>From reading other code that accesses memory regions directly,
it appears that the rcu_read_lock needs to be held. Note: the
original code for accessing RAM directly was added because
there is no other way to use atomic_cmpxchg easily.
Signed-off-by: Michael Clark <m...@sifive.com>
Signed-off-by: Stefan O'Rear <sore...@gmail.com>
Signed-off-by: Palmer Dabbelt <pal...@sifive.com>
---
target/riscv/helper.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/target/riscv/helper.c b/target/riscv/helper.c
index 02cbcea..228933c 100644
--- a/target/riscv/helper.c
+++ b/target/riscv/helper.c
@@ -209,6 +209,7 @@ restart:
as the PTE is no longer valid */
MemoryRegion *mr;
hwaddr l = sizeof(target_ulong), addr1;
+ rcu_read_lock();
mr = address_space_translate(cs->as, pte_addr,
&addr1, &l, false);
if (memory_access_is_direct(mr, true)) {
@@ -222,16 +223,19 @@ restart:
target_ulong old_pte =
atomic_cmpxchg(pte_pa, pte, updated_pte);
if (old_pte != pte) {
+ rcu_read_unlock();
goto restart;
} else {
pte = updated_pte;
}
#endif
} else {
+ rcu_read_unlock();
/* misconfigured PTE in ROM (AD bits are not preset) or
* PTE is in IO space and can't be updated atomically */
return TRANSLATE_FAIL;
}
+ rcu_read_unlock();
}
/* for superpage mappings, make a fake leaf PTE for the TLB's
--
2.7.0
