Re: [PATCH v1] arm64: efi: Make efi_rt_lock a raw_spinlock
From: Pierre Gondois
Date: Fri Feb 17 2023 - 03:24:12 EST
Hello Ard,
On 2/16/23 18:23, Ard Biesheuvel wrote:
On Thu, 16 Feb 2023 at 17:43, Pierre Gondois <pierre.gondois@xxxxxxx> wrote:
Hello,
Please ignore this patch for now. While running a kernel with this patch,
the following was triggered once (among multiple reboots). IRQ flags might
need to be saved, along with this present patch.
Hello Pierre,
This is probably related to the Altra firmware bug that we are trying
to narrow down and work around.
So when the firmware crashes, it is not entirely unexpected that it
might do so with the IRQ flags left in a different state, so this we
should be able to ignore. (Perhaps we should silence that diagnostic
in this case)
Could you share the output of dmidecode on this platform?
I forgot to mention, this was tested on an Ampere eMAG. I saw that
commit 550b33cfd445 ("arm64: efi: Force the use of SetVirtualAddressMap()
on Altra machines") was solving a similar issue, but this should not impact
this machine.
I ll try to reproduce it and get more information.
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 3.1.1 present.
Table at 0x8FFCAC0000.
Handle 0x0000, DMI type 0, 26 bytes
BIOS Information
Vendor: Ampere(TM)
Version: 1.0
Release Date: 06/28/2019
Address: 0xF0000
Runtime Size: 64 kB
ROM Size: 8192 kB
Characteristics:
PCI is supported
BIOS is upgradeable
Boot from CD is supported
Selectable boot is supported
ACPI is supported
UEFI is supported
BIOS Revision: 5.13
Firmware Revision: 1.0
Handle 0x0001, DMI type 1, 27 bytes
System Information
Manufacturer: MiTAC
Product Name: RAPTOR EV-883832-X3-0001
Version: PR010
Serial Number: 2AC2-B91602C
UUID: dfa0f1d6-835d-11e8-adb0-0cc47ad8d1fc
Wake-up Type: Power Switch
SKU Number: EV-883832-X3-OBX-1
Family: eMAG
Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
Manufacturer: MiTAC
Product Name: RAPTOR
Version: EV-883832-X3-ED0-1
Serial Number: 2AC2-B91602C
Asset Tag: AMPX3A1-A000-0000000000022
Features:
Board is a hosting board
Location In Chassis: Part Component
Chassis Handle: 0x0003
Type: Motherboard
Contained Object Handles: 0
Handle 0x0003, DMI type 3, 22 bytes
Chassis Information
Manufacturer: MiTAC
Type: Rack Mount Chassis
Lock: Not Present
Version: RAPTOR-00000000
Serial Number: A1A1-A000-0000000000022
Asset Tag: AMPX3A1-A000-0000000000022
Boot-up State: Safe
Power Supply State: Safe
Thermal State: Safe
Security Status: None
OEM Information: 0x00000000
Height: Unspecified
Number Of Power Cords: 1
Contained Elements: 0
SKU Number: EV-883832-X3-OBX-1
Handle 0x0004, DMI type 4, 48 bytes
Processor Information
Socket Designation: CPU 1
Type: Central Processor
Family: ARMv8
Manufacturer: Ampere(TM)
ID: 00 00 00 00 02 00 3F 50
Version: eMAG
Voltage: 0.9 V
External Clock: 3000 MHz
Max Speed: 3300 MHz
Current Speed: 3000 MHz
Status: Populated, Enabled
Upgrade: None
L1 Cache Handle: 0x0005
L2 Cache Handle: 0x0006
L3 Cache Handle: 0x0007
Serial Number: 00000000000000005011060302FB0988
Asset Tag: 00000000
Part Number: 00000000
Core Count: 32
Core Enabled: 32
Thread Count: 32
Characteristics:
64-bit capable
Multi-Core
Hardware Thread
Execute Protection
Enhanced Virtualization
[...]
Obviously, there is a related issue where some process keeps hitting
on the RTC. Mind testing the below to see if the system is usable
beyond the EFI problems, and perhaps have a stab at figuring out which
process keeps hitting on the RTC like that?
