git: 39cddbd7a07c - main - arm64: do not disable the kern.kstack_pages tunable on arm64

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=39cddbd7a07c182c4f121bea5a6effa36862fc63

commit 39cddbd7a07c182c4f121bea5a6effa36862fc63
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2023-10-10 00:02:06 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2023-10-13 09:26:45 +0000

    arm64: do not disable the kern.kstack_pages tunable on arm64
    
    Add a comment explaining what is not quite correct with arm64 and riscv.
    
    Reviewed by:    jhb, markj
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D42143
---
 sys/kern/subr_param.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sys/kern/subr_param.c b/sys/kern/subr_param.c
index f7d6cf848424..b7dbf606f492 100644
--- a/sys/kern/subr_param.c
+++ b/sys/kern/subr_param.c
@@ -170,9 +170,13 @@ init_param1(void)
 {
 
 	TSENTER();
-#if !defined(__arm64__)
+
+	/*
+	 * arm64 and riscv currently hard-code the thread0 kstack size
+	 * to KSTACK_PAGES, ignoring the tunable.
+	 */
 	TUNABLE_INT_FETCH("kern.kstack_pages", &kstack_pages);
-#endif
+
 	hz = -1;
 	TUNABLE_INT_FETCH("kern.hz", &hz);
 	if (hz == -1)