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>

8 files changed, 9 insertions, 25 deletions

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...) \
 ({ \