projects/linux·blob master · refs

130 lines · 5.6 KiB

1# SPDX-License-Identifier: GPL-2.0
2
3# List of files in the vdso, has to be asm only for now
4
5# Include the generic Makefile to check the built vdso.
6include $(srctree)/lib/vdso/Makefile.include
7
8obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o
9obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o note-64.o getcpu-64.o
10
11obj-vdso32 += getrandom-32.o vgetrandom-chacha-32.o
12obj-vdso64 += getrandom-64.o vgetrandom-chacha-64.o
13
14ifneq ($(c-gettimeofday-y),)
15 CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y)
16# Go prior to 1.16.x assumes r30 is not clobbered by any VDSO code. That used to be true
17# by accident when the VDSO was hand-written asm code, but may not be now that the VDSO is
18# compiler generated. To avoid breaking Go tell GCC not to use r30. Impact on code
19# generation is minimal, it will just use r29 instead.
20 CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y) $(call cc-option, -ffixed-r30)
21endif
22
23ifneq ($(c-getrandom-y),)
24 CFLAGS_vgetrandom-32.o += -include $(c-getrandom-y)
25 CFLAGS_vgetrandom-64.o += -include $(c-getrandom-y)
26endif
27
28# Build rules
29
30ifdef CROSS32_COMPILE
31 VDSOCC := $(CROSS32_COMPILE)gcc
32else
33 VDSOCC := $(CC)
34endif
35
36targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o vgetrandom-32.o
37targets += crtsavres-32.o
38obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
39targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o vgetrandom-64.o
40obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
41
42ccflags-y := -fno-common -fno-builtin -DBUILD_VDSO
43ccflags-y += $(DISABLE_LATENT_ENTROPY_PLUGIN)
44ccflags-y += $(call cc-option, -fno-stack-protector)
45ccflags-y += -DDISABLE_BRANCH_PROFILING
46ccflags-y += $(CONFIG_CC_OPT_INLINE_MEMSET)
47ccflags-y += -ffreestanding -fasynchronous-unwind-tables
48ccflags-remove-y := $(CC_FLAGS_FTRACE)
49ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack $(CLANG_FLAGS)
50ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
51ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
52
53# Filter flags that clang will warn are unused for linking
54ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
55
56CC32FLAGS := -m32
57CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc -mpcrel
58ifdef CONFIG_CC_IS_CLANG
59# This flag is supported by clang for 64-bit but not 32-bit so it will cause
60# an unused command line flag warning for this file.
61CC32FLAGSREMOVE += -fno-stack-clash-protection
62# -mstack-protector-guard values from the 64-bit build are not valid for the
63# 32-bit one. clang validates the values passed to these arguments during
64# parsing, even when -fno-stack-protector is passed afterwards.
65CC32FLAGSREMOVE += -mstack-protector-guard%
66# ftrace is disabled for the vdso but arch/powerpc/Makefile adds this define to
67# KBUILD_CPPFLAGS, which enables use of the 'patchable_function_entry'
68# attribute in the 'inline' define via 'notrace'. This attribute is not
69# supported for the powerpcle target, resulting in many instances of
70# -Wunknown-attributes.
71CC32FLAGSREMOVE += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
72endif
73LD32FLAGS := -Wl,-soname=linux-vdso32.so.1
74AS32FLAGS := -D__VDSO32__
75
76LD64FLAGS := -Wl,-soname=linux-vdso64.so.1
77AS64FLAGS := -D__VDSO64__
78
79targets += vdso32.lds
80CPPFLAGS_vdso32.lds += -P -C -Upowerpc
81targets += vdso64.lds
82CPPFLAGS_vdso64.lds += -P -C
83
84# link rule for the .so file, .lds has to be first
85$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/vgetrandom-32.o $(obj)/crtsavres-32.o FORCE
86 $(call if_changed,vdso32ld_and_check)
87$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o $(obj)/vgetrandom-64.o FORCE
88 $(call if_changed,vdso64ld_and_check)
89
90# assembly rules for the .S files
91$(obj-vdso32): %-32.o: %.S FORCE
92 $(call if_changed_dep,vdso32as)
93$(obj)/crtsavres-32.o: %-32.o: $(srctree)/arch/powerpc/lib/crtsavres.S FORCE
94 $(call if_changed_dep,vdso32as)
95$(obj)/vgettimeofday-32.o: %-32.o: %.c FORCE
96 $(call if_changed_dep,vdso32cc)
97$(obj)/vgetrandom-32.o: %-32.o: %.c FORCE
98 $(call if_changed_dep,vdso32cc)
99$(obj-vdso64): %-64.o: %.S FORCE
100 $(call if_changed_dep,vdso64as)
101$(obj)/vgettimeofday-64.o: %-64.o: %.c FORCE
102 $(call if_changed_dep,cc_o_c)
103$(obj)/vgetrandom-64.o: %-64.o: %.c FORCE
104 $(call if_changed_dep,cc_o_c)
105
106# Generate VDSO offsets using helper script
107gen-vdso32sym := $(src)/gen_vdso32_offsets.sh
108quiet_cmd_vdso32sym = VDSO32SYM $@
109 cmd_vdso32sym = $(NM) $< | $(gen-vdso32sym) | LC_ALL=C sort > $@
110gen-vdso64sym := $(src)/gen_vdso64_offsets.sh
111quiet_cmd_vdso64sym = VDSO64SYM $@
112 cmd_vdso64sym = $(NM) $< | $(gen-vdso64sym) | LC_ALL=C sort > $@
113
114include/generated/vdso32-offsets.h: $(obj)/vdso32.so.dbg FORCE
115 $(call if_changed,vdso32sym)
116include/generated/vdso64-offsets.h: $(obj)/vdso64.so.dbg FORCE
117 $(call if_changed,vdso64sym)
118
119# actual build commands
120quiet_cmd_vdso32ld_and_check = VDSO32L $@
121 cmd_vdso32ld_and_check = $(VDSOCC) $(ldflags-y) $(CC32FLAGS) $(LD32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
122quiet_cmd_vdso32as = VDSO32A $@
123 cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) $(AS32FLAGS) -c -o $@ $<
124quiet_cmd_vdso32cc = VDSO32C $@
125 cmd_vdso32cc = $(VDSOCC) $(filter-out $(CC32FLAGSREMOVE), $(c_flags)) $(CC32FLAGS) -c -o $@ $<
126
127quiet_cmd_vdso64ld_and_check = VDSO64L $@
128 cmd_vdso64ld_and_check = $(VDSOCC) $(ldflags-y) $(LD64FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
129quiet_cmd_vdso64as = VDSO64A $@
130 cmd_vdso64as = $(VDSOCC) $(a_flags) $(AS64FLAGS) -c -o $@ $<