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From:
Stuart Henderson <stu@spacehopper.org>
Subject:
Re: lang/luajit add support of IBT for amd64
To:
Yuichiro NAITO <naito.yuichiro@gmail.com>
Cc:
ports@openbsd.org
Date:
Fri, 10 Oct 2025 11:00:55 +0100

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Thread
On 2025/10/10 10:11, Stuart Henderson wrote:
> On 2025/10/10 17:27, Yuichiro NAITO wrote:
> > Hi, I see that the LuaJIT fails to run on a processor that enables
> > the IBT (Indirect Branch Tracking) feature since OpenBSD 7.4.
> 
> luajit in the ports tree is built with enforcement disabled (see
> USE_NOBTCFI in the Makefile).
> 
> It would be good to be able to remove that, but it would be preferable
> to get this landed upstream if possible, rather than as patches in
> the ports tree, which may end up needing to get removed if they
> conflict with future upstream code changes. (I'll consider adding
> as patches if there's no interest upstream, but I think that should
> be tried first).

a ports diff would look like this

other ports would need syncs to change USE_NOBTCFI and bump revision
(benchmarks/wrk, games/luanti, games/luasteam, games/openmw,
games/powder-toy, games/solarus/solarus, mail/rspamd, net/hexchat,
net/snort, www/luakit, x11/kde-applications/cantor)

Index: Makefile
===================================================================
RCS file: /cvs/ports/lang/luajit/Makefile,v
diff -u -p -r1.38 Makefile
--- Makefile	24 Jul 2025 14:40:51 -0000	1.38
+++ Makefile	10 Oct 2025 09:53:14 -0000
@@ -1,6 +1,7 @@
 # keep arch-defines.mk LUAJIT_ARCHS in sync
 # bump ports which use PROPERTIES:Mluajit if changing
 ONLY_FOR_ARCHS = aarch64 arm amd64 i386 powerpc
+USE_NOBTCFI-aarch64 = Yes
 #
 # games/tome4 is using embedded copy of luajit
 
@@ -18,6 +19,7 @@ GH_COMMIT =	871db2c84ecefd70a850e03a6c34
 # epoch time of the commit; easiest found in ${WRKSRC}/.relver of the
 # git-archive tar
 V =		2.1.1753364724
+REVISION=	0
 
 COMMENT =	just-in-time compiler for Lua
 DISTNAME =	LuaJIT-${V}
@@ -29,8 +31,6 @@ HOMEPAGE =	https://luajit.org/
 
 # MIT
 PERMIT_PACKAGE =	Yes
-
-USE_NOBTCFI =	Yes
 
 WANTLIB =	c m
 
Index: patches/patch-src_lj_asm_c
===================================================================
RCS file: patches/patch-src_lj_asm_c
diff -N patches/patch-src_lj_asm_c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ patches/patch-src_lj_asm_c	10 Oct 2025 09:53:14 -0000
@@ -0,0 +1,26 @@
+amd64 bti fixes
+
+Index: src/lj_asm.c
+--- src/lj_asm.c.orig
++++ src/lj_asm.c
+@@ -1917,6 +1917,9 @@ static void asm_head_root(ASMState *as)
+   spadj = asm_stack_adjust(as);
+   as->T->spadjust = (uint16_t)spadj;
+   emit_spsub(as, spadj);
++#if LJ_TARGET_X64
++  emit_endbr(as);
++#endif
+   /* Root traces assume a checked stack for the starting proto. */
+   as->T->topslot = gcref(as->T->startpt)->pt.framesize;
+ }
+@@ -2085,7 +2088,9 @@ static void asm_head_side(ASMState *as)
+     checkmclim(as);
+     /* Continue with coalescing to fix up the broken cycle(s). */
+   }
+-
++#if LJ_TARGET_X64
++  emit_endbr(as);
++#endif
+   /* Inherit top stack slot already checked by parent trace. */
+   as->T->topslot = as->parent->topslot;
+   if (as->topslot > as->T->topslot) {  /* Need to check for higher slot? */
Index: patches/patch-src_lj_emit_x86_h
===================================================================
RCS file: patches/patch-src_lj_emit_x86_h
diff -N patches/patch-src_lj_emit_x86_h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ patches/patch-src_lj_emit_x86_h	10 Oct 2025 09:53:14 -0000
@@ -0,0 +1,21 @@
+amd64 bti fixes
+
+Index: src/lj_emit_x86.h
+--- src/lj_emit_x86.h.orig
++++ src/lj_emit_x86.h
+@@ -70,6 +70,15 @@ static LJ_AINLINE MCode *emit_op(x86Op xo, Reg rr, Reg
+   return p;
+ }
+ 
++static void emit_endbr(ASMState *as)
++{
++#if LJ_64
++  emit_u32(as, 0xfa1e0ff3);      // endbr64
++#else
++  emit_u32(as, 0xfb1e0ff3);      // endbr32
++#endif
++}
++
+ /* op + modrm */
+ #define emit_opm(xo, mode, rr, rb, p, delta) \
+   (p[(delta)-1] = MODRM((mode), (rr), (rb)), \
Index: patches/patch-src_vm_x64_dasc
===================================================================
RCS file: patches/patch-src_vm_x64_dasc
diff -N patches/patch-src_vm_x64_dasc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ patches/patch-src_vm_x64_dasc	10 Oct 2025 09:53:14 -0000
@@ -0,0 +1,826 @@
+amd64 bti fixes
+
+Index: src/vm_x64.dasc
+--- src/vm_x64.dasc.orig
++++ src/vm_x64.dasc
+@@ -192,13 +192,13 @@
+ |//-----------------------------------------------------------------------
+ |
+ |// Instruction headers.
