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Commit 976b4891 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Ingo Molnar
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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: default avatarMarc Zyngier <marc.zyngier@arm.com>
Tested-by: default avatarJan Glauber <jglauber@cavium.com>
Tested-by: default avatarJohn Garry <john.garry@huawei.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Fixes: 63eb322d ("efi: Permit calling efi_mem_reserve_persistent() ...")
Link: http://lkml.kernel.org/r/20181123215132.7951-2-ard.biesheuvel@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2e6e902d

drivers/firmware/efi/efi.c

+26 −10
Original line number Diff line number Diff line
@@ -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);