// SPDX-License-Identifier: GPL-2.0 /* * For architectures where we want to allow direct access to the PCI config * stuff - it would probably be preferable on PCs too, but there people * just do it by hand with the magic northbridge registers. */ #include <linux/errno.h> #include <linux/pci.h> #include <linux/syscalls.h> #include <linux/uaccess.h> #include "pci.h" SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn, unsigned long, off, unsigned long, len, void __user *, buf) { struct pci_dev *dev; u8 byte; u16 word; u32 dword; long err; long cfg_ret; if (!capable(CAP_SYS_ADMIN)) return -EPERM; err = -ENODEV; dev = pci_get_domain_bus_and_slot(0, bus, dfn); if (!dev) goto error; switch (len) { case 1: cfg_ret = pci_user_read_config_byte(dev, off, &byte); break; case 2: cfg_ret = pci_user_read_config_word(dev, off, &word); break; case 4: cfg_ret = pci_user_read_config_dword(dev, off, &dword); break; default: err = -EINVAL; goto error; } err = -EIO; if (cfg_ret != PCIBIOS_SUCCESSFUL) goto error; switch (len) { case 1: err = put_user(byte, (unsigned char __user *)buf); break; case 2: err = put_user(word, (unsigned short __user *)buf); break; case 4: err = put_user(dword, (unsigned int __user *)buf); break; } pci_dev_put(dev); return err; error: /* ??? XFree86 doesn't even check the return value. They just look for 0xffffffff in the output, since that's what they get instead of a machine check on x86. */ switch (len) { case 1: put_user(-1, (unsigned char __user *)buf); break; case 2: put_user(-1, (unsigned short __user *)buf); break; case 4: put_user(-1, (unsigned int __user *)buf); break; } pci_dev_put(dev); return err; } SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn, unsigned long, off, unsigned long, len, void __user *, buf) { struct pci_dev *dev; u8 byte; u16 word; u32 dword; int err = 0; if (!capable(CAP_SYS_ADMIN)) return -EPERM; dev = pci_get_domain_bus_and_slot(0, bus, dfn); if (!dev) return -ENODEV; switch (len) { case 1: err = get_user(byte, (u8 __user *)buf); if (err) break; err = pci_user_write_config_byte(dev, off, byte); if (err != PCIBIOS_SUCCESSFUL) err = -EIO; break; case 2: err = get_user(word, (u16 __user *)buf); if (err) break; err = pci_user_write_config_word(dev, off, word); if (err != PCIBIOS_SUCCESSFUL) err = -EIO; break; case 4: err = get_user(dword, (u32 __user *)buf); if (err) break; err = pci_user_write_config_dword(dev, off, dword); if (err != PCIBIOS_SUCCESSFUL) err = -EIO; break; default: err = -EINVAL; break; } pci_dev_put(dev); return err; }