[PATCH Zisslpcfi 0/2] Support for zisslpcfi in opensbi

[PATCH Zisslpcfi 0/2] Support for zisslpcfi in opensbi

[Deepak Gupta]

Zisslpcfi [1] extension extends risc-v architecture to mitigate against
control-flow integrity attacks (ROP/JOP/COP). 

Zisslpcfi uses bits (b23-b29) in (m/s/vs) status CSR for enabling cfi in
lesser privileged mode and record cfi state. One such state is expected
landing pad (ELP). If forward cfi is enabled, indirect call/jmp updates
hart's ELP state (1bit) to true. ELP state is cleared only by a landing 
pad instruction else trap is delivered with ELP state recorded in sstatus
CSR.

This two patch series adds following changes to opensbi
    - Adds support in opensbi to detect zisslpcfi
    - trap redirection updates ELP state accordingly

[1] - https://github.com/riscv/riscv-cfi

Deepak Gupta (2):
  include: adding support for zsslpcfi encodings
  lib: sbi: zsslpcfi detection and elp cfi state reflect back in status

 include/sbi/riscv_encoding.h |  6 ++++++
 include/sbi/sbi_hart.h       |  2 ++
 lib/sbi/sbi_hart.c           | 21 +++++++++++++++++++++
 lib/sbi/sbi_trap.c           | 18 ++++++++++++++++++
 4 files changed, 47 insertions(+)

-- 
2.25.1

[PATCH Zisslpcfi 1/2] include: adding support for zsslpcfi encodings

[Deepak Gupta]

zsslpcfi extension (see links) introduces b60 (CFI) in menvcfg CSR to
enable shadow stack and landing pad for machine and lesser privileged
modes. Additionally extension introduces new bits in xstatus for cfi
state.

Links:https://github.com/riscv/riscv-cfi

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
---
 include/sbi/riscv_encoding.h | 4 ++++
 include/sbi/sbi_hart.h       | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h
index b0f08c8..1fb520f 100644
--- a/include/sbi/riscv_encoding.h
+++ b/include/sbi/riscv_encoding.h
@@ -210,9 +210,11 @@
 #if __riscv_xlen > 32
 #define ENVCFG_STCE			(_ULL(1) << 63)
 #define ENVCFG_PBMTE			(_ULL(1) << 62)
+#define ENVCFG_CFI			(_ULL(1) << 60)
 #else
 #define ENVCFGH_STCE			(_UL(1) << 31)
 #define ENVCFGH_PBMTE			(_UL(1) << 30)
+#define ENVCFGH_CFI			(_UL(1) << 28)
 #endif
 #define ENVCFG_CBZE			(_UL(1) << 7)
 #define ENVCFG_CBCFE			(_UL(1) << 6)
@@ -229,6 +231,8 @@
 #define CSR_USTATUS			0x000
 #define CSR_UIE				0x004
 #define CSR_UTVEC			0x005
+#define CSR_LPLR			0x006
+#define CSR_SSP				0x020
 
 /* User Trap Handling (N-extension) */
 #define CSR_USCRATCH			0x040
diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
index 95b40e7..d25227d 100644
--- a/include/sbi/sbi_hart.h
+++ b/include/sbi/sbi_hart.h
@@ -36,6 +36,8 @@ enum sbi_hart_extensions {
 	SBI_HART_EXT_SMSTATEEN,
 	/** HART has Sstc extension */
 	SBI_HART_EXT_SSTC,
+	/** HART has sslpcfi extension */
+	SBI_HART_EXT_SSLPCFI,
 
 	/** Maximum index of Hart extension */
 	SBI_HART_EXT_MAX,
-- 
2.25.1

[PATCH Zisslpcfi 2/2] lib: sbi: zsslpcfi detection and elp cfi state reflect back in status

[Deepak Gupta]

