From 976b489120cdab2b1b3a41ffa14661db43d58190 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 23 Nov 2018 22:51:32 +0100 Subject: [PATCH] efi: Prevent GICv3 WARN() by mapping the memreserve table before first use Mapping the MEMRESERVE EFI configuration table from an early initcall is too late: the GICv3 ITS code that creates persistent reservations for the boot CPU's LPI tables is invoked from init_IRQ(), which runs much earlier than the handling of the initcalls. This results in a WARN() splat because the LPI tables cannot be reserved persistently, which will result in silent memory corruption after a kexec reboot. So instead, invoke the initialization performed by the initcall from efi_mem_reserve_persistent() itself as well, but keep the initcall so that the init is guaranteed to have been called before SMP boot. Tested-by: Marc Zyngier Tested-by: Jan Glauber Tested-by: John Garry Signed-off-by: Ard Biesheuvel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Fixes: 63eb322d89c8 ("efi: Permit calling efi_mem_reserve_persistent() ...") Link: http://lkml.kernel.org/r/20181123215132.7951-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- drivers/firmware/efi/efi.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index fad7c62cfc0e..415849bab233 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -969,13 +969,33 @@ bool efi_is_table_address(unsigned long phys_addr) static DEFINE_SPINLOCK(efi_mem_reserve_persistent_lock); static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init; -int efi_mem_reserve_persistent(phys_addr_t addr, u64 size) +static int __init efi_memreserve_map_root(void) +{ + if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR) + return -ENODEV; + + efi_memreserve_root = memremap(efi.mem_reserve, + sizeof(*efi_memreserve_root), + MEMREMAP_WB); + if (WARN_ON_ONCE(!efi_memreserve_root)) + return -ENOMEM; + return 0; +} + +int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) { struct linux_efi_memreserve *rsv; + int rc; - if (!efi_memreserve_root) + if (efi_memreserve_root == (void *)ULONG_MAX) return -ENODEV; + if (!efi_memreserve_root) { + rc = efi_memreserve_map_root(); + if (rc) + return rc; + } + rsv = kmalloc(sizeof(*rsv), GFP_ATOMIC); if (!rsv) return -ENOMEM; @@ -993,14 +1013,10 @@ int efi_mem_reserve_persistent(phys_addr_t addr, u64 size) static int __init efi_memreserve_root_init(void) { - if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR) - return -ENODEV; - - efi_memreserve_root = memremap(efi.mem_reserve, - sizeof(*efi_memreserve_root), - MEMREMAP_WB); - if (!efi_memreserve_root) - return -ENOMEM; + if (efi_memreserve_root) + return 0; + if (efi_memreserve_map_root()) + efi_memreserve_root = (void *)ULONG_MAX; return 0; } early_initcall(efi_memreserve_root_init); -- 2.30.2