diff options
author | Andrew Waterman <andrew@sifive.com> | 2017-10-25 14:30:32 -0700 |
---|---|---|
committer | Palmer Dabbelt <palmer@sifive.com> | 2017-11-30 12:58:25 -0800 |
commit | 08f051eda33b51e8ee0f45f05bcfe49d0f0caf6b (patch) | |
tree | 46a1e3577de686377e859c7f346299e9ea726260 /arch/riscv/kernel/syscall_table.c | |
parent | 28dfbe6ed483e8a589cce88095d7787d61bf9c16 (diff) |
RISC-V: Flush I$ when making a dirty page executable
The RISC-V ISA allows for instruction caches that are not coherent WRT
stores, even on a single hart. As a result, we need to explicitly flush
the instruction cache whenever marking a dirty page as executable in
order to preserve the correct system behavior.
Local instruction caches aren't that scary (our implementations actually
flush the cache, but RISC-V is defined to allow higher-performance
implementations to exist), but RISC-V defines no way to perform an
instruction cache shootdown. When explicitly asked to do so we can
shoot down remote instruction caches via an IPI, but this is a bit on
the slow side.
Instead of requiring an IPI to all harts whenever marking a page as
executable, we simply flush the currently running harts. In order to
maintain correct behavior, we additionally mark every other hart as
needing a deferred instruction cache which will be taken before anything
runs on it.
Signed-off-by: Andrew Waterman <andrew@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/kernel/syscall_table.c')
0 files changed, 0 insertions, 0 deletions