+-|.macro ins_A; .endmacro
+-|.macro ins_AD; .endmacro
+-|.macro ins_AJ; .endmacro
+-|.macro ins_ABC; movzx RBd, RCH; movzx RCd, RCL; .endmacro
+-|.macro ins_AB_; movzx RBd, RCH; .endmacro
+-|.macro ins_A_C; movzx RCd, RCL; .endmacro
+-|.macro ins_AND; not RD; .endmacro
++|.macro ins_A; endbr64; .endmacro
++|.macro ins_AD; endbr64; .endmacro
++|.macro ins_AJ; endbr64; .endmacro
++|.macro ins_ABC; endbr64; movzx RBd, RCH; movzx RCd, RCL; .endmacro
++|.macro ins_AB_; endbr64; movzx RBd, RCH; .endmacro
++|.macro ins_A_C; endbr64; movzx RCd, RCL; .endmacro
++|.macro ins_AND; endbr64; not RD; .endmacro
+ |
+ |// Instruction decode+dispatch. Carefully tuned (nope, lodsd is not faster).
+ |.macro ins_NEXT
+@@ -387,6 +387,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-----------------------------------------------------------------------
+   |
+   |->vm_returnp:
++  |  endbr64
+   |  test PCd, FRAME_P
+   |  jz ->cont_dispatch
+   |
+@@ -400,6 +401,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  mov aword [BASE+RA], ITYPE		// Prepend true to results.
+   |
+   |->vm_returnc:
++  |  endbr64
+   |  add RDd, 1				// RD = nresults+1
+   |  jz ->vm_unwind_yield
+   |  mov MULTRES, RDd
+@@ -407,6 +409,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jz ->BC_RET_Z			// Handle regular return to Lua.
+   |
+   |->vm_return:
++  |  endbr64
+   |  // BASE = base, RA = resultofs, RD = nresults+1 (= MULTRES), PC = return
+   |  xor PC, FRAME_C
+   |  test PCd, FRAME_TYPE
+@@ -440,11 +443,13 @@ static void build_subroutines(BuildCtx *ctx)
+   |  mov L:RB->top, BASE
+   |
+   |->vm_leave_cp:
++  |  endbr64
+   |  mov RA, SAVE_CFRAME		// Restore previous C frame.
+   |  mov L:RB->cframe, RA
+   |  xor eax, eax			// Ok return status for vm_pcall.
+   |
+   |->vm_leave_unw:
++  |  endbr64
+   |  restoreregs
+   |  ret
+   |
+@@ -479,20 +484,24 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp <3
+   |
+   |->vm_unwind_yield:
++  |  endbr64
+   |  mov al, LUA_YIELD
+   |  jmp ->vm_unwind_c_eh
+   |
+   |->vm_unwind_c:			// Unwind C stack, return from vm_pcall.
++  |  endbr64
+   |  // (void *cframe, int errcode)
+   |  mov eax, CARG2d			// Error return status for vm_pcall.
+   |  mov rsp, CARG1
+   |->vm_unwind_c_eh:			// Landing pad for external unwinder.
++  |  endbr64
+   |  mov L:RB, SAVE_L
+   |  mov GL:RB, L:RB->glref
+   |  mov dword GL:RB->vmstate, ~LJ_VMST_C
+   |  jmp ->vm_leave_unw
+   |
+   |->vm_unwind_rethrow:
++  |  endbr64
+   |.if not X64WIN
+   |  mov CARG1, SAVE_L
+   |  mov CARG2d, eax
+@@ -501,10 +510,12 @@ static void build_subroutines(BuildCtx *ctx)
+   |.endif
+   |
+   |->vm_unwind_ff:			// Unwind C stack, return from ff pcall.
