linux-kernel - [Patch v2 1/2] firmware: dmi_scan: add symbol to get SMBIOS entry area

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Date:	Mon, 26 Jan 2015 15:28:37 +0200
From:	Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>
To:	linux-kernel@...r.kernel.org, ard.biesheuvel@...aro.org
Cc:	dmidecode-devel@...gnu.org, grant.likely@...aro.org,
	leif.lindholm@...aro.org, matt.fleming@...el.com,
	Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>
Subject: [Patch v2 1/2] firmware: dmi_scan: add symbol to get SMBIOS entry area

There are situations when code needs to access SMBIOS entry table
area. For example, to pass it via sysfs to userspace when it's not
allowed to get SMBIOS info via /dev/mem.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>
---
 drivers/firmware/dmi_scan.c | 26 ++++++++++++++++++++++++++
 include/linux/dmi.h         |  3 +++
 2 files changed, 29 insertions(+)

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 420c8d8..d94c6b7 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -113,6 +113,8 @@ static void dmi_table(u8 *buf, int len, int num,
 	}
 }
 
+static unsigned char smbios_header[32];
+static int smbios_header_size;
 static phys_addr_t dmi_base;
 static u16 dmi_len;
 static u16 dmi_num;
@@ -474,6 +476,8 @@ static int __init dmi_present(const u8 *buf)
 	if (memcmp(buf, "_SM_", 4) == 0 &&
 	    buf[5] < 32 && dmi_checksum(buf, buf[5])) {
 		smbios_ver = get_unaligned_be16(buf + 6);
+		smbios_header_size = buf[5];
+		memcpy(smbios_header, buf, smbios_header_size);
 
 		/* Some BIOS report weird SMBIOS version, fix that up */
 		switch (smbios_ver) {
@@ -505,6 +509,8 @@ static int __init dmi_present(const u8 *buf)
 				pr_info("SMBIOS %d.%d present.\n",
 				       dmi_ver >> 8, dmi_ver & 0xFF);
 			} else {
+				smbios_header_size = 15;
+				memcpy(smbios_header, buf, smbios_header_size);
 				dmi_ver = (buf[14] & 0xF0) << 4 |
 					   (buf[14] & 0x0F);
 				pr_info("Legacy DMI %d.%d present.\n",
@@ -531,6 +537,8 @@ static int __init dmi_smbios3_present(const u8 *buf)
 		dmi_ver &= 0xFFFFFF;
 		dmi_len = get_unaligned_le32(buf + 12);
 		dmi_base = get_unaligned_le64(buf + 16);
+		smbios_header_size = buf[6];
+		memcpy(smbios_header, buf, smbios_header_size);
 
 		/*
 		 * The 64-bit SMBIOS 3.0 entry point no longer has a field
@@ -944,3 +952,21 @@ void dmi_memdev_name(u16 handle, const char **bank, const char **device)
 	}
 }
 EXPORT_SYMBOL_GPL(dmi_memdev_name);
+
+/**
+ * dmi_get_smbios_entry_area - copy SMBIOS entry point area to array.
+ * @size - pointer to assign actual size of SMBIOS entry point area.
+ *
+ * returns NULL if table is not available, otherwise returns pointer on
+ * SMBIOS entry point area array.
+ */
+const u8 *dmi_get_smbios_entry_area(int *size)
+{
+	if (!smbios_header_size || !dmi_available)
+		return NULL;
+
+	*size = smbios_header_size;
+
+	return smbios_header;
+}
+EXPORT_SYMBOL_GPL(dmi_get_smbios_entry_area);
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index f820f0a..8e1a28d 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -109,6 +109,7 @@ extern int dmi_walk(void (*decode)(const struct dmi_header *, void *),
 	void *private_data);
 extern bool dmi_match(enum dmi_field f, const char *str);
 extern void dmi_memdev_name(u16 handle, const char **bank, const char **device);
+const u8 *dmi_get_smbios_entry_area(int *size);
 
 #else
 
@@ -140,6 +141,8 @@ static inline void dmi_memdev_name(u16 handle, const char **bank,
 		const char **device) { }
 static inline const struct dmi_system_id *
 	dmi_first_match(const struct dmi_system_id *list) { return NULL; }
+static inline const u8 *dmi_get_smbios_entry_area(int *size)
+	{ return NULL; }
 
 #endif
 
-- 
1.9.1

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