From 181bc19bef74650fb5dc05a58aed00607b8e358d Mon Sep 17 00:00:00 2001
From: Kalesh Singh <kaleshsingh@google.com>
Date: Mon, 20 Nov 2023 16:39:52 -0800
Subject: [PATCH] ANDROID: 16K: x86_64: Allow stack randomization of twice
 page-size

In page-compat mode, let stack randomization be 2x__PAGE_SIZE instead of
the hard coded 8KB.

Bug: 383389337
Bug: 315325080
Bug: 302403436
Change-Id: I9ab3c03a9a0fcd7210a1f0dc7834975ae2807473
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---
 arch/x86/kernel/process.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c7ce3655b707..84e68ab27c9b 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -4,6 +4,7 @@
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/page_size_compat.h>
 #include <linux/smp.h>
 #include <linux/cpu.h>
 #include <linux/prctl.h>
@@ -1006,7 +1007,7 @@ early_param("idle", idle_setup);
 unsigned long arch_align_stack(unsigned long sp)
 {
 	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
-		sp -= get_random_u32_below(8192);
+		sp -= get_random_u32_below(__PAGE_SIZE << 1);
 	return sp & ~0xf;
 }