++  |  endbr64
+   |  // (void *cframe)
+   |  and CARG1, CFRAME_RAWMASK
+   |  mov rsp, CARG1
+   |->vm_unwind_ff_eh:			// Landing pad for external unwinder.
++  |  endbr64
+   |  mov L:RB, SAVE_L
+   |  mov RDd, 1+1			// Really 1+2 results, incr. later.
+   |  mov BASE, L:RB->base
+@@ -524,14 +535,17 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-----------------------------------------------------------------------
+   |
+   |->vm_growstack_c:			// Grow stack for C function.
++  |  endbr64
+   |  mov CARG2d, LUA_MINSTACK
+   |  jmp >2
+   |
+   |->vm_growstack_v:			// Grow stack for vararg Lua function.
++  |  endbr64
+   |  sub RD, 16				// LJ_FR2
+   |  jmp >1
+   |
+   |->vm_growstack_f:			// Grow stack for fixarg Lua function.
++  |  endbr64
+   |  // BASE = new base, RD = nargs+1, RB = L, PC = first PC
+   |  lea RD, [BASE+NARGS:RD*8-8]
+   |1:
+@@ -560,6 +574,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-----------------------------------------------------------------------
+   |
+   |->vm_resume:				// Setup C frame and resume thread.
++  |  endbr64
+   |  // (lua_State *L, TValue *base, int nres1 = 0, ptrdiff_t ef = 0)
+   |  saveregs
+   |  mov L:RB, CARG1			// Caveat: CARG1 may be RA.
+@@ -595,6 +610,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp ->vm_return
+   |
+   |->vm_pcall:				// Setup protected C frame and enter VM.
++  |  endbr64
+   |  // (lua_State *L, TValue *base, int nres1, ptrdiff_t ef)
+   |  saveregs
+   |  mov PCd, FRAME_CP
+@@ -602,6 +618,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp >1
+   |
+   |->vm_call:				// Setup C frame and enter VM.
++  |  endbr64
+   |  // (lua_State *L, TValue *base, int nres1)
+   |  saveregs
+   |  mov PCd, FRAME_C
+@@ -632,15 +649,18 @@ static void build_subroutines(BuildCtx *ctx)
+   |  add NARGS:RDd, 1			// RD = nargs+1
+   |
+   |->vm_call_dispatch:
++  |  endbr64
+   |  mov LFUNC:RB, [RA-16]
+   |  checkfunc LFUNC:RB, ->vmeta_call	// Ensure KBASE defined and != BASE.
+   |
+   |->vm_call_dispatch_f:
++  |  endbr64
+   |  mov BASE, RA
+   |  ins_call
+   |  // BASE = new base, RB = func, RD = nargs+1, PC = caller PC
+   |
+   |->vm_cpcall:				// Setup protected C frame, call C.
++  |  endbr64
+   |  // (lua_State *L, lua_CFunction func, void *ud, lua_CPFunction cp)
+   |  saveregs
+   |  mov L:RB, CARG1			// Caveat: CARG1 may be RA.
+@@ -675,6 +695,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-- Continuation dispatch ----------------------------------------------
+   |
+   |->cont_dispatch:
++  |  endbr64
+   |  // BASE = meta base, RA = resultofs, RD = nresults+1 (also in MULTRES)
+   |  add RA, BASE
+   |  and PC, -8
+@@ -706,6 +727,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |.endif
+   |
+   |->cont_cat:				// BASE = base, RC = result, RB = mbase
++  |  endbr64
+   |  movzx RAd, PC_RB
+   |  sub RB, 32
+   |  lea RA, [BASE+RA*8]
+@@ -733,6 +755,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-- Table indexing metamethods -----------------------------------------
+   |
+   |->vmeta_tgets:
++  |  endbr64
+   |  settp STR:RC, LJ_TSTR		// STR:RC = GCstr *
+   |  mov TMP1, STR:RC
+   |  lea RC, TMP1
+@@ -744,6 +767,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp >2
+   |
+   |->vmeta_tgetb:
++  |  endbr64
+   |  movzx RCd, PC_RC
+   |.if DUALNUM
+   |  setint RC
+@@ -756,6 +780,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp >1
+   |
+   |->vmeta_tgetv:
++  |  endbr64
+   |  movzx RCd, PC_RC			// Reload TValue *k from RC.
