[boqun:rust-sync 9/12] arch/arm64/kernel/acpi.c:413:2: warning: unused variable 'nesting'

[boqun:rust-sync 9/12] arch/arm64/kernel/acpi.c:413:2: warning: unused variable 'nesting'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/boqun/linux.git rust-sync
head:   082cc4c201e4450ff9456c9bd093fd70d103595a
commit: 40c3e04e2248c0e5d78d23e6767a1c58d5678eac [9/12] preempt: x86: Avoid tracking NMI separately when 64BIT=y
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20260506/202605060326.PBJuOKXs-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260506/202605060326.PBJuOKXs-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605060326.PBJuOKXs-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/arm64/kernel/acpi.c:413:2: warning: unused variable 'nesting' [-Wunused-variable]
     413 |         nmi_exit();
         |         ^~~~~~~~~~
   include/linux/hardirq.h:164:3: note: expanded from macro 'nmi_exit'
     164 |                 __nmi_exit();                                   \
         |                 ^~~~~~~~~~~~
   include/linux/hardirq.h:150:16: note: expanded from macro '__nmi_exit'
     150 |                 unsigned int nesting;                           \
         |                              ^~~~~~~
   1 warning generated.


vim +/nesting +413 arch/arm64/kernel/acpi.c

1583052d111f8ea Ard Biesheuvel   2020-06-26  382  
d44f1b8dd7e66d8 James Morse      2019-01-29  383  /*
d44f1b8dd7e66d8 James Morse      2019-01-29  384   * Claim Synchronous External Aborts as a firmware first notification.
d44f1b8dd7e66d8 James Morse      2019-01-29  385   *
d44f1b8dd7e66d8 James Morse      2019-01-29  386   * Used by KVM and the arch do_sea handler.
d44f1b8dd7e66d8 James Morse      2019-01-29  387   * @regs may be NULL when called from process context.
d44f1b8dd7e66d8 James Morse      2019-01-29  388   */
d44f1b8dd7e66d8 James Morse      2019-01-29  389  int apei_claim_sea(struct pt_regs *regs)
d44f1b8dd7e66d8 James Morse      2019-01-29  390  {
d44f1b8dd7e66d8 James Morse      2019-01-29  391  	int err = -ENOENT;
8fcc4ae6faf8b45 James Morse      2020-05-01  392  	bool return_to_irqs_enabled;
d44f1b8dd7e66d8 James Morse      2019-01-29  393  	unsigned long current_flags;
d44f1b8dd7e66d8 James Morse      2019-01-29  394  
d44f1b8dd7e66d8 James Morse      2019-01-29  395  	if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
d44f1b8dd7e66d8 James Morse      2019-01-29  396  		return err;
d44f1b8dd7e66d8 James Morse      2019-01-29  397  
e533dbe9dcb199b Mark Rutland     2020-01-22  398  	current_flags = local_daif_save_flags();
d44f1b8dd7e66d8 James Morse      2019-01-29  399  
8fcc4ae6faf8b45 James Morse      2020-05-01  400  	/* current_flags isn't useful here as daif doesn't tell us about pNMI */
8fcc4ae6faf8b45 James Morse      2020-05-01  401  	return_to_irqs_enabled = !irqs_disabled_flags(arch_local_save_flags());
8fcc4ae6faf8b45 James Morse      2020-05-01  402  
8fcc4ae6faf8b45 James Morse      2020-05-01  403  	if (regs)
788b8f6af60b22f Jinjie Ruan      2025-08-15  404  		return_to_irqs_enabled = !regs_irqs_disabled(regs);
8fcc4ae6faf8b45 James Morse      2020-05-01  405  
d44f1b8dd7e66d8 James Morse      2019-01-29  406  	/*
d44f1b8dd7e66d8 James Morse      2019-01-29  407  	 * SEA can interrupt SError, mask it and describe this as an NMI so
d44f1b8dd7e66d8 James Morse      2019-01-29  408  	 * that APEI defers the handling.
d44f1b8dd7e66d8 James Morse      2019-01-29  409  	 */
d44f1b8dd7e66d8 James Morse      2019-01-29  410  	local_daif_restore(DAIF_ERRCTX);
d44f1b8dd7e66d8 James Morse      2019-01-29  411  	nmi_enter();
d44f1b8dd7e66d8 James Morse      2019-01-29  412  	err = ghes_notify_sea();
d44f1b8dd7e66d8 James Morse      2019-01-29 @413  	nmi_exit();
8fcc4ae6faf8b45 James Morse      2020-05-01  414  
8fcc4ae6faf8b45 James Morse      2020-05-01  415  	/*
8fcc4ae6faf8b45 James Morse      2020-05-01  416  	 * APEI NMI-like notifications are deferred to irq_work. Unless
8fcc4ae6faf8b45 James Morse      2020-05-01  417  	 * we interrupted irqs-masked code, we can do that now.
8fcc4ae6faf8b45 James Morse      2020-05-01  418  	 */
8fcc4ae6faf8b45 James Morse      2020-05-01  419  	if (!err) {
8fcc4ae6faf8b45 James Morse      2020-05-01  420  		if (return_to_irqs_enabled) {
8fcc4ae6faf8b45 James Morse      2020-05-01  421  			local_daif_restore(DAIF_PROCCTX_NOIRQ);
8fcc4ae6faf8b45 James Morse      2020-05-01  422  			__irq_enter();
8fcc4ae6faf8b45 James Morse      2020-05-01  423  			irq_work_run();
8fcc4ae6faf8b45 James Morse      2020-05-01  424  			__irq_exit();
8fcc4ae6faf8b45 James Morse      2020-05-01  425  		} else {
420cab0155033c1 Osama Abdelkader 2025-11-10  426  			pr_warn_ratelimited("APEI work queued but not completed\n");
8fcc4ae6faf8b45 James Morse      2020-05-01  427  			err = -EINPROGRESS;
8fcc4ae6faf8b45 James Morse      2020-05-01  428  		}
8fcc4ae6faf8b45 James Morse      2020-05-01  429  	}
8fcc4ae6faf8b45 James Morse      2020-05-01  430  
d44f1b8dd7e66d8 James Morse      2019-01-29  431  	local_daif_restore(current_flags);
d44f1b8dd7e66d8 James Morse      2019-01-29  432  
d44f1b8dd7e66d8 James Morse      2019-01-29  433  	return err;
d44f1b8dd7e66d8 James Morse      2019-01-29  434  }
a509a66a9d0d4f4 Ard Biesheuvel   2020-09-29  435  

:::::: The code at line 413 was first introduced by commit
:::::: d44f1b8dd7e66d80cc4205809e5ace866bd851da arm64: KVM/mm: Move SEA handling behind a single 'claim' interface

:::::: TO: James Morse <james.morse@arm.com>
:::::: CC: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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