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From: Calvin Owens <jcalvinowens@gmail.com>
To: Luis Chamberlain <mcgrof@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Naveen N Rao <naveen.n.rao@linux.ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
	David S Miller <davem@davemloft.net>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Calvin Owens <jcalvinowens@gmail.com>,
	bpf@vger.kernel.org, linux-modules@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [RFC][PATCH 1/4] module: mm: Make module_alloc() generally available
Date: Wed,  6 Mar 2024 12:05:08 -0800	[thread overview]
Message-ID: <a6b162aed1e6fea7f565ef9dd0204d6f2284bcce.1709676663.git.jcalvinowens@gmail.com> (raw)
In-Reply-To: <cover.1709676663.git.jcalvinowens@gmail.com>

Both BPF_JIT and KPROBES depend on CONFIG_MODULES, but only require
module_alloc() itself, which can be easily separated into a standalone
allocator for executable kernel memory.

Thomas Gleixner sent a patch to do that for x86 as part of a larger
series a couple years ago:

    https://lore.kernel.org/all/20220716230953.442937066@linutronix.de/

I've simply extended that approach to the whole kernel.

Signed-off-by: Calvin Owens <jcalvinowens@gmail.com>
---
 arch/Kconfig                     |   2 +-
 arch/arm/kernel/module.c         |  35 ---------
 arch/arm/mm/Makefile             |   2 +
 arch/arm/mm/module_alloc.c       |  40 ++++++++++
 arch/arm64/kernel/module.c       | 127 ------------------------------
 arch/arm64/mm/Makefile           |   1 +
 arch/arm64/mm/module_alloc.c     | 130 +++++++++++++++++++++++++++++++
 arch/loongarch/kernel/module.c   |   6 --
 arch/loongarch/mm/Makefile       |   2 +
 arch/loongarch/mm/module_alloc.c |  10 +++
 arch/mips/kernel/module.c        |  10 ---
 arch/mips/mm/Makefile            |   2 +
 arch/mips/mm/module_alloc.c      |  13 ++++
 arch/nios2/kernel/module.c       |  20 -----
 arch/nios2/mm/Makefile           |   2 +
 arch/nios2/mm/module_alloc.c     |  22 ++++++
 arch/parisc/kernel/module.c      |  12 ---
 arch/parisc/mm/Makefile          |   1 +
 arch/parisc/mm/module_alloc.c    |  15 ++++
 arch/powerpc/kernel/module.c     |  36 ---------
 arch/powerpc/mm/Makefile         |   1 +
 arch/powerpc/mm/module_alloc.c   |  41 ++++++++++
 arch/riscv/kernel/module.c       |  11 ---
 arch/riscv/mm/Makefile           |   1 +
 arch/riscv/mm/module_alloc.c     |  17 ++++
 arch/s390/kernel/module.c        |  37 ---------
 arch/s390/mm/Makefile            |   1 +
 arch/s390/mm/module_alloc.c      |  42 ++++++++++
 arch/sparc/kernel/module.c       |  31 --------
 arch/sparc/mm/Makefile           |   2 +
 arch/sparc/mm/module_alloc.c     |  31 ++++++++
 arch/x86/kernel/ftrace.c         |   2 +-
 arch/x86/kernel/module.c         |  56 -------------
 arch/x86/mm/Makefile             |   2 +
 arch/x86/mm/module_alloc.c       |  59 ++++++++++++++
 fs/proc/kcore.c                  |   2 +-
 kernel/module/Kconfig            |   1 +
 kernel/module/main.c             |  17 ----
 mm/Kconfig                       |   3 +
 mm/Makefile                      |   1 +
 mm/module_alloc.c                |  21 +++++
 mm/vmalloc.c                     |   2 +-
 42 files changed, 467 insertions(+), 402 deletions(-)
 create mode 100644 arch/arm/mm/module_alloc.c
 create mode 100644 arch/arm64/mm/module_alloc.c
 create mode 100644 arch/loongarch/mm/module_alloc.c
 create mode 100644 arch/mips/mm/module_alloc.c
 create mode 100644 arch/nios2/mm/module_alloc.c
 create mode 100644 arch/parisc/mm/module_alloc.c
 create mode 100644 arch/powerpc/mm/module_alloc.c
 create mode 100644 arch/riscv/mm/module_alloc.c
 create mode 100644 arch/s390/mm/module_alloc.c
 create mode 100644 arch/sparc/mm/module_alloc.c
 create mode 100644 arch/x86/mm/module_alloc.c
 create mode 100644 mm/module_alloc.c