+   |  lea RC, [BASE+RC*8]
+   |1:
+@@ -774,6 +799,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  test RC, RC
+   |  jz >3
+   |->cont_ra:				// BASE = base, RC = result
++  |  endbr64
+   |  movzx RAd, PC_RA
+   |  mov RB, [RC]
+   |  mov [BASE+RA*8], RB
+@@ -791,6 +817,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp ->vm_call_dispatch_f
+   |
+   |->vmeta_tgetr:
++  |  endbr64
+   |  mov CARG1, TAB:RB
+   |  mov RB, BASE			// Save BASE.
+   |  mov CARG2d, RCd			// Caveat: CARG2 == BASE
+@@ -806,6 +833,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-----------------------------------------------------------------------
+   |
+   |->vmeta_tsets:
++  |  endbr64
+   |  settp STR:RC, LJ_TSTR		// STR:RC = GCstr *
+   |  mov TMP1, STR:RC
+   |  lea RC, TMP1
+@@ -817,6 +845,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp >2
+   |
+   |->vmeta_tsetb:
++  |  endbr64
+   |  movzx RCd, PC_RC
+   |.if DUALNUM
+   |  setint RC
+@@ -829,6 +858,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp >1
+   |
+   |->vmeta_tsetv:
++  |  endbr64
+   |  movzx RCd, PC_RC			// Reload TValue *k from RC.
+   |  lea RC, [BASE+RC*8]
+   |1:
+@@ -851,6 +881,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  mov RB, [BASE+RA*8]
+   |  mov [RC], RB
+   |->cont_nop:				// BASE = base, (RC = result)
++  |  endbr64
+   |  ins_next
+   |
+   |3:  // Call __newindex metamethod.
+@@ -869,6 +900,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp ->vm_call_dispatch_f
+   |
+   |->vmeta_tsetr:
++  |  endbr64
+   |.if X64WIN
+   |  mov L:CARG1, SAVE_L
+   |  mov CARG3d, RCd
+@@ -891,6 +923,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-- Comparison metamethods ---------------------------------------------
+   |
+   |->vmeta_comp:
++  |  endbr64
+   |  movzx RDd, PC_RD
+   |  movzx RAd, PC_RA
+   |  mov L:RB, SAVE_L
+@@ -921,6 +954,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  ins_next
+   |
+   |->cont_condt:			// BASE = base, RC = result
++  |  endbr64
+   |  add PC, 4
+   |  mov ITYPE, [RC]
+   |  sar ITYPE, 47
+@@ -929,12 +963,14 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp <6
+   |
+   |->cont_condf:			// BASE = base, RC = result
++  |  endbr64
+   |  mov ITYPE, [RC]
+   |  sar ITYPE, 47
+   |  cmp ITYPEd, LJ_TISTRUECOND		// Branch if result is false.
+   |  jmp <4
+   |
+   |->vmeta_equal:
++  |  endbr64
+   |  cleartp TAB:RD
+   |  sub PC, 4
+   |.if X64WIN
+@@ -958,6 +994,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp <3
+   |
+   |->vmeta_equal_cd:
++  |  endbr64
+   |.if FFI
+   |  sub PC, 4
+   |  mov L:RB, SAVE_L
+@@ -971,6 +1008,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |.endif
+   |
+   |->vmeta_istype:
++  |  endbr64
+   |  mov L:RB, SAVE_L
+   |  mov L:RB->base, BASE		// Caveat: CARG2/CARG3 may be BASE.
+   |  mov CARG2d, RAd
+@@ -984,36 +1022,43 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-- Arithmetic metamethods ---------------------------------------------
+   |
+   |->vmeta_arith_vno:
++  |  endbr64
+   |.if DUALNUM
+   |  movzx RBd, PC_RB
+   |  movzx RCd, PC_RC
+   |.endif
+   |->vmeta_arith_vn:
++  |  endbr64
+   |  lea RC, [KBASE+RC*8]
+   |  jmp >1
+   |
+   |->vmeta_arith_nvo:
++  |  endbr64
+   |.if DUALNUM
+   |  movzx RBd, PC_RB
+   |  movzx RCd, PC_RC
+   |.endif
+   |->vmeta_arith_nv:
++  |  endbr64
+   |  lea TMPR, [KBASE+RC*8]
+   |  lea RC, [BASE+RB*8]
+   |  mov RB, TMPR
+   |  jmp >2
+   |
+   |->vmeta_unm:
++  |  endbr64
+   |  lea RC, [BASE+RD*8]
+   |  mov RB, RC
+   |  jmp >2
+   |
+   |->vmeta_arith_vvo:
++  |  endbr64
+   |.if DUALNUM
+   |  movzx RBd, PC_RB
+   |  movzx RCd, PC_RC
+   |.endif
+   |->vmeta_arith_vv:
++  |  endbr64
+   |  lea RC, [BASE+RC*8]
+   |1:
+   |  lea RB, [BASE+RB*8]
+@@ -1046,6 +1091,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |  // Call metamethod for binary op.
