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authorNathan Chancellor <natechancellor@gmail.com>2020-04-28 15:14:16 -0700
committerThomas Bogendoerfer <tsbogend@alpha.franken.de>2020-05-12 10:01:45 +0200
commite91946d6d93ef6167bd3b1456f163d1585095ea1 (patch)
tree88263cac5e8d2e65b37ffa64eaeee55dfa9007dc /arch/mips/vdso
parentb744b43f79cc758127042e71f9ad7b1afda30f84 (diff)
downloadlinux-e91946d6d93ef6167bd3b1456f163d1585095ea1.tar.bz2
MIPS: VDSO: Move disabling the VDSO logic to Kconfig
After commit 9553d16fa671 ("init/kconfig: Add LD_VERSION Kconfig"), we have access to GNU ld's version at configuration time. As a result, we can make it clearer under what configuration circumstances the MIPS VDSO needs to be disabled. This is a prerequisite for getting rid of the MIPS VDSO binutils warning and linking the VDSO when LD is ld.lld. Wrapping the call to ld-ifversion with CONFIG_LD_IS_LLD does not work because the config values are wiped away during 'make clean'. Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch/mips/vdso')
-rw-r--r--arch/mips/vdso/Kconfig18
-rw-r--r--arch/mips/vdso/Makefile30
-rw-r--r--arch/mips/vdso/vdso.lds.S2
3 files changed, 21 insertions, 29 deletions
diff --git a/arch/mips/vdso/Kconfig b/arch/mips/vdso/Kconfig
new file mode 100644
index 000000000000..36a52158d849
--- /dev/null
+++ b/arch/mips/vdso/Kconfig
@@ -0,0 +1,18 @@
+# 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
+# relocation in binutils > 2.25 but it will fail with older versions
+# because that relocation is not supported for that symbol. As a result
+# of which we are forced to disable the VDSO symbols when building
+# with < 2.25 binutils on pre-R6 kernels. For more references on why we
+# can't use other methods to get the base address of VDSO please refer to
+# the comments on that file.
+#
+# 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.
+
+config MIPS_LD_CAN_LINK_VDSO
+ def_bool LD_VERSION >= 225000000
+
+config MIPS_DISABLE_VDSO
+ def_bool CPU_MICROMIPS || (!CPU_MIPSR6 && !MIPS_LD_CAN_LINK_VDSO)
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index d7fe8408603e..92b53d1df42c 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -52,37 +52,11 @@ 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
-# relocation in binutils > 2.25 but it will fail with older versions
-# because that relocation is not supported for that symbol. As a result
-# of which we are forced to disable the VDSO symbols when building
-# with < 2.25 binutils on pre-R6 kernels. For more references on why we
-# can't use other methods to get the base address of VDSO please refer to
-# the comments on that file.
-#
-ifndef CONFIG_CPU_MIPSR6
- ifeq ($(call ld-ifversion, -lt, 225000000, y),y)
+ifdef CONFIG_MIPS_DISABLE_VDSO
+ ifndef CONFIG_MIPS_LD_CAN_LINK_VDSO
$(warning MIPS VDSO requires binutils >= 2.25)
- DISABLE_VDSO := y
endif
-endif
-
-#
-# GCC (at least up to version 9.2) appears to emit function calls that make use
-# of the GOT when targeting microMIPS, which we can't use in the VDSO due to
-# the lack of relocations. As such, we disable the VDSO for microMIPS builds.
-#
-ifdef CONFIG_CPU_MICROMIPS
- DISABLE_VDSO := y
-endif
-
-ifeq ($(DISABLE_VDSO),y)
obj-vdso-y := $(filter-out vgettimeofday.o, $(obj-vdso-y))
- ccflags-vdso += -DDISABLE_MIPS_VDSO
endif
# VDSO linker flags.
diff --git a/arch/mips/vdso/vdso.lds.S b/arch/mips/vdso/vdso.lds.S
index da4627430aba..d90b65724d78 100644
--- a/arch/mips/vdso/vdso.lds.S
+++ b/arch/mips/vdso/vdso.lds.S
@@ -91,7 +91,7 @@ PHDRS
VERSION
{
LINUX_2.6 {
-#ifndef DISABLE_MIPS_VDSO
+#ifndef CONFIG_MIPS_DISABLE_VDSO
global:
__vdso_clock_gettime;
__vdso_gettimeofday;