diff mbox series

[v3] target/riscv: Fix shift count overflow

Message ID 20240225174114.5298-1-demin.han@starfivetech.com (mailing list archive)
State New, archived
Headers show
Series [v3] target/riscv: Fix shift count overflow | expand

Commit Message

demin.han Feb. 25, 2024, 5:41 p.m. UTC
The result of (8 - 3 - vlmul) is negative when vlmul >= 6,
and results in wrong vill.

Signed-off-by: demin.han <demin.han@starfivetech.com>
---
Changes in v2:
- Add vlen var

Changes in v3:
- Fix commit msg typo

 target/riscv/vector_helper.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Daniel Henrique Barboza Feb. 26, 2024, 9:31 a.m. UTC | #1
On 2/25/24 14:41, demin.han wrote:
> The result of (8 - 3 - vlmul) is negative when vlmul >= 6,
> and results in wrong vill.
> 
> Signed-off-by: demin.han <demin.han@starfivetech.com>
> ---

Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

> Changes in v2:
> - Add vlen var
> 
> Changes in v3:
> - Fix commit msg typo
> 
>   target/riscv/vector_helper.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
> index 84cec73eb2..fe56c007d5 100644
> --- a/target/riscv/vector_helper.c
> +++ b/target/riscv/vector_helper.c
> @@ -44,6 +44,7 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
>       target_ulong reserved = s2 &
>                               MAKE_64BIT_MASK(R_VTYPE_RESERVED_SHIFT,
>                                               xlen - 1 - R_VTYPE_RESERVED_SHIFT);
> +    uint16_t vlen = cpu->cfg.vlenb << 3;
>       int8_t lmul;
>   
>       if (vlmul & 4) {
> @@ -53,10 +54,8 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
>            * VLEN * LMUL >= SEW
>            * VLEN >> (8 - lmul) >= sew
>            * (vlenb << 3) >> (8 - lmul) >= sew
> -         * vlenb >> (8 - 3 - lmul) >= sew
>            */
> -        if (vlmul == 4 ||
> -            cpu->cfg.vlenb >> (8 - 3 - vlmul) < sew) {
> +        if (vlmul == 4 || (vlen >> (8 - vlmul)) < sew) {
>               vill = true;
>           }
>       }
Daniel Henrique Barboza March 6, 2024, 9:37 a.m. UTC | #2
Hi Alistair,


Please don't forget to queue this up. Thanks,


Daniel

On 2/26/24 06:31, Daniel Henrique Barboza wrote:
> 
> 
> On 2/25/24 14:41, demin.han wrote:
>> The result of (8 - 3 - vlmul) is negative when vlmul >= 6,
>> and results in wrong vill.
>>
>> Signed-off-by: demin.han <demin.han@starfivetech.com>
>> ---
> 
> Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> 
>> Changes in v2:
>> - Add vlen var
>>
>> Changes in v3:
>> - Fix commit msg typo
>>
>>   target/riscv/vector_helper.c | 5 ++---
>>   1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
>> index 84cec73eb2..fe56c007d5 100644
>> --- a/target/riscv/vector_helper.c
>> +++ b/target/riscv/vector_helper.c
>> @@ -44,6 +44,7 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
>>       target_ulong reserved = s2 &
>>                               MAKE_64BIT_MASK(R_VTYPE_RESERVED_SHIFT,
>>                                               xlen - 1 - R_VTYPE_RESERVED_SHIFT);
>> +    uint16_t vlen = cpu->cfg.vlenb << 3;
>>       int8_t lmul;
>>       if (vlmul & 4) {
>> @@ -53,10 +54,8 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
>>            * VLEN * LMUL >= SEW
>>            * VLEN >> (8 - lmul) >= sew
>>            * (vlenb << 3) >> (8 - lmul) >= sew
>> -         * vlenb >> (8 - 3 - lmul) >= sew
>>            */
>> -        if (vlmul == 4 ||
>> -            cpu->cfg.vlenb >> (8 - 3 - vlmul) < sew) {
>> +        if (vlmul == 4 || (vlen >> (8 - vlmul)) < sew) {
>>               vill = true;
>>           }
>>       }
Alistair Francis March 7, 2024, 1:09 a.m. UTC | #3
On Mon, Feb 26, 2024 at 3:42 AM demin.han <demin.han@starfivetech.com> wrote:
>
> The result of (8 - 3 - vlmul) is negative when vlmul >= 6,
> and results in wrong vill.
>
> Signed-off-by: demin.han <demin.han@starfivetech.com>

Thanks!

Applied to riscv-to-apply.next

Alistair

> ---
> Changes in v2:
> - Add vlen var
>
> Changes in v3:
> - Fix commit msg typo
>
>  target/riscv/vector_helper.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
> index 84cec73eb2..fe56c007d5 100644
> --- a/target/riscv/vector_helper.c
> +++ b/target/riscv/vector_helper.c
> @@ -44,6 +44,7 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
>      target_ulong reserved = s2 &
>                              MAKE_64BIT_MASK(R_VTYPE_RESERVED_SHIFT,
>                                              xlen - 1 - R_VTYPE_RESERVED_SHIFT);
> +    uint16_t vlen = cpu->cfg.vlenb << 3;
>      int8_t lmul;
>
>      if (vlmul & 4) {
> @@ -53,10 +54,8 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
>           * VLEN * LMUL >= SEW
>           * VLEN >> (8 - lmul) >= sew
>           * (vlenb << 3) >> (8 - lmul) >= sew
> -         * vlenb >> (8 - 3 - lmul) >= sew
>           */
> -        if (vlmul == 4 ||
> -            cpu->cfg.vlenb >> (8 - 3 - vlmul) < sew) {
> +        if (vlmul == 4 || (vlen >> (8 - vlmul)) < sew) {
>              vill = true;
>          }
>      }
> --
> 2.43.2
>
>
diff mbox series

Patch

diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index 84cec73eb2..fe56c007d5 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -44,6 +44,7 @@  target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
     target_ulong reserved = s2 &
                             MAKE_64BIT_MASK(R_VTYPE_RESERVED_SHIFT,
                                             xlen - 1 - R_VTYPE_RESERVED_SHIFT);
+    uint16_t vlen = cpu->cfg.vlenb << 3;
     int8_t lmul;
 
     if (vlmul & 4) {
@@ -53,10 +54,8 @@  target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
          * VLEN * LMUL >= SEW
          * VLEN >> (8 - lmul) >= sew
          * (vlenb << 3) >> (8 - lmul) >= sew
-         * vlenb >> (8 - 3 - lmul) >= sew
          */
-        if (vlmul == 4 ||
-            cpu->cfg.vlenb >> (8 - 3 - vlmul) < sew) {
+        if (vlmul == 4 || (vlen >> (8 - vlmul)) < sew) {
             vill = true;
         }
     }