| Message ID | 20240823184735.4154272-3-debug@rivosinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v4,1/4] include: adding support for Zicfilp / Zicfiss encodings | expand |
On Fri, Aug 23, 2024 at 11:47 AM Deepak Gupta <debug@rivosinc.com> wrote: > > This patch adds support for zicfilp / zicfiss detection. > > Zicfilp records status of hart's ELP state in *status 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> > --- > include/sbi/sbi_hart.h | 3 +++ > lib/sbi/sbi_hart.c | 18 ++++++++++++++++++ > lib/sbi/sbi_trap.c | 20 ++++++++++++++++++++ > 3 files changed, 41 insertions(+) > > diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h > index 81ec061..2aa6867 100644 > --- a/include/sbi/sbi_hart.h > +++ b/include/sbi/sbi_hart.h > @@ -67,6 +67,9 @@ enum sbi_hart_extensions { > SBI_HART_EXT_SVADE, > /** Hart has Svadu extension */ > SBI_HART_EXT_SVADU, > + /** HART has zicfiss & zicfilp extension */ > + SBI_HART_EXT_ZICFILP, > + SBI_HART_EXT_ZICFISS, > > /** Maximum index of Hart extension */ > SBI_HART_EXT_MAX, > diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c > index c366701..0636021 100644 > --- a/lib/sbi/sbi_hart.c > +++ b/lib/sbi/sbi_hart.c > @@ -680,6 +680,8 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = { > __SBI_HART_EXT_DATA(ssccfg, SBI_HART_EXT_SSCCFG), > __SBI_HART_EXT_DATA(svade, SBI_HART_EXT_SVADE), > __SBI_HART_EXT_DATA(svadu, SBI_HART_EXT_SVADU), > + __SBI_HART_EXT_DATA(zicfilp, SBI_HART_EXT_ZICFILP), > + __SBI_HART_EXT_DATA(zicfiss, SBI_HART_EXT_ZICFISS), > }; > > _Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext), > @@ -776,6 +778,7 @@ static int hart_detect_features(struct sbi_scratch *scratch) > unsigned long val, oldval; > bool has_zicntr = false; > int rc; > + bool ssp_exist, elp_exist; > > /* If hart features already detected then do nothing */ > if (hfeatures->detected) > @@ -933,6 +936,21 @@ __pmp_skip: > /* Save trap based detection of Zicntr */ > has_zicntr = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR); > > + if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) { > + val = csr_read_allowed(CSR_SSP, (unsigned long)&trap); > + ssp_exist = trap.cause == 0; > + if (ssp_exist) > + __sbi_hart_update_extension(hfeatures, > + SBI_HART_EXT_ZICFISS, true); > + Why do we need to duplicate the code in __check_ext_csr ? You can set the SBI_HART_EXT_ZICFISS with __check_ext_csr and use sbi_hart_has_extension for the ZICFILP. > + csr_set(CSR_MSTATUS, MSTATUS_MPELP); > + val = csr_read_clear(CSR_MSTATUS, MSTATUS_MPELP); > + elp_exist = val & MSTATUS_MPELP; > + if (elp_exist) > + __sbi_hart_update_extension(hfeatures, > + SBI_HART_EXT_ZICFILP, true); > + } > + However, OpenSBI already supports enabling extension based isa string. Is there a reason that you can't use it for CFI extensions ? > /* Let platform populate extensions */ > rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(), > hfeatures); > diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c > index b4f3a17..e2502f2 100644 > --- a/lib/sbi/sbi_trap.c > +++ b/lib/sbi/sbi_trap.c > @@ -103,6 +103,7 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs, > const 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 > @@ -116,6 +117,17 @@ 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_ZICFILP)) { > +#if __riscv_xlen == 32 > + elp = regs->mstatusH & MSTATUSH_MPELP; > + regs->mstatusH &= ~MSTATUSH_MPELP; > +#else > + elp = regs->mstatus & MSTATUS_MPELP; > + regs->mstatus &= ~MSTATUS_MPELP; > +#endif > + } > + > /* If exceptions came from VS/VU-mode, redirect to VS-mode if > * delegated in hedeleg > */ > @@ -169,6 +181,10 @@ 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) > @@ -209,6 +225,10 @@ 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; > -- > 2.44.0 >
