[PATCH v4] ACPI: GTDT: Tighten the check for the array of platform timer structures

[Hanjun Guo]

On 2024/10/16 17:54, Zheng Zengkai wrote:
> As suggested by Marc and Lorenzo, first we need to check whether the
> platform_timer entry pointer is within gtdt bounds (< gtdt_end) before
> de-referencing what it points at to detect the length of the platform
> timer struct and then check that the length of current platform_timer
> struct is also valid, i.e. the length is not zero and within gtdt_end.
> Now next_platform_timer() only checks against gtdt_end for the entry of
> subsequent platform timer without checking the length of it and will
> not report error if the check failed and the existing check in function
> acpi_gtdt_init() is also not enough.
> 
> Modify the for_each_platform_timer() iterator and use it combined with
> a dedicated check function platform_timer_valid() to do the check
> against table length (gtdt_end) for each element of platform timer
> array in function acpi_gtdt_init(), making sure that both their entry
> and length actually fit in the table.
> 
> Suggested-by: Lorenzo Pieralisi <lpieralisi at kernel.org>
> Co-developed-by: Marc Zyngier <maz at kernel.org>
> Signed-off-by: Marc Zyngier <maz at kernel.org>

Nit: since there is a "Co-developed-by:" for Marc, the
"Signed-off-by:" can be removed. The rest of the patch looks
good to me.

I did a test again Kunpeng ARM sever and no regressions,
hopefully will not trigger firmware bugs for other
platforms.

Reviewed-by: Hanjun Guo <guohanjun at huawei.com>
Tested-by: Hanjun Guo <guohanjun at huawei.com>

Thanks
Hanjun