diff mbox series

[v6,1/2] misc: fastrpc: Define a new initmem size for user PD

Message ID 20240722080200.3530850-2-quic_ekangupt@quicinc.com
State Superseded
Headers show
Series Fix user PD inimem requirements | expand

Commit Message

Ekansh Gupta July 22, 2024, 8:01 a.m. UTC
For user PD initialization, initmem is allocated and sent to DSP for
initial memory requirements like shell loading. The size of this memory
is decided based on the shell size that is passed by the user space.
With the current implementation, a minimum of 2MB is always allocated
for initmem even if the size passed by user is less than that. For this
a MACRO is being used which is intended for shell size bound check.
This minimum size of 2MB is not recommended as the PD will have very
less memory for heap and will have to request HLOS again for memory.
Define a new macro for initmem minimum length of 3MB.

Fixes: d73f71c7c6ee ("misc: fastrpc: Add support for create remote init process")
Cc: stable <stable@kernel.org>
Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
---
 drivers/misc/fastrpc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Dmitry Baryshkov July 22, 2024, 8:32 a.m. UTC | #1
On Mon, Jul 22, 2024 at 01:31:59PM GMT, Ekansh Gupta wrote:
> For user PD initialization, initmem is allocated and sent to DSP for
> initial memory requirements like shell loading. The size of this memory
> is decided based on the shell size that is passed by the user space.
> With the current implementation, a minimum of 2MB is always allocated
> for initmem even if the size passed by user is less than that. For this
> a MACRO is being used which is intended for shell size bound check.
> This minimum size of 2MB is not recommended as the PD will have very
> less memory for heap and will have to request HLOS again for memory.
> Define a new macro for initmem minimum length of 3MB.
> 
> Fixes: d73f71c7c6ee ("misc: fastrpc: Add support for create remote init process")
> Cc: stable <stable@kernel.org>
> Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
> ---
>  drivers/misc/fastrpc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index a7a2bcedb37e..a3a5b745936e 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -39,6 +39,7 @@
>  #define FASTRPC_DSP_UTILITIES_HANDLE	2
>  #define FASTRPC_CTXID_MASK (0xFF0)
>  #define INIT_FILELEN_MAX (2 * 1024 * 1024)
> +#define FASTRPC_INITLEN_MIN (3 * 1024 * 1024)

So, what is the difference between INIT_FILELEN_MAX and
FASTRPC_INITLEN_MIN?

>  #define INIT_FILE_NAMELEN_MAX (128)
>  #define FASTRPC_DEVICE_NAME	"fastrpc"
>  
> @@ -1410,7 +1411,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
>  			goto err;
>  	}
>  
> -	memlen = ALIGN(max(INIT_FILELEN_MAX, (int)init.filelen * 4),
> +	memlen = ALIGN(max(FASTRPC_INITLEN_MIN, (int)init.filelen * 4),

BTW: why is the code multiplying filelen by 4? Nothing in the source
code suggests that filelen is in u32 words, so I'd assume it's measured
in bytes.

>  		       1024 * 1024);
>  	err = fastrpc_buf_alloc(fl, fl->sctx->dev, memlen,
>  				&imem);
> -- 
> 2.34.1
>
Ekansh Gupta July 23, 2024, 4:34 a.m. UTC | #2
On 7/22/2024 2:02 PM, Dmitry Baryshkov wrote:
> On Mon, Jul 22, 2024 at 01:31:59PM GMT, Ekansh Gupta wrote:
>> For user PD initialization, initmem is allocated and sent to DSP for
>> initial memory requirements like shell loading. The size of this memory
>> is decided based on the shell size that is passed by the user space.
>> With the current implementation, a minimum of 2MB is always allocated
>> for initmem even if the size passed by user is less than that. For this
>> a MACRO is being used which is intended for shell size bound check.
>> This minimum size of 2MB is not recommended as the PD will have very
>> less memory for heap and will have to request HLOS again for memory.
>> Define a new macro for initmem minimum length of 3MB.
>>
>> Fixes: d73f71c7c6ee ("misc: fastrpc: Add support for create remote init process")
>> Cc: stable <stable@kernel.org>
>> Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
>> ---
>>  drivers/misc/fastrpc.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
>> index a7a2bcedb37e..a3a5b745936e 100644
>> --- a/drivers/misc/fastrpc.c
>> +++ b/drivers/misc/fastrpc.c
>> @@ -39,6 +39,7 @@
>>  #define FASTRPC_DSP_UTILITIES_HANDLE	2
>>  #define FASTRPC_CTXID_MASK (0xFF0)
>>  #define INIT_FILELEN_MAX (2 * 1024 * 1024)
>> +#define FASTRPC_INITLEN_MIN (3 * 1024 * 1024)
> So, what is the difference between INIT_FILELEN_MAX and
> FASTRPC_INITLEN_MIN?

INIT_FILELEN_MAX is the maximum shell size that can be passed by user.
FASTRPC_INITLEN_MIN is the minimum initmem length for PD.

