| // 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 (probe_kernel_address(&check->fields.signature, sig)) |
| 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; |
| } |
| } |
| |