git: 5bc46055983d - stable/15 - linuxkpi: Define `CONFIG_PGTABLE_LEVELS`

The branch stable/15 has been updated by bz:

URL: https://cgit.FreeBSD.org/src/commit/?id=5bc46055983ddf24570b3fdd2a66e6a50947e990

commit 5bc46055983ddf24570b3fdd2a66e6a50947e990
Author:     Jean-Sébastien Pédron <dumbbell@FreeBSD.org>
AuthorDate: 2026-03-04 20:34:37 +0000
Commit:     Bjoern A. Zeeb <bz@FreeBSD.org>
CommitDate: 2026-04-22 20:57:01 +0000

    linuxkpi: Define `CONFIG_PGTABLE_LEVELS`
    
    This is a kernel configuration constant that is expected to be defined.
    
    The DRM generic code started to use it in Linux 6.11.
    
    Reviewed by:    bz
    Sponsored by:   The FreeBSD Foundation
    Differential Revision: https://reviews.freebsd.org/D55733
    
    (cherry picked from commit 7bf93680807e518853262f3f961f88eb8ec03c83)
---
 sys/compat/linuxkpi/common/include/linux/kconfig.h | 35 ++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/sys/compat/linuxkpi/common/include/linux/kconfig.h b/sys/compat/linuxkpi/common/include/linux/kconfig.h
index c1d186b56e1f..529d41991900 100644
--- a/sys/compat/linuxkpi/common/include/linux/kconfig.h
+++ b/sys/compat/linuxkpi/common/include/linux/kconfig.h
@@ -73,4 +73,39 @@
 #define	IS_REACHABLE(_x)	(IS_BUILTIN(_x) || \
 				    (IS_MODULE(_x) && IS_BUILTIN(MODULE)))
 
+/*
+ * On Linux, the CONFIG_PGTABLE_LEVELS value is defined by the config/build
+ * system. Here, we take the per-architecture default value defined in
+ * `arch/$ARCH/Kconfig` files upstream.
+ */
+#if defined(__amd64__)
+
+#define	CONFIG_PGTABLE_LEVELS	4
+
+#elif defined(__aarch64__)
+
+#define	CONFIG_PGTABLE_LEVELS	4
+
+#elif defined(__i386__)
+
+#define	CONFIG_PGTABLE_LEVELS	2
+
+#elif defined(__powerpc__)
+
+#if defined(__powerpc64__)
+#define	CONFIG_PGTABLE_LEVELS	4
+#else
+#define	CONFIG_PGTABLE_LEVELS	2
+#endif
+
+#elif defined(__riscv)
+
+#if defined(__riscv_xlen) && __riscv_xlen == 64
+#define	CONFIG_PGTABLE_LEVELS	5
+#else
+#define	CONFIG_PGTABLE_LEVELS	2
+#endif
+
+#endif
+
 #endif /* _LINUXKPI_LINUX_KCONFIG_H_ */