Re: [PATCH v2 04/18] acpi: Introduce acpi_invalid_table() to check if a table is invalid.

Toshi Kani
2013-08-01T22:28:12Z

On Thu, 2013-08-01 at 15:06 +0800, Tang Chen wrote:
> In acpi_initrd_override(), it checks several things to ensure the
> table it found is valid. In later patches, we need to do these check
> somewhere else. So this patch introduces a common function
> acpi_invalid_table() to do all these checks, and reuse it in different
> places. The function will be used in the subsequent patches.
>
> Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> ---
> drivers/acpi/osl.c | 86 +++++++++++++++++++++++++++++++++++++---------------
> 1 files changed, 61 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 91d9f54..8df8a93 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -572,9 +572,68 @@ static const char * const table_sigs[] = {
> /* Must not increase 10 or needs code modification below */
> #define ACPI_OVERRIDE_TABLES 10
>
> +/*******************************************************************************
> + *
> + * FUNCTION: acpi_invalid_table
> + *
> + * PARAMETERS: File - The initrd file
> + * Path - Path to acpi overriding tables in cpio file
> + * Signature - Signature of the table
> + *
> + * RETURN: 0 if it passes all the checks, -EINVAL if any check fails.
> + *
> + * DESCRIPTION: Check if an acpi table found in initrd is invalid.
> + * @signature can be NULL. If it is NULL, the function will check
> + * if the table signature matches any signature in table_sigs[].
> + *
> + ******************************************************************************/
> +int __init acpi_invalid_table(struct cpio_data *file,
> + const char *path, const char *signature)

Since this function verifies a given acpi table in initrd (not that the
table is invalid), I'd suggest to rename it something like
acpi_verify_initrd(). Otherwise, it looks good to me.

Acked-by: Toshi Kani <toshi.kani@hp.com>

Thanks,
-Toshi

> +{
> + int idx;
> + struct acpi_table_header *table = file->data;
> +
> + if (file->size < sizeof(struct acpi_table_header)) {
> + INVALID_TABLE("Table smaller than ACPI header",
> + path, file->name);
> + return -EINVAL;
> + }
> +
> + if (signature) {
> + if (memcmp(table->signature, signature, 4)) {
> + INVALID_TABLE("Table signature does not match",
> + path, file->name);
> + return -EINVAL;
> + }
> + } else {
> + for (idx = 0; table_sigs[idx]; idx++)
> + if (!memcmp(table->signature, table_sigs[idx], 4))
> + break;
> +
> + if (!table_sigs[idx]) {
> + INVALID_TABLE("Unknown signature", path, file->name);
> + return -EINVAL;
> + }
> + }
> +
> + if (file->size != table->length) {
> + INVALID_TABLE("File length does not match table length",
> + path, file->name);
> + return -EINVAL;
> + }
> +
> + if (acpi_table_checksum(file->data, table->length)) {
> + INVALID_TABLE("Bad table checksum",
> + path, file->name);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> void __init acpi_initrd_override(void *data, size_t size)
> {
> - int sig, no, table_nr = 0, total_offset = 0;
> + int no, table_nr = 0, total_offset = 0;
> long offset = 0;
> struct acpi_table_header *table;
> char cpio_path[32] = "kernel/firmware/acpi/";
> @@ -593,33 +652,10 @@ void __init acpi_initrd_override(void *data, size_t size)
> data += offset;
> size -= offset;
>
> - if (file.size < sizeof(struct acpi_table_header)) {
> - INVALID_TABLE("Table smaller than ACPI header",
> - cpio_path, file.name);
> - continue;
> - }
> -
> table = file.data;
>
> - for (sig = 0; table_sigs[sig]; sig++)
> - if (!memcmp(table->signature, table_sigs[sig], 4))
> - break;
> -
> - if (!table_sigs[sig]) {
> - INVALID_TABLE("Unknown signature",
> - cpio_path, file.name);
> + if (acpi_invalid_table(&file, cpio_path, NULL))
> continue;
> - }
> - if (file.size != table->length) {
> - INVALID_TABLE("File length does not match table length",
> - cpio_path, file.name);
> - continue;
> - }
> - if (acpi_table_checksum(file.data, table->length)) {
> - INVALID_TABLE("Bad table checksum",
> - cpio_path, file.name);
> - continue;
> - }
>
> pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
> table->signature, cpio_path, file.name, table->length);