From aea962c3bd70706b3a898b72c9032d8e0680b222 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 21 Sep 2018 09:32:44 -0700 Subject: [PATCH 0112/2944] efi: honour memory reservations passed via a linux specific config table commit 71e0940d52e107748b270213a01d3b1546657d74 upstream In order to allow the OS to reserve memory persistently across a kexec, introduce a Linux-specific UEFI configuration table that points to the head of a linked list in memory, allowing each kernel to add list items describing memory regions that the next kernel should treat as reserved. This is useful, e.g., for GICv3 based ARM systems that cannot disable DMA access to the LPI tables, forcing them to reuse the same memory region again after a kexec reboot. Tested-by: Jeremy Linton Signed-off-by: Ard Biesheuvel Signed-off-by: Zou Cao Reviewed-by: Baoyou Xie --- drivers/firmware/efi/efi.c | 27 ++++++++++++++++++++++++++- include/linux/efi.h | 8 ++++++++ 2 files changed, 34 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index d54fca9..f265309 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -52,7 +52,8 @@ struct efi __read_mostly efi = { .properties_table = EFI_INVALID_TABLE_ADDR, .mem_attr_table = EFI_INVALID_TABLE_ADDR, .rng_seed = EFI_INVALID_TABLE_ADDR, - .tpm_log = EFI_INVALID_TABLE_ADDR + .tpm_log = EFI_INVALID_TABLE_ADDR, + .mem_reserve = EFI_INVALID_TABLE_ADDR, }; EXPORT_SYMBOL(efi); @@ -487,6 +488,7 @@ void __init efi_mem_reserve(phys_addr_t addr, u64 size) {EFI_MEMORY_ATTRIBUTES_TABLE_GUID, "MEMATTR", &efi.mem_attr_table}, {LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &efi.rng_seed}, {LINUX_EFI_TPM_EVENT_LOG_GUID, "TPMEventLog", &efi.tpm_log}, + {LINUX_EFI_MEMRESERVE_TABLE_GUID, "MEMRESERVE", &efi.mem_reserve}, {NULL_GUID, NULL, NULL}, }; @@ -594,6 +596,29 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, early_memunmap(tbl, sizeof(*tbl)); } + if (efi.mem_reserve != EFI_INVALID_TABLE_ADDR) { + unsigned long prsv = efi.mem_reserve; + + while (prsv) { + struct linux_efi_memreserve *rsv; + + /* reserve the entry itself */ + memblock_reserve(prsv, sizeof(*rsv)); + + rsv = early_memremap(prsv, sizeof(*rsv)); + if (rsv == NULL) { + pr_err("Could not map UEFI memreserve entry!\n"); + return -ENOMEM; + } + + if (rsv->size) + memblock_reserve(rsv->base, rsv->size); + + prsv = rsv->next; + early_memunmap(rsv, sizeof(*rsv)); + } + } + return 0; } diff --git a/include/linux/efi.h b/include/linux/efi.h index cc33917..f43fc61 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -672,6 +672,7 @@ typedef efi_status_t efi_query_variable_store_t(u32 attributes, #define LINUX_EFI_LOADER_ENTRY_GUID EFI_GUID(0x4a67b082, 0x0a4c, 0x41cf, 0xb6, 0xc7, 0x44, 0x0b, 0x29, 0xbb, 0x8c, 0x4f) #define LINUX_EFI_RANDOM_SEED_TABLE_GUID EFI_GUID(0x1ce1e5bc, 0x7ceb, 0x42f2, 0x81, 0xe5, 0x8a, 0xad, 0xf1, 0x80, 0xf5, 0x7b) #define LINUX_EFI_TPM_EVENT_LOG_GUID EFI_GUID(0xb7799cb0, 0xeca2, 0x4943, 0x96, 0x67, 0x1f, 0xae, 0x07, 0xb7, 0x47, 0xfa) +#define LINUX_EFI_MEMRESERVE_TABLE_GUID EFI_GUID(0x888eb0c6, 0x8ede, 0x4ff5, 0xa8, 0xf0, 0x9a, 0xee, 0x5c, 0xb9, 0x77, 0xc2) typedef struct { efi_guid_t guid; @@ -957,6 +958,7 @@ struct efi_fdt_params { unsigned long mem_attr_table; /* memory attributes table */ unsigned long rng_seed; /* UEFI firmware random seed */ unsigned long tpm_log; /* TPM2 Event Log table */ + unsigned long mem_reserve; /* Linux EFI memreserve table */ efi_get_time_t *get_time; efi_set_time_t *set_time; efi_get_wakeup_time_t *get_wakeup_time; @@ -1667,4 +1669,10 @@ struct linux_efi_tpm_eventlog { /* Workqueue to queue EFI Runtime Services */ extern struct workqueue_struct *efi_rts_wq; +struct linux_efi_memreserve { + phys_addr_t next; + phys_addr_t base; + phys_addr_t size; +}; + #endif /* _LINUX_EFI_H */ -- 1.8.3.1