On 5/8/2023 2:56 PM, Dave Hansen wrote:
On 5/8/23 11:18, Chang S. Bae wrote:
On 5/5/2023 4:05 PM, Eric Biggers wrote:
On Mon, Apr 10, 2023 at 03:59:31PM -0700, Chang S. Bae wrote:
+#ifdef CONFIG_X86_KEYLOCKER
+void setup_keylocker(struct cpuinfo_x86 *c);
+void destroy_keylocker_data(void);
+#else
+#define setup_keylocker(c) do { } while (0)
+#define destroy_keylocker_data() do { } while (0)
+#endif
Shouldn't the !CONFIG_X86_KEYLOCKER stubs be static inline functions
instead of
macros, so that type checking works?
I think either way works here. This macro is just for nothing.
Chang, I do prefer the 'static inline' as a general rule. Think of this:
static inline void setup_keylocker(struct cpuinfo_x86 *c) {}
versus:
#define setup_keylocker(c) do { } while (0)
Imagine some dope does:
char c;
...
setup_keylocker(c);
With the macro, they'll get no type warning. The inline actually makes
it easier to find bugs because folks will get _some_ type checking no
matter how they compile the code.
Ah, when the prototype with one or more arguments, 'static inline'
allows the check. Then it is not an 'either-way' thing.
Looking at the x86 code, there are some seemingly related:
$ git grep "do { } while (0)" arch/x86 | grep -v "()"
arch/x86/include/asm/kprobes.h:#define flush_insn_slot(p) do { }
while (0)
arch/x86/include/asm/mc146818rtc.h:#define lock_cmos(reg) do { } while (0)
arch/x86/include/asm/pgtable.h:#define flush_tlb_fix_spurious_fault(vma,
address, ptep) do { } while (0)
arch/x86/include/asm/preempt.h:#define init_task_preempt_count(p) do { }
while (0)
arch/x86/kvm/ioapic.h:#define ASSERT(x) do { } while (0)
arch/x86/kvm/mmu/mmu_internal.h:#define pgprintk(x...) do { } while (0)
arch/x86/kvm/mmu/mmu_internal.h:#define rmap_printk(x...) do { } while (0)
arch/x86/kvm/mmu/mmu_internal.h:#define MMU_WARN_ON(x) do { } while (0)
Now I feel owed for some potential cleanup work.
Thanks,
Chang