+   |->vmeta_binop:
++  |  endbr64
+   |  // BASE = base, RC = new base, stack = cont/func/o1/o2
+   |  mov RA, RC
+   |  sub RC, BASE
+@@ -1055,6 +1101,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp ->vm_call_dispatch
+   |
+   |->vmeta_len:
++  |  endbr64
+   |  movzx RDd, PC_RD
+   |  mov L:RB, SAVE_L
+   |  mov L:RB->base, BASE
+@@ -1078,8 +1125,10 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-- Call metamethod ----------------------------------------------------
+   |
+   |->vmeta_call_ra:
++  |  endbr64
+   |  lea RA, [BASE+RA*8+16]
+   |->vmeta_call:			// Resolve and call __call metamethod.
++  |  endbr64
+   |  // BASE = old base, RA = new base, RC = nargs+1, PC = return
+   |  mov TMP1d, NARGS:RDd		// Save RA, RC for us.
+   |  mov RB, RA
+@@ -1113,6 +1162,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-- Argument coercion for 'for' statement ------------------------------
+   |
+   |->vmeta_for:
++  |  endbr64
+   |  mov L:RB, SAVE_L
+   |  mov L:RB->base, BASE
+   |  mov CARG2, RA			// Caveat: CARG2 == BASE
+@@ -1132,16 +1182,17 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |.macro .ffunc, name
+   |->ff_ .. name:
++  | endbr64
+   |.endmacro
+   |
+   |.macro .ffunc_1, name
+   |->ff_ .. name:
+-  |  cmp NARGS:RDd, 1+1;  jb ->fff_fallback
++  |  endbr64; cmp NARGS:RDd, 1+1;  jb ->fff_fallback
+   |.endmacro
+   |
+   |.macro .ffunc_2, name
+   |->ff_ .. name:
+-  |  cmp NARGS:RDd, 2+1;  jb ->fff_fallback
++  |  endbr64; cmp NARGS:RDd, 2+1;  jb ->fff_fallback
+   |.endmacro
+   |
+   |.macro .ffunc_n, name, op
+@@ -1414,6 +1465,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  mov RB, [RD]
+   |  mov [BASE-8], RB
+   |->fff_res2:
++  |  endbr64
+   |  mov RDd, 1+2
+   |  jmp ->fff_res
+   |2:  // Check for empty hash part first. Otherwise call C function.
+@@ -1434,6 +1486,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  test RD, RD
+   |  jnz <1
+   |->fff_res0:
++  |  endbr64
+   |  mov RDd, 1+0
+   |  jmp ->fff_res
+   |
+@@ -1665,8 +1718,10 @@ static void build_subroutines(BuildCtx *ctx)
+   |  neg RBd; js >2
+   |->fff_resbit:
+   |->fff_resi:
++  |  endbr64
+   |  setint RB
+   |->fff_resRB:
++  |  endbr64
+   |  mov PC, [BASE-8]
+   |  mov [BASE-16], RB
+   |  jmp ->fff_res1
+@@ -1686,15 +1741,19 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |.ffunc_n math_sqrt, sqrtsd
+   |->fff_resxmm0:
++  |  endbr64
+   |  mov PC, [BASE-8]
+   |  movsd qword [BASE-16], xmm0
+   |  // fallthrough
+   |
+   |->fff_res1:
++  |  endbr64
+   |  mov RDd, 1+1
+   |->fff_res:
++  |  endbr64
+   |  mov MULTRES, RDd
+   |->fff_res_:
++  |  endbr64
+   |  test PCd, FRAME_TYPE
+   |  jnz >7
+   |5:
+@@ -1907,6 +1966,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  mov TMPRd, 1
+   |  lea RD, TMP1			// Points to stack. Little-endian.
+   |->fff_newstr:
++  |  endbr64
+   |  mov L:RB, SAVE_L
+   |  mov L:RB->base, BASE
+   |  mov CARG3d, TMPRd			// Zero-extended to size_t.
+@@ -1915,6 +1975,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  mov SAVE_PC, PC
+   |  call extern lj_str_new		// (lua_State *L, char *str, size_t l)
+   |->fff_resstr:
++  |  endbr64
+   |  // GCstr * returned in eax (RD).
