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authorArd Biesheuvel2018-11-14 09:55:44 -0800
committerIngo Molnar2018-11-15 10:04:47 +0100
commit63eb322d89c8505af9b4a3d703e85e42281ebaa0 (patch)
tree6da384231bce837a16655294a2c40f3cfe916dcc /drivers/firmware
parenteff896288872d687d9662000ec9ae11b6d61766f (diff)
efi: Permit calling efi_mem_reserve_persistent() from atomic context
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>
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efi/efi.c31
1 files changed, 19 insertions, 12 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 72a4da76d274..fad7c62cfc0e 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -967,36 +967,43 @@ 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,