Put __cpu_up_stack_pointer and __cpu_up_task_pointer in data section.
Currently, these two variables are put in bss section, there is a
potential risk that secondary harts get the uninitialized value before
main hart finishing the bss clearing. In this case, all secondary
harts would pass the waiting loop and enable the MMU before main hart
set up the page table.
This issue happens on random booting of multiple harts, which means
it will manifest for BBL and OpenSBI v0.6 (or older version). In OpenSBI
v0.7 (or higher version), we have HSM extension so all the secondary harts
are brought-up by Linux kernel in an orderly fashion. This means we don't
need this change for OpenSBI v0.7 (or higher version).
Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Currently, all harts have to jump Linux in RISC-V. This complicates the
multi-stage boot process as every transient stage also has to ensure all
harts enter to that stage and jump to Linux afterwards. It also obstructs
a clean Kexec implementation.
SBI HSM extension provides alternate solutions where only a single hart
need to boot and enter Linux. The booting hart can bring up secondary
harts one by one afterwards.
Add SBI HSM based cpu_ops that implements an ordered booting method in
RISC-V. This change is also backward compatible with older firmware not
implementing HSM extension. If a latest kernel is used with older
firmware, it will continue to use the default spinning booting method.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Currently, all non-booting harts start booting after the booting hart
updates the per-hart stack pointer. This is done in a way that, it's
difficult to implement any other booting method without breaking the
backward compatibility.
Define a cpu_ops method that allows to introduce other booting methods
in future. Modify the current booting method to be compatible with
cpu_ops.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