On Mon, Sep 09, 2024 at 05:01:22PM -0700, Atish Kumar Patra wrote: >On Fri, Aug 23, 2024 at 11:47 AM Deepak Gupta <debug@rivosinc.com> wrote: >> >> This patch adds support for zicfilp / zicfiss detection. >> >> Zicfilp records status of hart's ELP state in *status 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> >> --- >> include/sbi/sbi_hart.h | 3 +++ >> lib/sbi/sbi_hart.c | 18 ++++++++++++++++++ >> lib/sbi/sbi_trap.c | 20 ++++++++++++++++++++ >> 3 files changed, 41 insertions(+) >> >> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h >> index 81ec061..2aa6867 100644 >> --- a/include/sbi/sbi_hart.h >> +++ b/include/sbi/sbi_hart.h >> @@ -67,6 +67,9 @@ enum sbi_hart_extensions { >> SBI_HART_EXT_SVADE, >> /** Hart has Svadu extension */ >> SBI_HART_EXT_SVADU, >> + /** HART has zicfiss & zicfilp extension */ >> + SBI_HART_EXT_ZICFILP, >> + SBI_HART_EXT_ZICFISS, >> >> /** Maximum index of Hart extension */ >> SBI_HART_EXT_MAX, >> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c >> index c366701..0636021 100644 >> --- a/lib/sbi/sbi_hart.c >> +++ b/lib/sbi/sbi_hart.c >> @@ -680,6 +680,8 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = { >> __SBI_HART_EXT_DATA(ssccfg, SBI_HART_EXT_SSCCFG), >> __SBI_HART_EXT_DATA(svade, SBI_HART_EXT_SVADE), >> __SBI_HART_EXT_DATA(svadu, SBI_HART_EXT_SVADU), >> + __SBI_HART_EXT_DATA(zicfilp, SBI_HART_EXT_ZICFILP), >> + __SBI_HART_EXT_DATA(zicfiss, SBI_HART_EXT_ZICFISS), >> }; >> >> _Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext), >> @@ -776,6 +778,7 @@ static int hart_detect_features(struct sbi_scratch *scratch) >> unsigned long val, oldval; >> bool has_zicntr = false; >> int rc; >> + bool ssp_exist, elp_exist; >> >> /* If hart features already detected then do nothing */ >> if (hfeatures->detected) >> @@ -933,6 +936,21 @@ __pmp_skip: >> /* Save trap based detection of Zicntr */ >> has_zicntr = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR); >> >> + if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) { > > + val = csr_read_allowed(CSR_SSP, (unsigned long)&trap); >> + ssp_exist = trap.cause == 0; >> + if (ssp_exist) >> + __sbi_hart_update_extension(hfeatures, >> + SBI_HART_EXT_ZICFISS, true); >> + > >Why do we need to duplicate the code in __check_ext_csr ? >You can set the SBI_HART_EXT_ZICFISS with __check_ext_csr and use >sbi_hart_has_extension for the ZICFILP. Hmm didn't pay attention while rebasing that something like `__check_ext_csr` exists. Will revise patch and use it. Thanks. I didn't get comment for ZICFILP `sbi_hart_has_extension` is the one which checks if extension is available or not. It doesn't do discovery and enumeration, Am I missing something. > >> + csr_set(CSR_MSTATUS, MSTATUS_MPELP); >> + val = csr_read_clear(CSR_MSTATUS, MSTATUS_MPELP); >> + elp_exist = val & MSTATUS_MPELP; >> + if (elp_exist) >> + __sbi_hart_update_extension(hfeatures, >> + SBI_HART_EXT_ZICFILP, true); >> + } >> + > >However, OpenSBI already supports enabling extension based isa string. >Is there a reason that >you can't use it for CFI extensions ? I am not aware of this. Or may be I am not following. I had been under the impression that firmware is supposed to detect/discover features. If OpenSBI receives ISA string froms somewhere and do light up of features based on that, I think CFI extensions can do that as well. Question: If OpenSBI supports enabling of extension based on parsing ISA string. Then why do we have detection mechanism(s) like `__check_ext_csr`. > >> /* Let platform populate extensions */ >> rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(), >> hfeatures); >> diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c >> index b4f3a17..e2502f2 100644 >> --- a/lib/sbi/sbi_trap.c >> +++ b/lib/sbi/sbi_trap.c >> @@ -103,6 +103,7 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs, >> const 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 >> @@ -116,6 +117,17 @@ 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_ZICFILP)) { >> +#if __riscv_xlen == 32 >> + elp = regs->mstatusH & MSTATUSH_MPELP; >> + regs->mstatusH &= ~MSTATUSH_MPELP; >> +#else >> + elp = regs->mstatus & MSTATUS_MPELP; >> + regs->mstatus &= ~MSTATUS_MPELP; >> +#endif >> + } >> + >> /* If exceptions came from VS/VU-mode, redirect to VS-mode if >> * delegated in hedeleg >> */ >> @@ -169,6 +181,10 @@ 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) >> @@ -209,6 +225,10 @@ 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; >> -- >> 2.44.0 >>