This patch adds support for zsslpcfi detection in sbi_hart.c
If zsslpcfi is detected, this turns on menvcfg.CFI

zsslpcfi 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>
---
 include/sbi/riscv_encoding.h |  2 ++
 lib/sbi/sbi_hart.c           | 21 +++++++++++++++++++++
 lib/sbi/sbi_trap.c           | 18 ++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h
index 1fb520f..d7886e7 100644
--- a/include/sbi/riscv_encoding.h
+++ b/include/sbi/riscv_encoding.h
@@ -32,6 +32,8 @@
 #define MSTATUS_TVM			_UL(0x00100000)
 #define MSTATUS_TW			_UL(0x00200000)
 #define MSTATUS_TSR			_UL(0x00400000)
+#define MSTATUS_SPELP     		_UL(0x10000000)
+#define MSTATUS_MPELP     		_UL(0x20000000)
 #define MSTATUS32_SD			_UL(0x80000000)
 #if __riscv_xlen == 64
 #define MSTATUS_UXL			_ULL(0x0000000300000000)
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index 5447c52..6beae2d 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -157,6 +157,16 @@ static void mstatus_init(struct sbi_scratch *scratch)
 #endif
 		}
 
+		if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SSLPCFI)) {
+#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);
 	}
 
@@ -555,6 +565,7 @@ static int hart_detect_features(struct sbi_scratch *scratch)
 		sbi_scratch_offset_ptr(scratch, hart_features_offset);
 	unsigned long val, oldval;
 	int rc;
+	int ssp_exist, lplr_exist;
 
 	/* If hart features already detected then do nothing */
 	if (hfeatures->detected)
@@ -693,6 +704,16 @@ __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?0:1;
+		val = csr_read_allowed(CSR_LPLR, (unsigned long)&trap);
+		lplr_exist = trap.cause?0:1;
+		if (lplr_exist & ssp_exist)
+			__sbi_hart_update_extension(hfeatures,
+					SBI_HART_EXT_SSLPCFI, 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 c875c90..a700041 100644
--- a/lib/sbi/sbi_trap.c
+++ b/lib/sbi/sbi_trap.c
@@ -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_SSLPCFI)) {
+		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 +161,11 @@ 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 +206,11 @@ 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;
-- 
2.25.1

[PATCH Zisslpcfi 0/2] Support for zisslpcfi in opensbi

[Deepak Gupta]

I forgot to include URLs to qemu and linux implementation of Zisslpcfi

This is where I am maintaining qemu implementation
https://github.com/deepak0414/qemu/tree/gh_Zisslpcfi-0.1

And kernel implementation here
https://github.com/deepak0414/linux-riscv-cfi/tree/Zisslpcfi-0.1_v6.1-rc2

On Sun, Dec 11, 2022 at 07:08:02PM -0800, Deepak Gupta wrote:
>Zisslpcfi [1] extension extends risc-v architecture to mitigate against
>control-flow integrity attacks (ROP/JOP/COP).
>
>Zisslpcfi uses bits (b23-b29) in (m/s/vs) status CSR for enabling cfi in
>lesser privileged mode and record cfi state. One such state is expected
>landing pad (ELP). If forward cfi is enabled, indirect call/jmp updates
>hart's ELP state (1bit) to true. ELP state is cleared only by a landing
>pad instruction else trap is delivered with ELP state recorded in sstatus
>CSR.
>
>This two patch series adds following changes to opensbi
>    - Adds support in opensbi to detect zisslpcfi
>    - trap redirection updates ELP state accordingly
>
>[1] - https://github.com/riscv/riscv-cfi
>
>Deepak Gupta (2):
>  include: adding support for zsslpcfi encodings
>  lib: sbi: zsslpcfi detection and elp cfi state reflect back in status
>
> include/sbi/riscv_encoding.h |  6 ++++++
> include/sbi/sbi_hart.h       |  2 ++
> lib/sbi/sbi_hart.c           | 21 +++++++++++++++++++++
> lib/sbi/sbi_trap.c           | 18 ++++++++++++++++++
> 4 files changed, 47 insertions(+)
>
>-- 
>2.25.1
>

[PATCH Zisslpcfi 1/2] include: adding support for zsslpcfi encodings

[Bin Meng]

On Mon, Dec 12, 2022 at 11:10 AM Deepak Gupta <debug@rivosinc.com> wrote:
>
> zsslpcfi extension (see links) introduces b60 (CFI) in menvcfg CSR to

The extension name is Zisslpcfi (capital Z)