diff --git a/arch/Kconfig b/arch/Kconfig
index a5af0edd3eb8..cfc24ced16dd 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1305,7 +1305,7 @@ config ARCH_HAS_STRICT_MODULE_RWX
 
 config STRICT_MODULE_RWX
 	bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
-	depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
+	depends on ARCH_HAS_STRICT_MODULE_RWX && MODULE_ALLOC
 	default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
 	help
 	  If this is set, module text and rodata memory will be made read-only,
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index e74d84f58b77..1c8798732d12 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -4,15 +4,12 @@
  *
  *  Copyright (C) 2002 Russell King.
  *  Modified for nommu by Hyok S. Choi
- *
- * Module allocation method suggested by Andi Kleen.
  */
 #include <linux/module.h>
 #include <linux/moduleloader.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/elf.h>
-#include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/gfp.h>
@@ -22,38 +19,6 @@
 #include <asm/unwind.h>
 #include <asm/opcodes.h>
 
-#ifdef CONFIG_XIP_KERNEL
-/*
- * The XIP kernel text is mapped in the module area for modules and
- * some other stuff to work without any indirect relocations.
- * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
- * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
- */
-#undef MODULES_VADDR
-#define MODULES_VADDR	(((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK)
-#endif
-
-#ifdef CONFIG_MMU
-void *module_alloc(unsigned long size)
-{
-	gfp_t gfp_mask = GFP_KERNEL;
-	void *p;
-
-	/* Silence the initial allocation */
-	if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS))
-		gfp_mask |= __GFP_NOWARN;
-
-	p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
-				gfp_mask, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
-				__builtin_return_address(0));
-	if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p)
-		return p;
-	return __vmalloc_node_range(size, 1,  VMALLOC_START, VMALLOC_END,
-				GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
-				__builtin_return_address(0));
-}
-#endif
-
 bool module_init_section(const char *name)
 {
 	return strstarts(name, ".init") ||
diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index 71b858c9b10c..a05a6701a884 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -100,3 +100,5 @@ obj-$(CONFIG_CACHE_UNIPHIER)	+= cache-uniphier.o
 
 KASAN_SANITIZE_kasan_init.o	:= n
 obj-$(CONFIG_KASAN)		+= kasan_init.o
+
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
diff --git a/arch/arm/mm/module_alloc.c b/arch/arm/mm/module_alloc.c
new file mode 100644
index 000000000000..e48be48b2b5f
--- /dev/null
+++ b/arch/arm/mm/module_alloc.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#ifdef CONFIG_XIP_KERNEL
+/*
+ * The XIP kernel text is mapped in the module area for modules and
+ * some other stuff to work without any indirect relocations.
+ * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
+ * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
+ */
+#undef MODULES_VADDR
+#define MODULES_VADDR	(((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK)
+#endif
+
+/*
+ * Module allocation method suggested by Andi Kleen.
+ */
+
+#ifdef CONFIG_MMU
+void *module_alloc(unsigned long size)
+{
+	gfp_t gfp_mask = GFP_KERNEL;
+	void *p;
+
+	/* Silence the initial allocation */
+	if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS))
+		gfp_mask |= __GFP_NOWARN;
+
+	p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
+				gfp_mask, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
+				__builtin_return_address(0));
+	if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p)
+		return p;
+	return __vmalloc_node_range(size, 1,  VMALLOC_START, VMALLOC_END,
+				GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
+				__builtin_return_address(0));
+}
+#endif
diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
index dd851297596e..78758ed818b0 100644
--- a/arch/arm64/kernel/module.c
+++ b/arch/arm64/kernel/module.c
@@ -13,143 +13,16 @@
 #include <linux/elf.h>
 #include <linux/ftrace.h>
 #include <linux/gfp.h>
-#include <linux/kasan.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/moduleloader.h>
-#include <linux/random.h>
 #include <linux/scs.h>
-#include <linux/vmalloc.h>
 
 #include <asm/alternative.h>
 #include <asm/insn.h>
 #include <asm/scs.h>
 #include <asm/sections.h>
 
