Re: [PATCH v4 1/5] remoteproc: Use u64 len for da_to_va

Clément Leger
2020-02-12T10:37:06Z

Hi Mathieu,

----- On 11 Feb, 2020, at 23:37, Mathieu Poirier mathieu.poirier@linaro.org wrote:

> On Tue, Feb 11, 2020 at 05:39:21PM +0100, Clément Leger wrote:
>> Hi Arnaud,
>>
>> ----- On 11 Feb, 2020, at 16:53, Arnaud Pouliquen arnaud.pouliquen@st.com wrote:
>>
>> > On 2/10/20 5:22 PM, Clement Leger wrote:
>> >> With upcoming changes in elf loader for elf64 support, section size will
>> >> be a u64. When used with da_to_va, this will potentially lead to
>> >> overflow if using the current "int" type for len argument. Change
>> >> da_to_va prototype to use a u64 for len and fix all users of this
>> >> function.
>> >>
>> >> Signed-off-by: Clement Leger <cleger@kalray.eu>
>> >> ---
>> >> drivers/remoteproc/imx_rproc.c | 11 ++++++-----
>> >> drivers/remoteproc/keystone_remoteproc.c | 4 ++--
>> >> drivers/remoteproc/qcom_q6v5_adsp.c | 2 +-
>> >> drivers/remoteproc/qcom_q6v5_mss.c | 2 +-
>> >> drivers/remoteproc/qcom_q6v5_pas.c | 2 +-
>> >> drivers/remoteproc/qcom_q6v5_wcss.c | 2 +-
>> >> drivers/remoteproc/qcom_wcnss.c | 2 +-
>> >> drivers/remoteproc/remoteproc_core.c | 2 +-
>> >> drivers/remoteproc/remoteproc_internal.h | 2 +-
>> >> drivers/remoteproc/st_slim_rproc.c | 4 ++--
>> >> drivers/remoteproc/wkup_m3_rproc.c | 4 ++--
>> >> include/linux/remoteproc.h | 2 +-
>> >> 12 files changed, 20 insertions(+), 19 deletions(-)
>> >>
>> >> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
>> >> index 3e72b6f38d4b..f497f5b49b18 100644
>> >> --- a/drivers/remoteproc/imx_rproc.c
>> >> +++ b/drivers/remoteproc/imx_rproc.c
>> >> @@ -186,7 +186,7 @@ static int imx_rproc_stop(struct rproc *rproc)
>> >> }
>> >>
>> >> static int imx_rproc_da_to_sys(struct imx_rproc *priv, u64 da,
>> >> - int len, u64 *sys)
>> >> + u64 len, u64 *sys)
>> >> {
>> >> const struct imx_rproc_dcfg *dcfg = priv->dcfg;
>> >> int i;
>> >> @@ -203,19 +203,19 @@ static int imx_rproc_da_to_sys(struct imx_rproc *priv, u64
>> >> da,
>> >> }
>> >> }
>> >>
>> >> - dev_warn(priv->dev, "Translation failed: da = 0x%llx len = 0x%x\n",
>> >> + dev_warn(priv->dev, "Translation failed: da = 0x%llx len = 0x%llx\n",
>> >> da, len);
>> >> return -ENOENT;
>> >> }
>> >>
>> >> -static void *imx_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *imx_rproc_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct imx_rproc *priv = rproc->priv;
>> >> void *va = NULL;
>> >> u64 sys;
>> >> int i;
>> >>
>> >> - if (len <= 0)
>> >> + if (len == 0)
>> >> return NULL;
>> >>
>> >> /*
>> >> @@ -235,7 +235,8 @@ static void *imx_rproc_da_to_va(struct rproc *rproc, u64 da,
>> >> int len)
>> >> }
>> >> }
>> >>
>> >> - dev_dbg(&rproc->dev, "da = 0x%llx len = 0x%x va = 0x%p\n", da, len, va);
>> >> + dev_dbg(&rproc->dev, "da = 0x%llx len = 0x%llx va = 0x%p\n",
>> >> + da, len, va);
>> >>
>> >> return va;
