[PATCH 24/29] x86/efi: Defer efi_esrt_init until after memblock_x86_fill

From: Matt Fleming
Date: Fri Sep 09 2016 - 11:19:41 EST

From: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>

Commit 7b02d53e7852 ("efi: Allow drivers to reserve boot services forever")
introduced a new efi_mem_reserve to reserve the boot services memory
regions forever. This reservation involves allocating a new EFI memory
range descriptor. However, allocation can only succeed if there is memory
available for the allocation. Otherwise, error such as the following may

esrt: Reserving ESRT space from 0x000000003dd6a000 to 0x000000003dd6a010.
Kernel panic - not syncing: ERROR: Failed to allocate 0x9f0 bytes below \
CPU: 0 PID: 0 Comm: swapper Not tainted 4.7.0-rc5+ #503
0000000000000000 ffffffff81e03ce0 ffffffff8131dae8 ffffffff81bb6c50
ffffffff81e03d70 ffffffff81e03d60 ffffffff8111f4df 0000000000000018
ffffffff81e03d70 ffffffff81e03d08 00000000000009f0 00000000000009f0
Call Trace:
[<ffffffff8131dae8>] dump_stack+0x4d/0x65
[<ffffffff8111f4df>] panic+0xc5/0x206
[<ffffffff81f7c6d3>] memblock_alloc_base+0x29/0x2e
[<ffffffff81f7c6e3>] memblock_alloc+0xb/0xd
[<ffffffff81f6c86d>] efi_arch_mem_reserve+0xbc/0x134
[<ffffffff81fa3280>] efi_mem_reserve+0x2c/0x31
[<ffffffff81fa3280>] ? efi_mem_reserve+0x2c/0x31
[<ffffffff81fa40d3>] efi_esrt_init+0x19e/0x1b4
[<ffffffff81f6d2dd>] efi_init+0x398/0x44a
[<ffffffff81f5c782>] setup_arch+0x415/0xc30
[<ffffffff81f55af1>] start_kernel+0x5b/0x3ef
[<ffffffff81f55434>] x86_64_start_reservations+0x2f/0x31
[<ffffffff81f55520>] x86_64_start_kernel+0xea/0xed
---[ end Kernel panic - not syncing: ERROR: Failed to allocate 0x9f0
bytes below 0x0.

An inspection of the memblock configuration reveals that there is no memory
available for the allocation:

MEMBLOCK configuration:
memory size = 0x0 reserved size = 0x4f339c0
memory.cnt = 0x1
memory[0x0] [0x00000000000000-0xffffffffffffffff], 0x0 bytes on node 0\
flags: 0x0
reserved.cnt = 0x4
reserved[0x0] [0x0000000008c000-0x0000000008c9bf], 0x9c0 bytes flags: 0x0
reserved[0x1] [0x0000000009f000-0x000000000fffff], 0x61000 bytes\
flags: 0x0
reserved[0x2] [0x00000002800000-0x0000000394bfff], 0x114c000 bytes\
flags: 0x0
reserved[0x3] [0x000000304e4000-0x00000034269fff], 0x3d86000 bytes\
flags: 0x0

This situation can be avoided if we call efi_esrt_init after memblock has
memory regions for the allocation.

Also, the EFI ESRT driver makes use of early_memremap'pings. Therfore, we
do not want to defer efi_esrt_init for too long. We must call such function
while calls to early_memremap are still valid.

A good place to meet the two aforementioned conditions is right after
memblock_x86_fill, grouped with other EFI-related functions.

Reported-by: Scott Lawson <scott.lawson@xxxxxxxxx>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Peter Jones <pjones@xxxxxxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
arch/x86/kernel/setup.c | 1 +
arch/x86/platform/efi/efi.c | 2 --
2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 4fd69e532c15..528b8eb24a04 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1101,6 +1101,7 @@ void __init setup_arch(char **cmdline_p)
if (efi_enabled(EFI_MEMMAP)) {
+ efi_esrt_init();

* The EFI specification says that boot service code won't be
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 342cebd1e17c..0955c70897ae 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -474,8 +474,6 @@ void __init efi_init(void)

if (efi_enabled(EFI_DBG))
- efi_esrt_init();

void __init efi_late_init(void)