-static u64 module_direct_base __ro_after_init = 0;
-static u64 module_plt_base __ro_after_init = 0;
-
-/*
- * Choose a random page-aligned base address for a window of 'size' bytes which
- * entirely contains the interval [start, end - 1].
- */
-static u64 __init random_bounding_box(u64 size, u64 start, u64 end)
-{
-	u64 max_pgoff, pgoff;
-
-	if ((end - start) >= size)
-		return 0;
-
-	max_pgoff = (size - (end - start)) / PAGE_SIZE;
-	pgoff = get_random_u32_inclusive(0, max_pgoff);
-
-	return start - pgoff * PAGE_SIZE;
-}
-
-/*
- * Modules may directly reference data and text anywhere within the kernel
- * image and other modules. References using PREL32 relocations have a +/-2G
- * range, and so we need to ensure that the entire kernel image and all modules
- * fall within a 2G window such that these are always within range.
- *
- * Modules may directly branch to functions and code within the kernel text,
- * and to functions and code within other modules. These branches will use
- * CALL26/JUMP26 relocations with a +/-128M range. Without PLTs, we must ensure
- * that the entire kernel text and all module text falls within a 128M window
- * such that these are always within range. With PLTs, we can expand this to a
- * 2G window.
- *
- * We chose the 128M region to surround the entire kernel image (rather than
- * just the text) as using the same bounds for the 128M and 2G regions ensures
- * by construction that we never select a 128M region that is not a subset of
- * the 2G region. For very large and unusual kernel configurations this means
- * we may fall back to PLTs where they could have been avoided, but this keeps
- * the logic significantly simpler.
- */
-static int __init module_init_limits(void)
-{
-	u64 kernel_end = (u64)_end;
-	u64 kernel_start = (u64)_text;
-	u64 kernel_size = kernel_end - kernel_start;
-
-	/*
-	 * The default modules region is placed immediately below the kernel
-	 * image, and is large enough to use the full 2G relocation range.
-	 */
-	BUILD_BUG_ON(KIMAGE_VADDR != MODULES_END);
-	BUILD_BUG_ON(MODULES_VSIZE < SZ_2G);
-
-	if (!kaslr_enabled()) {
-		if (kernel_size < SZ_128M)
-			module_direct_base = kernel_end - SZ_128M;
-		if (kernel_size < SZ_2G)
-			module_plt_base = kernel_end - SZ_2G;
-	} else {
-		u64 min = kernel_start;
-		u64 max = kernel_end;
-
-		if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) {
-			pr_info("2G module region forced by RANDOMIZE_MODULE_REGION_FULL\n");
-		} else {
-			module_direct_base = random_bounding_box(SZ_128M, min, max);
-			if (module_direct_base) {
-				min = module_direct_base;
-				max = module_direct_base + SZ_128M;
-			}
-		}
-
-		module_plt_base = random_bounding_box(SZ_2G, min, max);
-	}
-
-	pr_info("%llu pages in range for non-PLT usage",
-		module_direct_base ? (SZ_128M - kernel_size) / PAGE_SIZE : 0);
-	pr_info("%llu pages in range for PLT usage",
-		module_plt_base ? (SZ_2G - kernel_size) / PAGE_SIZE : 0);
-
-	return 0;
-}
-subsys_initcall(module_init_limits);
-
-void *module_alloc(unsigned long size)
-{
-	void *p = NULL;
-
-	/*
-	 * Where possible, prefer to allocate within direct branch range of the
-	 * kernel such that no PLTs are necessary.
-	 */
-	if (module_direct_base) {
-		p = __vmalloc_node_range(size, MODULE_ALIGN,
-					 module_direct_base,
-					 module_direct_base + SZ_128M,
-					 GFP_KERNEL | __GFP_NOWARN,
-					 PAGE_KERNEL, 0, NUMA_NO_NODE,
-					 __builtin_return_address(0));
-	}
-
-	if (!p && module_plt_base) {
-		p = __vmalloc_node_range(size, MODULE_ALIGN,
-					 module_plt_base,
-					 module_plt_base + SZ_2G,
-					 GFP_KERNEL | __GFP_NOWARN,
-					 PAGE_KERNEL, 0, NUMA_NO_NODE,
-					 __builtin_return_address(0));
-	}
-
-	if (!p) {
-		pr_warn_ratelimited("%s: unable to allocate memory\n",
-				    __func__);
-	}
-
-	if (p && (kasan_alloc_module_shadow(p, size, GFP_KERNEL) < 0)) {
-		vfree(p);
-		return NULL;
-	}
-
-	/* Memory is intended to be executable, reset the pointer tag. */
-	return kasan_reset_tag(p);
-}
-
 enum aarch64_reloc_op {
 	RELOC_OP_NONE,
 	RELOC_OP_ABS,
diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index dbd1bc95967d..cf616635a80d 100644
--- a/arch/arm64/mm/Makefile
+++ b/arch/arm64/mm/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_TRANS_TABLE)	+= trans_pgd.o
 obj-$(CONFIG_TRANS_TABLE)	+= trans_pgd-asm.o
 obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o
 obj-$(CONFIG_ARM64_MTE)		+= mteswap.o
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
 KASAN_SANITIZE_physaddr.o	+= n
 