>
>>  #define INIT_FILE_NAMELEN_MAX (128)
>>  #define FASTRPC_DEVICE_NAME	"fastrpc"
>>  
>> @@ -1410,7 +1411,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
>>  			goto err;
>>  	}
>>  
>> -	memlen = ALIGN(max(INIT_FILELEN_MAX, (int)init.filelen * 4),
>> +	memlen = ALIGN(max(FASTRPC_INITLEN_MIN, (int)init.filelen * 4),
> BTW: why is the code multiplying filelen by 4? Nothing in the source
> code suggests that filelen is in u32 words, so I'd assume it's measured
> in bytes.

The passed filelen is actually the size of fastrpc shell. This size is not sufficient for the user
PD initialization. The 4x of filelen gives the approx. needed memory for signed PD initialization.
Yes, filelen is measured in bytes.

>
>>  		       1024 * 1024);
>>  	err = fastrpc_buf_alloc(fl, fl->sctx->dev, memlen,
>>  				&imem);
>> -- 
>> 2.34.1
>>
Dmitry Baryshkov July 23, 2024, 9:13 a.m. UTC | #3
On Tue, 23 Jul 2024 at 07:35, Ekansh Gupta <quic_ekangupt@quicinc.com> wrote:
>
>
>
> On 7/22/2024 2:02 PM, Dmitry Baryshkov wrote:
> > On Mon, Jul 22, 2024 at 01:31:59PM GMT, Ekansh Gupta wrote:
> >> For user PD initialization, initmem is allocated and sent to DSP for
> >> initial memory requirements like shell loading. The size of this memory
> >> is decided based on the shell size that is passed by the user space.
> >> With the current implementation, a minimum of 2MB is always allocated
> >> for initmem even if the size passed by user is less than that. For this
> >> a MACRO is being used which is intended for shell size bound check.
> >> This minimum size of 2MB is not recommended as the PD will have very
> >> less memory for heap and will have to request HLOS again for memory.
> >> Define a new macro for initmem minimum length of 3MB.
> >>
> >> Fixes: d73f71c7c6ee ("misc: fastrpc: Add support for create remote init process")
> >> Cc: stable <stable@kernel.org>
> >> Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
> >> ---
> >>  drivers/misc/fastrpc.c | 3 ++-
> >>  1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> >> index a7a2bcedb37e..a3a5b745936e 100644
> >> --- a/drivers/misc/fastrpc.c
> >> +++ b/drivers/misc/fastrpc.c
> >> @@ -39,6 +39,7 @@
> >>  #define FASTRPC_DSP_UTILITIES_HANDLE        2
> >>  #define FASTRPC_CTXID_MASK (0xFF0)
> >>  #define INIT_FILELEN_MAX (2 * 1024 * 1024)
> >> +#define FASTRPC_INITLEN_MIN (3 * 1024 * 1024)
> > So, what is the difference between INIT_FILELEN_MAX and
> > FASTRPC_INITLEN_MIN?
>
> INIT_FILELEN_MAX is the maximum shell size that can be passed by user.
> FASTRPC_INITLEN_MIN is the minimum initmem length for PD.

At least this should be commented on in the source.

>
> >
> >>  #define INIT_FILE_NAMELEN_MAX (128)
> >>  #define FASTRPC_DEVICE_NAME "fastrpc"
> >>
> >> @@ -1410,7 +1411,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
> >>                      goto err;
> >>      }
> >>
> >> -    memlen = ALIGN(max(INIT_FILELEN_MAX, (int)init.filelen * 4),
> >> +    memlen = ALIGN(max(FASTRPC_INITLEN_MIN, (int)init.filelen * 4),
> > BTW: why is the code multiplying filelen by 4? Nothing in the source
> > code suggests that filelen is in u32 words, so I'd assume it's measured
> > in bytes.
>
> The passed filelen is actually the size of fastrpc shell. This size is not sufficient for the user
> PD initialization. The 4x of filelen gives the approx. needed memory for signed PD initialization.
> Yes, filelen is measured in bytes.

Ugh. Shouldn't it be sum(elf.ph[i].memsz) + some margin? I know this
is a separate topic, but since you were touching these lines it has
come to my attention.

>
> >
> >>                     1024 * 1024);
> >>      err = fastrpc_buf_alloc(fl, fl->sctx->dev, memlen,
> >>                              &imem);
> >> --
> >> 2.34.1
> >>
>
diff mbox series

Patch

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index a7a2bcedb37e..a3a5b745936e 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -39,6 +39,7 @@ 
 #define FASTRPC_DSP_UTILITIES_HANDLE	2
 #define FASTRPC_CTXID_MASK (0xFF0)
 #define INIT_FILELEN_MAX (2 * 1024 * 1024)
+#define FASTRPC_INITLEN_MIN (3 * 1024 * 1024)
 #define INIT_FILE_NAMELEN_MAX (128)
 #define FASTRPC_DEVICE_NAME	"fastrpc"
 
@@ -1410,7 +1411,7 @@  static int fastrpc_init_create_process(struct fastrpc_user *fl,
 			goto err;
 	}
 
-	memlen = ALIGN(max(INIT_FILELEN_MAX, (int)init.filelen * 4),
+	memlen = ALIGN(max(FASTRPC_INITLEN_MIN, (int)init.filelen * 4),
 		       1024 * 1024);
 	err = fastrpc_buf_alloc(fl, fl->sctx->dev, memlen,
 				&imem);