From: Hugh Dickins Date: Tue, 30 Jan 2018 02:17:58 +0000 (-0800) Subject: kaiser: allocate pgd with order 0 when pti=off X-Git-Tag: C0P2-H0.0--20200415~5437 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=400d3c8b0c7f6c942cd9bf201da1f32da9bdcc9f;p=linux.git kaiser: allocate pgd with order 0 when pti=off The 4.9.77 version of "x86/pti/efi: broken conversion from efi to kernel page table" looked nicer than the 4.4.112 version, but was suboptimal on machines booted with "pti=off" (or on AMD machines): it allocated pgd with an order 1 page whatever the setting of kaiser_enabled. Fix that by moving the definition of PGD_ALLOCATION_ORDER from asm/pgalloc.h to asm/pgtable.h, which already defines kaiser_enabled. Fixes: 1b92c48a2eeb ("x86/pti/efi: broken conversion from efi to kernel page table") Reviewed-by: Pavel Tatashin Cc: Steven Sistare Cc: Jiri Kosina Signed-off-by: Hugh Dickins Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index 1178a51b77f3..b6d425999f99 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -27,17 +27,6 @@ static inline void paravirt_release_pud(unsigned long pfn) {} */ extern gfp_t __userpte_alloc_gfp; -#ifdef CONFIG_PAGE_TABLE_ISOLATION -/* - * Instead of one PGD, we acquire two PGDs. Being order-1, it is - * both 8k in size and 8k-aligned. That lets us just flip bit 12 - * in a pointer to swap between the two 4k halves. - */ -#define PGD_ALLOCATION_ORDER 1 -#else -#define PGD_ALLOCATION_ORDER 0 -#endif - /* * Allocate and free page tables. */ diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 2536f90cd30c..5af0401ccff2 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -20,9 +20,15 @@ #ifdef CONFIG_PAGE_TABLE_ISOLATION extern int kaiser_enabled; +/* + * Instead of one PGD, we acquire two PGDs. Being order-1, it is + * both 8k in size and 8k-aligned. That lets us just flip bit 12 + * in a pointer to swap between the two 4k halves. + */ #else #define kaiser_enabled 0 #endif +#define PGD_ALLOCATION_ORDER kaiser_enabled void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd); void ptdump_walk_pgd_level_checkwx(void);