On ChromiumOS devices, the `ecc_size` is set to 0 (check dmesg | grep ecc to see `ecc: 0`): this disables ECC for ramoops region, even when `ramoops.ecc=1` is given to kernel command line parameter.
Introduce `ecc_size` module parameter to provide an method to turn on ECC for ramoops and set different values of ecc_size per devices. A large `ecc_size` value can cause a kernel panic due to a constraint in Reed-Solomon code library. The validation for this constraint should belong to the common pstore RAM layer, not in each individual driver. So this check is handled by a separate patch [1]. [1] https://lore.kernel.org/lkml/[email protected] Signed-off-by: Naoya Tezuka <[email protected]> --- Changes in v3: - Update commit message to use imperative mood as suggested. - Change module parameter permissions for `ecc_size` to 0400 as suggested. - State in commit message that the `ecc_size` upper bound issue is addressed in a separte patch instead of validating in this driver. - Link to v2: https://lore.kernel.org/lkml/[email protected] Changes in v2: - Remove an unnecessary blank line - Link to v1: https://lore.kernel.org/lkml/[email protected] --- drivers/platform/chrome/chromeos_pstore.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/platform/chrome/chromeos_pstore.c b/drivers/platform/chrome/chromeos_pstore.c index f37c0ef4af1f..a6eed99507d4 100644 --- a/drivers/platform/chrome/chromeos_pstore.c +++ b/drivers/platform/chrome/chromeos_pstore.c @@ -9,6 +9,10 @@ #include <linux/platform_device.h> #include <linux/pstore_ram.h> +static int ecc_size; +module_param(ecc_size, int, 0400); +MODULE_PARM_DESC(ecc_size, "ECC parity data size in bytes. A positive value enables ECC for the ramoops region."); + static const struct dmi_system_id chromeos_pstore_dmi_table[] __initconst = { { /* @@ -117,6 +121,9 @@ static int __init chromeos_pstore_init(void) { bool acpi_dev_found; + if (ecc_size > 0) + chromeos_ramoops_data.ecc_info.ecc_size = ecc_size; + /* First check ACPI for non-hardcoded values from firmware. */ acpi_dev_found = chromeos_check_acpi(); -- 2.50.0.rc2.701.gf1e915cc24-goog