On Mon, Sep 9, 2024 at 5:39 PM Deepak Gupta <debug@rivosinc.com> wrote: > > On Mon, Sep 09, 2024 at 05:01:22PM -0700, Atish Kumar Patra wrote: > >On Fri, Aug 23, 2024 at 11:47 AM Deepak Gupta <debug@rivosinc.com> wrote: > >> > >> This patch adds support for zicfilp / zicfiss detection. > >> > >> Zicfilp records status of hart's ELP state in *status 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> > >> --- > >> include/sbi/sbi_hart.h | 3 +++ > >> lib/sbi/sbi_hart.c | 18 ++++++++++++++++++ > >> lib/sbi/sbi_trap.c | 20 ++++++++++++++++++++ > >> 3 files changed, 41 insertions(+) > >> > >> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h > >> index 81ec061..2aa6867 100644 > >> --- a/include/sbi/sbi_hart.h > >> +++ b/include/sbi/sbi_hart.h > >> @@ -67,6 +67,9 @@ enum sbi_hart_extensions { > >> SBI_HART_EXT_SVADE, > >> /** Hart has Svadu extension */ > >> SBI_HART_EXT_SVADU, > >> + /** HART has zicfiss & zicfilp extension */ > >> + SBI_HART_EXT_ZICFILP, > >> + SBI_HART_EXT_ZICFISS, > >> > >> /** Maximum index of Hart extension */ > >> SBI_HART_EXT_MAX, > >> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c > >> index c366701..0636021 100644 > >> --- a/lib/sbi/sbi_hart.c > >> +++ b/lib/sbi/sbi_hart.c > >> @@ -680,6 +680,8 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = { > >> __SBI_HART_EXT_DATA(ssccfg, SBI_HART_EXT_SSCCFG), > >> __SBI_HART_EXT_DATA(svade, SBI_HART_EXT_SVADE), > >> __SBI_HART_EXT_DATA(svadu, SBI_HART_EXT_SVADU), > >> + __SBI_HART_EXT_DATA(zicfilp, SBI_HART_EXT_ZICFILP), > >> + __SBI_HART_EXT_DATA(zicfiss, SBI_HART_EXT_ZICFISS), > >> }; > >> > >> _Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext), > >> @@ -776,6 +778,7 @@ static int hart_detect_features(struct sbi_scratch *scratch) > >> unsigned long val, oldval; > >> bool has_zicntr = false; > >> int rc; > >> + bool ssp_exist, elp_exist; > >> > >> /* If hart features already detected then do nothing */ > >> if (hfeatures->detected) > >> @@ -933,6 +936,21 @@ __pmp_skip: > >> /* Save trap based detection of Zicntr */ > >> has_zicntr = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR); > >> > >> + if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) { > > > + val = csr_read_allowed(CSR_SSP, (unsigned long)&trap); > >> + ssp_exist = trap.cause == 0; > >> + if (ssp_exist) > >> + __sbi_hart_update_extension(hfeatures, > >> + SBI_HART_EXT_ZICFISS, true); > >> + > > > >Why do we need to duplicate the code in __check_ext_csr ? > >You can set the SBI_HART_EXT_ZICFISS with __check_ext_csr and use > >sbi_hart_has_extension for the ZICFILP. > > Hmm didn't pay attention while rebasing that something like `__check_ext_csr` > exists. Will revise patch and use it. Thanks. > > I didn't get comment for ZICFILP > `sbi_hart_has_extension` is the one which checks if extension is available or not. > It doesn't do discovery and enumeration, Am I missing something. > Ignore that comment. You are detecting the presence of SBI_HART_EXT_ZICFILP via mstatus not via read/trap method that __check_ext_csr provides. So you can't use __check_ext_csr for that. I misread the code earlier to assume that ZICFILP has some dependencies on ZICFISS. So I suggested that you can check the presence of ZICFISS with sbi_hart_has_extension. Sorry for the confusion. > > > >> + csr_set(CSR_MSTATUS, MSTATUS_MPELP); > >> + val = csr_read_clear(CSR_MSTATUS, MSTATUS_MPELP); > >> + elp_exist = val & MSTATUS_MPELP; > >> + if (elp_exist) > >> + __sbi_hart_update_extension(hfeatures, > >> + SBI_HART_EXT_ZICFILP, true); > >> + } > >> + > > > >However, OpenSBI already supports enabling extension based isa string. > >Is there a reason that > >you can't use it for CFI extensions ? > > I am not aware of this. Or may be I am not following. I had been under the > impression that firmware is supposed to detect/discover features. If OpenSBI > receives ISA string froms somewhere and do light up of features based on that, > I think CFI extensions can do that as well. > Yeah. That is simpler. This feature got added recently while the trap n detect feature has been there from the beginning. https://github.com/riscv-software-src/opensbi/blob/master/lib/utils/fdt/fdt_helper.c#L475C5-L475C29 That's why, any newer extension can just use DT based methods instead of adding its own csr trapping mechanism. __check_ext_csr continues to exist for legacy reasons. E.g. Zicntr/Zihpm can only be detected using traps. We also need to detect how many hpmcounters are