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Message-Id: <20210121122723.3446-6-rppt@kernel.org>
Date: Thu, 21 Jan 2021 14:27:17 +0200
From: Mike Rapoport <rppt@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
Andy Lutomirski <luto@...nel.org>,
Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...en8.de>,
Catalin Marinas <catalin.marinas@....com>,
Christopher Lameter <cl@...ux.com>,
Dan Williams <dan.j.williams@...el.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
David Hildenbrand <david@...hat.com>,
Elena Reshetova <elena.reshetova@...el.com>,
"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
James Bottomley <jejb@...ux.ibm.com>,
"Kirill A. Shutemov" <kirill@...temov.name>,
Matthew Wilcox <willy@...radead.org>,
Mark Rutland <mark.rutland@....com>,
Mike Rapoport <rppt@...ux.ibm.com>,
Mike Rapoport <rppt@...nel.org>,
Michael Kerrisk <mtk.manpages@...il.com>,
Palmer Dabbelt <palmer@...belt.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Peter Zijlstra <peterz@...radead.org>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
Roman Gushchin <guro@...com>,
Shakeel Butt <shakeelb@...gle.com>,
Shuah Khan <shuah@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Tycho Andersen <tycho@...ho.ws>, Will Deacon <will@...nel.org>,
linux-api@...r.kernel.org, linux-arch@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-nvdimm@...ts.01.org, linux-riscv@...ts.infradead.org,
x86@...nel.org, Hagen Paul Pfeifer <hagen@...u.net>,
Palmer Dabbelt <palmerdabbelt@...gle.com>
Subject: [PATCH v16 05/11] set_memory: allow querying whether set_direct_map_*() is actually enabled
From: Mike Rapoport <rppt@...ux.ibm.com>
On arm64, set_direct_map_*() functions may return 0 without actually
changing the linear map. This behaviour can be controlled using kernel
parameters, so we need a way to determine at runtime whether calls to
set_direct_map_invalid_noflush() and set_direct_map_default_noflush() have
any effect.
Extend set_memory API with can_set_direct_map() function that allows
checking if calling set_direct_map_*() will actually change the page table,
replace several occurrences of open coded checks in arm64 with the new
function and provide a generic stub for architectures that always modify
page tables upon calls to set_direct_map APIs.
Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@....com>
Reviewed-by: David Hildenbrand <david@...hat.com>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Christopher Lameter <cl@...ux.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Elena Reshetova <elena.reshetova@...el.com>
Cc: Hagen Paul Pfeifer <hagen@...u.net>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: James Bottomley <jejb@...ux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@...temov.name>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Michael Kerrisk <mtk.manpages@...il.com>
Cc: Palmer Dabbelt <palmer@...belt.com>
Cc: Palmer Dabbelt <palmerdabbelt@...gle.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@...el.com>
Cc: Roman Gushchin <guro@...com>
Cc: Shakeel Butt <shakeelb@...gle.com>
Cc: Shuah Khan <shuah@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Tycho Andersen <tycho@...ho.ws>
Cc: Will Deacon <will@...nel.org>
---
arch/arm64/include/asm/Kbuild | 1 -
arch/arm64/include/asm/cacheflush.h | 6 ------
arch/arm64/include/asm/set_memory.h | 17 +++++++++++++++++
arch/arm64/kernel/machine_kexec.c | 1 +
arch/arm64/mm/mmu.c | 6 +++---
arch/arm64/mm/pageattr.c | 13 +++++++++----
include/linux/set_memory.h | 12 ++++++++++++
7 files changed, 42 insertions(+), 14 deletions(-)
create mode 100644 arch/arm64/include/asm/set_memory.h
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index 07ac208edc89..73aa25843f65 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild
@@ -3,5 +3,4 @@ generic-y += early_ioremap.h
generic-y += mcs_spinlock.h
generic-y += qrwlock.h
generic-y += qspinlock.h
-generic-y += set_memory.h
generic-y += user.h
diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index d3598419a284..b1bdf83a73db 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -136,12 +136,6 @@ static __always_inline void __flush_icache_all(void)
dsb(ish);
}
-int set_memory_valid(unsigned long addr, int numpages, int enable);
-
-int set_direct_map_invalid_noflush(struct page *page, int numpages);
