[PATCH] lib: sbi/hart: preserve csr validation value.

[Dmitry Dunaev]

The OpenSBI hart init function hart_detect_features() try to read
important CSRs but reasign the last read value to the variable that
initially contains write probe value. So for series of CSRs (like
PMPADDRx) the secong CSR probe value will became the initial value of
first probing CSR. To avoid of this issue the CSR read value should be
saved in different variable. In this configuration the count of PMP
will detect rightly if any PMPADDR is hardwired to zero.
 
Signed-off-by: Dmitry Dunaev <dunaich at mail.ru>
---
 lib/sbi/sbi_hart.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
 
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index 7b602c3..891fa18 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -478,7 +478,7 @@ static void hart_detect_features(struct sbi_scratch
*scratch)
 {
     struct sbi_trap_info trap = {0};
     struct hart_features *hfeatures;
-    unsigned long val;
+    unsigned long val, oldval;
 
     /* Reset hart features */
     hfeatures = sbi_scratch_offset_ptr(scratch, hart_features_offset);
@@ -487,14 +487,14 @@ static void hart_detect_features(struct
sbi_scratch *scratch)
     hfeatures->mhpm_count = 0;
 
 #define __check_csr(__csr, __rdonly, __wrval, __field, __skip)    \
-    val = csr_read_allowed(__csr, (ulong)&trap);            \
+    oldval = csr_read_allowed(__csr, (ulong)&trap);            \
     if (!trap.cause) {                        \
         if (__rdonly) {                        \
             (hfeatures->__field)++;                \
         } else {                        \
             csr_write_allowed(__csr, (ulong)&trap, __wrval);\
             if (!trap.cause) {                \
-                if (csr_swap(__csr, val) == __wrval)    \
+                if (csr_swap(__csr, oldval) == __wrval)    \
                     (hfeatures->__field)++;        \
                 else                    \
                     goto __skip;            \
--
2.25.1
 
---
BW, Dmitry