soc/amd/(common,mendocino)/psp_verstage: Pass PSP FW hash table

Copy AMD PSP fw hash table into memory, then pass it to the PSP.
The PSP will use this hash to verify it's the correct firmware bundled
with coreboot build and not replaced.

BUG=b:203597980
TEST=Build Skyrim BIOS image with the hash table and boot to OS after
PSP verified the binaries against the hash table.

Change-Id: I84bea97c89620d0388b27891a898ffde77052239
Signed-off-by: Kangheui Won <khwon@chromium.org>
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60291
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jon Murphy <jpmurphy@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/common/psp_verstage/include/psp_verstage.h

@@ -66,4 +66,6 @@ int platform_set_sha_op(enum vb2_hash_algorithm hash_alg,
 			struct sha_generic_data *sha_op);
 void platform_report_mode(int developer_mode_enabled);
 
+void update_psp_fw_hash_table(const char *fname);
+
 #endif /* PSP_VERSTAGE_H */

src/soc/amd/common/psp_verstage/psp_verstage.c

@@ -74,6 +74,7 @@ static uint32_t update_boot_region(struct vb2_context *ctx)
 	uint32_t psp_dir_addr, bios_dir_addr;
 	uint32_t *psp_dir_in_spi, *bios_dir_in_spi;
 	const char *fname;
+	const char *hash_fname;
 	void *amdfw_location;
 	void *boot_dev_base = rdev_mmap_full(boot_device_ro());
 
@@ -85,8 +86,10 @@ static uint32_t update_boot_region(struct vb2_context *ctx)
 
 	if (vboot_is_firmware_slot_a(ctx)) {
 		fname = "apu/amdfw_a";
+		hash_fname = "apu/amdfw_a_hash";
 	} else {
 		fname = "apu/amdfw_b";
+		hash_fname = "apu/amdfw_b_hash";
 	}
 
 	amdfw_location = cbfs_map(fname, NULL);
@@ -130,6 +133,9 @@ static uint32_t update_boot_region(struct vb2_context *ctx)
 		return POSTCODE_UPDATE_PSP_BIOS_DIR_ERROR;
 	}
 
+	if (CONFIG(SEPARATE_SIGNED_PSPFW))
+		update_psp_fw_hash_table(hash_fname);
+
 	return 0;
 }
 

src/soc/amd/mendocino/psp_verstage/chipset.c

@@ -3,9 +3,67 @@
 /* TODO: Check if this is still correct */
 
 #include <bl_uapp/bl_syscall_public.h>
+#include <cbfs.h>
 #include <console/console.h>
 #include <psp_verstage.h>
 
+/*
+ * We can't pass pointer to hash table in the SPI.
+ * The AMD PSP team specifically required that whole hash table
+ * should be copied into memory before passing them to the PSP
+ * to reduce window of TOCTOU.
+ */
+#define MAX_NUM_HASH_ENTRIES 128
+static struct psp_fw_hash_table hash_table;
+static struct psp_fw_entry_hash_256 hash_256[MAX_NUM_HASH_ENTRIES];
+static struct psp_fw_entry_hash_384 hash_384[MAX_NUM_HASH_ENTRIES];
+
+void update_psp_fw_hash_table(const char *fname)
+{
+	uint8_t *spi_ptr = (uint8_t *)cbfs_map(fname, NULL);
+	uint32_t len;
+
+	if (!spi_ptr) {
+		printk(BIOS_ERR, "Error: AMD Firmware hash table %s not found\n", fname);
+		/*
+		 * If we don't supply hash table, the PSP will refuse to boot.
+		 * So returning here is safe to do.
+		 */
+		return;
+	}
+
+	memcpy(&hash_table, spi_ptr, offsetof(struct psp_fw_hash_table, fw_hash_256));
+
+	if (hash_table.no_of_entries_256 > MAX_NUM_HASH_ENTRIES ||
+			hash_table.no_of_entries_384 > MAX_NUM_HASH_ENTRIES) {
+		printk(BIOS_ERR, "Error: Too many entries in AMD Firmware hash table"
+				 " (SHA256:%d, SHA384:%d)\n",
+				 hash_table.no_of_entries_256, hash_table.no_of_entries_384);
+		return;
+	}
+
+	if (hash_table.no_of_entries_256 == 0 &&
+			hash_table.no_of_entries_384 == 0) {
+		printk(BIOS_ERR, "Error: No entries in AMD Firmware hash table"
+				 " (SHA256:%d, SHA384:%d)\n",
+				 hash_table.no_of_entries_256, hash_table.no_of_entries_384);
+		return;
+	}
+
+	spi_ptr += offsetof(struct psp_fw_hash_table, fw_hash_256);
+
+	hash_table.fw_hash_256 = hash_256;
+	hash_table.fw_hash_384 = hash_384;
+	len = sizeof(struct psp_fw_entry_hash_256) * hash_table.no_of_entries_256;
+	memcpy(hash_256, spi_ptr, len);
+
+	spi_ptr += len;
+	len = sizeof(struct psp_fw_entry_hash_384) * hash_table.no_of_entries_384;
+	memcpy(hash_384, spi_ptr, len);
+
+	svc_set_fw_hash_table(&hash_table);
+}
+
 uint32_t update_psp_bios_dir(uint32_t *psp_dir_offset, uint32_t *bios_dir_offset)
 {
 	return svc_update_psp_bios_dir(psp_dir_offset, bios_dir_offset);