2024-05-28 11:32:11

by Ekansh Gupta

Subject: [PATCH v2 8/8] misc: fastrpc: Add system unsigned PD support

Trusted CPU applications currently offload to signed PDs on CDSP to
gain some additional services provided by root PD. Unsigned PDs have
access to limited root PD services that may not be sufficient for
all use-cases. Signed PDs have a higher dynamic loading latency
which impacts the performance of applications. Limited root PD
services could be opened up for unsigned PDs but that should be
restricted for untrusted processes. For this requirement, System
unsigned PD is introduced which will be same as Unsigned PD for
most part but will have access to more root PD services. Add
changes to offload trusted applications to System unsigned PD
when unsigned offload is requested.

Signed-off-by: Ekansh Gupta <[email protected]>
---
drivers/misc/fastrpc.c | 9 +++++++++
include/uapi/misc/fastrpc.h | 2 ++
2 files changed, 11 insertions(+)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 7f81a18b8aea..ebe20915392f 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -122,6 +122,7 @@
enum fastrpc_userpd_type {
SIGNED_PD = 1,
UNSIGNED_PD = 2,
+ SYSTEM_UNSIGNED_PD = 3,
};

static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
@@ -1552,12 +1553,20 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
if (init.attrs & FASTRPC_MODE_UNSIGNED_MODULE)
fl->userpd_type = UNSIGNED_PD;

+ /* Disregard any system unsigned PD attribute from userspace */
+ init.attrs &= (~FASTRPC_MODE_SYSTEM_UNSIGNED_PD);

if (is_session_rejected(fl, !(fl->userpd_type == SIGNED_PD))) {
err = -EACCES;
goto err;
}

+ /* Trusted apps will be launched as system unsigned PDs */
+ if (!fl->untrusted_process && (fl->userpd_type != SIGNED_PD)) {
+ fl->userpd_type = SYSTEM_UNSIGNED_PD;
+ init.attrs |= FASTRPC_MODE_SYSTEM_UNSIGNED_PD;
+ }
+
if (init.filelen > INIT_FILELEN_MAX) {
err = -EINVAL;
goto err;
diff --git a/include/uapi/misc/fastrpc.h b/include/uapi/misc/fastrpc.h
index f33d914d8f46..3b3279bb2cf9 100644
--- a/include/uapi/misc/fastrpc.h
+++ b/include/uapi/misc/fastrpc.h
@@ -62,6 +62,8 @@ enum fastrpc_proc_attr {
FASTRPC_MODE_SYSTEM_PROCESS = (1 << 5),
/* Macro for Prvileged Process */
FASTRPC_MODE_PRIVILEGED = (1 << 6),
+ /* Macro for system unsigned PD */
+ FASTRPC_MODE_SYSTEM_UNSIGNED_PD = (1 << 17),
};

/* Fastrpc attribute for memory protection of buffers */
--
2.43.0

2024-05-28 13:25:01

by Dmitry Baryshkov

Subject: Re: [PATCH v2 8/8] misc: fastrpc: Add system unsigned PD support

On Tue, May 28, 2024 at 04:59:54PM +0530, Ekansh Gupta wrote:
> Trusted CPU applications currently offload to signed PDs on CDSP to
> gain some additional services provided by root PD. Unsigned PDs have
> access to limited root PD services that may not be sufficient for
> all use-cases. Signed PDs have a higher dynamic loading latency
> which impacts the performance of applications. Limited root PD
> services could be opened up for unsigned PDs but that should be
> restricted for untrusted processes. For this requirement, System
> unsigned PD is introduced which will be same as Unsigned PD for
> most part but will have access to more root PD services. Add
> changes to offload trusted applications to System unsigned PD
> when unsigned offload is requested.
>
> Signed-off-by: Ekansh Gupta <[email protected]>
> ---
> drivers/misc/fastrpc.c | 9 +++++++++
> include/uapi/misc/fastrpc.h | 2 ++
> 2 files changed, 11 insertions(+)
>
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 7f81a18b8aea..ebe20915392f 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -122,6 +122,7 @@
> enum fastrpc_userpd_type {
> SIGNED_PD = 1,
> UNSIGNED_PD = 2,
> + SYSTEM_UNSIGNED_PD = 3,

Any reason why this is not indented properly? Maybe you have
non-standard tab width?

Also the usage of non-bool type makes sense here, not in the 'unisgned
PD' patch. Please use bool beforehand and switch to an enum here.

> };
>
> static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
> @@ -1552,12 +1553,20 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
> if (init.attrs & FASTRPC_MODE_UNSIGNED_MODULE)
> fl->userpd_type = UNSIGNED_PD;
>
> + /* Disregard any system unsigned PD attribute from userspace */
> + init.attrs &= (~FASTRPC_MODE_SYSTEM_UNSIGNED_PD);
>
> if (is_session_rejected(fl, !(fl->userpd_type == SIGNED_PD))) {
> err = -EACCES;
> goto err;
> }
>
> + /* Trusted apps will be launched as system unsigned PDs */
> + if (!fl->untrusted_process && (fl->userpd_type != SIGNED_PD)) {
> + fl->userpd_type = SYSTEM_UNSIGNED_PD;
> + init.attrs |= FASTRPC_MODE_SYSTEM_UNSIGNED_PD;
> + }
> +
> if (init.filelen > INIT_FILELEN_MAX) {
> err = -EINVAL;
> goto err;
> diff --git a/include/uapi/misc/fastrpc.h b/include/uapi/misc/fastrpc.h
> index f33d914d8f46..3b3279bb2cf9 100644
> --- a/include/uapi/misc/fastrpc.h
> +++ b/include/uapi/misc/fastrpc.h
> @@ -62,6 +62,8 @@ enum fastrpc_proc_attr {
> FASTRPC_MODE_SYSTEM_PROCESS = (1 << 5),
> /* Macro for Prvileged Process */
> FASTRPC_MODE_PRIVILEGED = (1 << 6),
> + /* Macro for system unsigned PD */
> + FASTRPC_MODE_SYSTEM_UNSIGNED_PD = (1 << 17),
> };
>
> /* Fastrpc attribute for memory protection of buffers */
> --
> 2.43.0
>

--
With best wishes
Dmitry