Merge tag 'loongarch-fixes-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:
 "Complete CPUCFG registers definition, set correct protection_map[] for
  VM_NONE/VM_SHARED, fix some bugs in the orc stack unwinder, ftrace and
  BPF JIT"

* tag 'loongarch-fixes-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  samples/ftrace: Adjust LoongArch register restore order in direct calls
  LoongArch: BPF: Enhance the bpf_arch_text_poke() function
  LoongArch: BPF: Enable trampoline-based tracing for module functions
  LoongArch: BPF: Adjust the jump offset of tail calls
  LoongArch: BPF: Save return address register ra to t0 before trampoline
  LoongArch: BPF: Zero-extend bpf_tail_call() index
  LoongArch: BPF: Sign extend kfunc call arguments
  LoongArch: Refactor register restoration in ftrace_common_return
  LoongArch: Enable exception fixup for specific ADE subcode
  LoongArch: Remove unnecessary checks for ORC unwinder
  LoongArch: Remove is_entry_func() and kernel_entry_end
  LoongArch: Use UNWIND_HINT_END_OF_STACK for entry points
  LoongArch: Set correct protection_map[] for VM_NONE/VM_SHARED
  LoongArch: Complete CPUCFG registers definition

13 files changed, 120 insertions, 57 deletions

diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index e6b8ff61c8cc..553c4dc7a156 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -94,6 +94,12 @@
 #define  CPUCFG2_LSPW			BIT(21)
 #define  CPUCFG2_LAM			BIT(22)
 #define  CPUCFG2_PTW			BIT(24)
+#define  CPUCFG2_FRECIPE		BIT(25)
+#define  CPUCFG2_DIV32			BIT(26)
+#define  CPUCFG2_LAM_BH			BIT(27)
+#define  CPUCFG2_LAMCAS			BIT(28)
+#define  CPUCFG2_LLACQ_SCREL		BIT(29)
+#define  CPUCFG2_SCQ			BIT(30)
 
 #define LOONGARCH_CPUCFG3		0x3
 #define  CPUCFG3_CCDMA			BIT(0)
@@ -108,6 +114,7 @@
 #define  CPUCFG3_SPW_HG_HF		BIT(11)
 #define  CPUCFG3_RVA			BIT(12)
 #define  CPUCFG3_RVAMAX			GENMASK(16, 13)
+#define  CPUCFG3_DBAR_HINTS		BIT(17)
 #define  CPUCFG3_ALDORDER_CAP		BIT(18) /* All address load ordered, capability */
 #define  CPUCFG3_ASTORDER_CAP		BIT(19) /* All address store ordered, capability */
 #define  CPUCFG3_ALDORDER_STA		BIT(20) /* All address load ordered, status */
diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S
index aba548db2446..7f288e89573b 100644
--- a/arch/loongarch/kernel/head.S
+++ b/arch/loongarch/kernel/head.S
@@ -42,6 +42,7 @@ SYM_DATA(kernel_fsize, .long _kernel_fsize);
 	.align 12
 
 SYM_CODE_START(kernel_entry)			# kernel entry point
+	UNWIND_HINT_END_OF_STACK
 
 	SETUP_TWINS
 	SETUP_MODES	t0
@@ -113,6 +114,7 @@ SYM_CODE_END(kernel_entry)
  * function after setting up the stack and tp registers.
  */
 SYM_CODE_START(smpboot_entry)
+	UNWIND_HINT_END_OF_STACK
 
 	SETUP_TWINS
 	SETUP_MODES	t0
@@ -142,5 +144,3 @@ SYM_CODE_START(smpboot_entry)
 SYM_CODE_END(smpboot_entry)
 
