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7f3d349065
linux/arch/riscv/kernel
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Nathan Chancellor 7f3d349065
riscv: Use $(LD) instead of $(CC) to link vDSO 
Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variable.

When linking with clang, there are a couple of warnings about flags that
will not be used during the link:

clang-12: warning: argument unused during compilation: '-no-pie' [-Wunused-command-line-argument]
clang-12: warning: argument unused during compilation: '-pg' [-Wunused-command-line-argument]

'-no-pie' was added in commit 85602bea29 ("RISC-V: build vdso-dummy.o
with -no-pie") to override '-pie' getting added to the ld command from
distribution versions of GCC that enable PIE by default. It is
technically no longer needed after commit c2c81bb2f6 ("RISC-V: Fix the
VDSO symbol generaton for binutils-2.35+"), which removed vdso-dummy.o
in favor of generating vdso-syms.S from vdso.so with $(NM) but this also
resolves the issue in case it ever comes back due to having full control
over the $(LD) command. '-pg' is for function tracing, it is not used
during linking as clang states.

These flags could be removed/filtered to fix the warnings but it is
easier to just match the rest of the kernel and use $(LD) directly for
linking. See commits

  fe00e50b2d ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO")
  691efbedc6 ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO")
  2ff906994b ("MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO")
  2b2a25845d ("s390/vdso: Use $(LD) instead of $(CC) to link vDSO")

for more information.

The flags are converted to linker flags and '--eh-frame-hdr' is added to
match what is added by GCC implicitly, which can be seen by adding '-v'
to GCC's invocation.

Additionally, since this area is being modified, use the $(OBJCOPY)
variable instead of an open coded $(CROSS_COMPILE)objcopy so that the
user's choice of objcopy binary is respected.

Link: https://github.com/ClangBuiltLinux/linux/issues/803
Link: https://github.com/ClangBuiltLinux/linux/issues/970
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:24:59 -07:00
..
probes RISC-V: probes: Treat the instruction stream as host-endian 2021-02-18 23:18:02 -08:00
vdso riscv: Use $(LD) instead of $(CC) to link vDSO 2021-04-26 08:24:59 -07:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
asm-offsets.c riscv: Enable per-task stack canaries 2021-01-14 15:09:10 -08:00
cacheinfo.c riscv: cacheinfo: Fix using smp_processor_id() in preemptible 2021-01-12 20:25:32 -08:00
cpu_ops_sbi.c RISC-V: Support cpu hotplug 2020-03-31 11:28:30 -07:00
cpu_ops_spinwait.c RISC-V: Add cpu_ops and modify default booting method 2020-03-31 11:25:56 -07:00
cpu_ops.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
cpu-hotplug.c RISC-V: Support cpu hotplug 2020-03-31 11:28:30 -07:00
cpu.c RISC-V: Rename and move plic_find_hart_id() to arch directory 2020-06-09 19:11:20 -07:00
cpufeature.c RISC-V: Add bitmap reprensenting ISA features common across CPUs 2020-05-04 14:08:59 -07:00
efi-header.S RISC-V: Add PE/COFF header for EFI stub 2020-10-02 14:31:16 -07:00
efi.c RISC-V: Add EFI runtime services 2020-10-02 14:31:28 -07:00
entry.S riscv: sifive: Apply errata "cip-453" patch 2021-04-26 08:24:57 -07:00
fpu.S riscv: abstract out CSR names for supervisor vs machine mode 2019-11-05 09:20:42 -08:00
ftrace.c riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT 2021-01-14 15:09:05 -08:00
head.h RISC-V: Move DT mapping outof fixmap 2020-10-02 14:30:57 -07:00
head.S riscv: add BUILTIN_DTB support for MMU-enabled targets 2021-02-18 23:17:54 -08:00
image-vars.h arch/riscv:fix typo in a comment in arch/riscv/kernel/image-vars.h 2021-02-18 23:18:00 -08:00
irq.c RISC-V: Remove do_IRQ() function 2020-06-09 19:11:24 -07:00
jump_label.c riscv: Add jump-label implementation 2020-07-30 11:37:43 -07:00
kgdb.c riscv: Fix "no previous prototype" compile warning in kgdb.c file 2020-07-09 20:09:30 -07:00
Makefile riscv: Add kprobes supported 2021-01-14 15:09:06 -08:00
mcount-dyn.S riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT 2021-01-14 15:09:05 -08:00
mcount.S RISC-V: remove the unused return_to_handler export 2018-10-22 17:38:12 -07:00
module-sections.c riscv: add missing header file includes 2019-10-28 00:46:01 -07:00
module.c riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs 2020-07-30 11:37:41 -07:00
patch.c riscv: Fixup compile error BUILD_BUG_ON failed 2021-01-14 15:09:01 -08:00
perf_callchain.c riscv: Make stack walk callback consistent with generic code 2020-11-20 18:53:38 -08:00
perf_event.c riscv: perf_event: Make some funciton static 2020-05-11 13:48:19 -07:00
perf_regs.c perf/arch: Remove perf_sample_data::regs_user_copy 2020-11-09 18:12:34 +01:00
process.c io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
ptrace.c RISC-V: Implement ptrace regs and stack API 2021-01-14 15:09:01 -08:00
reset.c riscv: cleanup the default power off implementation 2019-11-13 13:22:52 -08:00
riscv_ksyms.c riscv: provide memmove implementation 2020-12-10 17:27:54 -08:00
sbi.c riscv: Add 3 SBI wrapper functions to get cpu manufacturer information 2021-04-26 08:24:54 -07:00
setup.c RISC-V Patches for the 5.12 Merge Window 2021-02-26 10:28:35 -08:00
signal.c riscv: Add uprobes supported 2021-01-14 15:09:08 -08:00
smp.c riscv: Enable generic clockevent broadcast 2021-03-16 20:40:06 -07:00
smpboot.c riscv: Introduce alternative mechanism to apply errata solution 2021-04-26 08:24:55 -07:00
soc.c riscv: Fix builtin DTB handling 2021-01-07 19:00:50 -08:00
stacktrace.c RISC-V Patches for the 5.12 Merge Window 2021-02-26 10:28:35 -08:00
sys_riscv.c RISC-V: Don't allow write+exec only page mapping request in mmap 2020-06-18 17:28:53 -07:00
syscall_table.c riscv: add missing header file includes 2019-10-28 00:46:01 -07:00
time.c riscv: Fix kernel time_init() 2021-01-07 18:01:36 -08:00
traps_misaligned.c riscv: Unaligned load/store handling for M_MODE 2020-04-03 10:45:33 -07:00
traps.c riscv: Add dump stack in show_regs 2021-01-14 15:09:11 -08:00
vdso.c riscv: Fixup CONFIG_GENERIC_TIME_VSYSCALL 2021-01-12 20:34:44 -08:00
vmlinux.lds.S riscv: Introduce alternative mechanism to apply errata solution 2021-04-26 08:24:55 -07:00