>> >> }
>> >> diff --git a/drivers/remoteproc/keystone_remoteproc.c
>> >> b/drivers/remoteproc/keystone_remoteproc.c
>> >> index 5c4658f00b3d..466093f48814 100644
>> >> --- a/drivers/remoteproc/keystone_remoteproc.c
>> >> +++ b/drivers/remoteproc/keystone_remoteproc.c
>> >> @@ -246,7 +246,7 @@ static void keystone_rproc_kick(struct rproc *rproc, int
>> >> vqid)
>> >> * can be used either by the remoteproc core for loading (when using kernel
>> >> * remoteproc loader), or by any rpmsg bus drivers.
>> >> */
>> >> -static void *keystone_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *keystone_rproc_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct keystone_rproc *ksproc = rproc->priv;
>> >> void __iomem *va = NULL;
>> >> @@ -255,7 +255,7 @@ static void *keystone_rproc_da_to_va(struct rproc *rproc,
>> >> u64 da, int len)
>> >> size_t size;
>> >> int i;
>> >>
>> >> - if (len <= 0)
>> >> + if (len == 0)
>> >> return NULL;
>> >>
>> >> for (i = 0; i < ksproc->num_mems; i++) {
>> >> diff --git a/drivers/remoteproc/qcom_q6v5_adsp.c
>> >> b/drivers/remoteproc/qcom_q6v5_adsp.c
>> >> index e953886b2eb7..7518e67a49e5 100644
>> >> --- a/drivers/remoteproc/qcom_q6v5_adsp.c
>> >> +++ b/drivers/remoteproc/qcom_q6v5_adsp.c
>> >> @@ -270,7 +270,7 @@ static int adsp_stop(struct rproc *rproc)
>> >> return ret;
>> >> }
>> >>
>> >> -static void *adsp_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *adsp_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct qcom_adsp *adsp = (struct qcom_adsp *)rproc->priv;
>> >> int offset;
>> >> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c
>> >> b/drivers/remoteproc/qcom_q6v5_mss.c
>> >> index 471128a2e723..248febde6fc1 100644
>> >> --- a/drivers/remoteproc/qcom_q6v5_mss.c
>> >> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
>> >> @@ -1148,7 +1148,7 @@ static int q6v5_stop(struct rproc *rproc)
>> >> return 0;
>> >> }
>> >>
>> >> -static void *q6v5_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *q6v5_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct q6v5 *qproc = rproc->priv;
>> >> int offset;
>> >> diff --git a/drivers/remoteproc/qcom_q6v5_pas.c
>> >> b/drivers/remoteproc/qcom_q6v5_pas.c
>> >> index db4b3c4bacd7..cf2cd609c90d 100644
>> >> --- a/drivers/remoteproc/qcom_q6v5_pas.c
>> >> +++ b/drivers/remoteproc/qcom_q6v5_pas.c
>> >> @@ -159,7 +159,7 @@ static int adsp_stop(struct rproc *rproc)
>> >> return ret;
>> >> }
>> >>
>> >> -static void *adsp_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *adsp_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct qcom_adsp *adsp = (struct qcom_adsp *)rproc->priv;
>> >> int offset;
>> >> diff --git a/drivers/remoteproc/qcom_q6v5_wcss.c
>> >> b/drivers/remoteproc/qcom_q6v5_wcss.c
>> >> index f93e1e4a1cc0..3a6b82a16961 100644
>> >> --- a/drivers/remoteproc/qcom_q6v5_wcss.c
>> >> +++ b/drivers/remoteproc/qcom_q6v5_wcss.c
