1 files changed, 429 insertions, 0 deletions

diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c
new file mode 100644
index 000000000..4f1528073
--- /dev/null
+++ b/arch/x86/pci/pcbios.c
@@ -0,0 +1,429 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * BIOS32 and PCI BIOS handling.
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+#include <asm/pci_x86.h>
+#include <asm/e820/types.h>
+#include <asm/pci-functions.h>
+#include <asm/set_memory.h>
+
+/* BIOS32 signature: "_32_" */
+#define BIOS32_SIGNATURE	(('_' << 0) + ('3' << 8) + ('2' << 16) + ('_' << 24))
+
+/* PCI signature: "PCI " */
+#define PCI_SIGNATURE		(('P' << 0) + ('C' << 8) + ('I' << 16) + (' ' << 24))
+
+/* PCI service signature: "$PCI" */
+#define PCI_SERVICE		(('$' << 0) + ('P' << 8) + ('C' << 16) + ('I' << 24))
+
+/* PCI BIOS hardware mechanism flags */
+#define PCIBIOS_HW_TYPE1		0x01
+#define PCIBIOS_HW_TYPE2		0x02
+#define PCIBIOS_HW_TYPE1_SPEC		0x10
+#define PCIBIOS_HW_TYPE2_SPEC		0x20
+
+int pcibios_enabled;
+
+/* According to the BIOS specification at:
+ * http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could
+ * restrict the x zone to some pages and make it ro. But this may be
+ * broken on some bios, complex to handle with static_protections.
+ * We could make the 0xe0000-0x100000 range rox, but this can break
+ * some ISA mapping.
+ *
+ * So we let's an rw and x hole when pcibios is used. This shouldn't
+ * happen for modern system with mmconfig, and if you don't want it
+ * you could disable pcibios...
+ */
+static inline void set_bios_x(void)
+{
+	pcibios_enabled = 1;
+	set_memory_x(PAGE_OFFSET + BIOS_BEGIN, (BIOS_END - BIOS_BEGIN) >> PAGE_SHIFT);
+	if (__supported_pte_mask & _PAGE_NX)
+		printk(KERN_INFO "PCI: PCI BIOS area is rw and x. Use pci=nobios if you want it NX.\n");
+}
+
+/*
+ * This is the standard structure used to identify the entry point
+ * to the BIOS32 Service Directory, as documented in
+ * 	Standard BIOS 32-bit Service Directory Proposal
+ * 	Revision 0.4 May 24, 1993
+ * 	Phoenix Technologies Ltd.
+ *	Norwood, MA
+ * and the PCI BIOS specification.
+ */
+
+union bios32 {
+	struct {
+		unsigned long signature;	/* _32_ */
+		unsigned long entry;		/* 32 bit physical address */
+		unsigned char revision;		/* Revision level, 0 */
+		unsigned char length;		/* Length in paragraphs should be 01 */
+		unsigned char checksum;		/* All bytes must add up to zero */
+		unsigned char reserved[5]; 	/* Must be zero */
+	} fields;
+	char chars[16];
+};
+
+/*
+ * Physical address of the service directory.  I don't know if we're
+ * allowed to have more than one of these or not, so just in case
+ * we'll make pcibios_present() take a memory start parameter and store
+ * the array there.
+ */
+
+static struct {
+	unsigned long address;
+	unsigned short segment;
+} bios32_indirect __initdata = { 0, __KERNEL_CS };
+
+/*
+ * Returns the entry point for the given service, NULL on error
+ */
+
+static unsigned long __init bios32_service(unsigned long service)
+{
+	unsigned char return_code;	/* %al */
+	unsigned long address;		/* %ebx */
+	unsigned long length;		/* %ecx */
+	unsigned long entry;		/* %edx */
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__asm__("lcall *(%%edi); cld"
+		: "=a" (return_code),
+		  "=b" (address),
+		  "=c" (length),
+		  "=d" (entry)
+		: "0" (service),
+		  "1" (0),
+		  "D" (&bios32_indirect));
+	local_irq_restore(flags);
+
+	switch (return_code) {
+		case 0:
+			return address + entry;
+		case 0x80:	/* Not present */
+			printk(KERN_WARNING "bios32_service(0x%lx): not present\n", service);
+			return 0;
+		default: /* Shouldn't happen */
+			printk(KERN_WARNING "bios32_service(0x%lx): returned 0x%x -- BIOS bug!\n",
