selftests/x86: Disable tests requiring 32-bit support on pure 64-bit systems

Web:        https://git.kernel.org/torvalds/c/9279ddf23ce78ff2676e8e8e19fec0f022c26d04
Commit:     9279ddf23ce78ff2676e8e8e19fec0f022c26d04
Parent:     4105c69703cdeba76f384b901712c9397b04e9c2
Refname:    refs/heads/master
Author:     Dominik Brodowski <[email protected]>
AuthorDate: Tue Feb 13 09:15:19 2018 +0100
Committer:  Ingo Molnar <[email protected]>
CommitDate: Thu Feb 15 01:15:48 2018 +0100

    selftests/x86: Disable tests requiring 32-bit support on pure 64-bit systems
    
    The ldt_gdt and ptrace_syscall selftests, even in their 64-bit variant, use
    hard-coded 32-bit syscall numbers and call "int $0x80".
    
    This will fail on 64-bit systems with CONFIG_IA32_EMULATION=y disabled.
    
    Therefore, do not build these tests if we cannot build 32-bit binaries
    (which should be a good approximation for CONFIG_IA32_EMULATION=y being enabled).
    
    Signed-off-by: Dominik Brodowski <[email protected]>
    Cc: Andy Lutomirski <[email protected]>
    Cc: Dmitry Safonov <[email protected]>
    Cc: Linus Torvalds <[email protected]>
    Cc: Peter Zijlstra <[email protected]>
    Cc: Thomas Gleixner <[email protected]>
    Cc: [email protected]
    Cc: [email protected]
    Link: http://lkml.kernel.org/r/[email protected]
    Signed-off-by: Ingo Molnar <[email protected]>
---
 tools/testing/selftests/x86/Makefile | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 73b8ef665c98..aa6e2d7f6a1f 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -5,16 +5,26 @@ include ../lib.mk
 
 .PHONY: all all_32 all_64 warn_32bit_failure clean
 
-TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall test_mremap_vdso \
-			check_initial_reg_state sigreturn ldt_gdt iopl mpx-mini-test ioperm \
+UNAME_M := $(shell uname -m)
+CAN_BUILD_I386 := $(shell ./check_cc.sh $(CC) trivial_32bit_program.c -m32)
+CAN_BUILD_X86_64 := $(shell ./check_cc.sh $(CC) trivial_64bit_program.c)
+
+TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
+			check_initial_reg_state sigreturn iopl mpx-mini-test ioperm \
 			protection_keys test_vdso test_vsyscall
 TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \
 			test_FCMOV test_FCOMI test_FISTTP \
 			vdso_restorer
 TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip
+# Some selftests require 32bit support enabled also on 64bit systems
+TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
 
-TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY)
+TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) $(TARGETS_C_32BIT_NEEDED)
 TARGETS_C_64BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_64BIT_ONLY)
+ifeq ($(CAN_BUILD_I386)$(CAN_BUILD_X86_64),11)
+TARGETS_C_64BIT_ALL += $(TARGETS_C_32BIT_NEEDED)
+endif
+
 BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32)
 BINARIES_64 := $(TARGETS_C_64BIT_ALL:%=%_64)
 
@@ -23,10 +33,6 @@ BINARIES_64 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_64))
 
 CFLAGS := -O2 -g -std=gnu99 -pthread -Wall -no-pie
 
-UNAME_M := $(shell uname -m)
-CAN_BUILD_I386 := $(shell ./check_cc.sh $(CC) trivial_32bit_program.c -m32)
-CAN_BUILD_X86_64 := $(shell ./check_cc.sh $(CC) trivial_64bit_program.c)