On 11/8/18 at 1:05 PM, Ard Biesheuvel wrote:
> 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 <[email protected]> > --- > drivers/firmware/efi/efi.c | 31 +++++++++++++++++++------------ > 1 file changed, 19 insertions(+), 12 deletions(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 249eb70691b0..cfc876e0b67b 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -963,36 +963,43 @@ 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, > -- > 2.19.1 BTW, I won’t be able to apply this patch on top of this series [1]. After applied that series, the original BUG sleep from atomic is gone as well as two other GIC warnings. Do you think a new patch is needed here? [1] https://www.spinics.net/lists/arm-kernel/msg685751.html
