linux/arch/x86/pci/pcbios.c

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/*
* BIOS32 and PCI BIOS handling.
*/
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include "pci.h"
#include "pci-functions.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
/*
* 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 = { 0, __KERNEL_CS };
/*
* Returns the entry point for the given service, NULL on error
*/
static unsigned long 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 = { 0, __KERNEL_CS };
static int pci_bios_present;
static int __devinit 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;
if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
return -EINVAL;
spin_lock_irqsave(&pci_config_lock, flags);
switch (len) {
case 1:
__asm__("lcall *(%%esi); cld\n\t"
"jc 1f\n\t"
"xor %%ah, %%ah\n"
"1:"
: "=c" (*value),
"=a" (result)
: "1" (PCIBIOS_READ_CONFIG_BYTE),
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
fix BIOS PCI config cycle buglet causing ACPI boot regression I figured out another ACPI related regression today. randconfig testing triggered an early boot-time hang on a laptop of mine (32-bit x86, config attached) - the screen was scrolling ACPI AML exceptions [with no serial port and no early debugging available]. v2.6.24 works fine on that laptop with the same .config, so after a few hours of bisection (had to restart it 3 times - other regressions interacted), it honed in on this commit: | 10270d4838bdc493781f5a1cf2e90e9c34c9142f is first bad commit | | Author: Linus Torvalds <torvalds@woody.linux-foundation.org> | Date: Wed Feb 13 09:56:14 2008 -0800 | | acpi: fix acpi_os_read_pci_configuration() misuse of raw_pci_read() reverting this commit ontop of -rc5 gave a correctly booting kernel. But this commit fixes a real bug so the real question is, why did it break the bootup? After quite some head-scratching, the following change stood out: - pci_id->bus = tu8; + pci_id->bus = val; pci_id->bus is defined as u16: struct acpi_pci_id { u16 segment; u16 bus; ... and 'tu8' changed from u8 to u32. So previously we'd unconditionally mask the return value of acpi_os_read_pci_configuration() (raw_pci_read()) to 8 bits, but now we just trust whatever comes back from the PCI access routines and only crop it to 16 bits. But if the high 8 bits of that result contains any noise then we'll write that into ACPI's PCI ID descriptor and confuse the heck out of the rest of ACPI. So lets check the PCI-BIOS code on that theory. We have this codepath for 8-bit accesses (arch/x86/pci/pcbios.c:pci_bios_read()): switch (len) { case 1: __asm__("lcall *(%%esi); cld\n\t" "jc 1f\n\t" "xor %%ah, %%ah\n" "1:" : "=c" (*value), "=a" (result) : "1" (PCIBIOS_READ_CONFIG_BYTE), "b" (bx), "D" ((long)reg), "S" (&pci_indirect)); Aha! The "=a" output constraint puts the full 32 bits of EAX into *value. But if the BIOS's routines set any of the high bits to nonzero, we'll return a value with more set in it than intended. The other, more common PCI access methods (v1 and v2 PCI reads) clear out the high bits already, for example pci_conf1_read() does: switch (len) { case 1: *value = inb(0xCFC + (reg & 3)); which explicitly converts the return byte up to 32 bits and zero-extends it. So zero-extending the result in the PCI-BIOS read routine fixes the regression on my laptop. ( It might fix some other long-standing issues we had with PCI-BIOS during the past decade ... ) Both 8-bit and 16-bit accesses were buggy. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-10 17:04:34 +00:00
/*
* Zero-extend the result beyond 8 bits, do not trust the
* BIOS having done it:
*/
*value &= 0xff;
break;
case 2:
__asm__("lcall *(%%esi); cld\n\t"
"jc 1f\n\t"
"xor %%ah, %%ah\n"
"1:"
: "=c" (*value),
"=a" (result)
: "1" (PCIBIOS_READ_CONFIG_WORD),
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