 #endif /* CONFIG_SMP */
-
-SYM_ENTRY(kernel_entry_end, SYM_L_GLOBAL, SYM_A_NONE)
diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S
index d6b474ad1d5e..5729c20e5b8b 100644
--- a/arch/loongarch/kernel/mcount_dyn.S
+++ b/arch/loongarch/kernel/mcount_dyn.S
@@ -94,7 +94,6 @@ SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL)
  * at the callsite, so there is no need to restore the T series regs.
  */
 ftrace_common_return:
-	PTR_L		ra, sp, PT_R1
 	PTR_L		a0, sp, PT_R4
 	PTR_L		a1, sp, PT_R5
 	PTR_L		a2, sp, PT_R6
@@ -104,12 +103,17 @@ ftrace_common_return:
 	PTR_L		a6, sp, PT_R10
 	PTR_L		a7, sp, PT_R11
 	PTR_L		fp, sp, PT_R22
-	PTR_L		t0, sp, PT_ERA
 	PTR_L		t1, sp, PT_R13
-	PTR_ADDI	sp, sp, PT_SIZE
 	bnez		t1, .Ldirect
+
+	PTR_L		ra, sp, PT_R1
+	PTR_L		t0, sp, PT_ERA
+	PTR_ADDI	sp, sp, PT_SIZE
 	jr		t0
 .Ldirect:
+	PTR_L		t0, sp, PT_R1
+	PTR_L		ra, sp, PT_ERA
+	PTR_ADDI	sp, sp, PT_SIZE
 	jr		t1
 SYM_CODE_END(ftrace_common)
 
@@ -161,6 +165,8 @@ SYM_CODE_END(return_to_handler)
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 SYM_CODE_START(ftrace_stub_direct_tramp)
 	UNWIND_HINT_UNDEFINED
-	jr		t0
+	move		t1, ra
+	move		ra, t0
+	jr		t1
 SYM_CODE_END(ftrace_stub_direct_tramp)
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index 004b8ebf0051..5d49b742e3bf 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -535,10 +535,15 @@ out:
 asmlinkage void noinstr do_ade(struct pt_regs *regs)
 {
 	irqentry_state_t state = irqentry_enter(regs);
+	unsigned int esubcode = FIELD_GET(CSR_ESTAT_ESUBCODE, regs->csr_estat);
+
+	if ((esubcode == EXSUBCODE_ADEM) && fixup_exception(regs))
+		goto out;
 
 	die_if_kernel("Kernel ade access", regs);
 	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)regs->csr_badvaddr);
 
+out:
 	irqentry_exit(regs, state);
 }
 
diff --git a/arch/loongarch/kernel/unwind_orc.c b/arch/loongarch/kernel/unwind_orc.c
index 0d5fa64a2225..8a6e3429a860 100644
--- a/arch/loongarch/kernel/unwind_orc.c
+++ b/arch/loongarch/kernel/unwind_orc.c
@@ -348,24 +348,10 @@ void unwind_start(struct unwind_state *state, struct task_struct *task,
 }
 EXPORT_SYMBOL_GPL(unwind_start);
 
-static bool is_entry_func(unsigned long addr)
-{
-	extern u32 kernel_entry;
-	extern u32 kernel_entry_end;
-
-	return addr >= (unsigned long)&kernel_entry && addr < (unsigned long)&kernel_entry_end;
-}
-
 static inline unsigned long bt_address(unsigned long ra)
 {
 	extern unsigned long eentry;
 
-	if (__kernel_text_address(ra))
-		return ra;
-
-	if (__module_text_address(ra))
-		return ra;
-
 	if (ra >= eentry && ra < eentry +  EXCCODE_INT_END * VECSIZE) {
 		unsigned long func;
 		unsigned long type = (ra - eentry) / VECSIZE;
@@ -383,10 +369,13 @@ static inline unsigned long bt_address(unsigned long ra)
 			break;
 		}
 
-		return func + offset;
+		ra = func + offset;
 	}
 
-	return ra;
+	if (__kernel_text_address(ra))
+		return ra;
+
+	return 0;
 }
 
 bool unwind_next_frame(struct unwind_state *state)
@@ -402,9 +391,6 @@ bool unwind_next_frame(struct unwind_state *state)
 	/* Don't let modules unload while we're reading their ORC data. */
 	guard(rcu)();
 
