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mtd: spi-nor: sfdp: reduce stack usage in spi_nor_parse_sfdp()

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Two large spi_nor_flash_parameter structures on a function stack
are really too much, and this can exceed an otherwise reasonable
frame limit:

drivers/mtd/spi-nor/sfdp.c: In function 'spi_nor_parse_sfdp':
drivers/mtd/spi-nor/sfdp.c:1717:1: error: the frame size of 1600 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

Allocate both rollback copies on the heap and use structure copies
for type safety.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: David Laight <david.laight.linux@gmail.com>
Fixes: d20029474a ("mtd: spi-nor: push the rollback mechanism into the sfdp module")
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Michael Walle <mwalle@kernel.org>
This commit is contained in:
Michael Walle 2026-10-15 13:31:52 +02:00
parent 7dc9a4e7b9
commit d7040c620d
1 changed files with 24 additions and 12 deletions
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36
drivers/mtd/spi-nor/sfdp.c
View File

@ -1540,7 +1540,7 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
{
const struct sfdp_parameter_header *param_header, *bfpt_header;
struct sfdp_parameter_header *param_headers = NULL;
struct spi_nor_flash_parameter params, params2;
struct spi_nor_flash_parameter *save_params;
struct sfdp_header header;
struct device *dev = nor->dev;
struct sfdp *sfdp;
@ -1552,17 +1552,22 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
* Get a backup of all the parameter to roll back to in case of an
* error.
*/
memcpy(&params, nor->params, sizeof(params));
save_params = kmalloc_objs(*save_params, 2);
if (!save_params)
return -ENOMEM;
save_params[0] = *nor->params;
/* Get the SFDP header. */
err = spi_nor_read_sfdp_dma_unsafe(nor, 0, sizeof(header), &header);
if (err < 0)
return err;
goto free_save_params;
/* Check the SFDP header version. */
if (le32_to_cpu(header.signature) != SFDP_SIGNATURE ||
header.major != SFDP_JESD216_MAJOR)
return -EINVAL;
header.major != SFDP_JESD216_MAJOR) {
err = -EINVAL;
goto free_save_params;
}
/*
* Verify that the first and only mandatory parameter header is a
@ -1570,8 +1575,10 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
*/
bfpt_header = &header.bfpt_header;
if (SFDP_PARAM_HEADER_ID(bfpt_header) != SFDP_BFPT_ID ||
bfpt_header->major != SFDP_JESD216_MAJOR)
return -EINVAL;
bfpt_header->major != SFDP_JESD216_MAJOR) {
err = -EINVAL;
goto free_save_params;
}
sfdp_size = SFDP_PARAM_HEADER_PTP(bfpt_header) +
SFDP_PARAM_HEADER_PARAM_LEN(bfpt_header);
@ -1591,8 +1598,10 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
psize = header.nph * sizeof(*param_headers);
param_headers = kmalloc(psize, GFP_KERNEL);
if (!param_headers)
return -ENOMEM;
if (!param_headers) {
err = -ENOMEM;
goto free_save_params;
}
err = spi_nor_read_sfdp(nor, sizeof(header),
psize, param_headers);
@ -1668,7 +1677,7 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
/* Parse optional parameter tables. */
for (i = 0; i < header.nph; i++) {
memcpy(&params2, nor->params, sizeof(params2));
save_params[1] = *nor->params;
param_header = &param_headers[i];
switch (SFDP_PARAM_HEADER_ID(param_header)) {
@ -1706,7 +1715,7 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
* spi_nor_flash_parameter data.
*/
err = 0;
memcpy(nor->params, &params2, sizeof(*nor->params));
*nor->params = save_params[1];
}
}
@ -1715,6 +1724,7 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
goto clear_sfdp_ptr;
kfree(param_headers);
kfree(save_params);
return 0;
@ -1727,7 +1737,9 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
free_param_headers:
kfree(param_headers);
if (err)
memcpy(nor->params, &params, sizeof(*nor->params));
*nor->params = save_params[0];
free_save_params:
kfree(save_params);
return err;
}