From: Juerg Haefliger <juerg.haefli...@canonical.com>
This patch adds support for XPFO for x86-64. It uses the generic
infrastructure in place for XPFO and adds the architecture specific
bits to enable XPFO on x86-64.
CC: x...@kernel.org
Suggested-by: Vasileios P. Kemerlis <v...@cs.columbia.edu>
Signed-off-by: Juerg Haefliger <juerg.haefli...@canonical.com>
Signed-off-by: Tycho Andersen <ty...@tycho.ws>
Signed-off-by: Marco Benatto <marco.antonio....@gmail.com>
Signed-off-by: Julian Stecklina <jstec...@amazon.de>
Signed-off-by: Khalid Aziz <khalid.a...@oracle.com>
Cc: Khalid Aziz <kha...@gonehiking.org>
---
.../admin-guide/kernel-parameters.txt | 10 +-
arch/x86/Kconfig | 1 +
arch/x86/include/asm/pgtable.h | 26 ++++
arch/x86/mm/Makefile | 2 +
arch/x86/mm/pageattr.c | 23 +---
arch/x86/mm/xpfo.c | 123 ++++++++++++++++++
include/linux/xpfo.h | 2 +
7 files changed, 162 insertions(+), 25 deletions(-)
create mode 100644 arch/x86/mm/xpfo.c
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 9b36da94760e..e65e3bc1efe0 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2997,11 +2997,11 @@
nox2apic [X86-64,APIC] Do not enable x2APIC mode.
- noxpfo [XPFO] Disable eXclusive Page Frame Ownership (XPFO)
- when CONFIG_XPFO is on. Physical pages mapped into
- user applications will also be mapped in the
- kernel's address space as if CONFIG_XPFO was not
- enabled.
+ noxpfo [XPFO,X86-64] Disable eXclusive Page Frame
+ Ownership (XPFO) when CONFIG_XPFO is on. Physical
+ pages mapped into user applications will also be
+ mapped in the kernel's address space as if
+ CONFIG_XPFO was not enabled.
cpu0_hotplug [X86] Turn on CPU0 hotplug feature when
CONFIG_BOOTPARAM_HOTPLUG_CPU0 is off.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 68261430fe6e..122786604252 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -209,6 +209,7 @@ config X86
select USER_STACKTRACE_SUPPORT
select VIRT_TO_BUS
select X86_FEATURE_NAMES if PROC_FS
+ select ARCH_SUPPORTS_XPFO if X86_64
config INSTRUCTION_DECODER
def_bool y
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2779ace16d23..5c0e1581fa56 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1437,6 +1437,32 @@ static inline bool arch_has_pfn_modify_check(void)
return boot_cpu_has_bug(X86_BUG_L1TF);
}
+/*
+ * The current flushing context - we pass it instead of 5 arguments:
+ */
+struct cpa_data {
+ unsigned long *vaddr;
+ pgd_t *pgd;
+ pgprot_t mask_set;
+ pgprot_t mask_clr;
+ unsigned long numpages;
+ unsigned long curpage;
+ unsigned long pfn;
+ unsigned int flags;
+ unsigned int force_split : 1,
+ force_static_prot : 1;
+ struct page **pages;
+};
+
+
+int
+should_split_large_page(pte_t *kpte, unsigned long address,
+ struct cpa_data *cpa);
+extern spinlock_t cpa_lock;
+int
+__split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
+ struct page *base);
+
#include <asm-generic/pgtable.h>
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 4b101dd6e52f..93b0fdaf4a99 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -53,3 +53,5 @@ obj-$(CONFIG_PAGE_TABLE_ISOLATION) += pti.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_identity.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_boot.o
+
+obj-$(CONFIG_XPFO) += xpfo.o
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 14e6119838a6..530b5df0617e 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -28,23 +28,6 @@
#include "mm_internal.h"
-/*
- * The current flushing context - we pass it instead of 5 arguments:
- */
-struct cpa_data {
- unsigned long *vaddr;
- pgd_t *pgd;
- pgprot_t mask_set;
- pgprot_t mask_clr;
- unsigned long numpages;
- unsigned long curpage;
- unsigned long pfn;
- unsigned int flags;
- unsigned int force_split : 1,
- force_static_prot : 1;
- struct page **pages;
-};
-
enum cpa_warn {
CPA_CONFLICT,
CPA_PROTECT,
@@ -59,7 +42,7 @@ static const int cpa_warn_level = CPA_PROTECT;
* entries change the page attribute in parallel to some other cpu
* splitting a large page entry along with changing the attribute.