> enable shadow stack and landing pad for machine and lesser privileged
> modes. Additionally extension introduces new bits in xstatus for cfi
> state.
>
> Links:https://github.com/riscv/riscv-cfi

nits: need a space after :

s/Links/Link

>
> Signed-off-by: Deepak Gupta <debug@rivosinc.com>
> ---
>  include/sbi/riscv_encoding.h | 4 ++++
>  include/sbi/sbi_hart.h       | 2 ++
>  2 files changed, 6 insertions(+)
>
> diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h
> index b0f08c8..1fb520f 100644
> --- a/include/sbi/riscv_encoding.h
> +++ b/include/sbi/riscv_encoding.h
> @@ -210,9 +210,11 @@
>  #if __riscv_xlen > 32
>  #define ENVCFG_STCE                    (_ULL(1) << 63)
>  #define ENVCFG_PBMTE                   (_ULL(1) << 62)
> +#define ENVCFG_CFI                     (_ULL(1) << 60)
>  #else
>  #define ENVCFGH_STCE                   (_UL(1) << 31)
>  #define ENVCFGH_PBMTE                  (_UL(1) << 30)
> +#define ENVCFGH_CFI                    (_UL(1) << 28)
>  #endif
>  #define ENVCFG_CBZE                    (_UL(1) << 7)
>  #define ENVCFG_CBCFE                   (_UL(1) << 6)
> @@ -229,6 +231,8 @@
>  #define CSR_USTATUS                    0x000
>  #define CSR_UIE                                0x004
>  #define CSR_UTVEC                      0x005
> +#define CSR_LPLR                       0x006
> +#define CSR_SSP                                0x020
>
>  /* User Trap Handling (N-extension) */
>  #define CSR_USCRATCH                   0x040
> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> index 95b40e7..d25227d 100644
> --- a/include/sbi/sbi_hart.h
> +++ b/include/sbi/sbi_hart.h
> @@ -36,6 +36,8 @@ enum sbi_hart_extensions {
>         SBI_HART_EXT_SMSTATEEN,
>         /** HART has Sstc extension */
>         SBI_HART_EXT_SSTC,
> +       /** HART has sslpcfi extension */

Zisslpcfi

> +       SBI_HART_EXT_SSLPCFI,

SBI_HART_EXT_ZISSLPCFI

>
>         /** Maximum index of Hart extension */
>         SBI_HART_EXT_MAX,
> --

Regards,
Bin

[PATCH Zisslpcfi 2/2] lib: sbi: zsslpcfi detection and elp cfi state reflect back in status

[Bin Meng]

On Mon, Dec 12, 2022 at 11:10 AM Deepak Gupta <debug@rivosinc.com> wrote:
>
> This patch adds support for zsslpcfi detection in sbi_hart.c
> If zsslpcfi is detected, this turns on menvcfg.CFI
>
> zsslpcfi 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>
> ---
>  include/sbi/riscv_encoding.h |  2 ++
>  lib/sbi/sbi_hart.c           | 21 +++++++++++++++++++++
>  lib/sbi/sbi_trap.c           | 18 ++++++++++++++++++
>  3 files changed, 41 insertions(+)
>
> diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h
> index 1fb520f..d7886e7 100644
> --- a/include/sbi/riscv_encoding.h
> +++ b/include/sbi/riscv_encoding.h
> @@ -32,6 +32,8 @@
>  #define MSTATUS_TVM                    _UL(0x00100000)
>  #define MSTATUS_TW                     _UL(0x00200000)
>  #define MSTATUS_TSR                    _UL(0x00400000)
> +#define MSTATUS_SPELP                  _UL(0x10000000)
> +#define MSTATUS_MPELP                  _UL(0x20000000)
>  #define MSTATUS32_SD                   _UL(0x80000000)
>  #if __riscv_xlen == 64
>  #define MSTATUS_UXL                    _ULL(0x0000000300000000)
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index 5447c52..6beae2d 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -157,6 +157,16 @@ static void mstatus_init(struct sbi_scratch *scratch)
>  #endif
>                 }
>
> +               if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SSLPCFI)) {
> +#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);
>         }
>
> @@ -555,6 +565,7 @@ static int hart_detect_features(struct sbi_scratch *scratch)
>                 sbi_scratch_offset_ptr(scratch, hart_features_offset);
>         unsigned long val, oldval;
>         int rc;
> +       int ssp_exist, lplr_exist;