-int set_direct_map_default_noflush(struct page *page, int numpages);
-bool kernel_page_present(struct page *page);
-
#include <asm-generic/cacheflush.h>
#endif /* __ASM_CACHEFLUSH_H */
diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h
new file mode 100644
index 000000000000..ecb6b0f449ab
--- /dev/null
+++ b/arch/arm64/include/asm/set_memory.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ASM_ARM64_SET_MEMORY_H
+#define _ASM_ARM64_SET_MEMORY_H
+
+#include <asm-generic/set_memory.h>
+
+bool can_set_direct_map(void);
+#define can_set_direct_map can_set_direct_map
+
+int set_memory_valid(unsigned long addr, int numpages, int enable);
+
+int set_direct_map_invalid_noflush(struct page *page, int numpages);
+int set_direct_map_default_noflush(struct page *page, int numpages);
+bool kernel_page_present(struct page *page);
+
+#endif /* _ASM_ARM64_SET_MEMORY_H */
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index a0b144cfaea7..0cbc50c4fa5a 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/page-flags.h>
+#include <linux/set_memory.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 30c6dd02e706..79604049fff5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -22,6 +22,7 @@
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
+#include <linux/set_memory.h>
#include <asm/barrier.h>
#include <asm/cputype.h>
@@ -492,7 +493,7 @@ static void __init map_mem(pgd_t *pgdp)
int flags = 0;
u64 i;
- if (rodata_full || crash_mem_map || debug_pagealloc_enabled())
+ if (can_set_direct_map() || crash_mem_map)
flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
/*
@@ -1468,8 +1469,7 @@ int arch_add_memory(int nid, u64 start, u64 size,
* KFENCE requires linear map to be mapped at page granularity, so that
* it is possible to protect/unprotect single pages in the KFENCE pool.
*/
- if (rodata_full || debug_pagealloc_enabled() ||
- IS_ENABLED(CONFIG_KFENCE))
+ if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE))
flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index b53ef37bf95a..d505172265b0 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -19,6 +19,11 @@ struct page_change_data {
bool rodata_full __ro_after_init = IS_ENABLED(CONFIG_RODATA_FULL_DEFAULT_ENABLED);
+bool can_set_direct_map(void)
+{
+ return rodata_full || debug_pagealloc_enabled();
+}
+
static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
{
struct page_change_data *cdata = data;
@@ -156,7 +161,7 @@ int set_direct_map_invalid_noflush(struct page *page, int numpages)
};
unsigned long size = PAGE_SIZE * numpages;
- if (!debug_pagealloc_enabled() && !rodata_full)
+ if (!can_set_direct_map())
return 0;
return apply_to_page_range(&init_mm,
@@ -172,7 +177,7 @@ int set_direct_map_default_noflush(struct page *page, int numpages)
};
unsigned long size = PAGE_SIZE * numpages;
- if (!debug_pagealloc_enabled() && !rodata_full)
+ if (!can_set_direct_map())
return 0;
return apply_to_page_range(&init_mm,
@@ -183,7 +188,7 @@ int set_direct_map_default_noflush(struct page *page, int numpages)
#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
- if (!debug_pagealloc_enabled() && !rodata_full)
+ if (!can_set_direct_map())
return;
set_memory_valid((unsigned long)page_address(page), numpages, enable);
@@ -208,7 +213,7 @@ bool kernel_page_present(struct page *page)
pte_t *ptep;
unsigned long addr = (unsigned long)page_address(page);
- if (!debug_pagealloc_enabled() && !rodata_full)
+ if (!can_set_direct_map())
return true;
pgdp = pgd_offset_k(addr);
diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index c650f82db813..7b4b6626032d 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -28,7 +28,19 @@ static inline bool kernel_page_present(struct page *page)
{
return true;
}
+#else /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */
+/*
+ * Some architectures, e.g. ARM64 can disable direct map modifications at
+ * boot time. Let them overrive this query.
+ */
+#ifndef can_set_direct_map
+static inline bool can_set_direct_map(void)
+{
+ return true;
+}
+#define can_set_direct_map can_set_direct_map
#endif
+#endif /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */
#ifndef set_mce_nospec
static inline int set_mce_nospec(unsigned long pfn, bool unmap)
--
2.28.0
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