This is a note to let you know that I've just added the patch titled
mtd: lpddr: fix excessive stack usage with clang
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mtd-lpddr-fix-excessive-stack-usage-with-clang.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit dfec1970976c023bf511363ee4ede17a7e6f36ff
Author: Arnd Bergmann <arnd@xxxxxxxx>
Date: Tue May 5 16:01:16 2020 +0200
mtd: lpddr: fix excessive stack usage with clang
[ Upstream commit 3e1b6469f8324bee5927b063e2aca30d3e56b907 ]
Building lpddr2_nvm with clang can result in a giant stack usage
in one function:
drivers/mtd/lpddr/lpddr2_nvm.c:399:12: error: stack frame size of 1144 bytes in function 'lpddr2_nvm_probe' [-Werror,-Wframe-larger-than=]
The problem is that clang decides to build a copy of the mtd_info
structure on the stack and then do a memcpy() into the actual version. It
shouldn't really do it that way, but it's not strictly a bug either.
As a workaround, use a static const version of the structure to assign
most of the members upfront and then only set the few members that
require runtime knowledge at probe time.
Fixes: 96ba9dd65788 ("mtd: lpddr: add driver for LPDDR2-NVM PCM memories")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Link: https://lore.kernel.org/linux-mtd/20200505140136.263461-1-arnd@xxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/mtd/lpddr/lpddr2_nvm.c b/drivers/mtd/lpddr/lpddr2_nvm.c
index c950c880ad590..90e6cb64db69c 100644
--- a/drivers/mtd/lpddr/lpddr2_nvm.c
+++ b/drivers/mtd/lpddr/lpddr2_nvm.c
@@ -402,6 +402,17 @@ static int lpddr2_nvm_lock(struct mtd_info *mtd, loff_t start_add,
return lpddr2_nvm_do_block_op(mtd, start_add, len, LPDDR2_NVM_LOCK);
}
+static const struct mtd_info lpddr2_nvm_mtd_info = {
+ .type = MTD_RAM,
+ .writesize = 1,
+ .flags = (MTD_CAP_NVRAM | MTD_POWERUP_LOCK),
+ ._read = lpddr2_nvm_read,
+ ._write = lpddr2_nvm_write,
+ ._erase = lpddr2_nvm_erase,
+ ._unlock = lpddr2_nvm_unlock,
+ ._lock = lpddr2_nvm_lock,
+};
+
/*
* lpddr2_nvm driver probe method
*/
@@ -442,6 +453,7 @@ static int lpddr2_nvm_probe(struct platform_device *pdev)
.pfow_base = OW_BASE_ADDRESS,
.fldrv_priv = pcm_data,
};
+
if (IS_ERR(map->virt))
return PTR_ERR(map->virt);
@@ -453,22 +465,13 @@ static int lpddr2_nvm_probe(struct platform_device *pdev)
return PTR_ERR(pcm_data->ctl_regs);
/* Populate mtd_info data structure */
- *mtd = (struct mtd_info) {
- .dev = { .parent = &pdev->dev },
- .name = pdev->dev.init_name,
- .type = MTD_RAM,
- .priv = map,
- .size = resource_size(add_range),
- .erasesize = ERASE_BLOCKSIZE * pcm_data->bus_width,
- .writesize = 1,
- .writebufsize = WRITE_BUFFSIZE * pcm_data->bus_width,
- .flags = (MTD_CAP_NVRAM | MTD_POWERUP_LOCK),
- ._read = lpddr2_nvm_read,
- ._write = lpddr2_nvm_write,
- ._erase = lpddr2_nvm_erase,
- ._unlock = lpddr2_nvm_unlock,
- ._lock = lpddr2_nvm_lock,
- };
+ *mtd = lpddr2_nvm_mtd_info;
+ mtd->dev.parent = &pdev->dev;
+ mtd->name = pdev->dev.init_name;
+ mtd->priv = map;
+ mtd->size = resource_size(add_range);
+ mtd->erasesize = ERASE_BLOCKSIZE * pcm_data->bus_width;
+ mtd->writebufsize = WRITE_BUFFSIZE * pcm_data->bus_width;
/* Verify the presence of the device looking for PFOW string */
if (!lpddr2_nvm_pfow_present(map)) {