Use bool

>
>         /* If hart features already detected then do nothing */
>         if (hfeatures->detected)
> @@ -693,6 +704,16 @@ __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?0:1;

need space around ? and :

use true/false instead of 1/0

> +               val = csr_read_allowed(CSR_LPLR, (unsigned long)&trap);
> +               lplr_exist = trap.cause?0:1;
> +               if (lplr_exist & ssp_exist)
> +                       __sbi_hart_update_extension(hfeatures,
> +                                       SBI_HART_EXT_SSLPCFI, 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 c875c90..a700041 100644
> --- a/lib/sbi/sbi_trap.c
> +++ b/lib/sbi/sbi_trap.c
> @@ -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;

s/FALSE/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_SSLPCFI)) {
> +               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 +161,11 @@ 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 */

need space after /*

> +               if (elp) {
> +                       vsstatus |= MSTATUS_SPELP;
> +               }
> +
>                 /* Set SPP for VS-mode */
>                 vsstatus &= ~SSTATUS_SPP;
>                 if (prev_mode == PRV_S)
> @@ -193,6 +206,11 @@ 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;
> +               }
>         }
>

Regards,
Bin

[PATCH Zisslpcfi 2/2] lib: sbi: zsslpcfi detection and elp cfi state reflect back in status

[Andreas Schwab]

On Dez 21 2022, Bin Meng wrote:

>> @@ -693,6 +704,16 @@ __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?0:1;

                   ssp_exist = trap.cause == 0;

-- 
Andreas Schwab, SUSE Labs, schwab at suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

[PATCH Zisslpcfi 2/2] lib: sbi: zsslpcfi detection and elp cfi state reflect back in status

[Deepak Gupta]

On Wed, Dec 21, 2022 at 5:43 AM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> > @@ -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;
>
> s/FALSE/false

I followed whatever rest of the code is following. In the same function

"
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
        bool prev_virt = (regs->mstatus & MSTATUS_MPV) ? TRUE : FALSE;
#endif
        /* By default, we redirect to HS-mode */
        bool next_virt = FALSE;
"
I can change it to false but it'll look ugly because at other places
we're using upper case FALSE.
Let me know what needs to be done.

>
> >  #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_SSLPCFI)) {
> > +               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 +161,11 @@ 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 */
>
> need space after /*
>
> > +               if (elp) {
> > +                       vsstatus |= MSTATUS_SPELP;
> > +               }
> > +
> >                 /* Set SPP for VS-mode */
> >                 vsstatus &= ~SSTATUS_SPP;
> >                 if (prev_mode == PRV_S)
> > @@ -193,6 +206,11 @@ 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;
> > +               }
> >         }
> >
>
> Regards,
> Bin

[PATCH Zisslpcfi 2/2] lib: sbi: zsslpcfi detection and elp cfi state reflect back in status

[Deepak Gupta]

Thanks Andreas and Bin for your review comments.
Sent out v2 version of the patch.

-Deepak

On Wed, Dec 21, 2022 at 5:59 AM Andreas Schwab <schwab@suse.de> wrote:
>
> On Dez 21 2022, Bin Meng wrote:
>
> >> @@ -693,6 +704,16 @@ __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?0:1;
>
>                    ssp_exist = trap.cause == 0;
>
> --
> Andreas Schwab, SUSE Labs, schwab at suse.de
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."

[PATCH Zisslpcfi 2/2] lib: sbi: zsslpcfi detection and elp cfi state reflect back in status

[Bin Meng]

On Thu, Dec 22, 2022 at 2:41 AM Deepak Gupta <debug@rivosinc.com> wrote:
>
> On Wed, Dec 21, 2022 at 5:43 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> >
> > > @@ -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;
> >
> > s/FALSE/false
>
> I followed whatever rest of the code is following. In the same function
>
> "
> 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
>         bool prev_virt = (regs->mstatus & MSTATUS_MPV) ? TRUE : FALSE;
> #endif
>         /* By default, we redirect to HS-mode */
>         bool next_virt = FALSE;
> "
> I can change it to false but it'll look ugly because at other places
> we're using upper case FALSE.
> Let me know what needs to be done.
>

No need to worry about other places, as I already sent one patch to
change all other places.

Regards,
Bin