On Mon, Dec 20, 2021 at 5:17 PM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > On Mon, 20 Dec 2021 at 10:11, Guo Ren <guoren@xxxxxxxxxx> wrote: > > > > On Tue, Dec 7, 2021 at 11:55 AM Alexandre Ghiti > > <alexandre.ghiti@xxxxxxxxxxxxx> 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 > > Shall we disable -fstack-protector for setup_vm() with __attribute__? > > Don't use __attribute__((optimize())) for that: it is known to be > broken, and documented as debug purposes only in the GCC info pages: > > https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html Oh, thx for the link. > > > > > > Actually, we've already init tp later. > > > > > 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@xxxxxxxxxxxxx> > > > --- > > > 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 > > > -- > > > 2.32.0 > > > > > > > > > -- > > Best Regards > > Guo Ren > > > > ML: https://lore.kernel.org/linux-csky/ -- Best Regards Guo Ren ML: https://lore.kernel.org/linux-csky/
