git: 1562a8f4b72f - stable/13 - arm64: do not disable the kern.kstack_pages tunable on arm64

The branch stable/13 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=1562a8f4b72ff44eef090d07624b9dfce1b02bf8

commit 1562a8f4b72ff44eef090d07624b9dfce1b02bf8
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2023-10-10 00:02:06 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2023-10-20 15:58:14 +0000

    arm64: do not disable the kern.kstack_pages tunable on arm64
    
    (cherry picked from commit 39cddbd7a07c182c4f121bea5a6effa36862fc63)
---
 sys/kern/subr_param.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/sys/kern/subr_param.c b/sys/kern/subr_param.c
index d26a1902f16c..c2672d98ba8d 100644
--- a/sys/kern/subr_param.c
+++ b/sys/kern/subr_param.c
@@ -173,9 +173,16 @@ void
 init_param1(void)
 {
 
-#if !defined(__mips__) && !defined(__arm64__)
+	TSENTER();
+
+	/*
+	 * arm64 and riscv currently hard-code the thread0 kstack size
+	 * to KSTACK_PAGES, ignoring the tunable.
+	 */
+#if !defined(__mips__)
 	TUNABLE_INT_FETCH("kern.kstack_pages", &kstack_pages);
 #endif
+
 	hz = -1;
 	TUNABLE_INT_FETCH("kern.hz", &hz);
 	if (hz == -1)