We don't yet have an upstream glibc port for riscv, so there is no user
space for the existing ABI, and we can remove the definitions for 32-bit
time_t, off_t and struct resource and system calls based on them,
including the vdso.
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
If you use a 64-bit compiler to build a 32-bit kernel then you'll get an
error when building the vDSO due to a library mismatch. The happens
because the relevant "-march" argument isn't supplied to the GCC run
that generates one of the vDSO intermediate files.
I'm not actually sure what the right thing to do here is as I'm not
particularly familiar with the kernel build system. I poked the
documentation and it appears that KCFLAGS is the correct thing to do
(it's suggested that should be used when building modules), but we set
KBUILD_CFLAGS in arch/riscv/Makefile.
This does at least fix the build error.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Debian toolcahin defaults to PIE, and I guess that will also be the case
of most distributions. This causes the following build failure:
AS arch/riscv/kernel/vdso/getcpu.o
AS arch/riscv/kernel/vdso/flush_icache.o
VDSOLD arch/riscv/kernel/vdso/vdso.so.dbg
OBJCOPY arch/riscv/kernel/vdso/vdso.so
AS arch/riscv/kernel/vdso/vdso.o
VDSOLD arch/riscv/kernel/vdso/vdso-dummy.o
LD arch/riscv/kernel/vdso/vdso-syms.o
riscv64-linux-gnu-ld: attempted static link of dynamic object `arch/riscv/kernel/vdso/vdso-dummy.o'
make[2]: *** [arch/riscv/kernel/vdso/Makefile:43: arch/riscv/kernel/vdso/vdso-syms.o] Error 1
make[1]: *** [scripts/Makefile.build:575: arch/riscv/kernel/vdso] Error 2
make: *** [Makefile:1018: arch/riscv/kernel] Error 2
While the root Makefile correctly passes "-fno-PIE" to build individual
object files, the RISC-V kernel also builds vdso-dummy.o as an
executable, which is therefore linked as PIE. Fix that by updating this
specific link rule to also include "-no-pie".
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Despite RISC-V having a direct 'fence.i' instruction available to
userspace (which we can't trap!), that's not actually viable when
running on Linux because the kernel might schedule a process on another
hart. There is no way for userspace to handle this without invoking the
kernel (as it doesn't know the thread->hart mappings), so we've defined
a RISC-V specific system call to flush the instruction cache.
This patch adds both a system call and a VDSO entry. If possible, we'd
like to avoid having the system call be considered part of the
user-facing ABI and instead restrict that to the VDSO entry -- both just
in general to avoid having additional user-visible ABI to maintain, and
because we'd prefer that users just call the VDSO entry because there
might be a better way to do this in the future (ie, one that doesn't
require entering the kernel).
Signed-off-by: Andrew Waterman <andrew@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
For now these are just placeholders that execute the syscall. We will
later optimize them to avoid kernel crossings, but we'd like to have the
VDSO entries from the first released kernel version to make the ABI
simpler.
Signed-off-by: Andrew Waterman <andrew@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This patch contains code that is in some way visible to the user:
including via system calls, the VDSO, module loading and signal
handling. It also contains some generic code that is ABI visible.
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Arnd Bergmann