diff mbox series

[v2,GCC] arm: Add support for new frame unwinding instruction "0xb5".

Message ID 1202edce-cd9c-45a2-a47c-7145bfdebae4@AZ-NEU-EX04.Arm.com
State Not Applicable
Headers
Series [v2,GCC] arm: Add support for new frame unwinding instruction "0xb5". |

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Context Check Description
snail/gcc-patch-check fail Git am fail log

Commit Message

Srinath Parvathaneni Jan. 20, 2023, 5:27 p.m. UTC 
  Hi,

This patch adds support for Arm frame unwinding instruction "0xb5" [1]. When
an exception is taken and "0xb5" instruction is encounter during runtime
stack-unwinding, we use effective vsp as modifier in pointer authentication.
On completion of stack unwinding if "0xb5" instruction is not encountered
then CFA will be used as modifier in pointer authentication.

[1] https://github.com/ARM-software/abi-aa/releases/download/2022Q3/ehabi32.pdf

Regression tested on arm-none-eabi target and found no regressions.

Ok for master?

Regards,
Srinath.

gcc/ChangeLog:

2022-11-09  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * libgcc/config/arm/pr-support.c (__gnu_unwind_execute): Decode opcode "0xb5".


###############     Attachment also inlined for ease of reply    ###############
diff --git a/libgcc/config/arm/pr-support.c b/libgcc/config/arm/pr-support.c
index e48854587c667a959aa66ccc4982231f63333ecc..1fbc41e17c227c21af1937344ded2a7fd80e61df 100644
--- a/libgcc/config/arm/pr-support.c
+++ b/libgcc/config/arm/pr-support.c
@@ -107,7 +107,9 @@ __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
   _uw op;
   int set_pc;
   int set_pac = 0;
+  int set_pac_sp = 0;
   _uw reg;
+  _uw sp;
 
   set_pc = 0;
   for (;;)
@@ -124,10 +126,11 @@ __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
 #if defined(TARGET_HAVE_PACBTI)
 	  if (set_pac)
 	    {
-	      _uw sp;
 	      _uw lr;
 	      _uw pac;
-	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &sp);
+	      if (!set_pac_sp)
+		_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,
+				 &sp);
 	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_LR, _UVRSD_UINT32, &lr);
 	      _Unwind_VRS_Get (context, _UVRSC_PAC, R_IP,
 			       _UVRSD_UINT32, &pac);
@@ -259,6 +262,14 @@ __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
 	      continue;
 	    }
 
+	  /* Use current VSP as modifier in PAC validation.  */
+	  if (op == 0xb5)
+	    {
+	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &sp);
+	      set_pac_sp = 1;
+	      continue;
+	    }
+
 	  if ((op & 0xfc) == 0xb4)  /* Obsolete FPA.  */
 	    return _URC_FAILURE;

Comments

Richard Earnshaw Jan. 20, 2023, 5:53 p.m. UTC | #1 
On 20/01/2023 17:27, Srinath Parvathaneni via Gcc-patches wrote:
> Hi,
> 
> This patch adds support for Arm frame unwinding instruction "0xb5" [1]. When
> an exception is taken and "0xb5" instruction is encounter during runtime
> stack-unwinding, we use effective vsp as modifier in pointer authentication.
> On completion of stack unwinding if "0xb5" instruction is not encountered
> then CFA will be used as modifier in pointer authentication.
> 
> [1] https://github.com/ARM-software/abi-aa/releases/download/2022Q3/ehabi32.pdf
> 
> Regression tested on arm-none-eabi target and found no regressions.
> 
> Ok for master?
> 
> Regards,
> Srinath.
> 
> gcc/ChangeLog:
> 
> 2022-11-09  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
> 
>          * libgcc/config/arm/pr-support.c (__gnu_unwind_execute): Decode opcode "0xb5".
> 
> 
> ###############     Attachment also inlined for ease of reply    ###############
> 
> 
> diff --git a/libgcc/config/arm/pr-support.c b/libgcc/config/arm/pr-support.c
> index e48854587c667a959aa66ccc4982231f63333ecc..1fbc41e17c227c21af1937344ded2a7fd80e61df 100644
> --- a/libgcc/config/arm/pr-support.c
> +++ b/libgcc/config/arm/pr-support.c
> @@ -107,7 +107,9 @@ __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
>     _uw op;
>     int set_pc;
>     int set_pac = 0;
> +  int set_pac_sp = 0;
>     _uw reg;
> +  _uw sp;
>   
>     set_pc = 0;
>     for (;;)
> @@ -124,10 +126,11 @@ __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
>   #if defined(TARGET_HAVE_PACBTI)
>   	  if (set_pac)
>   	    {
> -	      _uw sp;
>   	      _uw lr;
>   	      _uw pac;
> -	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &sp);
> +	      if (!set_pac_sp)
> +		_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,
> +				 &sp);
>   	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_LR, _UVRSD_UINT32, &lr);
>   	      _Unwind_VRS_Get (context, _UVRSC_PAC, R_IP,
>   			       _UVRSD_UINT32, &pac);
> @@ -259,6 +262,14 @@ __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
>   	      continue;
>   	    }
>   
> +	  /* Use current VSP as modifier in PAC validation.  */
> +	  if (op == 0xb5)
> +	    {
> +	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &sp);
> +	      set_pac_sp = 1;
> +	      continue;
> +	    }
> +
>   	  if ((op & 0xfc) == 0xb4)  /* Obsolete FPA.  */
>   	    return _URC_FAILURE;
>   
> 
> 
> 

OK.

R.
diff mbox series

Patch

diff --git a/libgcc/config/arm/pr-support.c b/libgcc/config/arm/pr-support.c
index e48854587c667a959aa66ccc4982231f63333ecc..1fbc41e17c227c21af1937344ded2a7fd80e61df 100644
--- a/libgcc/config/arm/pr-support.c
+++ b/libgcc/config/arm/pr-support.c
@@ -107,7 +107,9 @@  __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
   _uw op;
   int set_pc;
   int set_pac = 0;
+  int set_pac_sp = 0;
   _uw reg;
+  _uw sp;
 
   set_pc = 0;
   for (;;)
@@ -124,10 +126,11 @@  __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
 #if defined(TARGET_HAVE_PACBTI)
 	  if (set_pac)
 	    {
-	      _uw sp;
 	      _uw lr;
 	      _uw pac;
-	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &sp);
+	      if (!set_pac_sp)
+		_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,
+				 &sp);
 	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_LR, _UVRSD_UINT32, &lr);
 	      _Unwind_VRS_Get (context, _UVRSC_PAC, R_IP,
 			       _UVRSD_UINT32, &pac);
@@ -259,6 +262,14 @@  __gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
 	      continue;
 	    }
 
+	  /* Use current VSP as modifier in PAC validation.  */
+	  if (op == 0xb5)
+	    {
+	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &sp);
+	      set_pac_sp = 1;
+	      continue;
+	    }
+
 	  if ((op & 0xfc) == 0xb4)  /* Obsolete FPA.  */
 	    return _URC_FAILURE;