From 0ceac9e094b065fe3fec19669740f338d3480498 Mon Sep 17 00:00:00 2001 From: Mark Salter Date: Mon, 8 Sep 2014 13:01:08 -0400 Subject: [PATCH] efi/arm64: Fix fdt-related memory reservation Commit 86c8b27a01cf: "arm64: ignore DT memreserve entries when booting in UEFI mode prevents early_init_fdt_scan_reserved_mem() from being called for arm64 kernels booting via UEFI. This was done because the kernel will use the UEFI memory map to determine reserved memory regions. That approach has problems in that early_init_fdt_scan_reserved_mem() also reserves the FDT itself and any node-specific reserved memory. By chance of some kernel configs, the FDT may be overwritten before it can be unflattened and the kernel will fail to boot. More subtle problems will result if the FDT has node specific reserved memory which is not really reserved. This patch has the UEFI stub remove the memory reserve map entries from the FDT as it does with the memory nodes. This allows early_init_fdt_scan_reserved_mem() to be called unconditionally so that the other needed reservations are made. Signed-off-by: Mark Salter Acked-by: Ard Biesheuvel Acked-by: Mark Rutland Signed-off-by: Matt Fleming --- arch/arm64/mm/init.c | 3 +-- drivers/firmware/efi/libstub/fdt.c | 10 +++++++++- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 5472c2401876..a83061f37e43 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -149,8 +149,7 @@ void __init arm64_memblock_init(void) memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start); #endif - if (!efi_enabled(EFI_MEMMAP)) - early_init_fdt_scan_reserved_mem(); + early_init_fdt_scan_reserved_mem(); /* 4GB maximum for 32-bit only capable devices */ if (IS_ENABLED(CONFIG_ZONE_DMA)) diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c index a56bb3528755..c846a9608cbd 100644 --- a/drivers/firmware/efi/libstub/fdt.c +++ b/drivers/firmware/efi/libstub/fdt.c @@ -22,7 +22,7 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt, unsigned long map_size, unsigned long desc_size, u32 desc_ver) { - int node, prev; + int node, prev, num_rsv; int status; u32 fdt_val32; u64 fdt_val64; @@ -73,6 +73,14 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt, prev = node; } + /* + * Delete all memory reserve map entries. When booting via UEFI, + * kernel will use the UEFI memory map to find reserved regions. + */ + num_rsv = fdt_num_mem_rsv(fdt); + while (num_rsv-- > 0) + fdt_del_mem_rsv(fdt, num_rsv); + node = fdt_subnode_offset(fdt, 0, "chosen"); if (node < 0) { node = fdt_add_subnode(fdt, 0, "chosen"); -- 2.20.1