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efi: Permit calling efi_mem_reserve_persistent() from atomic context

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Currently, efi_mem_reserve_persistent() may not be called from atomic
context, since both the kmalloc() call and the memremap() call may
sleep.

The kmalloc() call is easy enough to fix, but the memremap() call
needs to be moved into an init hook since we cannot control the
memory allocation behavior of memremap() at the call site.

Signed-off-by: Ard 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
Link: http://lkml.kernel.org/r/20181114175544.12860-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ard Biesheuvel 2018-11-14 09:55:44 -08:00 committed by Ingo Molnar
parent eff8962888
commit 63eb322d89
1 changed files with 20 additions and 13 deletions
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33
drivers/firmware/efi/efi.c
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@ -967,37 +967,44 @@ 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)
{
struct linux_efi_memreserve *rsv, *parent;
struct linux_efi_memreserve *rsv;
if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
if (!efi_memreserve_root)
return -ENODEV;
rsv = kmalloc(sizeof(*rsv), GFP_KERNEL);
rsv = kmalloc(sizeof(*rsv), GFP_ATOMIC);
if (!rsv)
return -ENOMEM;
parent = memremap(efi.mem_reserve, sizeof(*rsv), MEMREMAP_WB);
if (!parent) {
kfree(rsv);
return -ENOMEM;
}
rsv->base = addr;
rsv->size = size;
spin_lock(&efi_mem_reserve_persistent_lock);
rsv->next = parent->next;
parent->next = __pa(rsv);
rsv->next = efi_memreserve_root->next;
efi_memreserve_root->next = __pa(rsv);
spin_unlock(&efi_mem_reserve_persistent_lock);
memunmap(parent);
return 0;
}
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;
return 0;
}
early_initcall(efi_memreserve_root_init);
#ifdef CONFIG_KEXEC
static int update_efi_random_seed(struct notifier_block *nb,
unsigned long code, void *unused)