RISC-V: Fix PLIC pending bitfield reads

The address calculation for the pending bitfield had
a copy paste bug. This bug went unnoticed because the Linux
PLIC driver does not read the pending bitfield, rather it
reads pending interrupt numbers from the claim register
and writes acknowledgements back to the claim register.

Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Reported-by: Vincent Siles <vincent.siles@ens-lyon.org>
Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

diff --git a/hw/riscv/sifive_plic.c b/hw/riscv/sifive_plic.c
index 9cf9a1f986443e753543ce1f1759d230604cd233..d12ec3fc9a543f56a0d0c1318796204d095cbdc0 100644 (file)
--- a/hw/riscv/sifive_plic.c
+++ b/hw/riscv/sifive_plic.c
@@ -214,7 +214,7 @@ static uint64_t sifive_plic_read(void *opaque, hwaddr addr, unsigned size)
     } else if (addr >= plic->pending_base && /* 1 bit per source */
                addr < plic->pending_base + (plic->num_sources >> 3))
     {
-        uint32_t word = (addr - plic->priority_base) >> 2;
+        uint32_t word = (addr - plic->pending_base) >> 2;
         if (RISCV_DEBUG_PLIC) {
             qemu_log("plic: read pending: word=%d value=%d\n",
                 word, plic->pending[word]);