Commit-ID: 6baf4bec02dbc41645c3a5130ee15a8e1d62b80f Gitweb: https://git.kernel.org/tip/6baf4bec02dbc41645c3a5130ee15a8e1d62b80f Author: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> AuthorDate: Fri, 6 Apr 2018 13:55:07 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Mon, 9 Apr 2018 18:27:33 +0200 x86/espfix: Document use of _PAGE_GLOBAL The "normal" kernel page table creation mechanisms using PAGE_KERNEL_* page protections will never set _PAGE_GLOBAL with PTI. The few places in the kernel that always want _PAGE_GLOBAL must avoid using PAGE_KERNEL_*. Document that we want it here and its use is not accidental. Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Nadav Amit <namit@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Link: http://lkml.kernel.org/r/20180406205507.BCF4D4F0@xxxxxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/espfix_64.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c index e5ec3cafa72e..aebd0d5bc086 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -195,6 +195,10 @@ void init_espfix_ap(int cpu) pte_p = pte_offset_kernel(&pmd, addr); stack_page = page_address(alloc_pages_node(node, GFP_KERNEL, 0)); + /* + * __PAGE_KERNEL_* includes _PAGE_GLOBAL, which we want since + * this is mapped to userspace. + */ pte = __pte(__pa(stack_page) | ((__PAGE_KERNEL_RO | _PAGE_ENC) & ptemask)); for (n = 0; n < ESPFIX_PTE_CLONES; n++) set_pte(&pte_p[n*PTE_STRIDE], pte); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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