd/agesa/Kconfig

@@ -31,6 +31,7 @@ config CPU_AMD_AGESA
 	select UDELAY_LAPIC
 	select LAPIC_MONOTONIC_TIMER
 	select SPI_FLASH if HAVE_ACPI_RESUME
+	select ACPI_TINY_LOWMEM_BACKUP
 
 if CPU_AMD_AGESA
 

src/cpu/amd/car/post_cache_as_ram.c

@@ -69,7 +69,7 @@ static void prepare_romstage_ramstack(int s3resume)
 	print_car_debug("Prepare CAR migration and stack regions...");
 
 	if (s3resume) {
-		void *resume_backup_memory = cbmem_find(CBMEM_ID_RESUME);
+		void *resume_backup_memory = acpi_backup_container(CONFIG_RAMBASE, HIGH_MEMORY_SAVE);
 		if (resume_backup_memory)
 			memcpy_(resume_backup_memory + HIGH_MEMORY_SAVE - backup_top,
 				(void *)(CONFIG_RAMTOP - backup_top), backup_top);
@@ -85,7 +85,7 @@ static void prepare_ramstage_region(int s3resume)
 	print_car_debug("Prepare ramstage memory region...");
 
 	if (s3resume) {
-		void *resume_backup_memory = cbmem_find(CBMEM_ID_RESUME);
+		void *resume_backup_memory = acpi_backup_container(CONFIG_RAMBASE, HIGH_MEMORY_SAVE);
 		if (resume_backup_memory)
 			memcpy_(resume_backup_memory, (void *) CONFIG_RAMBASE,
 				HIGH_MEMORY_SAVE - backup_top);

src/cpu/amd/pi/Kconfig

@@ -28,6 +28,7 @@ config CPU_AMD_PI
 	select UDELAY_LAPIC
 	select LAPIC_MONOTONIC_TIMER
 	select SPI_FLASH if HAVE_ACPI_RESUME
+	select ACPI_TINY_LOWMEM_BACKUP
 
 if CPU_AMD_PI
 

src/include/cbfs.h

@@ -47,6 +47,9 @@ size_t cbfs_boot_load_struct(const char *name, void *buf, size_t buf_size);
 size_t cbfs_load_and_decompress(const struct region_device *rdev, size_t offset,
 	size_t in_size, void *buffer, size_t buffer_size, uint32_t compression);
 
+/* Return the size and fill base of the memory pstage will occupy after loaded. */
+size_t cbfs_prog_stage_section(struct prog *pstage, uintptr_t *base);
+
 /* Load stage into memory filling in prog. Return 0 on success. < 0 on error. */
 int cbfs_prog_stage_load(struct prog *prog);
 

src/include/program_loading.h

@@ -173,6 +173,10 @@ uintptr_t romstage_ram_stack_base(size_t size, int src);
 uintptr_t romstage_ram_stack_top(void);
 uintptr_t romstage_ram_stack_bottom(void);
 
+/* Backup OS memory to CBMEM_ID_RESUME on ACPI S3 resume path,
+ * if ramstage overwrites low memory. */
+void backup_ramstage_section(uintptr_t base, size_t size);
+
 /***********************
  *   PAYLOAD LOADING   *
  ***********************/

src/lib/cbfs.c

@@ -187,6 +187,18 @@ size_t cbfs_boot_load_struct(const char *name, void *buf, size_t buf_size)
 					buf, buf_size, compression_algo);
 }
 
+size_t cbfs_prog_stage_section(struct prog *pstage, uintptr_t *base)
+{
+	struct cbfs_stage stage;
+	const struct region_device *fh = prog_rdev(pstage);
+
+	if (rdev_readat(fh, &stage, 0, sizeof(stage)) != sizeof(stage))
+		return 0;
+
+	*base = (uintptr_t)stage.load;
+	return stage.memlen;
+}
+
 int cbfs_prog_stage_load(struct prog *pstage)
 {
 	struct cbfs_stage stage;

src/lib/prog_loaders.c

@@ -110,6 +110,18 @@ static int load_relocatable_ramstage(struct prog *ramstage)
 	return rmodule_stage_load(&rmod_ram);
 }
 
+static int load_nonrelocatable_ramstage(struct prog *ramstage)
+{
+	if (IS_ENABLED(CONFIG_HAVE_ACPI_RESUME)) {
+		uintptr_t base = 0;
+		size_t size = cbfs_prog_stage_section(ramstage, &base);
+		if (size)
+			backup_ramstage_section(base, size);
+	}
+
+	return cbfs_prog_stage_load(ramstage);
+}
+
 void run_ramstage(void)
 {
 	struct prog ramstage =
@@ -135,7 +147,7 @@ void run_ramstage(void)
 	if (IS_ENABLED(CONFIG_RELOCATABLE_RAMSTAGE)) {
 		if (load_relocatable_ramstage(&ramstage))
 			goto fail;
-	} else if (cbfs_prog_stage_load(&ramstage))
+	} else if (load_nonrelocatable_ramstage(&ramstage))
 		goto fail;
 
 	stage_cache_add(STAGE_RAMSTAGE, &ramstage);