lib: sbi: fwft: add support for SBI_FWFT_MISALIGNED_EXC_DELEG

Add support for SBI_FWFT_MISALIGNED_EXC_DELEG withing FWFT support. This
support allows to delegate misaligned accesses traps.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

diff --git a/lib/sbi/sbi_fwft.c b/lib/sbi/sbi_fwft.c
index b302b5d74dacb8d79295d7d1b69fcfbff917fcda..289a344f97bd19ff206501ff0b2965dea106d4a9 100644 (file)
--- a/lib/sbi/sbi_fwft.c
+++ b/lib/sbi/sbi_fwft.c
@@ -32,6 +32,8 @@ static unsigned long fwft_ptr_offset;
 #define fwft_set_hart_state_ptr(__scratch, __phs)                      \
        sbi_scratch_write_type((__scratch), void *, fwft_ptr_offset, (__phs))
 
+#define MIS_DELEG (1UL << CAUSE_MISALIGNED_LOAD | 1UL << CAUSE_MISALIGNED_STORE)
+
 struct fwft_config;
 
 struct fwft_feature {
@@ -71,6 +73,33 @@ static bool fwft_is_defined_feature(enum sbi_fwft_feature_t feature)
        return false;
 }
 
+static int fwft_misaligned_delegation_supported(struct fwft_config *conf)
+{
+       if (!misa_extension('S'))
+               return SBI_ENOTSUPP;
+
+       return SBI_OK;
+}
+
+static int fwft_set_misaligned_delegation(struct fwft_config *conf,
+                                        unsigned long value)
+{
+       if (value)
+               csr_set(CSR_MEDELEG, MIS_DELEG);
+       else
+               csr_clear(CSR_MEDELEG, MIS_DELEG);
+
+       return SBI_OK;
+}
+
+static int fwft_get_misaligned_delegation(struct fwft_config *conf,
+                                        unsigned long *value)
+{
+       *value = (csr_read(CSR_MEDELEG) & MIS_DELEG) != 0;
+
+       return SBI_OK;
+}
+
 static struct fwft_config* get_feature_config(enum sbi_fwft_feature_t feature)
 {
        int i;
@@ -148,7 +177,15 @@ int sbi_fwft_get(enum sbi_fwft_feature_t feature, unsigned long *out_val)
        return conf->feature->get(conf, out_val);
 }
 
-static const struct fwft_feature features[] = {};
+static const struct fwft_feature features[] =
+{
+       {
+               .id = SBI_FWFT_MISALIGNED_EXC_DELEG,
+               .supported = fwft_misaligned_delegation_supported,
+               .set = fwft_set_misaligned_delegation,
+               .get = fwft_get_misaligned_delegation,
+       },
+};
 
 int sbi_fwft_init(struct sbi_scratch *scratch, bool cold_boot)
 {

diff --git a/lib/sbi/sbi_hsm.c b/lib/sbi/sbi_hsm.c
index be48d64eb78eebe8d87159c3b04289f4a20088b8..2b23e1398de5481662fd13422107e6fec3f96d51 100644 (file)
--- a/lib/sbi/sbi_hsm.c
+++ b/lib/sbi/sbi_hsm.c
@@ -44,6 +44,7 @@ struct sbi_hsm_data {
        unsigned long suspend_type;
        unsigned long saved_mie;
        unsigned long saved_mip;
+       unsigned long saved_medeleg;
        atomic_t start_ticket;
 };
 
@@ -417,6 +418,7 @@ void __sbi_hsm_suspend_non_ret_save(struct sbi_scratch *scratch)
 
        hdata->saved_mie = csr_read(CSR_MIE);
        hdata->saved_mip = csr_read(CSR_MIP) & (MIP_SSIP | MIP_STIP);
+       hdata->saved_medeleg = csr_read(CSR_MEDELEG);
 }
 
 static void __sbi_hsm_suspend_non_ret_restore(struct sbi_scratch *scratch)
@@ -424,6 +426,7 @@ static void __sbi_hsm_suspend_non_ret_restore(struct sbi_scratch *scratch)
        struct sbi_hsm_data *hdata = sbi_scratch_offset_ptr(scratch,
                                                            hart_data_offset);
 
+       csr_write(CSR_MEDELEG, hdata->saved_medeleg);
        csr_write(CSR_MIE, hdata->saved_mie);
        csr_set(CSR_MIP, (hdata->saved_mip & (MIP_SSIP | MIP_STIP)));
 }