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author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-06-06 17:26:33 +0300 |
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committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-06-06 18:22:20 +0300 |
commit | 2053bc57f36763febced0b5cd91821698bcf6b3d (patch) | |
tree | 731f4d2730f6284343c1fd63f73bdac65ff0558f | |
parent | 3fd1239a783522e7158a1f141fabc7b3b5dc84c6 (diff) | |
download | linux-2053bc57f36763febced0b5cd91821698bcf6b3d.tar.xz |
efi: Add unaccepted memory support
efi_config_parse_tables() reserves memory that holds unaccepted memory
configuration table so it won't be reused by page allocator.
Core-mm requires few helpers to support unaccepted memory:
- accept_memory() checks the range of addresses against the bitmap and
accept memory if needed.
- range_contains_unaccepted_memory() checks if anything within the
range requires acceptance.
Architectural code has to provide efi_get_unaccepted_table() that
returns pointer to the unaccepted memory configuration table.
arch_accept_memory() handles arch-specific part of memory acceptance.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230606142637.5171-6-kirill.shutemov@linux.intel.com
-rw-r--r-- | arch/x86/platform/efi/efi.c | 3 | ||||
-rw-r--r-- | drivers/firmware/efi/Makefile | 1 | ||||
-rw-r--r-- | drivers/firmware/efi/efi.c | 25 | ||||
-rw-r--r-- | drivers/firmware/efi/unaccepted_memory.c | 112 | ||||
-rw-r--r-- | include/linux/efi.h | 1 |
5 files changed, 142 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index f3f2d87cce1b..e9f99c56f3ce 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -96,6 +96,9 @@ static const unsigned long * const efi_tables[] = { #ifdef CONFIG_EFI_COCO_SECRET &efi.coco_secret, #endif +#ifdef CONFIG_UNACCEPTED_MEMORY + &efi.unaccepted, +#endif }; u64 efi_setup; /* efi setup_data physical address */ diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index b51f2a4c821e..e489fefd23da 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -41,3 +41,4 @@ obj-$(CONFIG_EFI_CAPSULE_LOADER) += capsule-loader.o obj-$(CONFIG_EFI_EARLYCON) += earlycon.o obj-$(CONFIG_UEFI_CPER_ARM) += cper-arm.o obj-$(CONFIG_UEFI_CPER_X86) += cper-x86.o +obj-$(CONFIG_UNACCEPTED_MEMORY) += unaccepted_memory.o diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 7dce06e419c5..d817e7afd266 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -50,6 +50,9 @@ struct efi __read_mostly efi = { #ifdef CONFIG_EFI_COCO_SECRET .coco_secret = EFI_INVALID_TABLE_ADDR, #endif +#ifdef CONFIG_UNACCEPTED_MEMORY + .unaccepted = EFI_INVALID_TABLE_ADDR, +#endif }; EXPORT_SYMBOL(efi); @@ -605,6 +608,9 @@ static const efi_config_table_type_t common_tables[] __initconst = { #ifdef CONFIG_EFI_COCO_SECRET {LINUX_EFI_COCO_SECRET_AREA_GUID, &efi.coco_secret, "CocoSecret" }, #endif +#ifdef CONFIG_UNACCEPTED_MEMORY + {LINUX_EFI_UNACCEPTED_MEM_TABLE_GUID, &efi.unaccepted, "Unaccepted" }, +#endif #ifdef CONFIG_EFI_GENERIC_STUB {LINUX_EFI_SCREEN_INFO_TABLE_GUID, &screen_info_table }, #endif @@ -759,6 +765,25 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables, } } + if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && + efi.unaccepted != EFI_INVALID_TABLE_ADDR) { + struct efi_unaccepted_memory *unaccepted; + + unaccepted = early_memremap(efi.unaccepted, sizeof(*unaccepted)); + if (unaccepted) { + unsigned long size; + + if (unaccepted->version == 1) { + size = sizeof(*unaccepted) + unaccepted->size; + memblock_reserve(efi.unaccepted, size); + } else { + efi.unaccepted = EFI_INVALID_TABLE_ADDR; + } + + early_memunmap(unaccepted, sizeof(*unaccepted)); + } + } + return 0; } diff --git a/drivers/firmware/efi/unaccepted_memory.c b/drivers/firmware/efi/unaccepted_memory.c new file mode 100644 index 000000000000..08a9a843550a --- /dev/null +++ b/drivers/firmware/efi/unaccepted_memory.