From 9cd95e13bba9986396fe55b33aacd6b42313d1d9 Mon Sep 17 00:00:00 2001 From: Dmitry Dunaev Date: Sun, 17 Apr 2022 14:43:08 +0530 Subject: [PATCH] lib: sbi/hart: preserve csr validation value 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 second 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 Signed-off-by: Anup Patel --- 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; \