+				service, return_code);
+			return 0;
+	}
+}
+
+static struct {
+	unsigned long address;
+	unsigned short segment;
+} pci_indirect __ro_after_init = {
+	.address = 0,
+	.segment = __KERNEL_CS,
+};
+
+static int pci_bios_present __ro_after_init;
+
+static int __init check_pcibios(void)
+{
+	u32 signature, eax, ebx, ecx;
+	u8 status, major_ver, minor_ver, hw_mech;
+	unsigned long flags, pcibios_entry;
+
+	if ((pcibios_entry = bios32_service(PCI_SERVICE))) {
+		pci_indirect.address = pcibios_entry + PAGE_OFFSET;
+
+		local_irq_save(flags);
+		__asm__(
+			"lcall *(%%edi); cld\n\t"
+			"jc 1f\n\t"
+			"xor %%ah, %%ah\n"
+			"1:"
+			: "=d" (signature),
+			  "=a" (eax),
+			  "=b" (ebx),
+			  "=c" (ecx)
+			: "1" (PCIBIOS_PCI_BIOS_PRESENT),
+			  "D" (&pci_indirect)
+			: "memory");
+		local_irq_restore(flags);
+
+		status = (eax >> 8) & 0xff;
+		hw_mech = eax & 0xff;
+		major_ver = (ebx >> 8) & 0xff;
+		minor_ver = ebx & 0xff;
+		if (pcibios_last_bus < 0)
+			pcibios_last_bus = ecx & 0xff;
+		DBG("PCI: BIOS probe returned s=%02x hw=%02x ver=%02x.%02x l=%02x\n",
+			status, hw_mech, major_ver, minor_ver, pcibios_last_bus);
+		if (status || signature != PCI_SIGNATURE) {
+			printk (KERN_ERR "PCI: BIOS BUG #%x[%08x] found\n",
+				status, signature);
+			return 0;
+		}
+		printk(KERN_INFO "PCI: PCI BIOS revision %x.%02x entry at 0x%lx, last bus=%d\n",
+			major_ver, minor_ver, pcibios_entry, pcibios_last_bus);
+#ifdef CONFIG_PCI_DIRECT
+		if (!(hw_mech & PCIBIOS_HW_TYPE1))
+			pci_probe &= ~PCI_PROBE_CONF1;
+		if (!(hw_mech & PCIBIOS_HW_TYPE2))
+			pci_probe &= ~PCI_PROBE_CONF2;
+#endif
+		return 1;
+	}
+	return 0;
+}
+
+static int pci_bios_read(unsigned int seg, unsigned int bus,
+			 unsigned int devfn, int reg, int len, u32 *value)
+{
+	unsigned long result = 0;
+	unsigned long flags;
+	unsigned long bx = (bus << 8) | devfn;
+	u16 number = 0, mask = 0;
+
+	WARN_ON(seg);
+	if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	switch (len) {
+	case 1:
+		number = PCIBIOS_READ_CONFIG_BYTE;
+		mask = 0xff;
+		break;
+	case 2:
+		number = PCIBIOS_READ_CONFIG_WORD;
+		mask = 0xffff;
+		break;
+	case 4:
+		number = PCIBIOS_READ_CONFIG_DWORD;
+		break;
+	}
+
+	__asm__("lcall *(%%esi); cld\n\t"
+		"jc 1f\n\t"
+		"xor %%ah, %%ah\n"
+		"1:"
+		: "=c" (*value),
+		  "=a" (result)
+		: "1" (number),
+		  "b" (bx),
+		  "D" ((long)reg),
+		  "S" (&pci_indirect));
+	/*
+	 * Zero-extend the result beyond 8 or 16 bits, do not trust the
+	 * BIOS having done it:
+	 */
+	if (mask)
+		*value &= mask;
+
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+
+	return (int)((result & 0xff00) >> 8);
+}
+
+static int pci_bios_write(unsigned int seg, unsigned int bus,
+			  unsigned int devfn, int reg, int len, u32 value)
+{
+	unsigned long result = 0;
+	unsigned long flags;
+	unsigned long bx = (bus << 8) | devfn;
+	u16 number = 0;
+
+	WARN_ON(seg);
+	if ((bus > 255) || (devfn > 255) || (reg > 255)) 
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	switch (len) {
+	case 1:
+		number = PCIBIOS_WRITE_CONFIG_BYTE;
+		break;
+	case 2:
+		number = PCIBIOS_WRITE_CONFIG_WORD;
+		break;
+	case 4:
+		number = PCIBIOS_WRITE_CONFIG_DWORD;
+		break;
+	}
+
+	__asm__("lcall *(%%esi); cld\n\t"
+		"jc 1f\n\t"
+		"xor %%ah, %%ah\n"
+		"1:"
+		: "=a" (result)
+		: "0" (number),
+		  "c" (value),
+		  "b" (bx),
+		  "D" ((long)reg),
+		  "S" (&pci_indirect));
+
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+
+	return (int)((result & 0xff00) >> 8);
+}
+
+
+/*
+ * Function table for BIOS32 access
+ */
+
+static const struct pci_raw_ops pci_bios_access = {
+	.read =		pci_bios_read,
+	.write =	pci_bios_write
+};
+
+/*
+ * Try to find PCI BIOS.
