[PATCH v1 1/2] arm64: set POR_EL0 for kernel threads

[Joey Gouly]

Restrict kernel threads to only have RWX overlays for pkey 0.  This matches
what arch/x86 does, by defaulting to a restrictive PKRU.

Signed-off-by: Joey Gouly <joey.gouly at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
---
 arch/arm64/kernel/process.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 0540653fbf38..94f42df249e3 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -410,6 +410,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 		memset(childregs, 0, sizeof(struct pt_regs));
 		childregs->pstate = PSR_MODE_EL1h | PSR_IL_BIT;
 
+		if (system_supports_poe())
+			p->thread.por_el0 = POR_EL0_INIT;
+
 		p->thread.cpu_context.x19 = (unsigned long)args->fn;
 		p->thread.cpu_context.x20 = (unsigned long)args->fn_arg;
 	}
-- 
2.25.1