This is a note to let you know that I've just added the patch titled
arm64: efi: Make efi_rt_lock a raw_spinlock
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-efi-make-efi_rt_lock-a-raw_spinlock.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0e68b5517d3767562889f1d83fdb828c26adb24f Mon Sep 17 00:00:00 2001
From: Pierre Gondois <pierre.gondois@xxxxxxx>
Date: Wed, 15 Feb 2023 17:10:47 +0100
Subject: arm64: efi: Make efi_rt_lock a raw_spinlock
From: Pierre Gondois <pierre.gondois@xxxxxxx>
commit 0e68b5517d3767562889f1d83fdb828c26adb24f upstream.
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.
[ardb: The EFI runtime services are called with a different set of
translation tables, and are permitted to use the SIMD registers.
The context switch code preserves/restores neither, and so EFI
calls must be made with preemption disabled, rather than only
disabling migration.]
Fixes: ff7a167961d1 ("arm64: efi: Execute runtime services from a dedicated stack")
Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v6.1+
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/efi.h | 6 +++---
arch/arm64/kernel/efi.c | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -33,7 +33,7 @@ int efi_set_mapping_permissions(struct m
({ \
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 m
#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;
extern u64 *efi_rt_stack_top;
efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -146,7 +146,7 @@ asmlinkage efi_status_t efi_handle_corru
return s;
}
-DEFINE_SPINLOCK(efi_rt_lock);
+DEFINE_RAW_SPINLOCK(efi_rt_lock);
asmlinkage u64 *efi_rt_stack_top __ro_after_init;
Patches currently in stable-queue which might be from pierre.gondois@xxxxxxx are
queue-6.2/arm64-efi-make-efi_rt_lock-a-raw_spinlock.patch
queue-6.2/cacheinfo-fix-shared_cpu_map-to-handle-shared-caches.patch
