cbfs: Introduce cbfs_ro_map() and cbfs_ro_load()

This patch introduces two new CBFS API functions which are equivalent to
cbfs_map() and cbfs_load(), respectively, with the difference that they
always operate on the read-only CBFS region ("COREBOOT" FMAP section).
Use it to replace some of the simple cases that needed to use
cbfs_locate_file_in_region().

Change-Id: I9c55b022b6502a333a9805ab0e4891dd7b97ef7f
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39306
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

6 files changed, 61 insertions, 93 deletions

diff --git a/src/drivers/pc80/rtc/option.c b/src/drivers/pc80/rtc/option.c
index bb9d29ab2d..409f0efb3b 100644
--- a/src/drivers/pc80/rtc/option.c
+++ b/src/drivers/pc80/rtc/option.c
@@ -49,36 +49,28 @@ static enum cb_err get_cmos_value(unsigned long bit, unsigned long length,
 	return CB_SUCCESS;
 }
 
-static enum cb_err locate_cmos_layout(struct region_device *rdev)
+static struct cmos_option_table *get_cmos_layout(void)
 {
-	uint32_t cbfs_type = CBFS_COMPONENT_CMOS_LAYOUT;
-	static struct cbfsf fh;
+	static struct cmos_option_table *ct = NULL;
 
 	/*
 	 * In case VBOOT is enabled and this function is called from SMM,
 	 * we have multiple CMOS layout files and to locate them we'd need to
 	 * include VBOOT into SMM...
 	 *
-	 * Support only one CMOS layout in the 'COREBOOT' region for now.
+	 * Support only one CMOS layout in the RO CBFS for now.
 	 */
-	if (!region_device_sz(&(fh.data))) {
-		if (cbfs_locate_file_in_region(&fh, "COREBOOT", "cmos_layout.bin",
-					       &cbfs_type)) {
-			printk(BIOS_ERR, "RTC: cmos_layout.bin could not be found. "
-						"Options are disabled\n");
-			return CB_CMOS_LAYOUT_NOT_FOUND;
-		}
-	}
-
-	cbfs_file_data(rdev, &fh);
-
-	return CB_SUCCESS;
+	if (!ct)
+		ct = cbfs_ro_map("cmos_layout.bin", NULL);
+	if (!ct)
+		printk(BIOS_ERR, "RTC: cmos_layout.bin could not be found. "
+				 "Options are disabled\n");
+	return ct;
 }
 
 enum cb_err cmos_get_option(void *dest, const char *name)
 {
 	struct cmos_option_table *ct;
-	struct region_device rdev;
 	struct cmos_entries *ce;
 	size_t namelen;
 	int found = 0;
@@ -86,16 +78,9 @@ enum cb_err cmos_get_option(void *dest, const char *name)
 	/* Figure out how long name is */
 	namelen = strnlen(name, CMOS_MAX_NAME_LENGTH);
 
-	if (locate_cmos_layout(&rdev) != CB_SUCCESS) {
+	ct = get_cmos_layout();
+	if (!ct)
 		return CB_CMOS_LAYOUT_NOT_FOUND;
-	}
-	ct = rdev_mmap_full(&rdev);
-	if (!ct) {
-		printk(BIOS_ERR, "RTC: cmos_layout.bin could not be mapped. "
-		       "Options are disabled\n");
-
-		return CB_CMOS_LAYOUT_NOT_FOUND;
-	}
 
 	/* find the requested entry record */
 	ce = (struct cmos_entries *)((unsigned char *)ct + ct->header_length);
@@ -108,19 +93,15 @@ enum cb_err cmos_get_option(void *dest, const char *name)
 	}
 	if (!found) {
 		printk(BIOS_DEBUG, "No CMOS option '%s'.\n", name);
-		rdev_munmap(&rdev, ct);
 		return CB_CMOS_OPTION_NOT_FOUND;
 	}
 
