jump_label: move 'asm goto' support test to Kconfig

Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".

The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:

  #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
  # define HAVE_JUMP_LABEL
  #endif

We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.

Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>

23 files changed, 19 insertions, 59 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index b70c952ac838..4cfb6de48f79 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -71,6 +71,7 @@ config KPROBES
 config JUMP_LABEL
        bool "Optimize very unlikely/likely branches"
        depends on HAVE_ARCH_JUMP_LABEL
+       depends on CC_HAS_ASM_GOTO
        help
          This option enables a transparent branch optimization that
          makes certain almost-always-true or almost-always-false branch
diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
index 90bce3d9928e..303b3ab87f7e 100644
--- a/arch/arm/kernel/jump_label.c
+++ b/arch/arm/kernel/jump_label.c
@@ -4,8 +4,6 @@
 #include <asm/patch.h>
 #include <asm/insn.h>
 
-#ifdef HAVE_JUMP_LABEL
-
 static void __arch_jump_label_transform(struct jump_entry *entry,
                                         enum jump_label_type type,
                                         bool is_static)
@@ -35,5 +33,3 @@ void arch_jump_label_transform_static(struct jump_entry *entry,
 {
         __arch_jump_label_transform(entry, type, true);
 }
-
-#endif
diff --git a/arch/arm64/kernel/jump_label.c b/arch/arm64/kernel/jump_label.c
index 646b9562ee64..1eff270e8861 100644
--- a/arch/arm64/kernel/jump_label.c
+++ b/arch/arm64/kernel/jump_label.c
@@ -20,8 +20,6 @@
 #include <linux/jump_label.h>
 #include <asm/insn.h>
 
-#ifdef HAVE_JUMP_LABEL
-
 void arch_jump_label_transform(struct jump_entry *entry,
                                enum jump_label_type type)
 {
@@ -49,5 +47,3 @@ void arch_jump_label_transform_static(struct jump_entry *entry,
          * NOP needs to be replaced by a branch.
          */
 }
-
-#endif  /* HAVE_JUMP_LABEL */
diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c
index 32e3168316cd..ab943927f97a 100644
--- a/arch/mips/kernel/jump_label.c
+++ b/arch/mips/kernel/jump_label.c
@@ -16,8 +16,6 @@
 #include <asm/cacheflush.h>
 #include <asm/inst.h>
 
-#ifdef HAVE_JUMP_LABEL
-
 /*
  * Define parameters for the standard MIPS and the microMIPS jump
  * instruction encoding respectively:
@@ -70,5 +68,3 @@ void arch_jump_label_transform(struct jump_entry *e,
 
         mutex_unlock(&text_mutex);
 }
-
-#endif /* HAVE_JUMP_LABEL */
diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index 6f201b199c02..1d911f68a23b 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -38,7 +38,7 @@ extern struct static_key hcall_tracepoint_key;
 void __trace_hcall_entry(unsigned long opcode, unsigned long *args);
 void __trace_hcall_exit(long opcode, long retval, unsigned long *retbuf);
 /* OPAL tracing */
-#ifdef HAVE_JUMP_LABEL
+#ifdef CONFIG_JUMP_LABEL
 extern struct static_key opal_tracepoint_key;
 #endif
 
diff --git a/arch/powerpc/kernel/jump_label.c b/arch/powerpc/kernel/jump_label.c
index 6472472093d0..0080c5fbd225 100644
--- a/arch/powerpc/kernel/jump_label.c
+++ b/arch/powerpc/kernel/jump_label.c
@@ -11,7 +11,6 @@
 #include <linux/jump_label.h>
 #include <asm/code-patching.h>
 
-#ifdef HAVE_JUMP_LABEL
 void arch_jump_label_transform(struct jump_entry *entry,
                                enum jump_label_type type)
 {
@@ -22,4 +21,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
         else
                 patch_instruction(addr, PPC_INST_NOP);
 }
-#endif
diff --git a/arch/powerpc/platforms/powernv/opal-tracepoints.c b/arch/powerpc/platforms/powernv/opal-tracepoints.c
index 1ab7d26c0a2c..f16a43540e30 100644
--- a/arch/powerpc/platforms/powernv/opal-tracepoints.c
+++ b/arch/powerpc/platforms/powernv/opal-tracepoints.c
@@ -4,7 +4,7 @@
 #include <asm/trace.h>
 #include <asm/asm-prototypes.h>
 
-#ifdef HAVE_JUMP_LABEL
+#ifdef CONFIG_JUMP_LABEL
 struct static_key opal_tracepoint_key = STATIC_KEY_INIT;
 
 int opal_tracepoint_regfunc(void)
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 251528231a9e..f4875fe3f8ff 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -20,7 +20,7 @@
         .section        ".text"
 
 #ifdef CONFIG_TRACEPOINTS
-#ifdef HAVE_JUMP_LABEL
+#ifdef CONFIG_JUMP_LABEL
 #define OPAL_BRANCH(LABEL)                                      \
         ARCH_STATIC_BRANCH(LABEL, opal_tracepoint_key)
 #else
diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
index d91412c591ef..50dc9426d0be 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -19,7 +19,7 @@
         