-	if (is_entry_func(state->pc))
-		goto end;
-
 	orc = orc_find(state->pc);
 	if (!orc) {
 		/*
@@ -512,9 +498,6 @@ bool unwind_next_frame(struct unwind_state *state)
 		goto err;
 	}
 
-	if (!__kernel_text_address(state->pc))
-		goto err;
-
 	return true;
 
 err:
diff --git a/arch/loongarch/mm/cache.c b/arch/loongarch/mm/cache.c
index 6be04d36ca07..496916845ff7 100644
--- a/arch/loongarch/mm/cache.c
+++ b/arch/loongarch/mm/cache.c
@@ -160,8 +160,8 @@ void cpu_cache_init(void)
 
 static const pgprot_t protection_map[16] = {
 	[VM_NONE]					= __pgprot(_CACHE_CC | _PAGE_USER |
-								   _PAGE_PROTNONE | _PAGE_NO_EXEC |
-								   _PAGE_NO_READ),
+								   _PAGE_NO_EXEC | _PAGE_NO_READ |
+								   (_PAGE_PROTNONE ? : _PAGE_PRESENT)),
 	[VM_READ]					= __pgprot(_CACHE_CC | _PAGE_VALID |
 								   _PAGE_USER | _PAGE_PRESENT |
 								   _PAGE_NO_EXEC),
@@ -180,8 +180,8 @@ static const pgprot_t protection_map[16] = {
 	[VM_EXEC | VM_WRITE | VM_READ]			= __pgprot(_CACHE_CC | _PAGE_VALID |
 								   _PAGE_USER | _PAGE_PRESENT),
 	[VM_SHARED]					= __pgprot(_CACHE_CC | _PAGE_USER |
-								   _PAGE_PROTNONE | _PAGE_NO_EXEC |
-								   _PAGE_NO_READ),
+								   _PAGE_NO_EXEC | _PAGE_NO_READ |
+								   (_PAGE_PROTNONE ? : _PAGE_PRESENT)),
 	[VM_SHARED | VM_READ]				= __pgprot(_CACHE_CC | _PAGE_VALID |
 								   _PAGE_USER | _PAGE_PRESENT |
 								   _PAGE_NO_EXEC),
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index 8dc58781b8eb..d1d5a65308b9 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -139,6 +139,7 @@ static void build_prologue(struct jit_ctx *ctx)
 	stack_adjust = round_up(stack_adjust, 16);
 	stack_adjust += bpf_stack_adjust;
 
+	move_reg(ctx, LOONGARCH_GPR_T0, LOONGARCH_GPR_RA);
 	/* Reserve space for the move_imm + jirl instruction */
 	for (i = 0; i < LOONGARCH_LONG_JUMP_NINSNS; i++)
 		emit_insn(ctx, nop);
@@ -238,7 +239,7 @@ static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call)
 		 * Call the next bpf prog and skip the first instruction
 		 * of TCC initialization.
 		 */
-		emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T3, 6);
+		emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T3, 7);
 	}
 }
 
@@ -280,6 +281,8 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn)
 	 *	 goto out;
 	 */
 	tc_ninsn = insn ? ctx->offset[insn+1] - ctx->offset[insn] : ctx->offset[0];
+	emit_zext_32(ctx, a2, true);
+
 	off = offsetof(struct bpf_array, map.max_entries);
 	emit_insn(ctx, ldwu, t1, a1, off);
 	/* bgeu $a2, $t1, jmp_offset */
@@ -950,6 +953,22 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
 			emit_insn(ctx, ldd, REG_TCC, LOONGARCH_GPR_SP, tcc_ptr_off);
 		}
 
+		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
+			const struct btf_func_model *m;
+			int i;
+
+			m = bpf_jit_find_kfunc_model(ctx->prog, insn);
+			if (!m)
+				return -EINVAL;
+
+			for (i = 0; i < m->nr_args; i++) {
+				u8 reg = regmap[BPF_REG_1 + i];
+				bool sign = m->arg_flags[i] & BTF_FMODEL_SIGNED_ARG;
+
+				emit_abi_ext(ctx, reg, m->arg_size[i], sign);
+			}
+		}
+
 		move_addr(ctx, t1, func_addr);
 		emit_insn(ctx, jirl, LOONGARCH_GPR_RA, t1, 0);
 
