From d7040c620d8b22f839af7750860b96e39cc58b7c Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Thu, 15 Oct 2026 13:31:52 +0200 Subject: [PATCH] mtd: spi-nor: sfdp: reduce stack usage in spi_nor_parse_sfdp() 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 Suggested-by: David Laight Fixes: d20029474a76 ("mtd: spi-nor: push the rollback mechanism into the sfdp module") Reviewed-by: Miquel Raynal Signed-off-by: Michael Walle --- drivers/mtd/spi-nor/sfdp.c | 36 ++++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c index 818c7d4d69d4..4a3f82e97cef 100644 --- a/drivers/mtd/spi-nor/sfdp.c +++ b/drivers/mtd/spi-nor/sfdp.c @@ -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(¶ms, 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(¶ms2, nor->params, sizeof(params2)); + save_params[1] = *nor->params; param_header = ¶m_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, ¶ms2, 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, ¶ms, sizeof(*nor->params)); + *nor->params = save_params[0]; +free_save_params: + kfree(save_params); return err; }