+ */
+
+static const struct pci_raw_ops *__init pci_find_bios(void)
+{
+	union bios32 *check;
+	unsigned char sum;
+	int i, length;
+
+	/*
+	 * Follow the standard procedure for locating the BIOS32 Service
+	 * directory by scanning the permissible address range from
+	 * 0xe0000 through 0xfffff for a valid BIOS32 structure.
+	 */
+
+	for (check = (union bios32 *) __va(0xe0000);
+	     check <= (union bios32 *) __va(0xffff0);
+	     ++check) {
+		long sig;
+		if (get_kernel_nofault(sig, &check->fields.signature))
+			continue;
+
+		if (check->fields.signature != BIOS32_SIGNATURE)
+			continue;
+		length = check->fields.length * 16;
+		if (!length)
+			continue;
+		sum = 0;
+		for (i = 0; i < length ; ++i)
+			sum += check->chars[i];
+		if (sum != 0)
+			continue;
+		if (check->fields.revision != 0) {
+			printk("PCI: unsupported BIOS32 revision %d at 0x%p\n",
+				check->fields.revision, check);
+			continue;
+		}
+		DBG("PCI: BIOS32 Service Directory structure at 0x%p\n", check);
+		if (check->fields.entry >= 0x100000) {
+			printk("PCI: BIOS32 entry (0x%p) in high memory, "
+					"cannot use.\n", check);
+			return NULL;
+		} else {
+			unsigned long bios32_entry = check->fields.entry;
+			DBG("PCI: BIOS32 Service Directory entry at 0x%lx\n",
+					bios32_entry);
+			bios32_indirect.address = bios32_entry + PAGE_OFFSET;
+			set_bios_x();
+			if (check_pcibios())
+				return &pci_bios_access;
+		}
+		break;	/* Hopefully more than one BIOS32 cannot happen... */
+	}
+
+	return NULL;
+}
+
+/*
+ *  BIOS Functions for IRQ Routing
+ */
+
+struct irq_routing_options {
+	u16 size;
+	struct irq_info *table;
+	u16 segment;
+} __attribute__((packed));
+
+struct irq_routing_table * pcibios_get_irq_routing_table(void)
+{
+	struct irq_routing_options opt;
+	struct irq_routing_table *rt = NULL;
+	int ret, map;
+	unsigned long page;
+
+	if (!pci_bios_present)
+		return NULL;
+	page = __get_free_page(GFP_KERNEL);
+	if (!page)
+		return NULL;
+	opt.table = (struct irq_info *) page;
+	opt.size = PAGE_SIZE;
+	opt.segment = __KERNEL_DS;
+
+	DBG("PCI: Fetching IRQ routing table... ");
+	__asm__("push %%es\n\t"
+		"push %%ds\n\t"
+		"pop  %%es\n\t"
+		"lcall *(%%esi); cld\n\t"
+		"pop %%es\n\t"
+		"jc 1f\n\t"
+		"xor %%ah, %%ah\n"
+		"1:"
+		: "=a" (ret),
+		  "=b" (map),
+		  "=m" (opt)
+		: "0" (PCIBIOS_GET_ROUTING_OPTIONS),
+		  "1" (0),
+		  "D" ((long) &opt),
+		  "S" (&pci_indirect),
+		  "m" (opt)
+		: "memory");
+	DBG("OK  ret=%d, size=%d, map=%x\n", ret, opt.size, map);
+	if (ret & 0xff00)
+		printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff);
+	else if (opt.size) {
+		rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL);
+		if (rt) {
+			memset(rt, 0, sizeof(struct irq_routing_table));
+			rt->size = opt.size + sizeof(struct irq_routing_table);
+			rt->exclusive_irqs = map;
+			memcpy(rt->slots, (void *) page, opt.size);
+			printk(KERN_INFO "PCI: Using BIOS Interrupt Routing Table\n");
+		}
+	}
+	free_page(page);
+	return rt;
+}
+EXPORT_SYMBOL(pcibios_get_irq_routing_table);
+
+int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq)
+{
+	int ret;
+
+	__asm__("lcall *(%%esi); cld\n\t"
+		"jc 1f\n\t"
+		"xor %%ah, %%ah\n"
+		"1:"
+		: "=a" (ret)
+		: "0" (PCIBIOS_SET_PCI_HW_INT),
+		  "b" ((dev->bus->number << 8) | dev->devfn),
+		  "c" ((irq << 8) | (pin + 10)),
+		  "S" (&pci_indirect));
+	return !(ret & 0xff00);
+}
+EXPORT_SYMBOL(pcibios_set_irq_routing);
+
+void __init pci_pcbios_init(void)
+{
+	if ((pci_probe & PCI_PROBE_BIOS) 
+		&& ((raw_pci_ops = pci_find_bios()))) {
+		pci_bios_present = 1;
+	}
+}
+