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
index 1e8bc6cc1e12d855..cc4edb85841e8f67 100644
--- a/drivers/rtc/rtc-efi.c
+++ b/drivers/rtc/rtc-efi.c
@@ -164,7 +164,7 @@ static int efi_read_time(struct device *dev,
struct rtc_time *tm)
if (status != EFI_SUCCESS) {
/* should never happen */
- dev_err(dev, "can't read time\n");
+ dev_err_ratelimited(dev, "can't read time\n");
return -EINVAL;
}
random: crng init done
[Firmware Bug]: Unable to handle write to read-only memory in EFI runtime service
------------[ cut here ]------------
WARNING: CPU: 7 PID: 325 at drivers/firmware/efi/runtime-wrappers.c:113 efi_call_virt_check_flags+0x48/0xb0
Modules linked in: btrfs blake2b_generic libcrc32c xor xor_neon raid6_pq crct10dif_ce
CPU: 7 PID: 325 Comm: kworker/u64:1 Tainted: G W I 6.2.0-rc8-rt1-[...]
Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.0 06/28/2019
Workqueue: efi_rts_wq efi_call_rts
pstate: 00000085 (nzcv daIf -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : efi_call_virt_check_flags+0x48/0xb0
lr : efi_call_rts+0x240/0x4b0
sp : ffff80000def3cf0
x29: ffff80000def3cf0 x28: ffff000801d10b05 x27: ffff80000b16d000
x26: 0000000000000000 x25: ffff80000b17e4a0 x24: ffff80000c84bd48
x23: ffff80000c84bd00 x22: ffff80000c84bd0c x21: 0000000000000080
x20: ffff80000a41d0e0 x19: 0000000000000000 x18: ffff80000a22b3a8
x17: 0000000000000000 x16: ffff80000d2dc000 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : ffff80000927cd60
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff80000a7d1008 x4 : 0000008ffd1d0018 x3 : 0000000000000000
x2 : 0000000000000001 x1 : ffff80000a41d0e0 x0 : 0000000000000080
Call trace:
efi_call_virt_check_flags+0x48/0xb0
efi_call_rts+0x240/0x4b0
process_one_work+0x2c8/0x7a0
worker_thread+0x54/0x410
kthread+0x130/0x140
ret_from_fork+0x10/0x20
irq event stamp: 540538
hardirqs last enabled at (540537): [<ffff80000927d97c>] efi_virtmap_load+0x28c/0x328
hardirqs last disabled at (540538): [<ffff8000095c8590>] el1_abort+0x28/0x100
softirqs last enabled at (534078): [<ffff80000819cec8>] __local_bh_enable_ip+0xa8/0x2a8
softirqs last disabled at (534066): [<ffff80000934b408>] neigh_managed_work+0x8/0x100
---[ end trace 0000000000000000 ]---
Disabling lock debugging due to kernel taint
efi: [Firmware Bug]: IRQ flags corrupted (0x00000000=>0x00000080) by EFI set_variable
------------[ cut here ]------------
WARNING: CPU: 0 PID: 14 at drivers/firmware/efi/runtime-wrappers.c:341 virt_efi_set_variable+0x164/0x1c0
Modules linked in: btrfs blake2b_generic libcrc32c xor xor_neon raid6_pq crct10dif_ce
CPU: 0 PID: 14 Comm: kworker/0:1 Tainted: G W I 6.2.0-rc8-rt1-custom-[...]
Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.0 06/28/2019
Workqueue: events refresh_nv_rng_seed
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : virt_efi_set_variable+0x164/0x1c0
lr : virt_efi_set_variable+0x150/0x1c0
sp : ffff80000c84bcc0
x29: ffff80000c84bcc0 x28: ffff008f35feb905 x27: ffff80000b16d000
x26: ffff80000b16ced0 x25: 0000000000000000 x24: ffff80000c344000
x23: ffff80000a41b2b0 x22: ffff80000c84bd38 x21: 8000000000000015
x20: ffff80000b63ecf8 x19: ffff80000c344480 x18: ffff80000a22b3a8
x17: 000000005a8ae2d0 x16: 0000000000000000 x15: ffff80000b16cfb8
x14: 0000000000000001 x13: 0000000000000030 x12: 0101010101010101
x11: 0000000571f160b9 x10: 0000000000002460 x9 : ffff8000095e2064
x8 : ffff80000a7d1008 x7 : 0000000000000004 x6 : ffff80000c84bb28
x5 : ffff80000c84c000 x4 : ffff80000c848000 x3 : ffff80000c84bc40
x2 : 0000000000000001 x1 : 0000000000000000 x0 : 8000000000000015
Call trace:
virt_efi_set_variable+0x164/0x1c0
refresh_nv_rng_seed+0x84/0xb8
process_one_work+0x2c8/0x7a0
worker_thread+0x54/0x410
kthread+0x130/0x140
ret_from_fork+0x10/0x20
irq event stamp: 35886
hardirqs last enabled at (35885): [<ffff8000095e2050>] _raw_spin_unlock_irq+0x40/0xb8
hardirqs last disabled at (35886): [<ffff8000095e215c>] _raw_spin_lock_irq+0x94/0x98
softirqs last enabled at (10754): [<ffff80000819cec8>] __local_bh_enable_ip+0xa8/0x2a8
softirqs last disabled at (10746): [<ffff800008256de0>] srcu_invoke_callbacks+0x100/0x1a8
---[ end trace 0000000000000000 ]---
[...]
