diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index c3e869eaef0c625b98f5bcafabd1a2aba02ab8c7..e007887a33b0d2c8b62eef451c40a1b2f875c2cb 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -767,7 +767,7 @@ static efi_status_t setup_e820(struct boot_params *params, m |= (u64)efi->efi_memmap_hi << 32; #endif - d = (efi_memory_desc_t *)(m + (i * efi->efi_memdesc_size)); + d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i); switch (d->type) { case EFI_RESERVED_TYPE: case EFI_RUNTIME_SERVICES_CODE: diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index 91f27ab970ef74347c1915e7ff6ac5f8a8803b8d..17818ba6906f84f6d4a90d59893875fe7f314731 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -37,7 +37,9 @@ #include #include #include +#include #include +#include /* Macros used by the included decompressor code below. */ #define STATIC @@ -479,35 +481,31 @@ static unsigned long slots_fetch_random(void) return 0; } -static void process_e820_entry(struct boot_e820_entry *entry, +static void process_mem_region(struct mem_vector *entry, unsigned long minimum, unsigned long image_size) { struct mem_vector region, overlap; struct slot_area slot_area; unsigned long start_orig, end; - struct boot_e820_entry cur_entry; - - /* Skip non-RAM entries. */ - if (entry->type != E820_TYPE_RAM) - return; + struct mem_vector cur_entry; /* On 32-bit, ignore entries entirely above our maximum. */ - if (IS_ENABLED(CONFIG_X86_32) && entry->addr >= KERNEL_IMAGE_SIZE) + if (IS_ENABLED(CONFIG_X86_32) && entry->start >= KERNEL_IMAGE_SIZE) return; /* Ignore entries entirely below our minimum. */ - if (entry->addr + entry->size < minimum) + if (entry->start + entry->size < minimum) return; /* Ignore entries above memory limit */ - end = min(entry->size + entry->addr, mem_limit); - if (entry->addr >= end) + end = min(entry->size + entry->start, mem_limit); + if (entry->start >= end) return; - cur_entry.addr = entry->addr; - cur_entry.size = end - entry->addr; + cur_entry.start = entry->start; + cur_entry.size = end - entry->start; - region.start = cur_entry.addr; + region.start = cur_entry.start; region.size = cur_entry.size; /* Give up if slot area array is full. */ @@ -521,8 +519,8 @@ static void process_e820_entry(struct boot_e820_entry *entry, /* Potentially raise address to meet alignment needs. */ region.start = ALIGN(region.start, CONFIG_PHYSICAL_ALIGN); - /* Did we raise the address above this e820 region? */ - if (region.start > cur_entry.addr + cur_entry.size) + /* Did we raise the address above the passed in memory entry? */ + if (region.start > cur_entry.start + cur_entry.size) return; /* Reduce size by any delta from the original address. */ @@ -562,31 +560,126 @@ static void process_e820_entry(struct boot_e820_entry *entry, } } -static unsigned long find_random_phys_addr(unsigned long minimum, - unsigned long image_size) +#ifdef CONFIG_EFI +/* + * Returns true if mirror region found (and must have been processed + * for slots adding) + */ +static bool +process_efi_entries(unsigned long minimum, unsigned long image_size) { + struct efi_info *e = &boot_params->efi_info; + bool efi_mirror_found = false; + struct mem_vector region; + efi_memory_desc_t *md; + unsigned long pmap; + char *signature; + u32 nr_desc; int i; - unsigned long addr; - /* Check if we had too many memmaps. */ - if (memmap_too_large) { - debug_putstr("Aborted e820 scan (more than 4 memmap= args)!\n"); - return 0; + signature = (char *)&e->efi_loader_signature; + if (strncmp(signature, EFI32_LOADER_SIGNATURE, 4) && + strncmp(signature, EFI64_LOADER_SIGNATURE, 4)) + return false; + +#ifdef CONFIG_X86_32 + /* Can't handle data above 4GB at this time */ + if (e->efi_memmap_hi) { + warn("EFI memmap is above 4GB, can't be handled now on x86_32. EFI should be disabled.\n"); + return false; } + pmap = e->efi_memmap; +#else + pmap = (e->efi_memmap | ((__u64)e->efi_memmap_hi << 32)); +#endif - /* Make sure minimum is aligned. */ - minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN); + nr_desc = e->efi_memmap_size / e->efi_memdesc_size; + for (i = 0; i < nr_desc; i++) { + md = efi_early_memdesc_ptr(pmap, e->efi_memdesc_size, i); + if (md->attribute & EFI_MEMORY_MORE_RELIABLE) { + efi_mirror_found = true; + break; + } + } + + for (i = 0; i < nr_desc; i++) { + md = efi_early_memdesc_ptr(pmap, e->efi_memdesc_size, i); + + /* + * Here we are more conservative in picking free memory than + * the EFI spec allows: + * + * According to the spec, EFI_BOOT_SERVICES_{CODE|DATA} are also + * free memory and thus available to place the kernel image into, + * but in practice there's firmware where using that memory leads + * to crashes. + * + * Only EFI_CONVENTIONAL_MEMORY is guaranteed to be free. + */ + if (md->type != EFI_CONVENTIONAL_MEMORY) + continue; + + if (efi_mirror_found && + !