>> >> @@ -406,7 +406,7 @@ static int q6v5_wcss_stop(struct rproc *rproc)
>> >> return 0;
>> >> }
>> >>
>> >> -static void *q6v5_wcss_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *q6v5_wcss_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct q6v5_wcss *wcss = rproc->priv;
>> >> int offset;
>> >> diff --git a/drivers/remoteproc/qcom_wcnss.c b/drivers/remoteproc/qcom_wcnss.c
>> >> index dc135754bb9c..f893219e45a8 100644
>> >> --- a/drivers/remoteproc/qcom_wcnss.c
>> >> +++ b/drivers/remoteproc/qcom_wcnss.c
>> >> @@ -287,7 +287,7 @@ static int wcnss_stop(struct rproc *rproc)
>> >> return ret;
>> >> }
>> >>
>> >> -static void *wcnss_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *wcnss_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct qcom_wcnss *wcnss = (struct qcom_wcnss *)rproc->priv;
>> >> int offset;
>> >> diff --git a/drivers/remoteproc/remoteproc_core.c
>> >> b/drivers/remoteproc/remoteproc_core.c
>> >> index 307df98347ba..9e6d3c6a60ee 100644
>> >> --- a/drivers/remoteproc/remoteproc_core.c
>> >> +++ b/drivers/remoteproc/remoteproc_core.c
>> >> @@ -185,7 +185,7 @@ EXPORT_SYMBOL(rproc_va_to_pa);
>> >> * here the output of the DMA API for the carveouts, which should be more
>> >> * correct.
>> >> */
>> >> -void *rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +void *rproc_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >
>> > This function is exported, don't see any update in consequence...
>> > references:
>> > https://elixir.bootlin.com/linux/v5.6-rc1/ident/rproc_da_to_va
>> > For instance the function rproc_trace_read use it. it quite strange that my gcc
>> > does not warns for the cast but i suppose that some could.
>>
>> Agreed, even if len should never have been a signed type since it can't be
>> negative. I will try to fix all callers.
>>
>> > An indirect consequence is that the len field in rproc_mem_entry struct should
>> > probably been updated to u64 to be aligned.
>>
>> Ok, I will do that once we settle on the type of len.
>>
>> >
>> > I'm still wondering about the use of size_t instead,which seems more rational
>> > from my window.
>> > So i you or Mathieu remember it was decided to use u64, please could remind me
>> > the arguments?
>>
>> I tried to find the notes of a meeting we had for OpenAMP but I did not found
>> them. Anyway, the argument was coming from Tomas or someone else, (I can't
>> remember) talking about a 32 bits CPU executing code on a 64 bits accelerator.
>> In that case, the size_t type could fail due to being only 32bits on the host
>> CPU but larger than 4G.
>>
>> However, I can't say if it's a real usecase or not... All I can say is
>> that keeping it open is probably better if one day somebody comes with such
>> architecture.
>
> In order to support a 32bit AP with a 64bit MCU we'd also have to deal with all
> the dma_attr_t in the structure we use.

