[PATCH v13 11/12] arm64: Use generic TIF bits for common thread flags
From: Jinjie Ruan
Date: Fri Mar 13 2026 - 05:52:06 EST
Use the generic TIF bits defined in <asm-generic/thread_info_tif.h> for
standard thread flags (TIF_SIGPENDING, TIF_NEED_RESCHED, TIF_NOTIFY_RESUME,
TIF_RESTORE_SIGMASK, TIF_SINGLESTEP, etc.) instead of defining
them locally.
Arm64-specific bits (TIF_FOREIGN_FPSTATE, TIF_MTE_ASYNC_FAULT, TIF_SVE,
TIF_SSBD, etc.) are renumbered to start at bit 16 to avoid conflicts.
This enables RSEQ optimizations which require CONFIG_HAVE_GENERIC_TIF_BITS
combined with the generic entry infrastructure (already used by arm64).
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/thread_info.h | 62 ++++++++++++---------------
arch/s390/include/asm/thread_info.h | 7 ++-
arch/x86/include/asm/thread_info.h | 6 +--
include/asm-generic/thread_info_tif.h | 5 +++
5 files changed, 38 insertions(+), 43 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 96fef01598be..33cf901fb1a0 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -224,6 +224,7 @@ config ARM64
select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
select HAVE_BUILDTIME_MCOUNT_SORT
select HAVE_EFFICIENT_UNALIGNED_ACCESS
+ select HAVE_GENERIC_TIF_BITS
select HAVE_GUP_FAST
select HAVE_FTRACE_GRAPH_FUNC
select HAVE_FUNCTION_TRACER
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index f89a15dc6ad5..be1a0651cfe2 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -58,42 +58,34 @@ void arch_setup_new_exec(void);
#endif
-#define TIF_SIGPENDING 0 /* signal pending */
-#define TIF_NEED_RESCHED 1 /* rescheduling necessary */
-#define TIF_NEED_RESCHED_LAZY 2 /* Lazy rescheduling needed */
-#define TIF_NOTIFY_RESUME 3 /* callback before returning to user */
-#define TIF_FOREIGN_FPSTATE 4 /* CPU's FP state is not current's */
-#define TIF_UPROBE 5 /* uprobe breakpoint or singlestep */
-#define TIF_MTE_ASYNC_FAULT 6 /* MTE Asynchronous Tag Check Fault */
-#define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */
-#define TIF_PATCH_PENDING 13 /* pending live patching update */
-#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
-#define TIF_FREEZE 19
-#define TIF_RESTORE_SIGMASK 20
-#define TIF_SINGLESTEP 21
-#define TIF_32BIT 22 /* 32bit process */
-#define TIF_SVE 23 /* Scalable Vector Extension in use */
-#define TIF_SVE_VL_INHERIT 24 /* Inherit SVE vl_onexec across exec */
-#define TIF_SSBD 25 /* Wants SSB mitigation */
-#define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */
-#define TIF_SME 27 /* SME in use */
-#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_PENDING 31 /* Ops pending for lazy mmu mode exit */
+/*
+ * Tell the generic TIF infrastructure which bits arm64 supports
+ */
+#define HAVE_TIF_NEED_RESCHED_LAZY
+#define HAVE_TIF_RESTORE_SIGMASK
+#define HAVE_TIF_SINGLESTEP
+
+#include <asm-generic/thread_info_tif.h>
+
+#define TIF_FOREIGN_FPSTATE 16 /* CPU's FP state is not current's */
+#define TIF_MTE_ASYNC_FAULT 17 /* MTE Asynchronous Tag Check Fault */
+#define TIF_FREEZE 18
+#define TIF_32BIT 19 /* 32bit process */
+#define TIF_SVE 20 /* Scalable Vector Extension in use */
+#define TIF_SVE_VL_INHERIT 21 /* Inherit SVE vl_onexec across exec */
+#define TIF_SSBD 22 /* Wants SSB mitigation */
+#define TIF_TAGGED_ADDR 23 /* Allow tagged user addresses */
+#define TIF_SME 24 /* SME in use */
+#define TIF_SME_VL_INHERIT 25 /* Inherit SME vl_onexec across exec */
+#define TIF_KERNEL_FPSTATE 26 /* Task is in a kernel mode FPSIMD section */
+#define TIF_TSC_SIGSEGV 27 /* SIGSEGV on counter-timer access */
+#define TIF_LAZY_MMU_PENDING 28 /* Ops pending for lazy mmu mode exit */
-#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
