From 36b05629226413836cfbb3fbe6689cd188bca156 Mon Sep 17 00:00:00 2001 From: Alexander Koskovich Date: Sun, 14 Dec 2025 19:16:18 +0000 Subject: [PATCH] power: reset: nvmem-reboot-mode: respect cell size for nvmem_cell_write Some platforms expose reboot mode cells that are smaller than an unsigned int, in which cases lead to write failures. Read the cell first to determine actual size and only write the number of bytes the cell can hold. Fixes: 7a78a7f7695b ("power: reset: nvmem-reboot-mode: use NVMEM as reboot mode write interface") Signed-off-by: Alexander Koskovich Link: https://patch.msgid.link/20251214191529.2470580-1-akoskovich@pm.me Signed-off-by: Sebastian Reichel --- drivers/power/reset/nvmem-reboot-mode.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/power/reset/nvmem-reboot-mode.c b/drivers/power/reset/nvmem-reboot-mode.c index 41530b70cfc48..d260715fccf67 100644 --- a/drivers/power/reset/nvmem-reboot-mode.c +++ b/drivers/power/reset/nvmem-reboot-mode.c @@ -10,6 +10,7 @@ #include #include #include +#include struct nvmem_reboot_mode { struct reboot_mode_driver reboot; @@ -19,12 +20,22 @@ struct nvmem_reboot_mode { static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot, unsigned int magic) { - int ret; struct nvmem_reboot_mode *nvmem_rbm; + size_t buf_len; + void *buf; + int ret; nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot); - ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic)); + buf = nvmem_cell_read(nvmem_rbm->cell, &buf_len); + if (IS_ERR(buf)) + return PTR_ERR(buf); + kfree(buf); + + if (buf_len > sizeof(magic)) + return -EINVAL; + + ret = nvmem_cell_write(nvmem_rbm->cell, &magic, buf_len); if (ret < 0) dev_err(reboot->dev, "update reboot mode bits failed\n"); -- 2.47.3