available which the DT doesn't describe. > Question: > If OpenSBI supports enabling of extension based on parsing ISA string. > Then why do we have detection mechanism(s) like `__check_ext_csr`. > > > > >> /* Let platform populate extensions */ > >> rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(), > >> hfeatures); > >> diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c > >> index b4f3a17..e2502f2 100644 > >> --- a/lib/sbi/sbi_trap.c > >> +++ b/lib/sbi/sbi_trap.c > >> @@ -103,6 +103,7 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs, > >> const 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 > >> @@ -116,6 +117,17 @@ 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_ZICFILP)) { > >> +#if __riscv_xlen == 32 > >> + elp = regs->mstatusH & MSTATUSH_MPELP; > >> + regs->mstatusH &= ~MSTATUSH_MPELP; > >> +#else > >> + elp = regs->mstatus & MSTATUS_MPELP; > >> + regs->mstatus &= ~MSTATUS_MPELP; > >> +#endif > >> + } > >> + > >> /* If exceptions came from VS/VU-mode, redirect to VS-mode if > >> * delegated in hedeleg > >> */ > >> @@ -169,6 +181,10 @@ 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) > >> @@ -209,6 +225,10 @@ 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; > >> -- > >> 2.44.0 > >>
diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h index 81ec061..2aa6867 100644 --- a/include/sbi/sbi_hart.h +++ b/include/sbi/sbi_hart.h @@ -67,6 +67,9 @@ enum sbi_hart_extensions { SBI_HART_EXT_SVADE, /** Hart has Svadu extension */ SBI_HART_EXT_SVADU, + /** HART has zicfiss & zicfilp extension */ + SBI_HART_EXT_ZICFILP, + SBI_HART_EXT_ZICFISS, /** Maximum index of Hart extension */ SBI_HART_EXT_MAX, diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c index c366701..0636021 100644 --- a/lib/sbi/sbi_hart.c +++ b/lib/sbi/sbi_hart.c @@ -680,6 +680,8 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = { __SBI_HART_EXT_DATA(ssccfg, SBI_HART_EXT_SSCCFG), __SBI_HART_EXT_DATA(svade, SBI_HART_EXT_SVADE), __SBI_HART_EXT_DATA(svadu, SBI_HART_EXT_SVADU), + __SBI_HART_EXT_DATA(zicfilp, SBI_HART_EXT_ZICFILP), + __SBI_HART_EXT_DATA(zicfiss, SBI_HART_EXT_ZICFISS), }; _Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext), @@ -776,6 +778,7 @@ static int hart_detect_features(struct sbi_scratch *scratch) unsigned long val, oldval; bool has_zicntr = false; int rc; + bool ssp_exist, elp_exist; /* If hart features already detected then do nothing */ if (hfeatures->detected) @@ -933,6 +936,21 @@ __pmp_skip: /* Save trap based detection of Zicntr */ has_zicntr = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR); + if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) { + val = csr_read_allowed(CSR_SSP, (unsigned long)&trap); + ssp_exist = trap.cause == 0; + if (ssp_exist) + __sbi_hart_update_extension(hfeatures, + SBI_HART_EXT_ZICFISS, true); + + csr_set(CSR_MSTATUS, MSTATUS_MPELP); + val = csr_read_clear(CSR_MSTATUS, MSTATUS_MPELP); + elp_exist = val & MSTATUS_MPELP; + if (elp_exist) + __sbi_hart_update_extension(hfeatures, + SBI_HART_EXT_ZICFILP, true); + } + /* Let platform populate extensions */ rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(), hfeatures); diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c index b4f3a17..e2502f2 100644 --- a/lib/sbi/sbi_trap.c +++ b/lib/sbi/sbi_trap.c @@ -103,6 +103,7 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs, const 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 @@ -116,6 +117,17 @@ 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_ZICFILP)) { +#if __riscv_xlen == 32 + elp = regs->mstatusH & MSTATUSH_MPELP; + regs->mstatusH &= ~MSTATUSH_MPELP; +#else + elp = regs->mstatus & MSTATUS_MPELP; + regs->mstatus &= ~MSTATUS_MPELP; +#endif + } + /* If exceptions came from VS/VU-mode, redirect to VS-mode if * delegated in hedeleg */ @@ -169,6 +181,10 @@ 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) @@ -209,6 +225,10 @@ 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 zicfilp / zicfiss detection. Zicfilp records status of hart's ELP state in *status 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> --- include/sbi/sbi_hart.h | 3 +++ lib/sbi/sbi_hart.c | 18 ++++++++++++++++++ lib/sbi/sbi_trap.c | 20 ++++++++++++++++++++ 3 files changed, 41 insertions(+)