[PATCH V2 0/2] remoteproc: elf: ignore PT_LOAD type segment with memsz as 0

[PATCH V2 0/2] remoteproc: elf: ignore PT_LOAD type segment with memsz as 0

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@nxp.com>

V2:
 Add R-b/A-b tag
 Drop inaccurate comment in patch 1

i.MX DSP firmware has segments with PT_LOAD and memsz/filesz as zero.
It is valid case the memsz set to zero according to elf spec:
https://refspecs.linuxbase.org/elf/elf.pdf page 40

So we could let remoteproc elf loader handle this case, then no
duplicate code in imx dsp rproc driver

Tested i.MX8MP DSP and M7 remoteproc

Peng Fan (2):
  remoteproc: elf_loader: skip segment with memsz as zero
  remoteproc: imx_dsp_rproc: use common rproc_elf_load_segments

 drivers/remoteproc/imx_dsp_rproc.c         | 95 +---------------------
 drivers/remoteproc/remoteproc_elf_loader.c |  2 +-
 2 files changed, 2 insertions(+), 95 deletions(-)

-- 
2.25.1

[PATCH V2 1/2] remoteproc: elf_loader: skip segment with memsz as zero

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@nxp.com>

Per elf specification,
p_filesz: This member gives the number of bytes in the file image of
the segment; it may be zero.
p_memsz: This member gives the number of bytes in the memory image
of the segment; it may be zero.

There is a case that i.MX DSP firmware has segment with PT_LOAD and
p_memsz/p_filesz set to zero. Such segment needs to be ignored,
otherwize rproc_da_to_va would report error.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/remoteproc/remoteproc_elf_loader.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/remoteproc/remoteproc_elf_loader.c b/drivers/remoteproc/remoteproc_elf_loader.c
index d635d19a5aa8..5a412d7b6e0b 100644
--- a/drivers/remoteproc/remoteproc_elf_loader.c
+++ b/drivers/remoteproc/remoteproc_elf_loader.c
@@ -181,7 +181,7 @@ int rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
 		bool is_iomem = false;
 		void *ptr;
 
-		if (type != PT_LOAD)
+		if (type != PT_LOAD || !memsz)
 			continue;
 
 		dev_dbg(dev, "phdr: type %d da 0x%llx memsz 0x%llx filesz 0x%llx\n",
-- 
2.25.1

[PATCH V2 2/2] remoteproc: imx_dsp_rproc: use common rproc_elf_load_segments

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@nxp.com>

remoteproc elf loader supports the specific case that segments
have PT_LOAD and memsz/filesz set to zero, so no duplicate
code.

Acked-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/remoteproc/imx_dsp_rproc.c | 95 +-----------------------------
 1 file changed, 1 insertion(+), 94 deletions(-)

diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
index 2abee78df96e..eee3c44c2146 100644
--- a/drivers/remoteproc/imx_dsp_rproc.c
+++ b/drivers/remoteproc/imx_dsp_rproc.c
@@ -649,99 +649,6 @@ static int imx_dsp_rproc_add_carveout(struct imx_dsp_rproc *priv)
 	return 0;
 }
 
