x86: Remove toolchain check for X32 ABI capability

Commit 0bf6276392e9 ("x32: Warn and disable rather than error if
binutils too old") added a small test in arch/x86/Makefile because
binutils 2.22 or newer is needed to properly support elf32-x86-64. This
check is no longer necessary, as the minimum supported version of
binutils is 2.23, which is enforced at configuration time with
scripts/min-tool-version.sh.

Remove this check and replace all uses of CONFIG_X86_X32 with
CONFIG_X86_X32_ABI, as two symbols are no longer necessary.

[nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still
         used, and simplify commit message to satisfy -tip requirements]

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220314194842.3452-2-nathan@kernel.org

6 files changed, 8 insertions, 28 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 870e0d10452d18..b903bfcd713c5e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2861,7 +2861,7 @@ config IA32_AOUT
 	help
 	  Support old a.out binaries in the 32bit emulation.
 
-config X86_X32
+config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
 	help
@@ -2870,10 +2870,6 @@ config X86_X32
 	  full 64-bit register file and wide data path while leaving
 	  pointers at 32 bits for smaller memory footprint.
 
-	  You will need a recent binutils (2.22 or later) with
-	  elf32_x86_64 support enabled to compile a kernel with this
-	  option set.
-
 config COMPAT_32
 	def_bool y
 	depends on IA32_EMULATION || X86_32
@@ -2882,7 +2878,7 @@ config COMPAT_32
 
 config COMPAT
 	def_bool y
-	depends on IA32_EMULATION || X86_X32
+	depends on IA32_EMULATION || X86_X32_ABI
 
 if COMPAT
 config COMPAT_FOR_U64_ALIGNMENT
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f29c2c9c3216a4..63d50f65b82834 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -152,22 +152,6 @@ else
         KBUILD_CFLAGS += -mcmodel=kernel
 endif
 
-ifdef CONFIG_X86_X32
-	x32_ld_ok := $(call try-run,\
-			/bin/echo -e '1: .quad 1b' | \
-			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
-			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \
-			$(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n)
-        ifeq ($(x32_ld_ok),y)
-                CONFIG_X86_X32_ABI := y
-                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
-                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
-        else
-                $(warning CONFIG_X86_X32 enabled but no binutils support)
-        endif
-endif
-export CONFIG_X86_X32_ABI
-
 #
 # If the function graph tracer is used with mcount instead of fentry,
 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
diff --git a/arch/x86/entry/syscalls/Makefile b/arch/x86/entry/syscalls/Makefile
index 5b3efed0e4e866..7f3886eeb2ffaa 100644
--- a/arch/x86/entry/syscalls/Makefile
+++ b/arch/x86/entry/syscalls/Makefile
@@ -67,7 +67,7 @@ uapisyshdr-y			+= unistd_32.h unistd_64.h unistd_x32.h
 syshdr-y			+= syscalls_32.h
 syshdr-$(CONFIG_X86_64)		+= unistd_32_ia32.h unistd_64_x32.h
 syshdr-$(CONFIG_X86_64)		+= syscalls_64.h
-syshdr-$(CONFIG_X86_X32)	+= syscalls_x32.h
+syshdr-$(CONFIG_X86_X32_ABI)	+= syscalls_x32.h
 syshdr-$(CONFIG_XEN)		+= xen-hypercalls.h
 
 uapisyshdr-y	:= $(addprefix $(uapi)/, $(uapisyshdr-y))
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 6a2827d0681fcd..59358d1bf88000 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -159,7 +159,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 #endif /* CONFIG_IA32_EMULATION */
 
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /*
  * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware
  * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
@@ -177,12 +177,12 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 
 #define __X32_COMPAT_SYS_NI(name)					\
 	__SYS_NI(x64, compat_sys_##name)
-#else /* CONFIG_X86_X32 */
+#else /* CONFIG_X86_X32_ABI */
 #define __X32_COMPAT_SYS_STUB0(name)
 #define __X32_COMPAT_SYS_STUBx(x, name, ...)
 #define __X32_COMPAT_COND_SYSCALL(name)
 #define __X32_COMPAT_SYS_NI(name)
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 98aa103eb4ab4a..2963a2f5dbc408 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -37,7 +37,7 @@ struct vdso_image {
 extern const struct vdso_image vdso_image_64;
 #endif
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 extern const struct vdso_image vdso_image_x32;
 #endif
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 3402edec236c4a..e459253649be23 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -681,7 +681,7 @@ void set_personality_64bit(void)
 
 static void __set_personality_x32(void)
 {
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	if (current->mm)
 		current->mm->context.flags = 0;