(md->attribute & EFI_MEMORY_MORE_RELIABLE)) + continue; + + region.start = md->phys_addr; + region.size = md->num_pages << EFI_PAGE_SHIFT; + process_mem_region(®ion, minimum, image_size); + if (slot_area_index == MAX_SLOT_AREA) { + debug_putstr("Aborted EFI scan (slot_areas full)!\n"); + break; + } + } + return true; +} +#else +static inline bool +process_efi_entries(unsigned long minimum, unsigned long image_size) +{ + return false; +} +#endif + +static void process_e820_entries(unsigned long minimum, + unsigned long image_size) +{ + int i; + struct mem_vector region; + struct boot_e820_entry *entry; /* Verify potential e820 positions, appending to slots list. */ for (i = 0; i < boot_params->e820_entries; i++) { - process_e820_entry(&boot_params->e820_table[i], minimum, - image_size); + entry = &boot_params->e820_table[i]; + /* Skip non-RAM entries. */ + if (entry->type != E820_TYPE_RAM) + continue; + region.start = entry->addr; + region.size = entry->size; + process_mem_region(®ion, minimum, image_size); if (slot_area_index == MAX_SLOT_AREA) { debug_putstr("Aborted e820 scan (slot_areas full)!\n"); break; } } +} + +static unsigned long find_random_phys_addr(unsigned long minimum, + unsigned long image_size) +{ + /* Check if we had too many memmaps. */ + if (memmap_too_large) { + debug_putstr("Aborted memory entries scan (more than 4 memmap= args)!\n"); + return 0; + } + + /* Make sure minimum is aligned. */ + minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN); + + if (process_efi_entries(minimum, image_size)) + return slots_fetch_random(); + process_e820_entries(minimum, image_size); return slots_fetch_random(); } @@ -645,7 +738,7 @@ void choose_random_location(unsigned long input, */ min_addr = min(*output, 512UL << 20); - /* Walk e820 and find a random address. */ + /* Walk available memory entries to find a random address. */ random_addr = find_random_phys_addr(min_addr, output_size); if (!random_addr) { warn("Physical KASLR disabled: no suitable memory region!"); diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index b0184360efc65553ba26a1d0fecc4e483dd2c462..50a9cab5a8340e542e2f8d12172bd4d500934d91 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -205,7 +205,7 @@ efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg, unsigned long m = (unsigned long)map; u64 start, end; - desc = (efi_memory_desc_t *)(m + (i * desc_size)); + desc = efi_early_memdesc_ptr(m, desc_size, i); if (desc->type != EFI_CONVENTIONAL_MEMORY) continue; @@ -298,7 +298,7 @@ efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg, unsigned long m = (unsigned long)map; u64 start, end; - desc = (efi_memory_desc_t *)(m + (i * desc_size)); + desc = efi_early_memdesc_ptr(m, desc_size, i); if (desc->type != EFI_CONVENTIONAL_MEMORY) continue; diff --git a/include/linux/efi.h b/include/linux/efi.h index 8269bcb8ccf7961bd01f52e39fc4d34d370f25d3..a686ca9a7e5ca76ffe9ccf643ee19a456f5a6d0b 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1020,6 +1020,28 @@ extern int efi_memattr_init(void); extern int efi_memattr_apply_permissions(struct mm_struct *mm, efi_memattr_perm_setter fn); +/* + * efi_early_memdesc_ptr - get the n-th EFI memmap descriptor + * @map: the start of efi memmap + * @desc_size: the size of space for each EFI memmap descriptor + * @n: the index of efi memmap descriptor + * + * EFI boot service provides the GetMemoryMap() function to get a copy of the + * current memory map which is an array of memory descriptors, each of + * which describes a contiguous block of memory. It also gets the size of the + * map, and the size of each descriptor, etc. + * + * Note that per section 6.2 of UEFI Spec 2.6 Errata A, the returned size of + * each descriptor might not be equal to sizeof(efi_memory_memdesc_t), + * since efi_memory_memdesc_t may be extended in the future. Thus the OS + * MUST use the returned size of the descriptor to find the start of each + * efi_memory_memdesc_t in the memory map array. This should only be used + * during bootup since for_each_efi_memory_desc_xxx() is available after the + * kernel initializes the EFI subsystem to set up struct efi_memory_map. + */ +#define efi_early_memdesc_ptr(map, desc_size, n) \ + (efi_memory_desc_t *)((void *)(map) + ((n) * (desc_size))) + /* Iterate through an efi_memory_map */ #define for_each_efi_memory_desc_in_map(m, md) \ for ((md) = (m)->map; \