 obj-$(CONFIG_KASAN)		+= kasan_init.o
diff --git a/arch/arm64/mm/module_alloc.c b/arch/arm64/mm/module_alloc.c
new file mode 100644
index 000000000000..302642ea9e26
--- /dev/null
+++ b/arch/arm64/mm/module_alloc.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/kasan.h>
+#include <linux/random.h>
+
+static u64 module_direct_base __ro_after_init = 0;
+static u64 module_plt_base __ro_after_init = 0;
+
+/*
+ * Choose a random page-aligned base address for a window of 'size' bytes which
+ * entirely contains the interval [start, end - 1].
+ */
+static u64 __init random_bounding_box(u64 size, u64 start, u64 end)
+{
+	u64 max_pgoff, pgoff;
+
+	if ((end - start) >= size)
+		return 0;
+
+	max_pgoff = (size - (end - start)) / PAGE_SIZE;
+	pgoff = get_random_u32_inclusive(0, max_pgoff);
+
+	return start - pgoff * PAGE_SIZE;
+}
+
+/*
+ * Modules may directly reference data and text anywhere within the kernel
+ * image and other modules. References using PREL32 relocations have a +/-2G
+ * range, and so we need to ensure that the entire kernel image and all modules
+ * fall within a 2G window such that these are always within range.
+ *
+ * Modules may directly branch to functions and code within the kernel text,
+ * and to functions and code within other modules. These branches will use
+ * CALL26/JUMP26 relocations with a +/-128M range. Without PLTs, we must ensure
+ * that the entire kernel text and all module text falls within a 128M window
+ * such that these are always within range. With PLTs, we can expand this to a
+ * 2G window.
+ *
+ * We chose the 128M region to surround the entire kernel image (rather than
+ * just the text) as using the same bounds for the 128M and 2G regions ensures
+ * by construction that we never select a 128M region that is not a subset of
+ * the 2G region. For very large and unusual kernel configurations this means
+ * we may fall back to PLTs where they could have been avoided, but this keeps
+ * the logic significantly simpler.
+ */
+static int __init module_init_limits(void)
+{
+	u64 kernel_end = (u64)_end;
+	u64 kernel_start = (u64)_text;
+	u64 kernel_size = kernel_end - kernel_start;
+
+	/*
+	 * The default modules region is placed immediately below the kernel
+	 * image, and is large enough to use the full 2G relocation range.
+	 */
+	BUILD_BUG_ON(KIMAGE_VADDR != MODULES_END);
+	BUILD_BUG_ON(MODULES_VSIZE < SZ_2G);
+
+	if (!kaslr_enabled()) {
+		if (kernel_size < SZ_128M)
+			module_direct_base = kernel_end - SZ_128M;
+		if (kernel_size < SZ_2G)
+			module_plt_base = kernel_end - SZ_2G;
+	} else {
+		u64 min = kernel_start;
+		u64 max = kernel_end;
+
+		if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) {
+			pr_info("2G module region forced by RANDOMIZE_MODULE_REGION_FULL\n");
+		} else {
+			module_direct_base = random_bounding_box(SZ_128M, min, max);
+			if (module_direct_base) {
+				min = module_direct_base;
+				max = module_direct_base + SZ_128M;
+			}
+		}
+
+		module_plt_base = random_bounding_box(SZ_2G, min, max);
+	}
+
+	pr_info("%llu pages in range for non-PLT usage",
+		module_direct_base ? (SZ_128M - kernel_size) / PAGE_SIZE : 0);
+	pr_info("%llu pages in range for PLT usage",
+		module_plt_base ? (SZ_2G - kernel_size) / PAGE_SIZE : 0);
+
+	return 0;
+}
+subsys_initcall(module_init_limits);
+
+void *module_alloc(unsigned long size)
+{
+	void *p = NULL;
+
+	/*
+	 * Where possible, prefer to allocate within direct branch range of the
+	 * kernel such that no PLTs are necessary.
+	 */
+	if (module_direct_base) {
+		p = __vmalloc_node_range(size, MODULE_ALIGN,
+					 module_direct_base,
+					 module_direct_base + SZ_128M,
+					 GFP_KERNEL | __GFP_NOWARN,
+					 PAGE_KERNEL, 0, NUMA_NO_NODE,
+					 __builtin_return_address(0));
+	}
+
+	if (!p && module_plt_base) {
+		p = __vmalloc_node_range(size, MODULE_ALIGN,
+					 module_plt_base,
+					 module_plt_base + SZ_2G,
+					 GFP_KERNEL | __GFP_NOWARN,
+					 PAGE_KERNEL, 0, NUMA_NO_NODE,
+					 __builtin_return_address(0));
+	}
+
+	if (!p) {
+		pr_warn_ratelimited("%s: unable to allocate memory\n",
+				    __func__);
+	}
+
+	if (p && (kasan_alloc_module_shadow(p, size, GFP_KERNEL) < 0)) {
+		vfree(p);
+		return NULL;
+	}
+
+	/* Memory is intended to be executable, reset the pointer tag. */
+	return kasan_reset_tag(p);
+}
diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index b13b2858fe39..7f03166513b3 100644
--- a/arch/loongarch/kernel/module.c
+++ b/arch/loongarch/kernel/module.c
@@ -489,12 +489,6 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
 	return 0;
 }
 