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/efi.h> +#include <linux/memblock.h> +#include <linux/spinlock.h> +#include <asm/unaccepted_memory.h> + +/* Protects unaccepted memory bitmap */ +static DEFINE_SPINLOCK(unaccepted_memory_lock); + +/* + * accept_memory() -- Consult bitmap and accept the memory if needed. + * + * Only memory that is explicitly marked as unaccepted in the bitmap requires + * an action. All the remaining memory is implicitly accepted and doesn't need + * acceptance. + * + * No need to accept: + * - anything if the system has no unaccepted table; + * - memory that is below phys_base; + * - memory that is above the memory that addressable by the bitmap; + */ +void accept_memory(phys_addr_t start, phys_addr_t end) +{ + struct efi_unaccepted_memory *unaccepted; + unsigned long range_start, range_end; + unsigned long flags; + u64 unit_size; + + unaccepted = efi_get_unaccepted_table(); + if (!unaccepted) + return; + + unit_size = unaccepted->unit_size; + + /* + * Only care for the part of the range that is represented + * in the bitmap. + */ + if (start < unaccepted->phys_base) + start = unaccepted->phys_base; + if (end < unaccepted->phys_base) + return; + + /* Translate to offsets from the beginning of the bitmap */ + start -= unaccepted->phys_base; + end -= unaccepted->phys_base; + + /* Make sure not to overrun the bitmap */ + if (end > unaccepted->size * unit_size * BITS_PER_BYTE) + end = unaccepted->size * unit_size * BITS_PER_BYTE; + + range_start = start / unit_size; + + spin_lock_irqsave(&unaccepted_memory_lock, flags); + for_each_set_bitrange_from(range_start, range_end, unaccepted->bitmap, + DIV_ROUND_UP(end, unit_size)) { + unsigned long phys_start, phys_end; + unsigned long len = range_end - range_start; + + phys_start = range_start * unit_size + unaccepted->phys_base; + phys_end = range_end * unit_size + unaccepted->phys_base; + + arch_accept_memory(phys_start, phys_end); + bitmap_clear(unaccepted->bitmap, range_start, len); + } + spin_unlock_irqrestore(&unaccepted_memory_lock, flags); +} + +bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end) +{ + struct efi_unaccepted_memory *unaccepted; + unsigned long flags; + bool ret = false; + u64 unit_size; + + unaccepted = efi_get_unaccepted_table(); + if (!unaccepted) + return false; + + unit_size = unaccepted->unit_size; + + /* + * Only care for the part of the range that is represented + * in the bitmap. + */ + if (start < unaccepted->phys_base) + start = unaccepted->phys_base; + if (end < unaccepted->phys_base) + return false; + + /* Translate to offsets from the beginning of the bitmap */ + start -= unaccepted->phys_base; + end -= unaccepted->phys_base; + + /* Make sure not to overrun the bitmap */ + if (end > unaccepted->size * unit_size * BITS_PER_BYTE) + end = unaccepted->size * unit_size * BITS_PER_BYTE; + + spin_lock_irqsave(&unaccepted_memory_lock, flags); + while (start < end) { + if (test_bit(start / unit_size, unaccepted->bitmap)) { + ret = true; + break; + } + + start += unit_size; + } + spin_unlock_irqrestore(&unaccepted_memory_lock, flags); + + return ret; +} diff --git a/include/linux/efi.h b/include/linux/efi.h index 8ffe451a6a2f..67cb72d7a764 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -646,6 +646,7 @@ extern struct efi { unsigned long tpm_final_log; /* TPM2 Final Events Log table */ unsigned long mokvar_table; /* MOK variable config table */ unsigned long coco_secret; /* Confidential computing secret table */ + unsigned long unaccepted; /* Unaccepted memory table */ efi_get_time_t *get_time; efi_set_time_t *set_time; |