Messages in this thread Patch in this message | | | Date | Wed, 20 Dec 2017 22:35:34 +0100 | From | Thomas Gleixner <> | Subject | [patch V181 31/54] x86/mm/pti: Populate user PGD |
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From: Dave Hansen <dave.hansen@linux.intel.com>
In clone_pgd_range() copy the init user PGDs which cover the kernel half of the address space, so a process has all the required kernel mappings visible.
[ tglx: Split out from the big kaiser dump and folded Andys simplification ]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com --- arch/x86/include/asm/pgtable.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1119,7 +1119,14 @@ static inline void pmdp_set_wrprotect(st */ static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count) { - memcpy(dst, src, count * sizeof(pgd_t)); + memcpy(dst, src, count * sizeof(pgd_t)); +#ifdef CONFIG_PAGE_TABLE_ISOLATION + if (!static_cpu_has(X86_FEATURE_PTI)) + return; + /* Clone the user space pgd as well */ + memcpy(kernel_to_user_pgdp(dst), kernel_to_user_pgdp(src), + count * sizeof(pgd_t)); +#endif } #define PTE_SHIFT ilog2(PTRS_PER_PTE)
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