-void *module_alloc(unsigned long size)
-{
-	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
-			GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0));
-}
-
 static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
 				   const Elf_Shdr *sechdrs, struct module *mod)
 {
diff --git a/arch/loongarch/mm/Makefile b/arch/loongarch/mm/Makefile
index e4d1e581dbae..3966fc6118f1 100644
--- a/arch/loongarch/mm/Makefile
+++ b/arch/loongarch/mm/Makefile
@@ -10,3 +10,5 @@ obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 obj-$(CONFIG_KASAN)		+= kasan_init.o
 
 KASAN_SANITIZE_kasan_init.o     := n
+
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
diff --git a/arch/loongarch/mm/module_alloc.c b/arch/loongarch/mm/module_alloc.c
new file mode 100644
index 000000000000..24b0cb3a2088
--- /dev/null
+++ b/arch/loongarch/mm/module_alloc.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+void *module_alloc(unsigned long size)
+{
+	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
+			GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0));
+}
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
index 7b2fbaa9cac5..ba0f62d8eff5 100644
--- a/arch/mips/kernel/module.c
+++ b/arch/mips/kernel/module.c
@@ -13,7 +13,6 @@
 #include <linux/elf.h>
 #include <linux/mm.h>
 #include <linux/numa.h>
-#include <linux/vmalloc.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/string.h>
@@ -31,15 +30,6 @@ struct mips_hi16 {
 static LIST_HEAD(dbe_list);
 static DEFINE_SPINLOCK(dbe_lock);
 
-#ifdef MODULE_START
-void *module_alloc(unsigned long size)
-{
-	return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
-				GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
-				__builtin_return_address(0));
-}
-#endif
-
 static void apply_r_mips_32(u32 *location, u32 base, Elf_Addr v)
 {
 	*location = base + v;
diff --git a/arch/mips/mm/Makefile b/arch/mips/mm/Makefile
index 304692391519..b9cfe37e41e4 100644
--- a/arch/mips/mm/Makefile
+++ b/arch/mips/mm/Makefile
@@ -45,3 +45,5 @@ obj-$(CONFIG_MIPS_CPU_SCACHE)	+= sc-mips.o
 obj-$(CONFIG_SCACHE_DEBUGFS)	+= sc-debugfs.o
 
 obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o
+
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
diff --git a/arch/mips/mm/module_alloc.c b/arch/mips/mm/module_alloc.c
new file mode 100644
index 000000000000..fcdbdece42f3
--- /dev/null
+++ b/arch/mips/mm/module_alloc.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#ifdef MODULE_START
+void *module_alloc(unsigned long size)
+{
+	return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
+				GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
+				__builtin_return_address(0));
+}
+#endif
diff --git a/arch/nios2/kernel/module.c b/arch/nios2/kernel/module.c
index 76e0a42d6e36..f4483243578d 100644
--- a/arch/nios2/kernel/module.c
+++ b/arch/nios2/kernel/module.c
@@ -13,7 +13,6 @@
 #include <linux/moduleloader.h>
 #include <linux/elf.h>
 #include <linux/mm.h>
-#include <linux/vmalloc.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/string.h>
@@ -21,25 +20,6 @@
 
