[PATCH v2] RISC-V: Don't mark init section as non-executable

From: Anup Patel
Date: Mon Jun 01 2020 - 01:07:47 EST


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@xxxxxxxxxxxxxxx
Signed-off-by: Anup Patel <anup.patel@xxxxxxx>
---
Changes since v1:
- Updated free_initmem() is same as generic free_initmem() defined in
init/main.c so we completely remove free_initmem() from arch/riscv
---
arch/riscv/mm/init.c | 11 -----------
1 file changed, 11 deletions(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 736de6c8739f..fdc772f57edc 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -479,17 +479,6 @@ static void __init setup_vm_final(void)
csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
local_flush_tlb_all();
}
-
-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);
-}
-
#else
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
--
2.25.1