-/**
- * imx_dsp_rproc_elf_load_segments() - load firmware segments to memory
- * @rproc: remote processor which will be booted using these fw segments
- * @fw: the ELF firmware image
- *
- * This function specially checks if memsz is zero or not, otherwise it
- * is mostly same as rproc_elf_load_segments().
- */
-static int imx_dsp_rproc_elf_load_segments(struct rproc *rproc,
-					   const struct firmware *fw)
-{
-	struct device *dev = &rproc->dev;
-	u8 class = fw_elf_get_class(fw);
-	u32 elf_phdr_get_size = elf_size_of_phdr(class);
-	const u8 *elf_data = fw->data;
-	const void *ehdr, *phdr;
-	int i, ret = 0;
-	u16 phnum;
-
-	ehdr = elf_data;
-	phnum = elf_hdr_get_e_phnum(class, ehdr);
-	phdr = elf_data + elf_hdr_get_e_phoff(class, ehdr);
-
-	/* go through the available ELF segments */
-	for (i = 0; i < phnum; i++, phdr += elf_phdr_get_size) {
-		u64 da = elf_phdr_get_p_paddr(class, phdr);
-		u64 memsz = elf_phdr_get_p_memsz(class, phdr);
-		u64 filesz = elf_phdr_get_p_filesz(class, phdr);
-		u64 offset = elf_phdr_get_p_offset(class, phdr);
-		u32 type = elf_phdr_get_p_type(class, phdr);
-		void *ptr;
-
-		/*
-		 *  There is a case that with PT_LOAD type, the
-		 *  filesz = memsz = 0. If memsz = 0, rproc_da_to_va
-		 *  should return NULL ptr, then error is returned.
-		 *  So this case should be skipped from the loop.
-		 *  Add !memsz checking here.
-		 */
-		if (type != PT_LOAD || !memsz)
-			continue;
-
-		dev_dbg(dev, "phdr: type %d da 0x%llx memsz 0x%llx filesz 0x%llx\n",
-			type, da, memsz, filesz);
-
-		if (filesz > memsz) {
-			dev_err(dev, "bad phdr filesz 0x%llx memsz 0x%llx\n",
-				filesz, memsz);
-			ret = -EINVAL;
-			break;
-		}
-
-		if (offset + filesz > fw->size) {
-			dev_err(dev, "truncated fw: need 0x%llx avail 0x%zx\n",
-				offset + filesz, fw->size);
-			ret = -EINVAL;
-			break;
-		}
-
-		if (!rproc_u64_fit_in_size_t(memsz)) {
-			dev_err(dev, "size (%llx) does not fit in size_t type\n",
-				memsz);
-			ret = -EOVERFLOW;
-			break;
-		}
-
-		/* grab the kernel address for this device address */
-		ptr = rproc_da_to_va(rproc, da, memsz, NULL);
-		if (!ptr) {
-			dev_err(dev, "bad phdr da 0x%llx mem 0x%llx\n", da,
-				memsz);
-			ret = -EINVAL;
-			break;
-		}
-
-		/* put the segment where the remote processor expects it */
-		if (filesz)
-			memcpy(ptr, elf_data + offset, filesz);
-
-		/*
-		 * Zero out remaining memory for this segment.
-		 *
-		 * This isn't strictly required since dma_alloc_coherent already
-		 * did this for us. albeit harmless, we may consider removing
-		 * this.
-		 */
-		if (memsz > filesz)
-			memset(ptr + filesz, 0, memsz - filesz);
-	}
-
-	return ret;
-}
-
 /* Prepare function for rproc_ops */
 static int imx_dsp_rproc_prepare(struct rproc *rproc)
 {
@@ -808,7 +715,7 @@ static const struct rproc_ops imx_dsp_rproc_ops = {
 	.start		= imx_dsp_rproc_start,
 	.stop		= imx_dsp_rproc_stop,
 	.kick		= imx_dsp_rproc_kick,
-	.load		= imx_dsp_rproc_elf_load_segments,
+	.load		= rproc_elf_load_segments,
 	.parse_fw	= rproc_elf_load_rsc_table,
 	.sanity_check	= rproc_elf_sanity_check,
 	.get_boot_addr	= rproc_elf_get_boot_addr,
-- 
2.25.1

Re: [PATCH V2 0/2] remoteproc: elf: ignore PT_LOAD type segment with memsz as 0

[Mathieu Poirier]

On Wed, Apr 13, 2022 at 11:30:36AM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> V2:
>  Add R-b/A-b tag
>  Drop inaccurate comment in patch 1
> 
> i.MX DSP firmware has segments with PT_LOAD and memsz/filesz as zero.
> It is valid case the memsz set to zero according to elf spec:
> https://refspecs.linuxbase.org/elf/elf.pdf page 40
> 
> So we could let remoteproc elf loader handle this case, then no
> duplicate code in imx dsp rproc driver
> 
> Tested i.MX8MP DSP and M7 remoteproc
> 
> Peng Fan (2):
>   remoteproc: elf_loader: skip segment with memsz as zero
>   remoteproc: imx_dsp_rproc: use common rproc_elf_load_segments
> 
>  drivers/remoteproc/imx_dsp_rproc.c         | 95 +---------------------
>  drivers/remoteproc/remoteproc_elf_loader.c |  2 +-
>  2 files changed, 2 insertions(+), 95 deletions(-)
>

I have applied this set but as I pointed out in the previous revision, it will
have to be backed-out if something breaks.  Hopefully it won't get to that.

Thanks,
Mathieu

> -- 
> 2.25.1
>