On Sun, May 31, 2020 at 3:28 PM Anup Patel anup.patel@wdc.com wrote:

The head text section (i.e. _start, secondary_start_sbi, etc) and the init section fall under same page table level-1 mapping.

Currently, the runtime CPU hotplug is broken because we are marking init section as non-executable which in-turn marks head text section as non-executable.

Further investigating other architectures, it seems marking the init section as non-executable is redundant because the init section pages are anyway poisoned and freed.

To fix broken runtime CPU hotplug, we simply remove the code marking the init section as non-executable.

Fixes: d27c3c90817e ("riscv: add STRICT_KERNEL_RWX support") Cc: stable@vger.kernel.org Signed-off-by: Anup Patel anup.patel@wdc.com

---

arch/riscv/mm/init.c | 5 ----- 1 file changed, 5 deletions(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 736de6c8739f..e0f8ccab8a41 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -482,11 +482,6 @@ static void __init setup_vm_final(void)

void free_initmem(void) {

•   unsigned long init_begin = (unsigned long)__init_begin;
  

•   unsigned long init_end = (unsigned long)__init_end;
  

•   /* Make the region as non-execuatble. */
  

•   set_memory_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
    free_initmem_default(POISON_FREE_INITMEM);
  

}

I just realized that updated free_initmem() over here is exactly same as generic free_initmem() defined in init/main.c so it's better to remove free_initmem() from here. I will send v2.

Regards, Anup