From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Poirier To: op-tee@lists.trustedfirmware.org Subject: Re: [PATCH v2 4/4] remoteproc: stm32: Add support of an OP-TEE TA to load the firmware Date: Wed, 31 Jan 2024 11:52:21 -0700 Message-ID: In-Reply-To: <7ec6c9e8-9267-4e7c-81a4-abcdb2ab4239@foss.st.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1468760235201102718==" List-Id: --===============1468760235201102718== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Tue, Jan 30, 2024 at 10:13:48AM +0100, Arnaud POULIQUEN wrote: >=20 >=20 > On 1/26/24 18:11, Mathieu Poirier wrote: > > On Thu, Jan 18, 2024 at 11:04:33AM +0100, Arnaud Pouliquen wrote: > >> The new TEE remoteproc device is used to manage remote firmware in a > >> secure, trusted context. The 'st,stm32mp1-m4-tee' compatibility is > >> introduced to delegate the loading of the firmware to the trusted > >> execution context. In such cases, the firmware should be signed and > >> adhere to the image format defined by the TEE. > >> > >> Signed-off-by: Arnaud Pouliquen > >> --- > >> V1 to V2 update: > >> - remove the select "TEE_REMOTEPROC" in STM32_RPROC config as detected by > >> the kernel test robot: > >> WARNING: unmet direct dependencies detected for TEE_REMOTEPROC > >> Depends on [n]: REMOTEPROC [=3Dy] && OPTEE [=3Dn] > >> Selected by [y]: > >> - STM32_RPROC [=3Dy] && (ARCH_STM32 || COMPILE_TEST [=3Dy]) && REMO= TEPROC [=3Dy] > >> - Fix initialized trproc variable in stm32_rproc_probe > >> --- > >> drivers/remoteproc/stm32_rproc.c | 149 +++++++++++++++++++++++++++++-- > >> 1 file changed, 144 insertions(+), 5 deletions(-) > >> > >> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32= _rproc.c > >> index fcc0001e2657..cf6a21bac945 100644 > >> --- a/drivers/remoteproc/stm32_rproc.c > >> +++ b/drivers/remoteproc/stm32_rproc.c > >> @@ -20,6 +20,7 @@ > >> #include > >> #include > >> #include > >> +#include > >> #include > >> =20 > >> #include "remoteproc_internal.h" > >> @@ -49,6 +50,9 @@ > >> #define M4_STATE_STANDBY 4 > >> #define M4_STATE_CRASH 5 > >> =20 > >> +/* Remote processor unique identifier aligned with the Trusted Executio= n Environment definitions */ > >> +#define STM32_MP1_M4_PROC_ID 0 > >> + > >> struct stm32_syscon { > >> struct regmap *map; > >> u32 reg; > >> @@ -90,6 +94,8 @@ struct stm32_rproc { > >> struct stm32_mbox mb[MBOX_NB_MBX]; > >> struct workqueue_struct *workqueue; > >> bool hold_boot_smc; > >> + bool fw_loaded; > >> + struct tee_rproc *trproc; > >> void __iomem *rsc_va; > >> }; > >> =20 > >> @@ -257,6 +263,91 @@ static int stm32_rproc_release(struct rproc *rproc) > >> return err; > >> } > >> =20 > >> +static int stm32_rproc_tee_elf_sanity_check(struct rproc *rproc, > >> + const struct firmware *fw) > >> +{ > >> + struct stm32_rproc *ddata =3D rproc->priv; > >> + unsigned int ret =3D 0; > >> + > >> + if (rproc->state =3D=3D RPROC_DETACHED) > >> + return 0; > >> + > >> + ret =3D tee_rproc_load_fw(ddata->trproc, fw); > >> + if (!ret) > >> + ddata->fw_loaded =3D true; > >> + > >> + return ret; > >> +} > >> + > >> +static int stm32_rproc_tee_elf_load(struct rproc *rproc, > >> + const struct firmware *fw) > >> +{ > >> + struct stm32_rproc *ddata =3D rproc->priv; > >> + unsigned int ret; > >> + > >> + /* > >> + * This function can be called by remote proc for recovery > >> + * without the sanity check. In this case we need to load the firmware > >> + * else nothing done here as the firmware has been preloaded for the > >> + * sanity check to be able to parse it for the resource table. > >> + */ > >=20 > > This comment is very confusing - please consider refactoring. =20 > >=20 > >> + if (ddata->fw_loaded) > >> + return 