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1fe09eb358
The problem is, -Wa is a flag for assembler, but CFLAGS are also used
to generate dependencies, and clang complains loudly when it is used
for deps:
> > DEP compel/arch/x86/plugins/std/syscalls-64.d
> > clang-3.8: error: argument unused during compilation:
> > '-Wa,--noexecstack'
This patch moved the noexecflag from assembler to linker. I am not
100% sure but the end result seems to be the same.
This fixes dependency generation when using clang instead of gcc.
I surely have done my research before proposing this change, and
I have tested this change as good as I could.
Sorry, I should have provided more background in the commit message.
Here it goes.
There are a few ways to have non-executable stack:
1. mark the assembler source file (.S) with .section
.note.GNU-stack,"",%progbits
2. pass the -Wa,--noexecstack to compiler
3. pass the -z execstack to linker
All three ways are fine, let's see them in greater details.
Some people say (1) is the best way, but we have way too many
.S files now (23 of them, to be exact). Anyway, I can certainly do it
this way if you like, just let me know. It would look like this:
--- a/compel/arch/aarch64/plugins/std/syscalls/syscall-aux.S
+++ b/compel/arch/aarch64/plugins/std/syscalls/syscall-aux.S
@@ -3,6 +3,8 @@
* that are not implemented in the AArch64 Linux kernel
*/
+.section .note.GNU-stack,"",%progbits
+
ENTRY(sys_open)
mov x3, x2
mov x2, x1
Way (2) is what is currently used. Unfortunately it breaks dependency
generation with clang. One way to fix it would be to filter-out the bad
flag when we're generating deps. I tried experimenting with
$(filter-out) function in Makefiles today but it's complicated and I failed
to make it work.
Way (3) is what this commit offers. It seem to work fine while being
the least intrusive.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
59 lines
1.5 KiB
Makefile
59 lines
1.5 KiB
Makefile
.PHONY: .FORCE
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CFLAGS := $(filter-out -pg $(CFLAGS-GCOV),$(CFLAGS))
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PLUGIN_ARCH_DIR := compel/arch/$(ARCH)/plugins
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#
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# CFLAGS, ASFLAGS, LDFLAGS
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# General compel includes
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ccflags-y += -iquote $(SRC_DIR)/compel/include
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ccflags-y += -fno-stack-protector
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# General compel/plugins includes
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ccflags-y += -iquote $(obj)/include
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ccflags-y += -iquote $(obj)/include/uapi
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asflags-y += -iquote $(obj)/include
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asflags-y += -iquote $(obj)/include/uapi
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# Arch compel/plugins includes
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ccflags-y += -iquote $(PLUGIN_ARCH_DIR)/include
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asflags-y += -iquote $(PLUGIN_ARCH_DIR)/include
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asflags-y += -iquote $(PLUGIN_ARCH_DIR)
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# General flags for assembly
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asflags-y += -fpie -Wstrict-prototypes
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asflags-y += -D__ASSEMBLY__ -nostdlib -fomit-frame-pointer
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asflags-y += -fno-stack-protector
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ldflags-y += -z noexecstack
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#
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# Fds plugin
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target += fds
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fds-obj-y += fds/fds.o
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#
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# Shmem plugin
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target += shmem
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shmem-obj-y += shmem/shmem.o
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#
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# STD plugin
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target += std
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std-obj-y += std/std.o
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std-obj-y += std/string.o
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include ./$(PLUGIN_ARCH_DIR)/std/syscalls/Makefile.syscalls
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define syscall-priority
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$(addprefix $(obj)/,$($(1):%.o=%.d)): | $($(2))
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$(addprefix $(obj)/,$($(1):%.o=%.i)): | $($(2))
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$(addprefix $(obj)/,$($(1):%.o=%.s)): | $($(2))
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$(addprefix $(obj)/,$($(1))): | $($(2))
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endef
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#
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# Almost all plugins depen on syscall headers
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# and definitions so we have to order their
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# generation manually.
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$(foreach t,$(target),$(eval $(call syscall-priority,$(t)-obj-y,std-headers-deps)))
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