-	if (!cmos_checksum_valid(LB_CKS_RANGE_START, LB_CKS_RANGE_END, LB_CKS_LOC)) {
-		rdev_munmap(&rdev, ct);
+	if (!cmos_checksum_valid(LB_CKS_RANGE_START, LB_CKS_RANGE_END, LB_CKS_LOC))
 		return CB_CMOS_CHECKSUM_INVALID;
-	}
-	if (get_cmos_value(ce->bit, ce->length, dest) != CB_SUCCESS) {
-		rdev_munmap(&rdev, ct);
+
+	if (get_cmos_value(ce->bit, ce->length, dest) != CB_SUCCESS)
 		return CB_CMOS_ACCESS_ERROR;
-	}
-	rdev_munmap(&rdev, ct);
+
 	return CB_SUCCESS;
 }
 
@@ -168,7 +149,6 @@ static enum cb_err set_cmos_value(unsigned long bit, unsigned long length,
 enum cb_err cmos_set_option(const char *name, void *value)
 {
 	struct cmos_option_table *ct;
-	struct region_device rdev;
 	struct cmos_entries *ce;
 	unsigned long length;
 	size_t namelen;
@@ -177,16 +157,9 @@ enum cb_err cmos_set_option(const char *name, void *value)
 	/* Figure out how long name is */
 	namelen = strnlen(name, CMOS_MAX_NAME_LENGTH);
 
-	if (locate_cmos_layout(&rdev) != CB_SUCCESS) {
+	ct = get_cmos_layout();
+	if (!ct)
 		return CB_CMOS_LAYOUT_NOT_FOUND;
-	}
-	ct = rdev_mmap_full(&rdev);
-	if (!ct) {
-		printk(BIOS_ERR, "RTC: cmos_layout.bin could not be mapped. "
-		       "Options are disabled\n");
-
-		return CB_CMOS_LAYOUT_NOT_FOUND;
-	}
 
 	/* find the requested entry record */
 	ce = (struct cmos_entries *)((unsigned char *)ct + ct->header_length);
@@ -199,7 +172,6 @@ enum cb_err cmos_set_option(const char *name, void *value)
 	}
 	if (!found) {
 		printk(BIOS_DEBUG, "WARNING: No CMOS option '%s'.\n", name);
-		rdev_munmap(&rdev, ct);
 		return CB_CMOS_OPTION_NOT_FOUND;
 	}
 
@@ -208,18 +180,13 @@ enum cb_err cmos_set_option(const char *name, void *value)
 		length = MAX(strlen((const char *)value) * 8, ce->length - 8);
 		/* make sure the string is null terminated */
 		if (set_cmos_value(ce->bit + ce->length - 8, 8, &(u8[]){0})
-		    != CB_SUCCESS) {
-			rdev_munmap(&rdev, ct);
+		    != CB_SUCCESS)
 			return CB_CMOS_ACCESS_ERROR;
-		}
 	}
 
-	if (set_cmos_value(ce->bit, length, value) != CB_SUCCESS) {
-		rdev_munmap(&rdev, ct);
+	if (set_cmos_value(ce->bit, length, value) != CB_SUCCESS)
 		return CB_CMOS_ACCESS_ERROR;
-	}
 