*/
-static DEFINE_SPINLOCK(cpa_lock);
+DEFINE_SPINLOCK(cpa_lock);
#define CPA_FLUSHTLB 1
#define CPA_ARRAY 2
@@ -876,7 +859,7 @@ static int __should_split_large_page(pte_t *kpte, unsigned
long address,
return 0;
}
-static int should_split_large_page(pte_t *kpte, unsigned long address,
+int should_split_large_page(pte_t *kpte, unsigned long address,
struct cpa_data *cpa)
{
int do_split;
@@ -926,7 +909,7 @@ static void split_set_pte(struct cpa_data *cpa, pte_t *pte,
unsigned long pfn,
set_pte(pte, pfn_pte(pfn, ref_prot));
}
-static int
+int
__split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
struct page *base)
{
diff --git a/arch/x86/mm/xpfo.c b/arch/x86/mm/xpfo.c
new file mode 100644
index 000000000000..3045bb7e4659
--- /dev/null
+++ b/arch/x86/mm/xpfo.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Hewlett Packard Enterprise Development, L.P.
+ * Copyright (C) 2016 Brown University. All rights reserved.
+ *
+ * Authors:
+ * Juerg Haefliger <juerg.haefli...@hpe.com>
+ * Vasileios P. Kemerlis <v...@cs.brown.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/mm.h>
+
+#include <asm/tlbflush.h>
+
+extern spinlock_t cpa_lock;
+
+/* Update a single kernel page table entry */
+inline void set_kpte(void *kaddr, struct page *page, pgprot_t prot)
+{
+ unsigned int level;
+ pgprot_t msk_clr;
+ pte_t *pte = lookup_address((unsigned long)kaddr, &level);
+
+ if (unlikely(!pte)) {
+ WARN(1, "xpfo: invalid address %p\n", kaddr);
+ return;
+ }
+
+ switch (level) {
+ case PG_LEVEL_4K:
+ set_pte_atomic(pte, pfn_pte(page_to_pfn(page),
+ canon_pgprot(prot)));
+ break;
+ case PG_LEVEL_2M:
+ case PG_LEVEL_1G: {
+ struct cpa_data cpa = { };
+ int do_split;
+
+ if (level == PG_LEVEL_2M)
+ msk_clr = pmd_pgprot(*(pmd_t *)pte);
+ else
+ msk_clr = pud_pgprot(*(pud_t *)pte);
+
+ cpa.vaddr = kaddr;
+ cpa.pages = &page;
+ cpa.mask_set = prot;
+ cpa.mask_clr = msk_clr;
+ cpa.numpages = 1;
+ cpa.flags = 0;
+ cpa.curpage = 0;
+ cpa.force_split = 0;
+
+
+ do_split = should_split_large_page(pte, (unsigned long)kaddr,
+ &cpa);
+ if (do_split) {
+ struct page *base;
+
+ base = alloc_pages(GFP_ATOMIC, 0);
+ if (!base) {
+ WARN(1, "xpfo: failed to split large page\n");
+ break;
+ }
+
+ if (!debug_pagealloc_enabled())
+ spin_lock(&cpa_lock);
+ if (__split_large_page(&cpa, pte, (unsigned long)kaddr,
+ base) < 0) {
+ __free_page(base);
+ WARN(1, "xpfo: failed to split large page\n");
+ }
+ if (!debug_pagealloc_enabled())
+ spin_unlock(&cpa_lock);
+ }
+
+ break;
+ }
+ case PG_LEVEL_512G:
+ /* fallthrough, splitting infrastructure doesn't
+ * support 512G pages.
+ */
+ default:
+ WARN(1, "xpfo: unsupported page level %x\n", level);
+ }
+
+}
+EXPORT_SYMBOL_GPL(set_kpte);
+
+inline void xpfo_flush_kernel_tlb(struct page *page, int order)
+{
+ int level;
+ unsigned long size, kaddr;
+
+ kaddr = (unsigned long)page_address(page);
+
+ if (unlikely(!lookup_address(kaddr, &level))) {
+ WARN(1, "xpfo: invalid address to flush %lx %d\n", kaddr,
+ level);
+ return;
+ }
+
+ switch (level) {
+ case PG_LEVEL_4K:
+ size = PAGE_SIZE;
+ break;
+ case PG_LEVEL_2M:
+ size = PMD_SIZE;
+ break;
+ case PG_LEVEL_1G:
+ size = PUD_SIZE;
+ break;
+ default:
+ WARN(1, "xpfo: unsupported page level %x\n", level);
+ return;
+ }
+
+ flush_tlb_kernel_range(kaddr, kaddr + (1 << order) * size);
+}
+EXPORT_SYMBOL_GPL(xpfo_flush_kernel_tlb);
diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h
index 93a1b5aceca3..c1d232da7ee0 100644
--- a/include/linux/xpfo.h
+++ b/include/linux/xpfo.h
@@ -25,6 +25,8 @@ struct page;
#ifdef CONFIG_XPFO
+#include <linux/dma-mapping.h>
+
DECLARE_STATIC_KEY_TRUE(xpfo_inited);
/* Architecture specific implementations */
--
2.17.1
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