[PATCH v3 12/13] riscv: Initialize thread pointer before calling C functions

[Alexandre ghiti]

Hi Palmer,

I fell onto this issue again today, do you think you could take this 
patch in for-next? Because I assume it is too late now to take the sv48 
patchset: if not, I can respin it today or tomorrow.

Thanks,

Alex

On 12/6/21 11:46, Alexandre Ghiti wrote:
> Because of the stack canary feature that reads from the current task
> structure the stack canary value, the thread pointer register "tp" must
> be set before calling any C function from head.S: by chance, setup_vm
> and all the functions that it calls does not seem to be part of the
> functions where the canary check is done, but in the following commits,
> some functions will.
>
> Fixes: f2c9699f65557a31 ("riscv: Add STACKPROTECTOR supported")
> Signed-off-by: Alexandre Ghiti <alexandre.ghiti at canonical.com>
> ---
>   arch/riscv/kernel/head.S | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> index c3c0ed559770..86f7ee3d210d 100644
> --- a/arch/riscv/kernel/head.S
> +++ b/arch/riscv/kernel/head.S
> @@ -302,6 +302,7 @@ clear_bss_done:
>   	REG_S a0, (a2)
>   
>   	/* Initialize page tables and relocate to virtual addresses */
> +	la tp, init_task
>   	la sp, init_thread_union + THREAD_SIZE
>   	XIP_FIXUP_OFFSET sp
>   #ifdef CONFIG_BUILTIN_DTB