Re: [PATCH v16 00/23] selftests, powerpc, x86: Memory Protection Keys

[Sandipan Das <sandipan@linux.ibm.com>]

Hi Dave,

On 23/01/20 12:15 am, Dave Hansen wrote:
> Still doesn't build for me:
> 

I have this patch that hopefully fixes this. My understanding was
that the vm tests are supposed to be generic but this has quite a
bit of x86-specific conditional code which complicates things even
though it is not used by any of the other tests.

I'm not sure if we should keep x86 multilib build support for these
selftests but I'll let the maintainers take a call.

From a5609f79e5d5164c99c3cb599e14ca620de9c8d4 Mon Sep 17 00:00:00 2001
From: Sandipan Das <sandipan@linux.ibm.com>
Date: Sat, 18 Jan 2020 15:59:04 +0530
Subject: [PATCH] selftests: vm: pkeys: Fix multilib builds for x86

This ensures that both 32-bit and 64-bit binaries are generated
when this is built on a x86_64 system that has both 32-bit and
64-bit libraries. Most of the changes have been borrowed from
tools/testing/selftests/x86/Makefile.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
---
 tools/testing/selftests/vm/Makefile | 72 +++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 4e9c741be6af..82031f84af21 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -18,7 +18,30 @@ TEST_GEN_FILES += on-fault-limit
 TEST_GEN_FILES += thuge-gen
 TEST_GEN_FILES += transhuge-stress
 TEST_GEN_FILES += userfaultfd
+
+ifeq ($(ARCH),x86_64)
+CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_32bit_program.c -m32)
+CAN_BUILD_X86_64 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_64bit_program.c)
+CAN_BUILD_WITH_NOPIE := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_program.c -no-pie)
+
+TARGETS := protection_keys
+BINARIES_32 := $(TARGETS:%=%_32)
+BINARIES_64 := $(TARGETS:%=%_64)
+
+ifeq ($(CAN_BUILD_WITH_NOPIE),1)
+CFLAGS += -no-pie
+endif
+
+ifeq ($(CAN_BUILD_I386),1)
+TEST_GEN_FILES += $(BINARIES_32)
+endif
+
+ifeq ($(CAN_BUILD_X86_64),1)
+TEST_GEN_FILES += $(BINARIES_64)
+endif
+else
 TEST_GEN_FILES += protection_keys
+endif
 
 ifneq (,$(filter $(ARCH),arm64 ia64 mips64 parisc64 ppc64 riscv64 s390x sh64 sparc64 x86_64))
 TEST_GEN_FILES += va_128TBswitch
@@ -32,6 +55,55 @@ TEST_FILES := test_vmalloc.sh
 KSFT_KHDR_INSTALL := 1
 include ../lib.mk
 
+ifeq ($(ARCH),x86_64)
+BINARIES_32 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_32))
+BINARIES_64 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_64))
+
+define gen-target-rule-32
+$(1) $(1)_32: $(OUTPUT)/$(1)_32
+.PHONY: $(1) $(1)_32
+endef
+
+define gen-target-rule-64
+$(1) $(1)_64: $(OUTPUT)/$(1)_64
+.PHONY: $(1) $(1)_64
+endef
+
+ifeq ($(CAN_BUILD_I386),1)
+$(BINARIES_32): CFLAGS += -m32
+$(BINARIES_32): LDLIBS += -lrt -ldl -lm
+$(BINARIES_32): %_32: %.c
+	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $(notdir $^) $(LDLIBS) -o $@
+$(foreach t,$(TARGETS),$(eval $(call gen-target-rule-32,$(t))))
+endif
+
+ifeq ($(CAN_BUILD_X86_64),1)
+$(BINARIES_64): CFLAGS += -m64
+$(BINARIES_64): LDLIBS += -lrt -ldl
+$(BINARIES_64): %_64: %.c
+	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $(notdir $^) $(LDLIBS) -o $@
+$(foreach t,$(TARGETS),$(eval $(call gen-target-rule-64,$(t))))
+endif
+
+# x86_64 users should be encouraged to install 32-bit libraries
+ifeq ($(CAN_BUILD_I386)$(CAN_BUILD_X86_64),01)
+all: warn_32bit_failure
+
+warn_32bit_failure:
+	@echo "Warning: you seem to have a broken 32-bit build" 2>&1;		\
+	echo  "environment. This will reduce test coverage of 64-bit" 2>&1;	\
+	echo  "kernels. If you are using a Debian-like distribution," 2>&1;	\
+	echo  "try:"; 2>&1;							\
+	echo  "";								\
+	echo  "  apt-get install gcc-multilib libc6-i386 libc6-dev-i386";	\
+	echo  "";								\
+	echo  "If you are using a Fedora-like distribution, try:";		\
+	echo  "";								\
+	echo  "  yum install glibc-devel.*i686";				\
+	exit 0;
+endif
+endif
+
 $(OUTPUT)/userfaultfd: LDLIBS += -lpthread
 
 $(OUTPUT)/mlock-random-test: LDLIBS += -lcap
-- 
2.24.1

This can also be viewed at:
https://github.com/sandip4n/linux/commit/a5609f79e5d5164c99c3cb599e14ca620de9c8d4

- Sandipan