0; > >> + > >=20 > > I'm not sure about keeping a flag to indicate the status of the loaded fi= rmware. > > It is not done for the non-secure method, I don't see why it would be nee= ded for > > the secure one. > >=20 >=20 > The difference is on the sanity check. > - in rproc_elf_sanity_check we parse the elf file to verify that it is > valid. > - in stm32_rproc_tee_elf_sanity_check we have to do the same, that means to > authenticate it. the authentication is done during the load. >=20 > So this flag is used to avoid to reload it twice time. > refactoring the comment should help to understand this flag >=20 >=20 > An alternative would be to bypass the sanity check. But this lead to same > limitation. > Before loading the firmware in remoteproc_core, we call rproc_parse_fw() th= at is > used to get the resource table address. To get it from tee we need to > authenticate the firmware so load it... > I spent a long time thinking about this patchset. Looking at the code as it is now, request_firmware() in rproc_boot() is called even when the TEE is responsible for loading the firmware. There should be some conditional code that calls either request_firmware() or tee_rproc_load_fw(). The latter shou= ld also be renamed to tee_rproc_request_firmware() to avoid confusion. I touched on that before but please rename rproc_tee_get_rsc_table() to rproc_tee_elf_load_rsc_table(). I also suggest to introduce a new function, rproc_tee_get_loaded_rsc_table() that would be called from rproc_tee_elf_load_rsc_table(). That way we don't need trproc->rsc_va. =20 I also think tee_rproc should be renamed to "rproc_tee_interface" and folded under struct rproc. =20 With the above most of the problems with the current implementation should naturally go away. Thanks, Mathieu >=20 > >> + ret =3D tee_rproc_load_fw(ddata->trproc, fw); > >> + if (ret) > >> + return ret; > >> + ddata->fw_loaded =3D true; > >> + > >> + /* Update the resource table parameters. */ > >> + if (rproc_tee_get_rsc_table(ddata->trproc)) { > >> + /* No resource table: reset the related fields. */ > >> + rproc->cached_table =3D NULL; > >> + rproc->table_ptr =3D NULL; > >> + rproc->table_sz =3D 0; > >> + } > >> + > >> + return 0; > >> +} > >> + > >> +static struct resource_table * > >> +stm32_rproc_tee_elf_find_loaded_rsc_table(struct rproc *rproc, > >> + const struct firmware *fw) > >> +{ > >> + struct stm32_rproc *ddata =3D rproc->priv; > >> + > >> + return tee_rproc_get_loaded_rsc_table(ddata->trproc); > >> +} > >> + > >> +static int stm32_rproc_tee_start(struct rproc *rproc) > >> +{ > >> + struct stm32_rproc *ddata =3D rproc->priv; > >> + > >> + return tee_rproc_start(ddata->trproc); > >> +} > >> + > >> +static int stm32_rproc_tee_attach(struct rproc *rproc) > >> +{ > >> + /* Nothing to do, remote proc already started by the secured context. = */ > >> + return 0; > >> +} > >> + > >> +static int stm32_rproc_tee_stop(struct rproc *rproc) > >> +{ > >> + struct stm32_rproc *ddata =3D rproc->priv; > >> + int err; > >> + > >> + stm32_rproc_request_shutdown(rproc); > >> + > >> + err =3D tee_rproc_stop(ddata->trproc); > >> + if (err) > >> + return err; > >> + > >> + ddata->fw_loaded =3D false; > >> + > >> + return stm32_rproc_release(rproc); > >> +} > >> + > >> static int stm32_rproc_prepare(struct rproc *rproc) > >> { > >> struct device *dev =3D rproc->dev.parent; > >> @@ -319,7 +410,14 @@ static int stm32_rproc_prepare(struct rproc *rproc) > >> =20 > >> static int stm32_rproc_parse_fw(struct rproc *rproc, const struct firmw= are *fw) > >> { > >> - if (rproc_elf_load_rsc_table(rproc, fw)) > >> + struct stm32_rproc *ddata =3D rproc->priv; > >> + int ret; > >> + > >> + if (ddata->trproc) > >> + ret =3D rproc_tee_get_rsc_table(ddata->trproc); > >> + else > >> + ret =3D rproc_elf_load_rsc_table(rproc, fw); > >> + if (ret) > >> dev_warn(&rproc->dev, "no resource table found for this firmware\n"); > >> =20 > >> return 0; > >> @@ -693,8 +791,22 @@ static const struct rproc_ops st_rproc_ops =3D { > >> .get_boot_addr =3D rproc_elf_get_boot_addr, > >> }; > >> =20 > >> +static const struct rproc_ops st_rproc_tee_ops =3D { > >> + .prepare =3D stm32_rproc_prepare, > >> + .start =3D stm32_rproc_tee_start, > >> + .stop =3D stm32_rproc_tee_stop, > >> + .attach =3D stm32_rproc_tee_attach, > >> + .kick =3D stm32_rproc_kick, > >> + .parse_fw =3D stm32_rproc_parse_fw, > >> + .find_loaded_rsc_table =3D stm32_rproc_tee_elf_find_loaded_rsc_table, > >> + .get_loaded_rsc_table =3D stm32_rproc_get_loaded_rsc_table, > >> + .sanity_check =3D stm32_rproc_tee_elf_sanity_check, > >> + .load =3D stm32_rproc_tee_elf_load, > >> +}; > >> + > >> static const struct of_device_id stm32_rproc_match[] =3D { > >> - { .compatible =3D "st,stm32mp1-m4" }, > >> + {.compatible =3D "st,stm32mp1-m4",}, > >> + {.compatible =3D "st,stm32mp1-m4-tee",}, > >> {}, > >> }; > >> MODULE_DEVICE_TABLE(of, stm32_rproc_match); > >> @@ -853,6 +965,7 @@ static int stm32_rproc_probe(struct platform_device = *pdev) > >> struct device *dev =3D &pdev->dev; > >> struct stm32_rproc *ddata; > >> struct device_node *np =3D dev->of_node; > >> + struct tee_rproc *trproc =3D NULL; > >> struct rproc *rproc; > >> unsigned int state; > >> int ret; > >> @@ -861,11 +974,31 @@ static int stm32_rproc_probe(struct platform_devic= e *pdev) > >> if (ret) > >> return ret; > >> =20 > >> - rproc =3D rproc_alloc(dev, np->name, &st_rproc_ops, NULL, sizeof(*ddat= a)); > >> - if (!rproc) > >> - return -ENOMEM; > >> + if (of_device_is_compatible(np, "st,stm32mp1-m4-tee")) { > >> + trproc =3D tee_rproc_register(dev, STM32_MP1_M4_PROC_ID); > >> + if (IS_ERR(trproc)) { > >> + dev_err_probe(dev, PTR_ERR(trproc), > >> + "signed firmware not supported by TEE\n"); > >> + return PTR_ERR(trproc); > >> + } > >> + /* > >> + * Delegate the firmware management to the secure context. > >> + * The firmware loaded has to be signed. > >> + */ > >> + dev_info(dev, "Support of signed firmware only\n"); > >=20 > > Not sure what this adds. Please remove. >=20 > This is used to inform the user that only a signed firmware can be loaded, = not > an ELF file. > I have a patch in my pipe to provide the supported format in the debugfs. I= n a > first step, I can suppress this message and we can revisit the issue when I= push > the debugfs proposal. >=20 > Thanks, > Arnaud >=20 > >=20 > >> + } > >> + rproc =3D rproc_alloc(dev, np->name, > >> + trproc ? &st_rproc_tee_ops : &st_rproc_ops, > >> + NULL, sizeof(*ddata)); > >> + if (!rproc) { > >> + ret =3D -ENOMEM; > >> + goto free_tee; > >> + } > >> =20 > >> ddata =3D rproc->priv; > >> + ddata->trproc =3D trproc; > >> + if (trproc) > >> + trproc->rproc =3D rproc; > >> =20 > >> rproc_coredump_set_elf_info(rproc, ELFCLASS32, EM_NONE); > >> =20 > >> @@ -916,6 +1049,10 @@ static int stm32_rproc_probe(struct platform_devic= e *pdev) > >> device_init_wakeup(dev, false); > >> } > >> rproc_free(rproc); > >> +free_tee: > >> + if (trproc) > >> + tee_rproc_unregister(trproc); > >> + > >> return ret; > >> } > >> =20 > >> @@ -937,6 +1074,8 @@ static void stm32_rproc_remove(struct platform_devi= ce *pdev) > >> device_init_wakeup(dev, false); > >> } > >> rproc_free(rproc); > >> + if (ddata->trproc) > >> + tee_rproc_unregister(ddata->trproc); > >> } > >> =20 > >> static int stm32_rproc_suspend(struct device *dev) > >> --=20 > >> 2.25.1 > >> --===============1468760235201102718==--