 #include <asm/cacheflush.h>
 
-/*
- * Modules should NOT be allocated with kmalloc for (obvious) reasons.
- * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
- * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
- * addresses in 0xc0000000)
- */
-void *module_alloc(unsigned long size)
-{
-	if (size == 0)
-		return NULL;
-	return kmalloc(size, GFP_KERNEL);
-}
-
-/* Free memory returned from module_alloc */
-void module_memfree(void *module_region)
-{
-	kfree(module_region);
-}
-
 int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 			unsigned int symindex, unsigned int relsec,
 			struct module *mod)
diff --git a/arch/nios2/mm/Makefile b/arch/nios2/mm/Makefile
index 9d37fafd1dd1..facbb3e60013 100644
--- a/arch/nios2/mm/Makefile
+++ b/arch/nios2/mm/Makefile
@@ -13,3 +13,5 @@ obj-y	+= mmu_context.o
 obj-y	+= pgtable.o
 obj-y	+= tlb.o
 obj-y	+= uaccess.o
+
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
diff --git a/arch/nios2/mm/module_alloc.c b/arch/nios2/mm/module_alloc.c
new file mode 100644
index 000000000000..92c7c32ef8b3
--- /dev/null
+++ b/arch/nios2/mm/module_alloc.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/moduleloader.h>
+#include <linux/slab.h>
+
+/*
+ * Modules should NOT be allocated with kmalloc for (obvious) reasons.
+ * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
+ * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
+ * addresses in 0xc0000000)
+ */
+void *module_alloc(unsigned long size)
+{
+	if (size == 0)
+		return NULL;
+	return kmalloc(size, GFP_KERNEL);
+}
+
+/* Free memory returned from module_alloc */
+void module_memfree(void *module_region)
+{
+	kfree(module_region);
+}
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index d214bbe3c2af..4e5d991b2b65 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -41,7 +41,6 @@
 
 #include <linux/moduleloader.h>
 #include <linux/elf.h>
-#include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/ftrace.h>
 #include <linux/string.h>
@@ -173,17 +172,6 @@ static inline int reassemble_22(int as22)
 		((as22 & 0x0003ff) << 3));
 }
 
-void *module_alloc(unsigned long size)
-{
-	/* using RWX means less protection for modules, but it's
-	 * easier than trying to map the text, data, init_text and
-	 * init_data correctly */
-	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
-				    GFP_KERNEL,
-				    PAGE_KERNEL_RWX, 0, NUMA_NO_NODE,
-				    __builtin_return_address(0));
-}
-
 #ifndef CONFIG_64BIT
 static inline unsigned long count_gots(const Elf_Rela *rela, unsigned long n)
 {
diff --git a/arch/parisc/mm/Makefile b/arch/parisc/mm/Makefile
index ffdb5c0a8cc6..95a6d4469785 100644
--- a/arch/parisc/mm/Makefile
+++ b/arch/parisc/mm/Makefile
@@ -5,3 +5,4 @@
 
 obj-y	 := init.o fault.o ioremap.o fixmap.o
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
+obj-$(CONFIG_MODULE_ALLOC) += module_alloc.o
diff --git a/arch/parisc/mm/module_alloc.c b/arch/parisc/mm/module_alloc.c
new file mode 100644
index 000000000000..5ad9bfc3ffab
--- /dev/null
+++ b/arch/parisc/mm/module_alloc.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+void *module_alloc(unsigned long size)
+{
+	/* using RWX means less protection for modules, but it's
+	 * easier than trying to map the text, data, init_text and
+	 * init_data correctly */
+	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
+				    GFP_KERNEL,
+				    PAGE_KERNEL_RWX, 0, NUMA_NO_NODE,
+				    __builtin_return_address(0));
+}
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index f6d6ae0a1692..b5fe9c61e527 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -89,39 +89,3 @@ int module_finalize(const Elf_Ehdr *hdr,
 	return 0;
 }
 
