From be92ad6b12a5046cecf25477e7a3e88f70e5daee Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jean-S=C3=A9bastien=20P=C3=A9dron?= Date: Wed, 4 Mar 2026 21:36:20 +0100 Subject: [PATCH] linuxkpi: Define `PMD_SHIFT` For now, only define it for x86 architectures. The DRM generic code started to use it in Linux 6.11. Reviewed by: bz, emaste Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D55734 --- .../linuxkpi/common/include/asm/pgtable.h | 34 +++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/sys/compat/linuxkpi/common/include/asm/pgtable.h b/sys/compat/linuxkpi/common/include/asm/pgtable.h index 865662d587d..166d6142d51 100644 --- a/sys/compat/linuxkpi/common/include/asm/pgtable.h +++ b/sys/compat/linuxkpi/common/include/asm/pgtable.h @@ -53,6 +53,40 @@ typedef struct page *pgtable_t; #define _PAGE_PWT (((pteval_t) 1) << _PAGE_BIT_PWT) #define _PAGE_PCD (((pteval_t) 1) << _PAGE_BIT_PCD) #define _PAGE_PAT (((pteval_t) 1) << _PAGE_BIT_PAT) + +/* + * On Linux, the value of `PMD_SHIFT` is hard-coded to 21. This corresponds to + * the FreeBSD `PDRSHIFT` constant. + */ +#define PMD_SHIFT PDRSHIFT + +#elif defined(__aarch64__) + +/* + * On Linux, the value of `PMD_SHIFT` is computed from `CONFIG_PGTABLE_LEVELS`. + * The result corresponds to one of the FreeBSD `L*_SHIFT` constants. Here, we + * take the value 21 computed from `CONFIG_PGTABLE_LEVELS = 4`, the default on + * aarch64, which equals to `L2_SHIFT`. + */ +#define PMD_SHIFT L2_SHIFT + +#elif defined(__powerpc__) + +/* + * On Linux, the value of `PMD_SHIFT` is the addition of `PAGE_SHIFT` and + * `PTE_INDEX_SIZE` (hard-coded to 9). The result corresponds to the FreeBSD + * `L3_PAGE_SIZE_SHIFT` constant. + */ +#define PMD_SHIFT L3_PAGE_SIZE_SHIFT + +#elif defined(__riscv) + +/* + * On Linux, the value of `PMD_SHIFT` is hard-coded to 21. This corresponds to + * the FreeBSD `L2_SHIFT` constant. + */ +#define PMD_SHIFT L2_SHIFT + #endif #endif /* _LINUXKPI_ASM_PGTABLE_H_ */