From bbd065d903c8cafdcdc01aea5ccf280e17137013 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Wed, 27 Dec 2023 12:25:09 +0530 Subject: lib: sbi: Detect Zicntr extension only based on traps OpenSBI uses time CSR if Zicntr extension present which causes it to crash on an older QEMU because QEMU generates Zicntr in the ISA string for unleashed machine which only has CYCLE and INSTRET counters. Fixes: 776770d2adbf ("lib: sbi: Using one array to define the name of extensions") Signed-off-by: Anup Patel Signed-off-by: Anup Patel --- lib/sbi/sbi_hart.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'lib/sbi') diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c index e2b93e6..770fee0 100644 --- a/lib/sbi/sbi_hart.c +++ b/lib/sbi/sbi_hart.c @@ -748,6 +748,7 @@ static int hart_detect_features(struct sbi_scratch *scratch) struct sbi_hart_features *hfeatures = sbi_scratch_offset_ptr(scratch, hart_features_offset); unsigned long val, oldval; + bool has_zicntr = false; int rc; /* If hart features already detected then do nothing */ @@ -900,12 +901,19 @@ __pmp_skip: #undef __check_ext_csr + /* Save trap based detection of Zicntr */ + has_zicntr = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR); + /* Let platform populate extensions */ rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(), hfeatures); if (rc) return rc; + /* Zicntr should only be detected using traps */ + __sbi_hart_update_extension(hfeatures, SBI_HART_EXT_ZICNTR, + has_zicntr); + /* Extensions implied by other extensions and features */ if (hfeatures->mhpm_mask) __sbi_hart_update_extension(hfeatures, -- cgit v1.1