-	rdev_munmap(&rdev, ct);
 	return CB_SUCCESS;
 }
 
diff --git a/src/include/cbfs.h b/src/include/cbfs.h
index 992b6583ca..8d4c2209d2 100644
--- a/src/include/cbfs.h
+++ b/src/include/cbfs.h
@@ -23,9 +23,12 @@ int cbfs_boot_locate(struct cbfsf *fh, const char *name, uint32_t *type);
    NOTE: Since this may return a direct pointer to memory-mapped hardware,
    compressed files are NOT transparently decompressed (unlike cbfs_load()). */
 void *cbfs_map(const char *name, size_t *size_out);
-/* Removes a mapping previously allocated with cbfs_map(). Should try to unmap
-   mappings in strict LIFO order where possible, since mapping backends often
-   don't support more complicated cases. */
+/* Like cbfs_map(), except that it will always read from the read-only CBFS
+   ("COREBOOT" FMAP region), even when CONFIG(VBOOT) is enabled. */
+void *cbfs_ro_map(const char *name, size_t *size_out);
+/* Removes a previously allocated CBFS mapping. Should try to unmap mappings in
+   strict LIFO order where possible, since mapping backends often don't support
+   more complicated cases. */
 int cbfs_unmap(void *mapping);
 /* Locate file in a specific region of fmap. Return 0 on success. < 0 on error*/
 int cbfs_locate_file_in_region(struct cbfsf *fh, const char *region_name,
@@ -34,6 +37,9 @@ int cbfs_locate_file_in_region(struct cbfsf *fh, const char *region_name,
    success or 0 on error. File will get decompressed as necessary. Same
    decompression requirements as cbfs_load_and_decompress(). */
 size_t cbfs_load(const char *name, void *buf, size_t buf_size);
+/* Like cbfs_load(), except that it will always read from the read-only CBFS
+   ("COREBOOT" FMAP region), even when CONFIG(VBOOT) is enabled. */
+size_t cbfs_ro_load(const char *name, void *buf, size_t buf_size);
 /* Load |in_size| bytes from |rdev| at |offset| to the |buffer_size| bytes
  * large |buffer|, decompressing it according to |compression| in the process.
  * Returns the decompressed file size, or 0 on error.
diff --git a/src/lib/cbfs.c b/src/lib/cbfs.c
index 8d868a6be3..beab74ec4d 100644
--- a/src/lib/cbfs.c
+++ b/src/lib/cbfs.c
@@ -70,12 +70,12 @@ int cbfs_boot_locate(struct cbfsf *fh, const char *name, uint32_t *type)
 	return 0;
 }
 
-void *cbfs_map(const char *name, size_t *size_out)
+static void *_cbfs_map(const char *name, size_t *size_out, bool force_ro)
 {
 	struct region_device rdev;
 	union cbfs_mdata mdata;
 
-	if (cbfs_boot_lookup(name, false, &mdata, &rdev))
+	if (cbfs_boot_lookup(name, force_ro, &mdata, &rdev))
 		return NULL;
 
 	if (size_out != NULL)
@@ -84,6 +84,16 @@ void *cbfs_map(const char *name, size_t *size_out)
 	return rdev_mmap_full(&rdev);
 }
 
+void *cbfs_map(const char *name, size_t *size_out)
+{
+	return _cbfs_map(name, size_out, false);
+}
+
+void *cbfs_ro_map(const char *name, size_t *size_out)
+{
+	return _cbfs_map(name, size_out, true);
+}
+
 int cbfs_unmap(void *mapping)
 {
 	/* This works because munmap() only works on the root rdev and never
@@ -281,12 +291,13 @@ void *cbfs_boot_map_optionrom_revision(uint16_t vendor, uint16_t device, uint8_t
 	return cbfs_map(name, NULL);
 }
 
-size_t cbfs_load(const char *name, void *buf, size_t buf_size)
+static size_t _cbfs_load(const char *name, void *buf, size_t buf_size,
+			 bool force_ro)
 {
 	struct region_device rdev;
 	union cbfs_mdata mdata;
 
-	if (cbfs_boot_lookup(name, false, &mdata, &rdev))
+	if (cbfs_boot_lookup(name, force_ro, &mdata, &rdev))
 		return 0;
 
 	uint32_t compression = CBFS_COMPRESS_NONE;
@@ -302,6 +313,16 @@ size_t cbfs_load(const char *name, void *buf, size_t buf_size)
 					buf, buf_size, compression);
 }
 
+size_t cbfs_load(const char *name, void *buf, size_t buf_size)
+{
+	return _cbfs_load(name, buf, buf_size, false);
+}
+
+size_t cbfs_ro_load(const char *name, void *buf, size_t buf_size)
+{
+	return _cbfs_load(name, buf, buf_size, true);
+}
+
 int cbfs_prog_stage_load(struct prog *pstage)
 {
 	struct cbfs_stage stage;
diff --git a/src/northbridge/intel/haswell/raminit.c b/src/northbridge/intel/haswell/raminit.c
index 290e402fcb..9617ffb59d 100644
--- a/src/northbridge/intel/haswell/raminit.c
+++ b/src/northbridge/intel/haswell/raminit.c
@@ -107,9 +107,6 @@ void sdram_initialize(struct pei_data *pei_data)
 {
 	int (*entry)(struct pei_data *pei_data) __attribute__((regparm(1)));
 
