linux/drivers/pci/rom.c
Mikel Rychliski 72e0ef0e5f PCI: Use ioremap(), not phys_to_virt() for platform ROM
On some EFI systems, the video BIOS is provided by the EFI firmware.  The
boot stub code stores the physical address of the ROM image in pdev->rom.
Currently we attempt to access this pointer using phys_to_virt(), which
doesn't work with CONFIG_HIGHMEM.

On these systems, attempting to load the radeon module on a x86_32 kernel
can result in the following:

  BUG: unable to handle page fault for address: 3e8ed03c
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  *pde = 00000000
  Oops: 0000 [#1] PREEMPT SMP
  CPU: 0 PID: 317 Comm: systemd-udevd Not tainted 5.6.0-rc3-next-20200228 #2
  Hardware name: Apple Computer, Inc. MacPro1,1/Mac-F4208DC8, BIOS     MP11.88Z.005C.B08.0707021221 07/02/07
  EIP: radeon_get_bios+0x5ed/0xe50 [radeon]
  Code: 00 00 84 c0 0f 85 12 fd ff ff c7 87 64 01 00 00 00 00 00 00 8b 47 08 8b 55 b0 e8 1e 83 e1 d6 85 c0 74 1a 8b 55 c0 85 d2 74 13 <80> 38 55 75 0e 80 78 01 aa 0f 84 a4 03 00 00 8d 74 26 00 68 dc 06
  EAX: 3e8ed03c EBX: 00000000 ECX: 3e8ed03c EDX: 00010000
  ESI: 00040000 EDI: eec04000 EBP: eef3fc60 ESP: eef3fbe0
  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010206
  CR0: 80050033 CR2: 3e8ed03c CR3: 2ec77000 CR4: 000006d0
  Call Trace:
   r520_init+0x26/0x240 [radeon]
   radeon_device_init+0x533/0xa50 [radeon]
   radeon_driver_load_kms+0x80/0x220 [radeon]
   drm_dev_register+0xa7/0x180 [drm]
   radeon_pci_probe+0x10f/0x1a0 [radeon]
   pci_device_probe+0xd4/0x140

Fix the issue by updating all drivers which can access a platform provided
ROM. Instead of calling the helper function pci_platform_rom() which uses
phys_to_virt(), call ioremap() directly on the pdev->rom.

radeon_read_platform_bios() previously directly accessed an __iomem
pointer. Avoid this by calling memcpy_fromio() instead of kmemdup().

pci_platform_rom() now has no remaining callers, so remove it.

Link: https://lore.kernel.org/r/20200319021623.5426-1-mikel@mikelr.com
Signed-off-by: Mikel Rychliski <mikel@mikelr.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
2020-03-30 09:52:23 -05:00

198 lines
5.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* PCI ROM access routines
*
* (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
* (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include "pci.h"
/**
* pci_enable_rom - enable ROM decoding for a PCI device
* @pdev: PCI device to enable
*
* Enable ROM decoding on @dev. This involves simply turning on the last
* bit of the PCI ROM BAR. Note that some cards may share address decoders
* between the ROM and other resources, so enabling it may disable access
* to MMIO registers or other card memory.
*/
int pci_enable_rom(struct pci_dev *pdev)
{
struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
struct pci_bus_region region;
u32 rom_addr;
if (!res->flags)
return -1;
/* Nothing to enable if we're using a shadow copy in RAM */
if (res->flags & IORESOURCE_ROM_SHADOW)
return 0;
/*
* Ideally pci_update_resource() would update the ROM BAR address,
* and we would only set the enable bit here. But apparently some
* devices have buggy ROM BARs that read as zero when disabled.
*/
pcibios_resource_to_bus(pdev->bus, &region, res);
pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
rom_addr &= ~PCI_ROM_ADDRESS_MASK;
rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_rom);
/**
* pci_disable_rom - disable ROM decoding for a PCI device
* @pdev: PCI device to disable
*
* Disable ROM decoding on a PCI device by turning off the last bit in the
* ROM BAR.
*/
void pci_disable_rom(struct pci_dev *pdev)
{
struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
u32 rom_addr;
if (res->flags & IORESOURCE_ROM_SHADOW)
return;
pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
}
EXPORT_SYMBOL_GPL(pci_disable_rom);
/**
* pci_get_rom_size - obtain the actual size of the ROM image
* @pdev: target PCI device
* @rom: kernel virtual pointer to image of ROM
* @size: size of PCI window
* return: size of actual ROM image
*
* Determine the actual length of the ROM image.
* The PCI window size could be much larger than the
* actual image size.
*/
static size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom,
size_t size)
{
void __iomem *image;
int last_image;
unsigned length;
image = rom;
do {
void __iomem *pds;
/* Standard PCI ROMs start out with these bytes 55 AA */
if (readw(image) != 0xAA55) {
pci_info(pdev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n",
readw(image));
break;
}
/* get the PCI data structure and check its "PCIR" signature */
pds = image + readw(image + 24);
if (readl(pds) != 0x52494350) {
pci_info(pdev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n",
readl(pds));
break;
}
last_image = readb(pds + 21) & 0x80;
length = readw(pds + 16);
image += length * 512;
/* Avoid iterating through memory outside the resource window */
if (image >= rom + size)
break;
if (!last_image) {
if (readw(image) != 0xAA55) {
pci_info(pdev, "No more image in the PCI ROM\n");
break;
}
}
} while (length && !last_image);
/* never return a size larger than the PCI resource window */
/* there are known ROMs that get the size wrong */
return min((size_t)(image - rom), size);
}
/**
* pci_map_rom - map a PCI ROM to kernel space
* @pdev: pointer to pci device struct
* @size: pointer to receive size of pci window over ROM
*
* Return: kernel virtual pointer to image of ROM
*
* Map a PCI ROM into kernel space. If ROM is boot video ROM,
* the shadow BIOS copy will be returned instead of the
* actual ROM.
*/
void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
{
struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
loff_t start;
void __iomem *rom;
/* assign the ROM an address if it doesn't have one */
if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE))
return NULL;
start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
*size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
if (*size == 0)
return NULL;
/* Enable ROM space decodes */
if (pci_enable_rom(pdev))
return NULL;
rom = ioremap(start, *size);
if (!rom)
goto err_ioremap;
/*
* Try to find the true size of the ROM since sometimes the PCI window
* size is much larger than the actual size of the ROM.
* True size is important if the ROM is going to be copied.
*/
*size = pci_get_rom_size(pdev, rom, *size);
if (!*size)
goto invalid_rom;
return rom;
invalid_rom:
iounmap(rom);
err_ioremap:
/* restore enable if ioremap fails */
if (!(res->flags & IORESOURCE_ROM_ENABLE))
pci_disable_rom(pdev);
return NULL;
}
EXPORT_SYMBOL(pci_map_rom);
/**
* pci_unmap_rom - unmap the ROM from kernel space
* @pdev: pointer to pci device struct
* @rom: virtual address of the previous mapping
*
* Remove a mapping of a previously mapped ROM
*/
void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
{
struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
iounmap(rom);
/* Disable again before continuing */
if (!(res->flags & IORESOURCE_ROM_ENABLE))
pci_disable_rom(pdev);
}
EXPORT_SYMBOL(pci_unmap_rom);