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/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;