+   |  mov BASE, L:RB->base
+   |  mov PC, [BASE-8]
+@@ -1979,6 +2040,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp <3
+   |
+   |->fff_emptystr:  // Range underflow.
++  |  endbr64
+   |  xor TMPRd, TMPRd			// Zero length. Any ptr in RD is ok.
+   |  jmp <4
+   |
+@@ -2090,11 +2152,13 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp ->fff_resbit
+   |.else
+   |->fff_resbit:
++  |  endbr64
+   |  cvtsi2sd xmm0, RBd
+   |  jmp ->fff_resxmm0
+   |.endif
+   |
+   |->fff_fallback_bit_op:
++  |  endbr64
+   |  mov NARGS:RDd, TMPRd		// Restore for fallback
+   |  jmp ->fff_fallback
+   |
+@@ -2125,11 +2189,14 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-----------------------------------------------------------------------
+   |
+   |->fff_fallback_2:
++  |  endbr64
+   |  mov NARGS:RDd, 1+2			// Other args are ignored, anyway.
+   |  jmp ->fff_fallback
+   |->fff_fallback_1:
++  |  endbr64
+   |  mov NARGS:RDd, 1+1			// Other args are ignored, anyway.
+   |->fff_fallback:			// Call fast function fallback handler.
++  |  endbr64
+   |  // BASE = new base, RD = nargs+1
+   |  mov L:RB, SAVE_L
+   |  mov PC, [BASE-8]			// Fallback may overwrite PC.
+@@ -2160,6 +2227,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |// Reconstruct previous base for vmeta_call during tailcall.
+   |->vm_call_tail:
++  |  endbr64
+   |  mov RA, BASE
+   |  test PCd, FRAME_TYPE
+   |  jnz >3
+@@ -2182,6 +2250,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp <1				// Dumb retry (goes through ff first).
+   |
+   |->fff_gcstep:			// Call GC step function.
++  |  endbr64
+   |  // BASE = new base, RD = nargs+1
+   |  pop RB				// Must keep stack at same level.
+   |  mov TMP1, RB			// Save return address
+@@ -2207,6 +2276,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |->vm_record:				// Dispatch target for recording phase.
+   |.if JIT
++  |  endbr64
+   |  movzx RDd, byte [DISPATCH+DISPATCH_GL(hookmask)]
+   |  test RDL, HOOK_VMEVENT		// No recording while in vmevent.
+   |  jnz >5
+@@ -2220,12 +2290,14 @@ static void build_subroutines(BuildCtx *ctx)
+   |.endif
+   |
+   |->vm_rethook:			// Dispatch target for return hooks.
++  |  endbr64
+   |  movzx RDd, byte [DISPATCH+DISPATCH_GL(hookmask)]
+   |  test RDL, HOOK_ACTIVE		// Hook already active?
+   |  jnz >5
+   |  jmp >1
+   |
+   |->vm_inshook:			// Dispatch target for instr/line hooks.
++  |  endbr64
+   |  movzx RDd, byte [DISPATCH+DISPATCH_GL(hookmask)]
+   |  test RDL, HOOK_ACTIVE		// Hook already active?
+   |  jnz >5
+@@ -2253,6 +2325,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp aword [DISPATCH+OP*8+GG_DISP2STATIC]	// Re-dispatch to static ins.
+   |
+   |->cont_hook:				// Continue from hook yield.
++  |  endbr64
+   |  add PC, 4
+   |  mov RA, [RB-40]
+   |  mov MULTRES, RAd			// Restore MULTRES for *M ins.
+@@ -2260,6 +2333,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |->vm_hotloop:			// Hot loop counter underflow.
+   |.if JIT
++  |  endbr64
+   |  mov LFUNC:RB, [BASE-16]		// Same as curr_topL(L).
+   |  cleartp LFUNC:RB
+   |  mov RB, LFUNC:RB->pc
+@@ -2277,6 +2351,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |.endif
+   |
+   |->vm_callhook:			// Dispatch target for call hooks.
++  |  endbr64
+   |  mov SAVE_PC, PC
+   |.if JIT
+   |  jmp >1
+@@ -2284,6 +2359,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |->vm_hotcall:			// Hot call counter underflow.
+   |.if JIT
++  |  endbr64
+   |  mov SAVE_PC, PC
+   |  or PC, 1				// Marker for hot call.
+   |1:
+@@ -2312,6 +2388,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |->cont_stitch:			// Trace stitching.
+   |.if JIT
++  |  endbr64
+   |  // BASE = base, RC = result, RB = mbase
+   |  mov TRACE:ITYPE, [RB-40]		// Save previous trace.
