linux/arch
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
..
alpha io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
arc arch: setup PF_IO_WORKER threads like PF_KTHREAD 2021-02-21 17:25:22 -07:00
arm xen: branch for v5.12-rc2 2021-03-04 11:24:47 -08:00
arm64 io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
csky arch/csky patches for 5.12-rc1 2021-02-28 12:06:45 -08:00
h8300 arch: setup PF_IO_WORKER threads like PF_KTHREAD 2021-02-21 17:25:22 -07:00
hexagon io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
ia64 ia64: don't call handle_signal() unless there's actually a signal queued 2021-03-02 17:22:11 -07:00
m68k io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
microblaze io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
mips io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
nds32 io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
nios2 io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
openrisc io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
parisc io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
powerpc io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
riscv riscv: Use $(LD) instead of $(CC) to link vDSO 2021-04-26 08:24:59 -07:00
s390 io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
sh io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
sparc io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
um io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
x86 * Doc fixes 2021-03-04 11:26:17 -08:00
xtensa io_uring-worker.v3-2021-02-25 2021-02-27 08:29:02 -08:00
.gitignore
Kconfig Rework of the X86 irq stack handling: 2021-02-24 16:32:23 -08:00