 #ifdef CONFIG_TRACEPOINTS
 
-#ifndef HAVE_JUMP_LABEL
+#ifndef CONFIG_JUMP_LABEL
         .section        ".toc","aw"
 
         .globl hcall_tracepoint_refcount
@@ -79,7 +79,7 @@ hcall_tracepoint_refcount:
         mr      r5,BUFREG;                                      \
         __HCALL_INST_POSTCALL
 
-#ifdef HAVE_JUMP_LABEL
+#ifdef CONFIG_JUMP_LABEL
 #define HCALL_BRANCH(LABEL)                                     \
         ARCH_STATIC_BRANCH(LABEL, hcall_tracepoint_key)
 #else
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 32d4452973e7..f2a9f0adc2d3 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -1040,7 +1040,7 @@ EXPORT_SYMBOL(arch_free_page);
 #endif /* CONFIG_PPC_BOOK3S_64 */
 
 #ifdef CONFIG_TRACEPOINTS
-#ifdef HAVE_JUMP_LABEL
+#ifdef CONFIG_JUMP_LABEL
 struct static_key hcall_tracepoint_key = STATIC_KEY_INIT;
 
 int hcall_tracepoint_regfunc(void)
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 386b1abb217b..e216e116a9a9 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -48,7 +48,7 @@ CFLAGS_ptrace.o		+= -DUTS_MACHINE='"$(UTS_MACHINE)"'
 obj-y   := traps.o time.o process.o base.o early.o setup.o idle.o vtime.o
 obj-y   += processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
 obj-y   += debug.o irq.o ipl.o dis.o diag.o vdso.o early_nobss.o
-obj-y   += sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o
+obj-y   += sysinfo.o lgr.o os_info.o machine_kexec.o pgm_check.o
 obj-y   += runtime_instr.o cache.o fpu.o dumpstack.o guarded_storage.o sthyi.o
 obj-y   += entry.o reipl.o relocate_kernel.o kdebugfs.o alternative.o
 obj-y   += nospec-branch.o ipl_vmparm.o
@@ -72,6 +72,7 @@ obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_FUNCTION_TRACER)   += mcount.o ftrace.o
 obj-$(CONFIG_CRASH_DUMP)        += crash_dump.o
 obj-$(CONFIG_UPROBES)           += uprobes.o
+obj-$(CONFIG_JUMP_LABEL)        += jump_label.o
 
 obj-$(CONFIG_KEXEC_FILE)        += machine_kexec_file.o kexec_image.o
 obj-$(CONFIG_KEXEC_FILE)        += kexec_elf.o
diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c
index 50a1798604a8..3f10b56bd5a3 100644
--- a/arch/s390/kernel/jump_label.c
+++ b/arch/s390/kernel/jump_label.c
@@ -10,8 +10,6 @@
 #include <linux/jump_label.h>
 #include <asm/ipl.h>
 
-#ifdef HAVE_JUMP_LABEL
-
 struct insn {
         u16 opcode;
         s32 offset;
@@ -103,5 +101,3 @@ void arch_jump_label_transform_static(struct jump_entry *entry,
 {
         __jump_label_transform(entry, type, 1);
 }
-
-#endif
diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index cf8640841b7a..97c0e19263d1 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -118,4 +118,4 @@ pc--$(CONFIG_PERF_EVENTS) := perf_event.o
 obj-$(CONFIG_SPARC64)   += $(pc--y)
 
 obj-$(CONFIG_UPROBES)   += uprobes.o
-obj-$(CONFIG_SPARC64)   += jump_label.o
+obj-$(CONFIG_JUMP_LABEL) += jump_label.o
diff --git a/arch/sparc/kernel/jump_label.c b/arch/sparc/kernel/jump_label.c
index 7f8eac51df33..a4cfaeecaf5e 100644
--- a/arch/sparc/kernel/jump_label.c
+++ b/arch/sparc/kernel/jump_label.c
@@ -9,8 +9,6 @@
 
 #include <asm/cacheflush.h>
 
-#ifdef HAVE_JUMP_LABEL
-
 void arch_jump_label_transform(struct jump_entry *entry,
                                enum jump_label_type type)
 {
@@ -47,5 +45,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
         flushi(insn);
         mutex_unlock(&text_mutex);
 }
-
-#endif
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 16c3145c0a5f..9c5a67d1b9c1 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -289,7 +289,7 @@ vdso_install:
 
 archprepare: checkbin
 checkbin:
-ifndef CC_HAVE_ASM_GOTO
+ifndef CONFIG_CC_HAS_ASM_GOTO
         @echo Compiler lacks asm-goto support.
         @exit 1
 endif
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 20d0885b00fb..efb0d1b1f15f 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -351,7 +351,7 @@ For 32-bit we have the following conventions - kernel is built with
  */
 .macro CALL_enter_from_user_mode
 #ifdef CONFIG_CONTEXT_TRACKING
-#ifdef HAVE_JUMP_LABEL
+#ifdef CONFIG_JUMP_LABEL
         STATIC_JUMP_IF_FALSE .Lafter_call_\@, context_tracking_enabled, def=0
 #endif
         call enter_from_user_mode
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index aced6c9290d6..ce95b8cbd229 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -140,7 +140,7 @@ extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
 
