2017-04-12 15:27:26

by Matt Fleming

[permalink] [raw]
Subject: [GIT PULL] EFI urgent fix

Folks, please pull the single below fix from Omar which fixes a kexec
boot regression.

I've based the pull on tip/efi/urgent since the EFI urgent queue
hasn't reached Linus' tree yet.

The following changes since commit 55d728a40d368ba80443be85c02e641fc9082a3f:

efi/fb: Avoid reconfiguration of BAR that covers the framebuffer (2017-04-05 12:25:53 +0200)

are available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git tags/efi-urgent

for you to fetch changes up to 09ca0b10e8100a48aa94eb8649f4c6c904e5d196:

x86/efi: Don't try to reserve runtime regions (2017-04-12 16:17:20 +0100)

----------------------------------------------------------------
- Fix a crash on kexec boot introduced by the recent
efi_mem_reserve() code in the ESRT driver, which double-reserved
EFI runtime regions - Omar Sandoval

----------------------------------------------------------------
Omar Sandoval (1):
x86/efi: Don't try to reserve runtime regions

arch/x86/platform/efi/quirks.c | 4 ++++
1 file changed, 4 insertions(+)


2017-04-12 15:27:30

by Matt Fleming

[permalink] [raw]
Subject: [PATCH] x86/efi: Don't try to reserve runtime regions

From: Omar Sandoval <[email protected]>

Reserving a runtime region results in splitting the efi memory
descriptors for the runtime region. This results in runtime region
descriptors with bogus memory mappings, leading to interesting crashes
like the following during a kexec:

[ 0.001000] general protection fault: 0000 [#1] SMP
[ 0.001000] Modules linked in:
[ 0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc1 #53
[ 0.001000] Hardware name: Wiwynn Leopard-Orv2/Leopard-DDR BW, BIOS LBM05 09/30/2016
[ 0.001000] task: ffffffff81e0e4c0 task.stack: ffffffff81e00000
[ 0.001000] RIP: 0010:virt_efi_set_variable+0x85/0x1a0
[ 0.001000] RSP: 0000:ffffffff81e03e18 EFLAGS: 00010202
[ 0.001000] RAX: afafafafafafafaf RBX: ffffffff81e3a4e0 RCX: 0000000000000007
[ 0.001000] RDX: ffffffff81e03e70 RSI: ffffffff81e3a4e0 RDI: ffff88407f8c2de0
[ 0.001000] RBP: ffffffff81e03e60 R08: 0000000000000000 R09: 0000000000000000
[ 0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff81e03e70
[ 0.001000] R13: 0000000000000007 R14: 0000000000000000 R15: 0000000000000000
[ 0.001000] FS: 0000000000000000(0000) GS:ffff881fff600000(0000) knlGS:0000000000000000
[ 0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.001000] CR2: ffff88407f30f000 CR3: 0000001fff102000 CR4: 00000000000406b0
[ 0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 0.001000] Call Trace:
[ 0.001000] efi_delete_dummy_variable+0x7a/0x80
[ 0.001000] efi_enter_virtual_mode+0x3e2/0x494
[ 0.001000] start_kernel+0x392/0x418
[ 0.001000] ? set_init_arg+0x55/0x55
[ 0.001000] x86_64_start_reservations+0x2a/0x2c
[ 0.001000] x86_64_start_kernel+0xea/0xed
[ 0.001000] start_cpu+0x14/0x14
[ 0.001000] Code: 42 25 8d ff 80 3d 43 77 95 00 00 75 68 9c 8f 04 24 48 8b 05 3e 7d 7e 00 48 89 de 4d 89 f9 4d 89 f0 44 89 e9 4c 89 e2 48 8b 40 58 <48> 8b 78 58 31 c0 e8 90 e4 92 ff 48 8b 3c 24 48 c7 c6 2b 0a ca
[ 0.001000] RIP: virt_efi_set_variable+0x85/0x1a0 RSP: ffffffff81e03e18
[ 0.001000] ---[ end trace 0bd213e540e9b19f ]---
[ 0.001000] Kernel panic - not syncing: Fatal exception
[ 0.001000] ---[ end Kernel panic - not syncing: Fatal exception

Runtime regions will not be freed and do not need to be reserved, so
skip the memmap modification in this case.

Fixes: 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")
Signed-off-by: Omar Sandoval <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Jones <[email protected]>
Cc: <[email protected]> # v4.9+
Signed-off-by: Matt Fleming <[email protected]>
---
arch/x86/platform/efi/quirks.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 30031d5293c4..cdfe8c628959 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -201,6 +201,10 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
return;
}

+ /* No need to reserve regions that will never be freed. */
+ if (md.attribute & EFI_MEMORY_RUNTIME)
+ return;
+
size += addr % EFI_PAGE_SIZE;
size = round_up(size, EFI_PAGE_SIZE);
addr = round_down(addr, EFI_PAGE_SIZE);
--
2.10.0

Subject: [tip:efi/urgent] x86/efi: Don't try to reserve runtime regions

Commit-ID: 6f6266a561306e206e0e31a5038f029b6a7b1d89
Gitweb: http://git.kernel.org/tip/6f6266a561306e206e0e31a5038f029b6a7b1d89
Author: Omar Sandoval <[email protected]>
AuthorDate: Wed, 12 Apr 2017 16:27:19 +0100
Committer: Ingo Molnar <[email protected]>
CommitDate: Thu, 13 Apr 2017 08:09:27 +0200

x86/efi: Don't try to reserve runtime regions

Reserving a runtime region results in splitting the EFI memory
descriptors for the runtime region. This results in runtime region
descriptors with bogus memory mappings, leading to interesting crashes
like the following during a kexec:

general protection fault: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc1 #53
Hardware name: Wiwynn Leopard-Orv2/Leopard-DDR BW, BIOS LBM05 09/30/2016
RIP: 0010:virt_efi_set_variable()
...
Call Trace:
efi_delete_dummy_variable()
efi_enter_virtual_mode()
start_kernel()
? set_init_arg()
x86_64_start_reservations()
x86_64_start_kernel()
start_cpu()
...
Kernel panic - not syncing: Fatal exception

Runtime regions will not be freed and do not need to be reserved, so
skip the memmap modification in this case.

Signed-off-by: Omar Sandoval <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Cc: <[email protected]> # v4.9+
Cc: Ard Biesheuvel <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Jones <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Fixes: 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/platform/efi/quirks.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 30031d5..cdfe8c6 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -201,6 +201,10 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
return;
}

+ /* No need to reserve regions that will never be freed. */
+ if (md.attribute & EFI_MEMORY_RUNTIME)
+ return;
+
size += addr % EFI_PAGE_SIZE;
size = round_up(size, EFI_PAGE_SIZE);
addr = round_down(addr, EFI_PAGE_SIZE);