@@ -1265,7 +1284,7 @@ static int emit_jump_or_nops(void *target, void *ip, u32 *insns, bool is_call)
 		return 0;
 	}
 
-	return emit_jump_and_link(&ctx, is_call ? LOONGARCH_GPR_T0 : LOONGARCH_GPR_ZERO, (u64)target);
+	return emit_jump_and_link(&ctx, is_call ? LOONGARCH_GPR_RA : LOONGARCH_GPR_ZERO, (u64)target);
 }
 
 static int emit_call(struct jit_ctx *ctx, u64 addr)
@@ -1290,15 +1309,30 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type old_t,
 {
 	int ret;
 	bool is_call;
+	unsigned long size = 0;
+	unsigned long offset = 0;
+	void *image = NULL;
+	char namebuf[KSYM_NAME_LEN];
 	u32 old_insns[LOONGARCH_LONG_JUMP_NINSNS] = {[0 ... 4] = INSN_NOP};
 	u32 new_insns[LOONGARCH_LONG_JUMP_NINSNS] = {[0 ... 4] = INSN_NOP};
 
 	/* Only poking bpf text is supported. Since kernel function entry
 	 * is set up by ftrace, we rely on ftrace to poke kernel functions.
 	 */
-	if (!is_bpf_text_address((unsigned long)ip))
+	if (!__bpf_address_lookup((unsigned long)ip, &size, &offset, namebuf))
 		return -ENOTSUPP;
 
+	image = ip - offset;
+
+	/* zero offset means we're poking bpf prog entry */
+	if (offset == 0) {
+		/* skip to the nop instruction in bpf prog entry:
+		 * move t0, ra
+		 * nop
+		 */
+		ip = image + LOONGARCH_INSN_SIZE;
+	}
+
 	is_call = old_t == BPF_MOD_CALL;
 	ret = emit_jump_or_nops(old_addr, ip, old_insns, is_call);
 	if (ret)
@@ -1622,14 +1656,12 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i
 
 	/* To traced function */
 	/* Ftrace jump skips 2 NOP instructions */
-	if (is_kernel_text((unsigned long)orig_call))
+	if (is_kernel_text((unsigned long)orig_call) ||
+	    is_module_text_address((unsigned long)orig_call))
 		orig_call += LOONGARCH_FENTRY_NBYTES;
 	/* Direct jump skips 5 NOP instructions */
 	else if (is_bpf_text_address((unsigned long)orig_call))
 		orig_call += LOONGARCH_BPF_FENTRY_NBYTES;
-	/* Module tracing not supported - cause kernel lockups */
-	else if (is_module_text_address((unsigned long)orig_call))
-		return -ENOTSUPP;
 
 	if (flags & BPF_TRAMP_F_CALL_ORIG) {
 		move_addr(ctx, LOONGARCH_GPR_A0, (const u64)im);
@@ -1722,12 +1754,16 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i
 		emit_insn(ctx, ldd, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, 0);
 		emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, 16);
 
-		if (flags & BPF_TRAMP_F_SKIP_FRAME)
+		if (flags & BPF_TRAMP_F_SKIP_FRAME) {
 			/* return to parent function */
-			emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_RA, 0);
-		else
-			/* return to traced function */
+			move_reg(ctx, LOONGARCH_GPR_RA, LOONGARCH_GPR_T0);
 			emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T0, 0);
+		} else {
+			/* return to traced function */
+			move_reg(ctx, LOONGARCH_GPR_T1, LOONGARCH_GPR_RA);
+			move_reg(ctx, LOONGARCH_GPR_RA, LOONGARCH_GPR_T0);
+			emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T1, 0);
+		}
 	}
 
 	ret = ctx->idx;
diff --git a/arch/loongarch/net/bpf_jit.h b/arch/loongarch/net/bpf_jit.h
index 5697158fd164..75b6330030a9 100644
--- a/arch/loongarch/net/bpf_jit.h
+++ b/arch/loongarch/net/bpf_jit.h
@@ -88,6 +88,32 @@ static inline void emit_sext_32(struct jit_ctx *ctx, enum loongarch_gpr reg, boo
 	emit_insn(ctx, addiw, reg, reg, 0);
 }
 
