From f146c7bc85a51f95c05e0f8173d484eb301ece78 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Thu, 13 Aug 2026 18:52:04 +0200 Subject: PCI: Add pci_irq_type() to query the allocated interrupt type Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX based on the interrupt type the PCI core selected after pci_alloc_irq_vectors(). Several drivers already open-code this check against pdev->msix_enabled and pdev->msi_enabled, or even open code this helper [1]. A common helper avoids the duplication and keeps drivers from accessing the bitfield directly (see also [2]). Acked-by: Bjorn Helgaas Tested-by: John Hubbard Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1] Inspired-by: John Hubbard Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2] Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org [ Add missing pci_irq_type() stub for CONFIG_PCI=n. ] Signed-off-by: Danilo Krummrich --- Documentation/usb/usbdevfs-drop-permissions.c | 120 ++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 Documentation/usb/usbdevfs-drop-permissions.c (limited to 'Documentation/usb/usbdevfs-drop-permissions.c') diff --git a/Documentation/usb/usbdevfs-drop-permissions.c b/Documentation/usb/usbdevfs-drop-permissions.c new file mode 100644 index 000000000..6b8da6ef0 --- /dev/null +++ b/Documentation/usb/usbdevfs-drop-permissions.c @@ -0,0 +1,120 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +/* For building without an updated set of headers */ +#ifndef USBDEVFS_DROP_PRIVILEGES +#define USBDEVFS_DROP_PRIVILEGES _IOW('U', 30, __u32) +#define USBDEVFS_CAP_DROP_PRIVILEGES 0x40 +#endif + +void drop_privileges(int fd, uint32_t mask) +{ + int res; + + res = ioctl(fd, USBDEVFS_DROP_PRIVILEGES, &mask); + if (res) + printf("ERROR: USBDEVFS_DROP_PRIVILEGES returned %d\n", res); + else + printf("OK: privileges dropped!\n"); +} + +void reset_device(int fd) +{ + int res; + + res = ioctl(fd, USBDEVFS_RESET); + if (!res) + printf("OK: USBDEVFS_RESET succeeded\n"); + else + printf("ERROR: reset failed! (%d - %s)\n", + -res, strerror(-res)); +} + +void claim_some_intf(int fd) +{ + int i, res; + + for (i = 0; i < 4; i++) { + res = ioctl(fd, USBDEVFS_CLAIMINTERFACE, &i); + if (!res) + printf("OK: claimed if %d\n", i); + else + printf("ERROR claiming if %d (%d - %s)\n", + i, -res, strerror(-res)); + } +} + +int main(int argc, char *argv[]) +{ + uint32_t mask, caps; + int c, fd; + + fd = open(argv[1], O_RDWR); + if (fd < 0) { + printf("Failed to open file\n"); + goto err_fd; + } + + /* + * check if dropping privileges is supported, + * bail on systems where the capability is not present + */ + ioctl(fd, USBDEVFS_GET_CAPABILITIES, &caps); + if (!(caps & USBDEVFS_CAP_DROP_PRIVILEGES)) { + printf("DROP_PRIVILEGES not supported\n"); + goto err; + } + + /* + * Drop privileges but keep the ability to claim all + * free interfaces (i.e., those not used by kernel drivers) + */ + drop_privileges(fd, -1U); + + printf("Available options:\n" + "[0] Exit now\n" + "[1] Reset device. Should fail if device is in use\n" + "[2] Claim 4 interfaces. Should succeed where not in use\n" + "[3] Narrow interface permission mask\n" + "Which option shall I run?: "); + + while (scanf("%d", &c) == 1) { + switch (c) { + case 0: + goto exit; + case 1: + reset_device(fd); + break; + case 2: + claim_some_intf(fd); + break; + case 3: + printf("Insert new mask: "); + scanf("%x", &mask); + drop_privileges(fd, mask); + break; + default: + printf("I don't recognize that\n"); + } + + printf("Which test shall I run next?: "); + } + +exit: + close(fd); + return 0; + +err: + close(fd); +err_fd: + return 1; +} -- cgit v1.3.1