[PATCH v3 08/13] arm64: mm: replace TIF_LAZY_MMU with in_lazy_mmu_mode()

Kevin Brodsky
2025-10-15T08:28:26Z

The generic lazy_mmu layer now tracks whether a task is in lazy MMU
mode. As a result we no longer need a TIF flag for that purpose -
let's use the new in_lazy_mmu_mode() helper instead.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
arch/arm64/include/asm/pgtable.h | 16 +++-------------
arch/arm64/include/asm/thread_info.h | 3 +--
2 files changed, 4 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index f15ca4d62f09..944e512767db 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -62,30 +62,21 @@ static inline void emit_pte_barriers(void)

static inline void queue_pte_barriers(void)
{
- unsigned long flags;
-
if (in_interrupt()) {
emit_pte_barriers();
return;
}

- flags = read_thread_flags();
-
- if (flags & BIT(TIF_LAZY_MMU)) {
- /* Avoid the atomic op if already set. */
- if (!(flags & BIT(TIF_LAZY_MMU_PENDING)))
- set_thread_flag(TIF_LAZY_MMU_PENDING);
- } else {
+ if (in_lazy_mmu_mode())
+ test_and_set_thread_flag(TIF_LAZY_MMU_PENDING);
+ else
emit_pte_barriers();
- }
}

static inline void arch_enter_lazy_mmu_mode(void)
{
if (in_interrupt())
return;
-
- set_thread_flag(TIF_LAZY_MMU);
}

static inline void arch_flush_lazy_mmu_mode(void)
@@ -103,7 +94,6 @@ static inline void arch_leave_lazy_mmu_mode(void)
return;

arch_flush_lazy_mmu_mode();
- clear_thread_flag(TIF_LAZY_MMU);
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index f241b8601ebd..4ff8da0767d9 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -84,8 +84,7 @@ void arch_setup_new_exec(void);
#define TIF_SME_VL_INHERIT 28 /* Inherit SME vl_onexec across exec */
#define TIF_KERNEL_FPSTATE 29 /* Task is in a kernel mode FPSIMD section */
#define TIF_TSC_SIGSEGV 30 /* SIGSEGV on counter-timer access */
-#define TIF_LAZY_MMU 31 /* Task in lazy mmu mode */
-#define TIF_LAZY_MMU_PENDING 32 /* Ops pending for lazy mmu mode exit */
+#define TIF_LAZY_MMU_PENDING 31 /* Ops pending for lazy mmu mode exit */

#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
--
2.47.0