+/* Emit proper extension according to ABI requirements.
+ * Note that it requires a value of size `size` already resides in register `reg`.
+ */
+static inline void emit_abi_ext(struct jit_ctx *ctx, int reg, u8 size, bool sign)
+{
+	/* ABI requires unsigned char/short to be zero-extended */
+	if (!sign && (size == 1 || size == 2))
+		return;
+
+	switch (size) {
+	case 1:
+		emit_insn(ctx, extwb, reg, reg);
+		break;
+	case 2:
+		emit_insn(ctx, extwh, reg, reg);
+		break;
+	case 4:
+		emit_insn(ctx, addiw, reg, reg, 0);
+		break;
+	case 8:
+		break;
+	default:
+		pr_warn("bpf_jit: invalid size %d for extension\n", size);
+	}
+}
+
 static inline void move_addr(struct jit_ctx *ctx, enum loongarch_gpr rd, u64 addr)
 {
 	u64 imm_11_0, imm_31_12, imm_51_32, imm_63_52;
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index da3a9f2091f5..1ba1927b548e 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -176,8 +176,8 @@ asm (
 "	st.d	$t0, $sp, 0\n"
 "	st.d	$ra, $sp, 8\n"
 "	bl	my_direct_func1\n"
-"	ld.d	$t0, $sp, 0\n"
-"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$ra, $sp, 0\n"
+"	ld.d	$t0, $sp, 8\n"
 "	addi.d	$sp, $sp, 16\n"
 "	jr	$t0\n"
 "	.size		my_tramp1, .-my_tramp1\n"
@@ -189,8 +189,8 @@ asm (
 "	st.d	$t0, $sp, 0\n"
 "	st.d	$ra, $sp, 8\n"
 "	bl	my_direct_func2\n"
-"	ld.d	$t0, $sp, 0\n"
-"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$ra, $sp, 0\n"
+"	ld.d	$t0, $sp, 8\n"
 "	addi.d	$sp, $sp, 16\n"
 "	jr	$t0\n"
 "	.size		my_tramp2, .-my_tramp2\n"
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index 8f7986d698d8..7a7822dfeb50 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -199,8 +199,8 @@ asm (
 "	move	$a0, $t0\n"
 "	bl	my_direct_func1\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp1, .-my_tramp1\n"
@@ -215,8 +215,8 @@ asm (
 "	move	$a0, $t0\n"
 "	bl	my_direct_func2\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp2, .-my_tramp2\n"
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index db326c81a27d..3fe6ddaf0b69 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -131,8 +131,8 @@ asm (
 "	move	$a0, $t0\n"
 "	bl	my_direct_func\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp, .-my_tramp\n"
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 3d0fa260332d..bf2411aa6fd7 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -143,8 +143,8 @@ asm (
 "	ld.d	$a0, $sp, 0\n"
 "	ld.d	$a1, $sp, 8\n"
 "	ld.d	$a2, $sp, 16\n"
-"	ld.d	$t0, $sp, 24\n"
-"	ld.d	$ra, $sp, 32\n"
+"	ld.d	$ra, $sp, 24\n"
+"	ld.d	$t0, $sp, 32\n"
 "	addi.d	$sp, $sp, 48\n"
 "	jr	$t0\n"
 "	.size		my_tramp, .-my_tramp\n"
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index 956834b0d19a..5368c8c39cbb 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -124,8 +124,8 @@ asm (
 "	st.d	$ra, $sp, 16\n"
 "	bl	my_direct_func\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp, .-my_tramp\n"