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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-10-02 12:17:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-10-02 12:17:24 -0700 |
| commit | 3f1fe48a36b0b6722dc3fd421d93512bac138e9a (patch) | |
| tree | b767d7f6e26bc64334d3f14f8422d187239dc45d /drivers/pci/rom.c | |
| download | linux-stable-3f1fe48a36b0b6722dc3fd421d93512bac138e9a.tar.gz linux-stable-3f1fe48a36b0b6722dc3fd421d93512bac138e9a.zip | |
Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted
Pull io_uring fixes from Jens Axboe:
- Fix a task_work add use-after-free with SQPOLL.
The sqpoll thread could pop and complete the last request while
io_req_normal_work_add() was still looking at them after the mpscq
push.
Use the same approach as DEFER_TASKRUN to protect from that, holding
an RCU read lock across the add, and have exit wait for an RCU grace
period for SQPOLL rings as well.
- CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the
big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED
rings
- Mark the source filter table as COW when cloning bpf filters, so
registering another filter on the source doesn't modify the shared
table in place
- Initialize the task context before running the BPF loop
- Requeue zcrx multishot receives stopped by a local resource
- End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit)
* tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
io_uring: fix task_work add use-after-free with SQPOLL
io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full
io_uring/zcrx: requeue multishot receives stopped by a local resource
io_uring: initialize task context before running the BPF loop
io_uring: zero big_cqe for aux CQEs on CQE32 rings
io_uring: fix free entry check for 32b CQEs on CQE32 rings
io_uring: only post the dummy skip CQE on CQE_MIXED rings
io_uring/bpf_filter: mark source as COW when cloning filters
Diffstat (limited to 'drivers/pci/rom.c')
| -rw-r--r-- | drivers/pci/rom.c | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c new file mode 100644 index 000000000..f2105c6ce --- /dev/null +++ b/drivers/pci/rom.c @@ -0,0 +1,300 @@ +// 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/align.h> +#include <linux/bits.h> +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/io.h> +#include <linux/overflow.h> +#include <linux/pci.h> +#include <linux/sizes.h> +#include <linux/slab.h> + +#include "pci.h" + +#define PCI_ROM_HEADER_SIZE 0x1A +#define PCI_ROM_POINTER_TO_DATA_STRUCT 0x18 +#define PCI_ROM_LAST_IMAGE_INDICATOR 0x15 +#define PCI_ROM_LAST_IMAGE_INDICATOR_BIT BIT(7) +#define PCI_ROM_IMAGE_LEN 0x10 +#define PCI_ROM_IMAGE_SECTOR_SIZE SZ_512 +#define PCI_ROM_IMAGE_SIGNATURE 0xAA55 + +/* Data structure signature is "PCIR" in ASCII representation */ +#define PCI_ROM_DATA_STRUCT_SIGNATURE 0x52494350 +#define PCI_ROM_DATA_STRUCT_LEN 0x0A + +/* + * Per PCI Firmware r3.3, sec 5.1.3, a conformant PCI Data Structure is at + * least 24 bytes (0x18), large enough to cover every fixed field this + * driver reads (up to the Indicator byte at offset 0x15). Reject smaller + * device-claimed lengths so the follow-up readers in pci_get_rom_size() + * cannot escape the mapped ROM window. + */ +#define PCI_ROM_DATA_STRUCT_MIN_LEN 0x18 + +/** + * 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, ®ion, 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); + +static bool pci_rom_header_valid(struct pci_dev *pdev, void __iomem *image, + void __iomem *rom, size_t size, + bool expect_valid) +{ + unsigned long rom_end = (unsigned long)rom + size - 1; + unsigned long header_end; + u16 signature; + + /* + * Per PCI Firmware r3.3, sec 5.1, each image must start on a + * 512-byte boundary and must contain the PCI Expansion ROM header. + * Because @rom is page-aligned (returned by ioremap()), checking + * 512-byte alignment of @image is equivalent to enforcing the + * spec's sector-aligned layout within the ROM. This also + * satisfies the natural-alignment requirement of readw() on archs + * such as arm64 that disallow unaligned IOMEM access. + */ + if (!IS_ALIGNED((unsigned long)image, PCI_ROM_IMAGE_SECTOR_SIZE)) + return false; + + if (check_add_overflow((unsigned long)image, PCI_ROM_HEADER_SIZE - 1, + &header_end)) + return false; + + if (image < rom || header_end > rom_end) + return false; + + /* Standard PCI ROMs start out with these bytes 55 AA */ + signature = readw(image); + if (signature != PCI_ROM_IMAGE_SIGNATURE) { + if (expect_valid) { + pci_info(pdev, "Invalid PCI ROM header signature: expecting %#06x, got %#06x\n", + PCI_ROM_IMAGE_SIGNATURE, signature); + } else { + pci_info(pdev, "No more images in PCI ROM\n"); + } + return false; + } + + return true; +} + +static bool pci_rom_data_struct_valid(struct pci_dev *pdev, void __iomem *pds, + void __iomem *rom, size_t size) +{ + unsigned long rom_end = (unsigned long)rom + size - 1; + unsigned long end; + u32 signature; + u16 data_len; + + /* + * Some CPU architectures require IOMEM access addresses to be + * aligned, for example arm64, so since we're about to call + * readl(), check here for 4-byte alignment. + */ + if (!IS_ALIGNED((unsigned long)pds, 4)) + return false; + + if (check_add_overflow((unsigned long)pds, PCI_ROM_DATA_STRUCT_LEN + 1, + &end)) + return false; + + if (pds < rom || end > rom_end) + return false; + + signature = readl(pds); + if (signature != PCI_ROM_DATA_STRUCT_SIGNATURE) { + pci_info(pdev, "Invalid PCI ROM data signature: expecting %#010x, got %#010x\n", + PCI_ROM_DATA_STRUCT_SIGNATURE, signature); + return false; + } + + data_len = readw(pds + PCI_ROM_DATA_STRUCT_LEN); + if (data_len < PCI_ROM_DATA_STRUCT_MIN_LEN || data_len == U16_MAX) + return false; + + if (check_add_overflow((unsigned long)pds, data_len - 1, &end)) + return false; + + if (end > rom_end) + return false; + + return true; +} + +/** + * 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; + unsigned int length; + bool last_image; + + image = rom; + do { + void __iomem *pds; + if (!pci_rom_header_valid(pdev, image, rom, size, true)) + break; + + /* Get the PCI data structure and check its "PCIR" signature */ + pds = image + readw(image + PCI_ROM_POINTER_TO_DATA_STRUCT); + if (!pci_rom_data_struct_valid(pdev, pds, rom, size)) + break; + + last_image = readb(pds + PCI_ROM_LAST_IMAGE_INDICATOR) & + PCI_ROM_LAST_IMAGE_INDICATOR_BIT; + length = readw(pds + PCI_ROM_IMAGE_LEN); + image += length * PCI_ROM_IMAGE_SECTOR_SIZE; + + if (!last_image && + !pci_rom_header_valid(pdev, image, rom, size, false)) + 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); |
