@@ -157,6 +157,16 @@ static void mstatus_init(struct sbi_scratch *scratch)
#endif
}
+ if (sbi_hart_has_extension(scratch, SBI_HART_EXT_ZISSLPCFI)) {
+#if __riscv_xlen == 32
+ unsigned long menvcfgh_val;
+ menvcfgh_val = csr_read(CSR_MENVCFGH);
+ menvcfgh_val |= ENVCFGH_CFI;
+ csr_write(CSR_MENVCFGH, menvcfgh_val);
+#else
+ menvcfg_val |= ENVCFG_CFI;
+#endif
+ }
csr_write(CSR_MENVCFG, menvcfg_val);
}
@@ -446,6 +456,8 @@ static inline char *sbi_hart_extension_id2string(int ext)
case SBI_HART_EXT_SMSTATEEN:
estr = "smstateen";
break;
+ case SBI_HART_EXT_ZISSLPCFI:
+ estr = "zisslpcfi";
default:
break;
}
@@ -555,6 +567,7 @@ static int hart_detect_features(struct sbi_scratch *scratch)
sbi_scratch_offset_ptr(scratch, hart_features_offset);
unsigned long val, oldval;
int rc;
+ bool ssp_exist, lplr_exist;
/* If hart features already detected then do nothing */
if (hfeatures->detected)
@@ -693,6 +706,16 @@ __mhpm_skip:
SBI_HART_EXT_SMSTATEEN, true);
}
+ if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
+ val = csr_read_allowed(CSR_SSP, (unsigned long)&trap);
+ ssp_exist = trap.cause == 0;
+ val = csr_read_allowed(CSR_LPLR, (unsigned long)&trap);
+ lplr_exist = trap.cause == 0;
+ if (lplr_exist & ssp_exist)
+ __sbi_hart_update_extension(hfeatures,
+ SBI_HART_EXT_ZISSLPCFI, true);
+ }
+
/* Let platform populate extensions */
rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(),
hfeatures);
@@ -87,6 +87,7 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs,
struct sbi_trap_info *trap)
{
ulong hstatus, vsstatus, prev_mode;
+ bool elp = false;
#if __riscv_xlen == 32
bool prev_virt = (regs->mstatusH & MSTATUSH_MPV) ? TRUE : FALSE;
#else
@@ -100,6 +101,13 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs,
if (prev_mode != PRV_S && prev_mode != PRV_U)
return SBI_ENOTSUPP;
+ /* If extension has support for CFI, clear MPELP because redirecting to VS or (H)S */
+ if (sbi_hart_has_extension(sbi_scratch_thishart_ptr(), SBI_HART_EXT_ZISSLPCFI)) {
+ elp = (regs->mstatus & MSTATUS_MPELP)? true: false;
+ /* Since redirecting, clear mpelp unconditionally */
+ regs->mstatus &= ~MSTATUS_MPELP;
+ }
+
/* If exceptions came from VS/VU-mode, redirect to VS-mode if
* delegated in hedeleg
*/
@@ -153,6 +161,10 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs,
/* Get VS-mode SSTATUS CSR */
vsstatus = csr_read(CSR_VSSTATUS);
+ /*if elp was set, set it back in vsstatus */
+ if (elp)
+ vsstatus |= MSTATUS_SPELP;
+
/* Set SPP for VS-mode */
vsstatus &= ~SSTATUS_SPP;
if (prev_mode == PRV_S)
@@ -193,6 +205,10 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs,
/* Clear SIE for S-mode */
regs->mstatus &= ~MSTATUS_SIE;
+
+ /* if elp was set, set it back in mstatus */
+ if (elp)
+ regs->mstatus |= MSTATUS_SPELP;
}
return 0;
This patch adds support for zisslpcfi detection in sbi_hart.c If Zisslpcfi is detected, this turns on menvcfg.CFI Zisslpcfi records status of cfi state in xstatus csr. Missing landing pad sets MPELP in mstatus. When SBI is redirecting back to S/VS/HS, SPELP is set in sstatus/vsstatus. Signed-off-by: Deepak Gupta <debug@rivosinc.com> --- changelog v1 --> v3: - instead of using "int" for lplr_exist/ssp_exist use "bool" - use smaller case true/false - updates to use correct extension name "zisslpcfi" --- lib/sbi/sbi_hart.c | 23 +++++++++++++++++++++++ lib/sbi/sbi_trap.c | 16 ++++++++++++++++ 2 files changed, 39 insertions(+)