+   |  cleartp TRACE:ITYPE
+@@ -2364,6 +2441,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |->vm_profhook:			// Dispatch target for profiler hook.
+ #if LJ_HASPROFILE
++  |  endbr64
+   |  mov L:RB, SAVE_L
+   |  mov L:RB->base, BASE
+   |  mov CARG2, PC			// Caveat: CARG2 == BASE
+@@ -2383,6 +2461,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |// The 16 bit exit number is stored with two (sign-extended) push imm8.
+   |->vm_exit_handler:
+   |.if JIT
++  |  endbr64
+   |  push r13; push r12
+   |  push r11; push r10; push r9; push r8
+   |  push rdi; push rsi; push rbp; lea rbp, [rsp+88]; push rbp
+@@ -2431,6 +2510,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  jmp >1
+   |.endif
+   |->vm_exit_interp:
++  |  endbr64
+   |  // RD = MULTRES or negated error code, BASE, PC and DISPATCH set.
+   |.if JIT
+   |  // Restore additional callee-save registers only used in compiled code.
+@@ -2524,6 +2604,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |.macro vm_round, name, mode, cond
+   |->name:
+   |->name .. _sse:
++  |  endbr64
+   |  sseconst_abs xmm2, RD
+   |  sseconst_2p52 xmm3, RD
+   |  movaps xmm1, xmm0
+@@ -2569,6 +2650,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |->vm_mod:
+   |// Args in xmm0/xmm1, return value in xmm0.
+   |// Caveat: xmm0-xmm5 and RC (eax) modified!
++  |  endbr64
+   |  movaps xmm5, xmm0
+   |  divsd xmm0, xmm1
+   |  sseconst_abs xmm2, RD
+@@ -2601,6 +2683,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |// int lj_vm_cpuid(uint32_t f, uint32_t res[4])
+   |->vm_cpuid:
++  |  endbr64
+   |  mov eax, CARG1d
+   |  .if X64WIN; push rsi; mov rsi, CARG2; .endif
+   |  push rbx
+@@ -2634,6 +2717,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |// Next idx returned in edx.
+   |->vm_next:
+   |.if JIT
++  |  endbr64
+   |  mov NEXT_ASIZE, NEXT_TAB->asize
+   |1:  // Traverse array part.
+   |  cmp NEXT_IDX, NEXT_ASIZE;  jae >5
+@@ -2680,6 +2764,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |//-----------------------------------------------------------------------
+   |
+   |->assert_bad_for_arg_type:
++  |  endbr64
+ #ifdef LUA_USE_ASSERT
+   |  int3
+ #endif
+@@ -2693,6 +2778,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |->vm_ffi_callback:
+   |.if FFI
+   |.type CTSTATE, CTState, PC
++  |  endbr64
+   |  saveregs_	// ebp/rbp already saved. ebp now holds global_State *.
+   |  lea DISPATCH, [ebp+GG_G2DISP]
+   |  mov CTSTATE, GL:ebp->ctype_state
+@@ -2736,6 +2822,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |
+   |->cont_ffi_callback:			// Return from FFI callback.
+   |.if FFI
++  |  endbr64
+   |  mov L:RA, SAVE_L
+   |  mov CTSTATE, [DISPATCH+DISPATCH_GL(ctype_state)]
+   |  mov aword CTSTATE->L, L:RA
+@@ -2753,7 +2840,7 @@ static void build_subroutines(BuildCtx *ctx)
+   |  // Caveat: needs special frame unwinding, see below.
+   |.if FFI
+   |  .type CCSTATE, CCallState, rbx
+-  |  push rbp; mov rbp, rsp; push rbx; mov CCSTATE, CARG1
++  |  endbr64; push rbp; mov rbp, rsp; push rbx; mov CCSTATE, CARG1
+   |
+   |  // Readjust stack.
+   |  mov eax, CCSTATE->spadj
+@@ -3221,6 +3308,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     |3:
+ #endif
+     |->BC_LEN_Z:
++    |  endbr64
+     |  mov RB, BASE			// Save BASE.
+     |  call extern lj_tab_len		// (GCtab *t)
+     |  // Length of table returned in eax (RD).
