MIPS: vdso: Wrap -mexplicit-relocs in cc-option

[tomoyo/tomoyo-test1.git] / arch / mips / vdso / Makefile

diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index b2a2e03..d7fe840 100644 (file)
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -33,6 +33,7 @@ endif
 cflags-vdso := $(ccflags-vdso) \
        $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
        -O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
+       -mrelax-pic-calls $(call cc-option, -mexplicit-relocs) \
        -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \
        $(call cc-option, -fno-asynchronous-unwind-tables) \
        $(call cc-option, -fno-stack-protector)
@@ -51,6 +52,8 @@ endif
 
 CFLAGS_REMOVE_vgettimeofday.o = -pg
 
+DISABLE_VDSO := n
+
 #
 # For the pre-R6 code in arch/mips/vdso/vdso.h for locating
 # the base address of VDSO, the linker will emit a R_MIPS_PC32
@@ -64,11 +67,24 @@ CFLAGS_REMOVE_vgettimeofday.o = -pg
 ifndef CONFIG_CPU_MIPSR6
   ifeq ($(call ld-ifversion, -lt, 225000000, y),y)
     $(warning MIPS VDSO requires binutils >= 2.25)
-    obj-vdso-y := $(filter-out vgettimeofday.o, $(obj-vdso-y))
-    ccflags-vdso += -DDISABLE_MIPS_VDSO
+    DISABLE_VDSO := y
   endif
 endif
 
+#
+# GCC (at least up to version 9.2) appears to emit function calls that make use
+# of the GOT when targeting microMIPS, which we can't use in the VDSO due to
+# the lack of relocations. As such, we disable the VDSO for microMIPS builds.
+#
+ifdef CONFIG_CPU_MICROMIPS
+  DISABLE_VDSO := y
+endif
+
+ifeq ($(DISABLE_VDSO),y)
+  obj-vdso-y := $(filter-out vgettimeofday.o, $(obj-vdso-y))
+  ccflags-vdso += -DDISABLE_MIPS_VDSO
+endif
+
 # VDSO linker flags.
 VDSO_LDFLAGS := \
        -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 \
@@ -81,12 +97,18 @@ GCOV_PROFILE := n
 UBSAN_SANITIZE := n
 KCOV_INSTRUMENT := n
 
+# Check that we don't have PIC 'jalr t9' calls left
+quiet_cmd_vdso_mips_check = VDSOCHK $@
+      cmd_vdso_mips_check = if $(OBJDUMP) --disassemble $@ | egrep -h "jalr.*t9" > /dev/null; \
+                      then (echo >&2 "$@: PIC 'jalr t9' calls are not supported"; \
+                            rm -f $@; /bin/false); fi
+
 #
 # Shared build commands.
 #
 
 quiet_cmd_vdsold_and_vdso_check = LD      $@
-      cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check)
+      cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check); $(cmd_vdso_mips_check)
 
 quiet_cmd_vdsold = VDSO    $@
       cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \
@@ -100,7 +122,7 @@ $(obj)/%.so.raw: OBJCOPYFLAGS := -S
 $(obj)/%.so.raw: $(obj)/%.so.dbg.raw FORCE
        $(call if_changed,objcopy)
 
-hostprogs-y := genvdso
+hostprogs := genvdso
 
 quiet_cmd_genvdso = GENVDSO $@
 define cmd_genvdso