target/riscv/pmp.c: Fix pmp_decode_napot()

Currently, start and end address of a PMP region are not decoded
correctly by pmp_decode_napot().

Let's say we have a 128KB PMP region with base address as 0x80000000.
Now, the PMPADDRx CSR value for this region will be 0x20003fff.

The current pmp_decode_napot() implementation will decode PMPADDRx
CSR as t1=14, base=0x100000000, and range=0x1ffff whereas it should
have decoded PMPADDRx CSR as t1=14, base=0x80000000, and range=0x1fff.

This patch fixes the base value decoding in pmp_decode_napot() when
PMPADDRx CSR is not -1 (i.e. 0xffffffffffffffff).

Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 03abd8f..15a5366 100644 (file)
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -138,7 +138,7 @@ static void pmp_decode_napot(target_ulong a, target_ulong *sa, target_ulong *ea)
         return;
     } else {
         target_ulong t1 = ctz64(~a);
-        target_ulong base = (a & ~(((target_ulong)1 << t1) - 1)) << 3;
+        target_ulong base = (a & ~(((target_ulong)1 << t1) - 1)) << 2;
         target_ulong range = ((target_ulong)1 << (t1 + 3)) - 1;
         *sa = base;
         *ea = base + range;