-#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
-#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY)
-#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
-#define _TIF_FOREIGN_FPSTATE (1 << TIF_FOREIGN_FPSTATE)
-#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
-#define _TIF_UPROBE (1 << TIF_UPROBE)
-#define _TIF_32BIT (1 << TIF_32BIT)
-#define _TIF_SVE (1 << TIF_SVE)
-#define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT)
-#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
-#define _TIF_TSC_SIGSEGV (1 << TIF_TSC_SIGSEGV)
+#define _TIF_FOREIGN_FPSTATE BIT(TIF_FOREIGN_FPSTATE)
+#define _TIF_32BIT BIT(TIF_32BIT)
+#define _TIF_SVE BIT(TIF_SVE)
+#define _TIF_MTE_ASYNC_FAULT BIT(TIF_MTE_ASYNC_FAULT)
+#define _TIF_TSC_SIGSEGV BIT(TIF_TSC_SIGSEGV)
#ifdef CONFIG_SHADOW_CALL_STACK
#define INIT_SCS \
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index 1bcd42614e41..95be5258a422 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -61,6 +61,7 @@ void arch_setup_new_exec(void);
*/
#define HAVE_TIF_NEED_RESCHED_LAZY
#define HAVE_TIF_RESTORE_SIGMASK
+#define HAVE_TIF_SINGLESTEP
#include <asm-generic/thread_info_tif.h>
@@ -69,15 +70,13 @@ void arch_setup_new_exec(void);
#define TIF_GUARDED_STORAGE 17 /* load guarded storage control block */
#define TIF_ISOLATE_BP_GUEST 18 /* Run KVM guests with isolated BP */
#define TIF_PER_TRAP 19 /* Need to handle PER trap on exit to usermode */
-#define TIF_SINGLESTEP 21 /* This task is single stepped */
-#define TIF_BLOCK_STEP 22 /* This task is block stepped */
-#define TIF_UPROBE_SINGLESTEP 23 /* This task is uprobe single stepped */
+#define TIF_BLOCK_STEP 20 /* This task is block stepped */
+#define TIF_UPROBE_SINGLESTEP 21 /* This task is uprobe single stepped */
#define _TIF_ASCE_PRIMARY BIT(TIF_ASCE_PRIMARY)
#define _TIF_GUARDED_STORAGE BIT(TIF_GUARDED_STORAGE)
#define _TIF_ISOLATE_BP_GUEST BIT(TIF_ISOLATE_BP_GUEST)
#define _TIF_PER_TRAP BIT(TIF_PER_TRAP)
-#define _TIF_SINGLESTEP BIT(TIF_SINGLESTEP)
#define _TIF_BLOCK_STEP BIT(TIF_BLOCK_STEP)
#define _TIF_UPROBE_SINGLESTEP BIT(TIF_UPROBE_SINGLESTEP)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 0067684afb5b..f59072ba1473 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -98,9 +98,8 @@ struct thread_info {
#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
#define TIF_SPEC_FORCE_UPDATE 23 /* Force speculation MSR update in context switch */
#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
-#define TIF_SINGLESTEP 25 /* reenable singlestep on user return*/
-#define TIF_BLOCKSTEP 26 /* set when we want DEBUGCTLMSR_BTF */
-#define TIF_ADDR32 27 /* 32-bit address space on 64 bits */
+#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
+#define TIF_ADDR32 26 /* 32-bit address space on 64 bits */
#define _TIF_SSBD BIT(TIF_SSBD)
#define _TIF_SPEC_IB BIT(TIF_SPEC_IB)
@@ -112,7 +111,6 @@ struct thread_info {
#define _TIF_SPEC_FORCE_UPDATE BIT(TIF_SPEC_FORCE_UPDATE)
#define _TIF_FORCED_TF BIT(TIF_FORCED_TF)
#define _TIF_BLOCKSTEP BIT(TIF_BLOCKSTEP)
-#define _TIF_SINGLESTEP BIT(TIF_SINGLESTEP)
#define _TIF_ADDR32 BIT(TIF_ADDR32)
/* flags to check in __switch_to() */
diff --git a/include/asm-generic/thread_info_tif.h b/include/asm-generic/thread_info_tif.h
index da1610a78f92..b277fe06aee3 100644
--- a/include/asm-generic/thread_info_tif.h
+++ b/include/asm-generic/thread_info_tif.h
@@ -48,4 +48,9 @@
#define TIF_RSEQ 11 // Run RSEQ fast path
#define _TIF_RSEQ BIT(TIF_RSEQ)
+#ifdef HAVE_TIF_SINGLESTEP
+#define TIF_SINGLESTEP 12 /* reenable singlestep on user return*/
+#define _TIF_SINGLESTEP BIT(TIF_SINGLESTEP)
+#endif
+
#endif /* _ASM_GENERIC_THREAD_INFO_TIF_H_ */
--
2.34.1