ipmi_smbios: Deduplicate smbios entry point discovery logic

Sponsored by:	Ampere Computing LLC
Submitted by:	Klara Inc.
Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D28743

sys/dev/ipmi/ipmi_isa.c

@@ -286,3 +286,4 @@ static driver_t ipmi_isa_driver = {
 };
 
 DRIVER_MODULE(ipmi_isa, isa, ipmi_isa_driver, ipmi_devclass, 0, 0);
+MODULE_DEPEND(ipmi_isa, smbios, 1, 1, 1);

sys/dev/ipmi/ipmi_pci.c

@@ -179,6 +179,7 @@ static driver_t ipmi_pci_driver = {
 };
 
 DRIVER_MODULE(ipmi_pci, pci, ipmi_pci_driver, ipmi_devclass, 0, 0);
+MODULE_DEPEND(ipmi_pci, smbios, 1, 1, 1);
 
 /* Native IPMI on PCI driver. */
 

sys/dev/ipmi/ipmi_smbios.c

@@ -88,7 +88,7 @@ MTX_SYSINIT(ipmi_info, &ipmi_info_mtx, "ipmi info", MTX_DEF);
 
 static void	ipmi_smbios_probe(struct ipmi_get_info *);
 static int	smbios_cksum(struct smbios_eps *);
-static void	smbios_walk_table(uint8_t *, int, smbios_callback_t,
+static void	smbios_walk_table(uint8_t *, vm_size_t, smbios_callback_t,
 		    void *);
 static void	smbios_ipmi_info(struct smbios_structure_header *, void *);
 
@@ -147,11 +147,12 @@ smbios_ipmi_info(struct smbios_structure_header *h, void *arg)
 }
 
 static void
-smbios_walk_table(uint8_t *p, int entries, smbios_callback_t cb, void *arg)
+smbios_walk_table(uint8_t *table, vm_size_t size, smbios_callback_t cb, void *arg)
 {
 	struct smbios_structure_header *s;
+	uint8_t *p;
 
-	while (entries--) {
+	for (p = table; p < table + size;) {
 		s = (struct smbios_structure_header *)p;
 		cb(s, arg);
 
@@ -160,8 +161,11 @@ smbios_walk_table(uint8_t *p, int entries, smbios_callback_t cb, void *arg)
 		 * formatted area of this structure.
 		 */
 		p += s->length;
-		while (!(p[0] == 0 && p[1] == 0))
+		while (!(p[0] == 0 && p[1] == 0)) {
 			p++;
+			if (p >= table + size)
+				return;
+		}
 
 		/*
 		 * Skip over the double-nul to the start of the next
@@ -179,41 +183,23 @@ smbios_walk_table(uint8_t *p, int entries, smbios_callback_t cb, void *arg)
 static void
 ipmi_smbios_probe(struct ipmi_get_info *info)
 {
-	struct smbios_eps *header;
 	void *table;
-	u_int32_t addr;
+	vm_paddr_t table_paddr;
+	vm_size_t table_size;
+	int err;
 
 	bzero(info, sizeof(struct ipmi_get_info));
 
-	/* Find the SMBIOS table header. */
-	addr = bios_sigsearch(SMBIOS_START, SMBIOS_SIG, SMBIOS_LEN,
-			      SMBIOS_STEP, SMBIOS_OFF);
-	if (addr == 0)
+	err = smbios_get_structure_table(&table_paddr, &table_size);
+	if (err != 0)
 		return;
 
-	/*
-	 * Map the header.  We first map a fixed size to get the actual
-	 * length and then map it a second time with the actual length so
-	 * we can verify the checksum.
-	 */
-	header = pmap_mapbios(addr, sizeof(struct smbios_eps));
-	table = pmap_mapbios(addr, header->length);
-	pmap_unmapbios((vm_offset_t)header, sizeof(struct smbios_eps));
-	header = table;
-	if (smbios_cksum(header) != 0) {
-		pmap_unmapbios((vm_offset_t)header, header->length);
-		return;
-	}
+	table = pmap_mapbios(table_paddr, table_size);
 
-	/* Now map the actual table and walk it looking for an IPMI entry. */
-	table = pmap_mapbios(header->structure_table_address,
-	    header->structure_table_length);
-	smbios_walk_table(table, header->number_structures, smbios_ipmi_info,
-	    info);
+	smbios_walk_table(table, table_size, smbios_ipmi_info, info);
 
 	/* Unmap everything. */
-	pmap_unmapbios((vm_offset_t)table, header->structure_table_length);
-	pmap_unmapbios((vm_offset_t)header, header->length);
+	pmap_unmapbios((vm_offset_t)table, table_size);
 }
 
 /*

sys/dev/ipmi/ipmi_smbus.c

@@ -131,3 +131,4 @@ static driver_t ipmi_smbus_driver = {
 
 DRIVER_MODULE(ipmi_smbus, smbus, ipmi_smbus_driver, ipmi_devclass, 0, 0);
 MODULE_DEPEND(ipmi_smbus, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
+MODULE_DEPEND(ipmi_smbus, smbios, 1, 1, 1);

sys/dev/smbios/smbios.c

@@ -51,6 +51,8 @@ __FBSDID("$FreeBSD$");
 #endif
 #include <dev/smbios/smbios.h>
 
+static struct smbios_softc *smbios;
+
 /*
  * System Management BIOS Reference Specification, v2.4 Final
  * http://www.dmtf.org/standards/published_documents/DSP0134.pdf
@@ -179,6 +181,7 @@ smbios_attach (device_t dev)
 			bcd2bin(sc->eps->BCD_revision & 0x0f));
 	printf("\n");
 
+	smbios = sc;
 	return (0);
 bad:
 	if (sc->res)
@@ -191,6 +194,7 @@ smbios_detach (device_t dev)
 {
 	struct smbios_softc *sc;
 
+	smbios = NULL;
 	sc = device_get_softc(dev);
 
 	if (sc->res)
@@ -199,6 +203,23 @@ smbios_detach (device_t dev)
 	return (0);
 }
 
+int
+smbios_get_structure_table(vm_paddr_t *table, vm_size_t *size)
+{
+
+	if (smbios == NULL)
+		return (ENXIO);
+	if (smbios->eps_64bit) {
+		*table = smbios->eps3->structure_table_address;
+		*size = smbios->eps3->structure_table_max_size;
+	} else {
+		*table = smbios->eps->structure_table_address;
+		*size = smbios->eps->structure_table_length;
+	}
+	return (0);
+}
+
+
 static int
 smbios_modevent (mod, what, arg)
         module_t        mod;

sys/dev/smbios/smbios.h

@@ -32,6 +32,8 @@
 #ifndef _SMBIOS_H_
 #define _SMBIOS_H_
 
+int smbios_get_structure_table(vm_paddr_t *table, vm_size_t *size);
+
 /*
  * System Management BIOS
  */