-	uint32_t type = CBFS_TYPE_MRC;
-	struct cbfsf f;
-
 	printk(BIOS_DEBUG, "Starting UEFI PEI System Agent\n");
 
 	/*
@@ -130,13 +127,10 @@ void sdram_initialize(struct pei_data *pei_data)
 
 	/*
 	 * Locate and call UEFI System Agent binary. The binary needs to be at a fixed offset
-	 * in the flash and can therefore only reside in the COREBOOT fmap region.
+	 * in the flash and can therefore only reside in the COREBOOT fmap region. We don't care
+	 * about leaking the mapping.
 	 */
-	if (cbfs_locate_file_in_region(&f, "COREBOOT", "mrc.bin", &type) < 0)
-		die("mrc.bin not found!");
-
-	/* We don't care about leaking the mapping */
-	entry = rdev_mmap_full(&f.data);
+	entry = cbfs_ro_map("mrc.bin", NULL);
 	if (entry) {
 		int rv = entry(pei_data);
 
diff --git a/src/soc/intel/broadwell/raminit.c b/src/soc/intel/broadwell/raminit.c
index e51b4f7b66..44a89377d4 100644
--- a/src/soc/intel/broadwell/raminit.c
+++ b/src/soc/intel/broadwell/raminit.c
@@ -80,8 +80,6 @@ void raminit(struct pei_data *pei_data)
 	struct memory_info *mem_info;
 	pei_wrapper_entry_t entry;
 	int ret;
-	struct cbfsf f;
-	uint32_t type = CBFS_TYPE_MRC;
 
 	broadwell_fill_pei_data(pei_data);
 
@@ -114,15 +112,10 @@ void raminit(struct pei_data *pei_data)
 		pei_data->saved_data_size = 0;
 	}
 
-	/* Determine if mrc.bin is in the cbfs. */
-	if (cbfs_locate_file_in_region(&f, "COREBOOT", "mrc.bin", &type) < 0)
-		die("mrc.bin not found!");
 	/* We don't care about leaking the mapping */
-	entry = (pei_wrapper_entry_t)rdev_mmap_full(&f.data);
-	if (entry == NULL) {
-		printk(BIOS_DEBUG, "Couldn't find mrc.bin\n");
-		return;
-	}
+	entry = cbfs_ro_map("mrc.bin", NULL);
+	if (entry == NULL)
+		die("mrc.bin not found!");
 
 	printk(BIOS_DEBUG, "Starting Memory Reference Code\n");
 
diff --git a/src/soc/intel/quark/romstage/romstage.c b/src/soc/intel/quark/romstage/romstage.c
index 9800aa4be6..23a551ef57 100644
--- a/src/soc/intel/quark/romstage/romstage.c
+++ b/src/soc/intel/quark/romstage/romstage.c
@@ -49,29 +49,16 @@ void disable_rom_shadow(void)
 
 void *locate_rmu_file(size_t *rmu_file_len)
 {
-	struct cbfsf fh;
 	size_t fsize;
 	void *rmu_data;
-	uint32_t type;
 
 	/* Locate the rmu.bin file in the read-only region of the flash */
-	type = CBFS_TYPE_RAW;
-	if (cbfs_locate_file_in_region(&fh, "COREBOOT", "rmu.bin", &type))
+	rmu_data = cbfs_ro_map("rmu.bin", &fsize);
+	if (!rmu_data)
 		return NULL;
 
-	/* Get the file size */
-	fsize = region_device_sz(&fh.data);
 	if (rmu_file_len != NULL)
 		*rmu_file_len = fsize;
 
-	/* Get the data address */
-	rmu_data = rdev_mmap(&fh.data, 0, fsize);
-
-	/* Since the SPI flash is directly mapped into memory, we do not need
-	 * the mapping provided by the rdev service.  Unmap the file to prevent
-	 * a memory leak.  Return/leak the SPI flash address for the rmu.bin
-	 * file data which will be directly accessed by FSP MemoryInit.
-	 */
-	rdev_munmap(&fh.data, rmu_data);
 	return rmu_data;
 }