-static __always_inline void *
-__module_alloc(unsigned long size, unsigned long start, unsigned long end, bool nowarn)
-{
-	pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL : PAGE_KERNEL_EXEC;
-	gfp_t gfp = GFP_KERNEL | (nowarn ? __GFP_NOWARN : 0);
-
-	/*
-	 * Don't do huge page allocations for modules yet until more testing
-	 * is done. STRICT_MODULE_RWX may require extra work to support this
-	 * too.
-	 */
-	return __vmalloc_node_range(size, 1, start, end, gfp, prot,
-				    VM_FLUSH_RESET_PERMS,
-				    NUMA_NO_NODE, __builtin_return_address(0));
-}
-
-void *module_alloc(unsigned long size)
-{
-#ifdef MODULES_VADDR
-	unsigned long limit = (unsigned long)_etext - SZ_32M;
-	void *ptr = NULL;
-
-	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
-
-	/* First try within 32M limit from _etext to avoid branch trampolines */
-	if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit)
-		ptr = __module_alloc(size, limit, MODULES_END, true);
-
-	if (!ptr)
-		ptr = __module_alloc(size, MODULES_VADDR, MODULES_END, false);
-
-	return ptr;
-#else
-	return __module_alloc(size, VMALLOC_START, VMALLOC_END, false);
-#endif
-}
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index 503a6e249940..4572273a838f 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -19,3 +19,4 @@ obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o
 obj-$(CONFIG_PPC_COPRO_BASE)	+= copro_fault.o
 obj-$(CONFIG_PTDUMP_CORE)	+= ptdump/
 obj-$(CONFIG_KASAN)		+= kasan/
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
diff --git a/arch/powerpc/mm/module_alloc.c b/arch/powerpc/mm/module_alloc.c
new file mode 100644
index 000000000000..818e5cd8fbc6
--- /dev/null
+++ b/arch/powerpc/mm/module_alloc.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+static __always_inline void *
+__module_alloc(unsigned long size, unsigned long start, unsigned long end, bool nowarn)
+{
+	pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL : PAGE_KERNEL_EXEC;
+	gfp_t gfp = GFP_KERNEL | (nowarn ? __GFP_NOWARN : 0);
+
+	/*
+	 * Don't do huge page allocations for modules yet until more testing
+	 * is done. STRICT_MODULE_RWX may require extra work to support this
+	 * too.
+	 */
+	return __vmalloc_node_range(size, 1, start, end, gfp, prot,
+				    VM_FLUSH_RESET_PERMS,
+				    NUMA_NO_NODE, __builtin_return_address(0));
+}
+
+void *module_alloc(unsigned long size)
+{
+#ifdef MODULES_VADDR
+	unsigned long limit = (unsigned long)_etext - SZ_32M;
+	void *ptr = NULL;
+
+	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
+
+	/* First try within 32M limit from _etext to avoid branch trampolines */
+	if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit)
+		ptr = __module_alloc(size, limit, MODULES_END, true);
+
+	if (!ptr)
+		ptr = __module_alloc(size, MODULES_VADDR, MODULES_END, false);
+
+	return ptr;
+#else
+	return __module_alloc(size, VMALLOC_START, VMALLOC_END, false);
+#endif
+}
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 5e5a82644451..53d7005fdbdb 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -11,7 +11,6 @@
 #include <linux/kernel.h>
 #include <linux/log2.h>
 #include <linux/moduleloader.h>
-#include <linux/vmalloc.h>
 #include <linux/sizes.h>
 #include <linux/pgtable.h>
 #include <asm/alternative.h>
@@ -905,16 +904,6 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
 	return 0;
 }
 
-#if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
-void *module_alloc(unsigned long size)
-{
-	return __vmalloc_node_range(size, 1, MODULES_VADDR,
-				    MODULES_END, GFP_KERNEL,
-				    PAGE_KERNEL, VM_FLUSH_RESET_PERMS,
-				    NUMA_NO_NODE,
-				    __builtin_return_address(0));
-}
-#endif
 