fix BIOS PCI config cycle buglet causing ACPI boot regression I figured out another ACPI related regression today. randconfig testing triggered an early boot-time hang on a laptop of mine (32-bit x86, config attached) - the screen was scrolling ACPI AML exceptions [with no serial port and no early debugging available]. v2.6.24 works fine on that laptop with the same .config, so after a few hours of bisection (had to restart it 3 times - other regressions interacted), it honed in on this commit: | 10270d4838bdc493781f5a1cf2e90e9c34c9142f is first bad commit | | Author: Linus Torvalds <torvalds@woody.linux-foundation.org> | Date: Wed Feb 13 09:56:14 2008 -0800 | | acpi: fix acpi_os_read_pci_configuration() misuse of raw_pci_read() reverting this commit ontop of -rc5 gave a correctly booting kernel. But this commit fixes a real bug so the real question is, why did it break the bootup? After quite some head-scratching, the following change stood out: - pci_id->bus = tu8; + pci_id->bus = val; pci_id->bus is defined as u16: struct acpi_pci_id { u16 segment; u16 bus; ... and 'tu8' changed from u8 to u32. So previously we'd unconditionally mask the return value of acpi_os_read_pci_configuration() (raw_pci_read()) to 8 bits, but now we just trust whatever comes back from the PCI access routines and only crop it to 16 bits. But if the high 8 bits of that result contains any noise then we'll write that into ACPI's PCI ID descriptor and confuse the heck out of the rest of ACPI. So lets check the PCI-BIOS code on that theory. We have this codepath for 8-bit accesses (arch/x86/pci/pcbios.c:pci_bios_read()): switch (len) { case 1: __asm__("lcall *(%%esi); cld\n\t" "jc 1f\n\t" "xor %%ah, %%ah\n" "1:" : "=c" (*value), "=a" (result) : "1" (PCIBIOS_READ_CONFIG_BYTE), "b" (bx), "D" ((long)reg), "S" (&pci_indirect)); Aha! The "=a" output constraint puts the full 32 bits of EAX into *value. But if the BIOS's routines set any of the high bits to nonzero, we'll return a value with more set in it than intended. The other, more common PCI access methods (v1 and v2 PCI reads) clear out the high bits already, for example pci_conf1_read() does: switch (len) { case 1: *value = inb(0xCFC + (reg & 3)); which explicitly converts the return byte up to 32 bits and zero-extends it. So zero-extending the result in the PCI-BIOS read routine fixes the regression on my laptop. ( It might fix some other long-standing issues we had with PCI-BIOS during the past decade ... ) Both 8-bit and 16-bit accesses were buggy. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-10 17:04:34 +00:00
/*
* Zero-extend the result beyond 16 bits, do not trust the
* BIOS having done it:
*/
*value &= 0xffff;
break;
case 4:
__asm__("lcall *(%%esi); cld\n\t"
"jc 1f\n\t"
"xor %%ah, %%ah\n"
"1:"
: "=c" (*value),
"=a" (result)
: "1" (PCIBIOS_READ_CONFIG_DWORD),
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
break;
}
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;
if ((bus > 255) || (devfn > 255) || (reg > 255))
return -EINVAL;
spin_lock_irqsave(&pci_config_lock, flags);
switch (len) {
case 1:
__asm__("lcall *(%%esi); cld\n\t"
"jc 1f\n\t"
"xor %%ah, %%ah\n"
"1:"
: "=a" (result)
: "0" (PCIBIOS_WRITE_CONFIG_BYTE),
"c" (value),
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
break;
case 2:
__asm__("lcall *(%%esi); cld\n\t"
"jc 1f\n\t"
"xor %%ah, %%ah\n"
"1:"
: "=a" (result)
: "0" (PCIBIOS_WRITE_CONFIG_WORD),
"c" (value),
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
break;
case 4:
__asm__("lcall *(%%esi); cld\n\t"
"jc 1f\n\t"
"xor %%ah, %%ah\n"
"1:"
: "=a" (result)
: "0" (PCIBIOS_WRITE_CONFIG_DWORD),
"c" (value),
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
break;
}
spin_unlock_irqrestore(&pci_config_lock, flags);
return (int)((result & 0xff00) >> 8);
}
/*
* Function table for BIOS32 access
*/
static struct pci_raw_ops pci_bios_access = {
.read = pci_bios_read,
.write = pci_bios_write
};
/*
* Try to find PCI BIOS.
*/
static struct pci_raw_ops * __devinit 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;
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;
}
}