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c5a8f13f1e
In the EFI config table, rename LINUX_EFI_SCREEN_INFO_TABLE_GUID to LINUX_EFI_PRIMARY_DISPLAY_TABLE_GUID. Read sysfb_primary_display from the entry. In addition to the screen_info, the entry now also contains EDID information. In libstub, replace struct screen_info with struct sysfb_display_info from the kernel's sysfb_primary_display and rename functions accordingly. Transfer it to the runtime kernel using the kernel's global state or the LINUX_EFI_PRIMARY_DISPLAY_TABLE_GUID config-table entry. With CONFIG_FIRMWARE_EDID=y, libstub now transfers the GOP device's EDID information to the kernel. If CONFIG_FIRMWARE_EDID=n, EDID information is disabled. Make the Kconfig symbol CONFIG_FIRMWARE_EDID available with EFI. Setting the value to 'n' disables EDID support. Also rename screen_info.c to primary_display.c and adapt the contained comment according to the changes. Link: https://lore.kernel.org/all/20251126160854.553077-8-tzimmermann@suse.de/ Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> [ardb: depend on EFI_GENERIC_STUB not EFI, fix conflicts after dropping the preceding patch from the series] Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/efi.h>
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#include <linux/pe.h>
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#include <asm/efi.h>
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#include <linux/unaligned.h>
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#include "efistub.h"
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static unsigned long alloc_preferred_address(unsigned long alloc_size)
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{
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#ifdef EFI_KIMG_PREFERRED_ADDRESS
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efi_physical_addr_t efi_addr = EFI_KIMG_PREFERRED_ADDRESS;
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if (efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
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alloc_size / EFI_PAGE_SIZE, &efi_addr) == EFI_SUCCESS)
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return efi_addr;
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#endif
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return ULONG_MAX;
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}
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void __weak efi_cache_sync_image(unsigned long image_base,
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unsigned long alloc_size)
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{
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// Provided by the arch to perform the cache maintenance necessary for
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// executable code loaded into memory to be safe for execution.
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}
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struct sysfb_display_info *alloc_primary_display(void)
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{
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return __alloc_primary_display();
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}
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asmlinkage efi_status_t __efiapi
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efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
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{
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char *cmdline_ptr __free(efi_pool) = NULL;
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unsigned long image_base, alloc_size;
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efi_loaded_image_t *image;
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efi_status_t status;
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WRITE_ONCE(efi_system_table, systab);
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status = efi_bs_call(handle_protocol, handle,
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&LOADED_IMAGE_PROTOCOL_GUID, (void **)&image);
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if (status != EFI_SUCCESS) {
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efi_err("Failed to locate parent's loaded image protocol\n");
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return status;
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}
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status = efi_handle_cmdline(image, &cmdline_ptr);
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if (status != EFI_SUCCESS)
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return status;
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efi_info("Decompressing Linux Kernel...\n");
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status = efi_zboot_decompress_init(&alloc_size);
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if (status != EFI_SUCCESS)
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return status;
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// If the architecture has a preferred address for the image,
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// try that first.
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image_base = alloc_preferred_address(alloc_size);
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if (image_base == ULONG_MAX) {
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unsigned long min_kimg_align = efi_get_kimg_min_align();
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u32 seed = U32_MAX;
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if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
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// Setting the random seed to 0x0 is the same as
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// allocating as low as possible
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seed = 0;
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} else if (efi_nokaslr) {
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efi_info("KASLR disabled on kernel command line\n");
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} else {
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status = efi_get_random_bytes(sizeof(seed), (u8 *)&seed);
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if (status == EFI_NOT_FOUND) {
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efi_info("EFI_RNG_PROTOCOL unavailable\n");
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efi_nokaslr = true;
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} else if (status != EFI_SUCCESS) {
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efi_err("efi_get_random_bytes() failed (0x%lx)\n",
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status);
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efi_nokaslr = true;
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}
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}
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status = efi_random_alloc(alloc_size, min_kimg_align, &image_base,
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seed, EFI_LOADER_CODE, 0, EFI_ALLOC_LIMIT);
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if (status != EFI_SUCCESS) {
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efi_err("Failed to allocate memory\n");
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return status;
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}
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}
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// Decompress the payload into the newly allocated buffer
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status = efi_zboot_decompress((void *)image_base, alloc_size) ?:
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efi_stub_common(handle, image, image_base, cmdline_ptr);
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efi_free(alloc_size, image_base);
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return status;
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}
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