+@@ -3341,6 +3429,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+   case BC_MODVN:
+     |  ins_arithpre movsd, xmm1
+     |->BC_MODVN_Z:
++    |  endbr64
+     |  call ->vm_mod
+     |  ins_arithpost
+     |  ins_next
+@@ -3367,6 +3456,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     |  mov CARG3d, RCd
+     |  sub CARG3d, RBd
+     |->BC_CAT_Z:
++    |  endbr64
+     |  mov L:RB, L:CARG1
+     |  mov SAVE_PC, PC
+     |  call extern lj_meta_cat		// (lua_State *L, TValue *top, int left)
+@@ -3701,6 +3791,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     |  mov STR:RC, [KBASE+RC*8]
+     |  checktab TAB:RB, ->vmeta_tgets
+     |->BC_TGETS_Z:	// RB = GCtab *, RC = GCstr *
++    |  endbr64
+     |  mov TMPRd, TAB:RB->hmask
+     |  and TMPRd, STR:RC->sid
+     |  imul TMPRd, #NODE
+@@ -3771,8 +3862,10 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     |  add RC, TAB:RB->array
+     |  // Get array slot.
+     |->BC_TGETR_Z:
++    |  endbr64
+     |  mov ITYPE, [RC]
+     |->BC_TGETR2_Z:
++    |  endbr64
+     |  mov [BASE+RA*8], ITYPE
+     |  ins_next
+     break;
+@@ -3833,6 +3926,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     |  mov STR:RC, [KBASE+RC*8]
+     |  checktab TAB:RB, ->vmeta_tsets
+     |->BC_TSETS_Z:	// RB = GCtab *, RC = GCstr *
++    |  endbr64
+     |  mov TMPRd, TAB:RB->hmask
+     |  and TMPRd, STR:RC->sid
+     |  imul TMPRd, #NODE
+@@ -3940,6 +4034,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     |  add RC, TAB:RB->array
+     |  // Set array slot.
+     |->BC_TSETR_Z:
++    |  endbr64
+     |  mov ITYPE, [BASE+RA*8]
+     |  mov [RC], ITYPE
+     |  ins_next
+@@ -4021,6 +4116,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     |  mov LFUNC:RB, [RA-16]
+     |  checktp_nc LFUNC:RB, LJ_TFUNC, ->vmeta_call
+     |->BC_CALLT_Z:
++    |  endbr64
+     |  mov PC, [BASE-8]
+     |  test PCd, FRAME_TYPE
+     |  jnz >7
+@@ -4087,6 +4183,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+ 
+   case BC_ITERN:
+     |.if JIT
++    |  endbr64
+     |  hotloop RBd
+     |.endif
+     |->vm_IITERN:
+@@ -4267,6 +4364,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     switch (op) {
+     case BC_RET:
+       |->BC_RET_Z:
++      |  endbr64
+       |  mov KBASE, BASE		// Use KBASE for result move.
+       |  sub RDd, 1
+       |  jz >3
+@@ -4284,10 +4382,12 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+       |  ja >6
+       break;
+     case BC_RET1:
++      |  endbr64
+       |  mov RB, [BASE+RA]
+       |  mov [BASE-16], RB
+       /* fallthrough */
+     case BC_RET0:
++      |  endbr64
+       |5:
+       |  cmp PC_RB, RDL			// More results expected?
+       |  ja >6
+@@ -4334,6 +4434,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+ 
+   case BC_FORL:
+     |.if JIT
++    |  endbr64
+     |  hotloop RBd
+     |.endif
+     | // Fall through. Assumes BC_IFORL follows and ins_AJ is a no-op.
+@@ -4342,6 +4443,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+   case BC_JFORI:
+   case BC_JFORL:
+ #if !LJ_HASJIT
++    |  endbr64
+     break;
+ #endif
+   case BC_FORI:
+@@ -4485,6 +4587,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+ 
+   case BC_ITERL:
+     |.if JIT
++    |  endbr64
+     |  hotloop RBd
+     |.endif
+     | // Fall through. Assumes BC_IITERL follows and ins_AJ is a no-op.
+@@ -4492,6 +4595,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+ 
+   case BC_JITERL:
+ #if !LJ_HASJIT
++    |  endbr64
+     break;
+ #endif
+   case BC_IITERL:
+@@ -4578,13 +4682,16 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+ 
+   case BC_FUNCF:
+     |.if JIT
++    |  endbr64
+     |  hotcall RBd
+     |.endif
+   case BC_FUNCV:  /* NYI: compiled vararg functions. */
+     | // Fall through. Assumes BC_IFUNCF/BC_IFUNCV follow and ins_AD is a no-op.
++    |  endbr64
+     break;
+ 
+   case BC_JFUNCF:
++    |  endbr64
+ #if !LJ_HASJIT
+     break;
+ #endif
+@@ -4615,6 +4722,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defo
+     break;
+ 
+   case BC_JFUNCV:
++    |  endbr64
+ #if !LJ_HASJIT
+     break;
+ #endif