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| author | Palmer Dabbelt <palmer@sifive.com> | 2018-08-27 14:42:53 -0700 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@sifive.com> | 2018-10-22 17:38:00 -0700 |
| commit | 86e581e310785782e2025a076dc9a3f5138e5bf3 (patch) | |
| tree | fd97fa14f75e9defd4488733bef5aa5bb4d8481a /arch/riscv/kernel/cpufeature.c | |
| parent | 1760debb51f73ed3e089c8d4e847554901dee4bb (diff) | |
| download | linux-86e581e310785782e2025a076dc9a3f5138e5bf3.tar.bz2 | |
RISC-V: Mask out the F extension on systems without D
The RISC-V Linux port doesn't support systems that have the F extension
but don't have the D extension -- we actually don't support systems
without D either, but Alan's patch set is rectifying that soon. For now
I think we can leave this in a semi-broken state and just wait for
Alan's patch set to get merged for proper non-FPU support -- the patch
set is starting to look good, so doing something in-between doesn't seem
like it's worth the work.
I don't think it's worth fretting about support for systems with F but
not D for now: our glibc ABIs are IMAC and IMAFDC so they probably won't
end up being popular. We can always extend this in the future.
CC: Alan Kao <alankao@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/kernel/cpufeature.c')
| -rw-r--r-- | arch/riscv/kernel/cpufeature.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 17011a870044..652d102ffa06 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -57,5 +57,12 @@ void riscv_fill_hwcap(void) for (i = 0; i < strlen(isa); ++i) elf_hwcap |= isa2hwcap[(unsigned char)(isa[i])]; + /* We don't support systems with F but without D, so mask those out + * here. */ + if ((elf_hwcap & COMPAT_HWCAP_ISA_F) && !(elf_hwcap & COMPAT_HWCAP_ISA_D)) { + pr_info("This kernel does not support systems with F but not D"); + elf_hwcap &= ~COMPAT_HWCAP_ISA_F; + } + pr_info("elf_hwcap is 0x%lx", elf_hwcap); } |