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arm64: efi: Make efi_rt_lock a raw_spinlock 

commit 0e68b5517d 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 ff7a167961 ("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: ff7a167961 ("arm64: efi: Execute runtime services from a dedicated stack")
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Cc: <stable@vger.kernel.org> # v6.1+
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Pierre Gondois 2023-02-15 17:10:47 +01:00 committed by Greg Kroah-Hartman
parent c6b9c79c3d
commit 8b38969fa0
2 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/arm64/include/asm/efi.h
View File

@ -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;
extern u64 *efi_rt_stack_top;
efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);

2
arch/arm64/kernel/efi.c
View File

@ -146,7 +146,7 @@ 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;