 #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
 
-#if defined(__clang__) && !defined(CC_HAVE_ASM_GOTO)
+#if defined(__clang__) && !defined(CONFIG_CC_HAS_ASM_GOTO)
 
 /*
  * Workaround for the sake of BPF compilation which utilizes kernel
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 21efc9d07ed9..65191ce8e1cf 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -2,19 +2,6 @@
 #ifndef _ASM_X86_JUMP_LABEL_H
 #define _ASM_X86_JUMP_LABEL_H
 
-#ifndef HAVE_JUMP_LABEL
-/*
- * For better or for worse, if jump labels (the gcc extension) are missing,
- * then the entire static branch patching infrastructure is compiled out.
- * If that happens, the code in here will malfunction.  Raise a compiler
- * error instead.
- *
- * In theory, jump labels and the static branch patching infrastructure
- * could be decoupled to fix this.
- */
-#error asm/jump_label.h included on a non-jump-label kernel
-#endif
-
 #define JUMP_LABEL_NOP_SIZE 5
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h
index 46ac84b506f5..8a9eba191516 100644
--- a/arch/x86/include/asm/rmwcc.h
+++ b/arch/x86/include/asm/rmwcc.h
@@ -11,7 +11,7 @@
 
 #define __CLOBBERS_MEM(clb...)  "memory", ## clb
 
-#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO)
+#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CONFIG_CC_HAS_ASM_GOTO)
 
 /* Use asm goto */
 
@@ -27,7 +27,7 @@ cc_label:	c = true;						\
         c;                                                              \
 })
 
-#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
+#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CONFIG_CC_HAS_ASM_GOTO) */
 
 /* Use flags output or a set instruction */
 
@@ -40,7 +40,7 @@ cc_label:	c = true;						\
         c;                                                              \
 })
 
-#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
+#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CONFIG_CC_HAS_ASM_GOTO) */
 
 #define GEN_UNARY_RMWcc_4(op, var, cc, arg0)                            \
         __GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM())
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index eb51b0e1189c..00b7e27bc2b7 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -49,7 +49,8 @@ obj-$(CONFIG_COMPAT)	+= signal_compat.o
 obj-y                   += traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
 obj-y                   += time.o ioport.o dumpstack.o nmi.o
 obj-$(CONFIG_MODIFY_LDT_SYSCALL)        += ldt.o
-obj-y                   += setup.o x86_init.o i8259.o irqinit.o jump_label.o
+obj-y                   += setup.o x86_init.o i8259.o irqinit.o
+obj-$(CONFIG_JUMP_LABEL)        += jump_label.o
 obj-$(CONFIG_IRQ_WORK)  += irq_work.o
 obj-y                   += probe_roms.o
 obj-$(CONFIG_X86_64)    += sys_x86_64.o
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index aac0c1f7e354..f99bd26bd3f1 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -16,8 +16,6 @@
 #include <asm/alternative.h>
 #include <asm/text-patching.h>
 
-#ifdef HAVE_JUMP_LABEL
-
 union jump_code_union {
         char code[JUMP_LABEL_NOP_SIZE];
         struct {
@@ -130,5 +128,3 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry,
         if (jlstate == JL_STATE_UPDATE)
                 __jump_label_transform(entry, type, text_poke_early, 1);
 }
-
-#endif
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 78e430f4e15c..c338984c850d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -456,7 +456,7 @@ FOP_END;
 
 /*
  * XXX: inoutclob user must know where the argument is being expanded.
- *      Relying on CC_HAVE_ASM_GOTO would allow us to remove _fault.
+ *      Relying on CONFIG_CC_HAS_ASM_GOTO would allow us to remove _fault.
  */
 #define asm_safe(insn, inoutclob...) \
 ({ \
diff --git a/arch/xtensa/kernel/jump_label.c b/arch/xtensa/kernel/jump_label.c
index d108f721c116..61cf6497a646 100644
--- a/arch/xtensa/kernel/jump_label.c
+++ b/arch/xtensa/kernel/jump_label.c
@@ -10,8 +10,6 @@
 
 #include <asm/cacheflush.h>
 
-#ifdef HAVE_JUMP_LABEL
-
 #define J_OFFSET_MASK 0x0003ffff
 #define J_SIGN_MASK (~(J_OFFSET_MASK >> 1))
 
@@ -95,5 +93,3 @@ void arch_jump_label_transform(struct jump_entry *e,
 
         patch_text(jump_entry_code(e), &insn, JUMP_LABEL_NOP_SIZE);
 }
-
-#endif /* HAVE_JUMP_LABEL */