[PULL,18/18] target/riscv: PMP violation due to wrong size parameter

Commit Message

Palmer Dabbelt Oct. 28, 2019, 3:49 p.m. UTC

From: Dayeol Lee <[e-mail]>

riscv_cpu_tlb_fill() uses the `size` parameter to check PMP violation
using pmp_hart_has_privs().
However, if the size is unknown (=0), the ending address will be
`addr - 1` as it is `addr + size - 1` in `pmp_hart_has_privs()`.
This always causes a false PMP violation on the starting address of the
range, as `addr - 1` is not in the range.

In order to fix, we just assume that all bytes from addr to the end of
the page will be accessed if the size is unknown.

Signed-off-by: Dayeol Lee <[e-mail]>
Reviewed-by: Richard Henderson <[e-mail]>
Signed-off-by: Palmer Dabbelt <[e-mail]>
---
 target/riscv/pmp.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

Patch

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index d4f1007109..0e6b640fbd 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -223,6 +223,7 @@  bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr,
 {
     int i = 0;
     int ret = -1;
+    int pmp_size = 0;
     target_ulong s = 0;
     target_ulong e = 0;
     pmp_priv_t allowed_privs = 0;
@@ -232,11 +233,21 @@  bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr,
         return true;
     }
 
+    /*
+     * if size is unknown (0), assume that all bytes
+     * from addr to the end of the page will be accessed.
+     */
+    if (size == 0) {
+        pmp_size = -(addr | TARGET_PAGE_MASK);
+    } else {
+        pmp_size = size;
+    }
+
     /* 1.10 draft priv spec states there is an implicit order
          from low to high */
     for (i = 0; i < MAX_RISCV_PMPS; i++) {
         s = pmp_is_in_range(env, i, addr);
-        e = pmp_is_in_range(env, i, addr + size - 1);
+        e = pmp_is_in_range(env, i, addr + pmp_size - 1);
 
         /* partially inside */
         if ((s + e) == 1) {