In-situ OAM (IOAM) with IPv6
efi: EFI Runtime Services are disabled!
efivars: get_next_variable: status=8000000000000007
[...]
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
rtc-efi rtc-efi.0: can't read time
[...]
On 2/15/23 17:10, Pierre Gondois wrote:
Running a rt-kernel base on 6.2.0-rc3-rt1 on an Ampere Altra outputs
the following:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 9, name: kworker/u320:0
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
3 locks held by kworker/u320:0/9:
#0: ffff3fff8c27d128 ((wq_completion)efi_rts_wq){+.+.}-{0:0}, at: process_one_work (./include/linux/atomic/atomic-long.h:41)
#1: ffff80000861bdd0 ((work_completion)(&efi_rts_work.work)){+.+.}-{0:0}, at: process_one_work (./include/linux/atomic/atomic-long.h:41)
#2: ffffdf7e1ed3e460 (efi_rt_lock){+.+.}-{3:3}, at: efi_call_rts (drivers/firmware/efi/runtime-wrappers.c:101)
Preemption disabled at:
efi_virtmap_load (./arch/arm64/include/asm/mmu_context.h:248)
CPU: 0 PID: 9 Comm: kworker/u320:0 Tainted: G W 6.2.0-rc3-rt1
Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18
Workqueue: efi_rts_wq efi_call_rts
Call trace:
dump_backtrace (arch/arm64/kernel/stacktrace.c:158)
show_stack (arch/arm64/kernel/stacktrace.c:165)
dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4))
dump_stack (lib/dump_stack.c:114)
__might_resched (kernel/sched/core.c:10134)
rt_spin_lock (kernel/locking/rtmutex.c:1769 (discriminator 4))
efi_call_rts (drivers/firmware/efi/runtime-wrappers.c:101)
[...]
This seems to come from commit ff7a167961d1 ("arm64: efi: Execute
runtime services from a dedicated stack") which adds a spinlock. This
spinlock is taken through:
efi_call_rts()
\-efi_call_virt()
\-efi_call_virt_pointer()
\-arch_efi_call_virt_setup()
Make 'efi_rt_lock' a raw_spinlock to avoid being preempted.
Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
---
arch/arm64/include/asm/efi.h | 6 +++---
arch/arm64/kernel/efi.c | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 31d13a6001df..37dc2e8c3500 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -33,7 +33,7 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
({ \
efi_virtmap_load(); \
__efi_fpsimd_begin(); \
- spin_lock(&efi_rt_lock); \
+ raw_spin_lock(&efi_rt_lock); \
})
#undef arch_efi_call_virt
@@ -42,12 +42,12 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
#define arch_efi_call_virt_teardown() \
({ \
- spin_unlock(&efi_rt_lock); \
+ raw_spin_unlock(&efi_rt_lock); \
__efi_fpsimd_end(); \
efi_virtmap_unload(); \
})
-extern spinlock_t efi_rt_lock;
+extern raw_spinlock_t efi_rt_lock;
efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
#define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index fab05de2e12d..216933cf47ee 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -145,7 +145,7 @@ asmlinkage efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f)
return s;
}
-DEFINE_SPINLOCK(efi_rt_lock);
+DEFINE_RAW_SPINLOCK(efi_rt_lock);
asmlinkage u64 *efi_rt_stack_top __ro_after_init;