Re: [PATCH 2/6] powerpc sstep: Add darn instruction emulation

[Sandipan Das]

Hi Michael,

On 20/02/19 6:20 AM, Michael Ellerman wrote:
> Sandipan Das  writes:
> 
>> This adds emulation support for the following integer instructions:
>>   * Deliver A Random Number (darn)
> 
> This doesn't build with old binutils. We need to support old binutils.
> 
> {standard input}:4343: Error: Unrecognized opcode: `darn'
> 
> 
> You need to use PPC_DARN().
> 
> cheers
> 
> [...]

Thanks for pointing these out. Will post v2 with the required changes.

- Sandipan

Re: [PATCH 2/6] powerpc sstep: Add darn instruction emulation

[Michael Ellerman]

Sandipan Das  writes:

> This adds emulation support for the following integer instructions:
>   * Deliver A Random Number (darn)

This doesn't build with old binutils. We need to support old binutils.

{standard input}:4343: Error: Unrecognized opcode: `darn'


You need to use PPC_DARN().

cheers

> diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> index b40ec18515bd..18ac0a26c4fc 100644
> --- a/arch/powerpc/lib/sstep.c
> +++ b/arch/powerpc/lib/sstep.c
> @@ -1728,6 +1728,25 @@ int analyse_instr(struct instruction_op *op, const 
> struct pt_regs *regs,
>   (int) regs->gpr[rb];
>   goto arith_done;
>  
> + case 755:   /* darn */
> + if (!cpu_has_feature(CPU_FTR_ARCH_300))
> + return -1;
> + switch (ra & 0x3) {
> + case 0:
> + asm("darn %0,0" : "=r" (op->val));
> + goto compute_done;
> +
> + case 1:
> + asm("darn %0,1" : "=r" (op->val));
> + goto compute_done;
> +
> + case 2:
> + asm("darn %0,2" : "=r" (op->val));
> + goto compute_done;
> + }
> +
> + return -1;
> +
>  
>  /*
>   * Logical instructions
> -- 
> 2.14.4

[PATCH 2/6] powerpc sstep: Add darn instruction emulation

[Sandipan Das]

This adds emulation support for the following integer instructions:
  * Deliver A Random Number (darn)

Signed-off-by: Sandipan Das 
---
 arch/powerpc/lib/sstep.c | 19 +++
 1 file changed, 19 insertions(+)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index b40ec18515bd..18ac0a26c4fc 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1728,6 +1728,25 @@ int analyse_instr(struct instruction_op *op, const 
struct pt_regs *regs,
(int) regs->gpr[rb];
goto arith_done;
 
+   case 755:   /* darn */
+   if (!cpu_has_feature(CPU_FTR_ARCH_300))
+   return -1;
+   switch (ra & 0x3) {
+   case 0:
+   asm("darn %0,0" : "=r" (op->val));
+   goto compute_done;
+
+   case 1:
+   asm("darn %0,1" : "=r" (op->val));
+   goto compute_done;
+
+   case 2:
+   asm("darn %0,2" : "=r" (op->val));
+   goto compute_done;
+   }
+
+   return -1;
+
 
 /*
  * Logical instructions
-- 
2.14.4