Totally ok with that...

>
> Also something that became very clear to me while thinking about this patchset
> is that supporting elf64 does __not__ mean we support 64bit MCU. As long as
> the addresses conveyed by the elf64 image fit within 32 bits we are fine.
> Supporting 64bit MCUs is a completely different topic, one that will demand
> serious refactoring.

Exactly, an elf64 can potentially contain an executable fitting in 32 bits.

>
> So moving from "int len" to "u64 len" doesn't give us much. It doesn't hurt to
> do it but if @len ever becomes bigger than 31 bits we'll have other problems to
> deal with.

Agreed, so what would be your recommendation reagrding the type of len ?
I'm ok with Arnaud statement too and using a size_t is probably more
"type-safe" than a u64. At least it adds some information.

Thanks,

Clément

>
>>
>> > As an alternative a check should be added for 32 bits processors to ensure that
>> > the size is not higher than
>> > its address range capability...
>>
>> Agreed.
>> I was even thinking about a mecanism for remoteproc drivers to declare the type
>> of supported elfs files (such as EM_*, ELFCLASS* and other needed thing).
>> Or should it be supported by overriding .sanity_check in drivers to reject
>> elf64 for instance ?
>>
>> Since elf is a "specific format" and that rproc can support other formats,
>> I did not want to add a specific elf_sanity_check field to rproc ops.
>>
>> Regards,
>>
>> Clément
>>
>> >
>> > Regards
>> > Arnaud
>> >
>> >> {
>> >> struct rproc_mem_entry *carveout;
>> >> void *ptr = NULL;
>> >> diff --git a/drivers/remoteproc/remoteproc_internal.h
>> >> b/drivers/remoteproc/remoteproc_internal.h
>> >> index 493ef9262411..004867061721 100644
>> >> --- a/drivers/remoteproc/remoteproc_internal.h
>> >> +++ b/drivers/remoteproc/remoteproc_internal.h
>> >> @@ -50,7 +50,7 @@ void rproc_exit_sysfs(void);
>> >> void rproc_free_vring(struct rproc_vring *rvring);
>> >> int rproc_alloc_vring(struct rproc_vdev *rvdev, int i);
>> >>
>> >> -void *rproc_da_to_va(struct rproc *rproc, u64 da, int len);
>> >> +void *rproc_da_to_va(struct rproc *rproc, u64 da, u64 len);
>> >> phys_addr_t rproc_va_to_pa(void *cpu_addr);
>> >> int rproc_trigger_recovery(struct rproc *rproc);
>> >>
>> >> diff --git a/drivers/remoteproc/st_slim_rproc.c
>> >> b/drivers/remoteproc/st_slim_rproc.c
>> >> index 04492fead3c8..fc01cd879b60 100644
>> >> --- a/drivers/remoteproc/st_slim_rproc.c
>> >> +++ b/drivers/remoteproc/st_slim_rproc.c
>> >> @@ -174,7 +174,7 @@ static int slim_rproc_stop(struct rproc *rproc)
>> >> return 0;
>> >> }
>> >>
>> >> -static void *slim_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *slim_rproc_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct st_slim_rproc *slim_rproc = rproc->priv;
>> >> void *va = NULL;
>> >> @@ -191,7 +191,7 @@ static void *slim_rproc_da_to_va(struct rproc *rproc, u64
>> >> da, int len)
>> >> }
>> >> }
>> >>
>> >> - dev_dbg(&rproc->dev, "da = 0x%llx len = 0x%x va = 0x%pK\n",
>> >> + dev_dbg(&rproc->dev, "da = 0x%llx len = 0x%llx va = 0x%pK\n",
>> >> da, len, va);
>> >>
>> >> return va;
>> >> diff --git a/drivers/remoteproc/wkup_m3_rproc.c
>> >> b/drivers/remoteproc/wkup_m3_rproc.c
>> >> index 3984e585c847..91485b467407 100644
>> >> --- a/drivers/remoteproc/wkup_m3_rproc.c
>> >> +++ b/drivers/remoteproc/wkup_m3_rproc.c
>> >> @@ -80,14 +80,14 @@ static int wkup_m3_rproc_stop(struct rproc *rproc)
>> >> return 0;
>> >> }
>> >>
>> >> -static void *wkup_m3_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> +static void *wkup_m3_rproc_da_to_va(struct rproc *rproc, u64 da, u64 len)
>> >> {
>> >> struct wkup_m3_rproc *wkupm3 = rproc->priv;
>> >> void *va = NULL;
>> >> int i;
>> >> u32 offset;
>> >>
>> >> - if (len <= 0)
>> >> + if (len == 0)
>> >> return NULL;
>> >>
>> >> for (i = 0; i < WKUPM3_MEM_MAX; i++) {
>> >> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>> >> index 16ad66683ad0..f84bd5fe0211 100644
>> >> --- a/include/linux/remoteproc.h
>> >> +++ b/include/linux/remoteproc.h
>> >> @@ -374,7 +374,7 @@ struct rproc_ops {
>> >> int (*start)(struct rproc *rproc);
>> >> int (*stop)(struct rproc *rproc);
>> >> void (*kick)(struct rproc *rproc, int vqid);
>> >> - void * (*da_to_va)(struct rproc *rproc, u64 da, int len);
>> >> + void * (*da_to_va)(struct rproc *rproc, u64 da, u64 len);
>> >> int (*parse_fw)(struct rproc *rproc, const struct firmware *fw);
>> >> int (*handle_rsc)(struct rproc *rproc, u32 rsc_type, void *rsc,
> > >> int offset, int avail);