 int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs,
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
index 2c869f8026a8..fba8e3595459 100644
--- a/arch/riscv/mm/Makefile
+++ b/arch/riscv/mm/Makefile
@@ -36,3 +36,4 @@ endif
 obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o
 obj-$(CONFIG_RISCV_DMA_NONCOHERENT) += dma-noncoherent.o
 obj-$(CONFIG_RISCV_NONSTANDARD_CACHE_OPS) += cache-ops.o
+obj-$(CONFIG_MODULE_ALLOC) += module_alloc.o
diff --git a/arch/riscv/mm/module_alloc.c b/arch/riscv/mm/module_alloc.c
new file mode 100644
index 000000000000..2c1fb95a57e2
--- /dev/null
+++ b/arch/riscv/mm/module_alloc.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/pgtable.h>
+#include <asm/alternative.h>
+#include <asm/sections.h>
+
+#if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
+void *module_alloc(unsigned long size)
+{
+	return __vmalloc_node_range(size, 1, MODULES_VADDR,
+				    MODULES_END, GFP_KERNEL,
+				    PAGE_KERNEL, VM_FLUSH_RESET_PERMS,
+				    NUMA_NO_NODE,
+				    __builtin_return_address(0));
+}
+#endif
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 42215f9404af..ef8a7539bb0b 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -36,43 +36,6 @@
 
 #define PLT_ENTRY_SIZE 22
 
-static unsigned long get_module_load_offset(void)
-{
-	static DEFINE_MUTEX(module_kaslr_mutex);
-	static unsigned long module_load_offset;
-
-	if (!kaslr_enabled())
-		return 0;
-	/*
-	 * Calculate the module_load_offset the first time this code
-	 * is called. Once calculated it stays the same until reboot.
-	 */
-	mutex_lock(&module_kaslr_mutex);
-	if (!module_load_offset)
-		module_load_offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
-	mutex_unlock(&module_kaslr_mutex);
-	return module_load_offset;
-}
-
-void *module_alloc(unsigned long size)
-{
-	gfp_t gfp_mask = GFP_KERNEL;
-	void *p;
-
-	if (PAGE_ALIGN(size) > MODULES_LEN)
-		return NULL;
-	p = __vmalloc_node_range(size, MODULE_ALIGN,
-				 MODULES_VADDR + get_module_load_offset(),
-				 MODULES_END, gfp_mask, PAGE_KERNEL,
-				 VM_FLUSH_RESET_PERMS | VM_DEFER_KMEMLEAK,
-				 NUMA_NO_NODE, __builtin_return_address(0));
-	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
-		vfree(p);
-		return NULL;
-	}
-	return p;
-}
-
 #ifdef CONFIG_FUNCTION_TRACER
 void module_arch_cleanup(struct module *mod)
 {
diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile
index 352ff520fd94..4f44c4096c6d 100644
--- a/arch/s390/mm/Makefile
+++ b/arch/s390/mm/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 obj-$(CONFIG_PTDUMP_CORE)	+= dump_pagetables.o
 obj-$(CONFIG_PGSTE)		+= gmap.o
 obj-$(CONFIG_PFAULT)		+= pfault.o
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
diff --git a/arch/s390/mm/module_alloc.c b/arch/s390/mm/module_alloc.c
new file mode 100644
index 000000000000..88eadce4bc68
--- /dev/null
+++ b/arch/s390/mm/module_alloc.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/kasan.h>
+
+static unsigned long get_module_load_offset(void)
+{
+	static DEFINE_MUTEX(module_kaslr_mutex);
+	static unsigned long module_load_offset;
+
+	if (!kaslr_enabled())
+		return 0;
+	/*
+	 * Calculate the module_load_offset the first time this code
+	 * is called. Once calculated it stays the same until reboot.
+	 */
+	mutex_lock(&module_kaslr_mutex);
+	if (!module_load_offset)
+		module_load_offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
+	mutex_unlock(&module_kaslr_mutex);
+	return module_load_offset;
+}
+
+void *module_alloc(unsigned long size)
+{
+	gfp_t gfp_mask = GFP_KERNEL;
+	void *p;
+
+	if (PAGE_ALIGN(size) > MODULES_LEN)
+		return NULL;
+	p = __vmalloc_node_range(size, MODULE_ALIGN,
+				 MODULES_VADDR + get_module_load_offset(),
+				 MODULES_END, gfp_mask, PAGE_KERNEL,
+				 VM_FLUSH_RESET_PERMS | VM_DEFER_KMEMLEAK,
+				 NUMA_NO_NODE, __builtin_return_address(0));
+	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
+		vfree(p);
+		return NULL;
+	}
+	return p;
+}
diff --git a/arch/sparc/kernel/module.c b/arch/sparc/kernel/module.c
index 66c45a2764bc..0611a41cd586 100644
--- a/arch/sparc/kernel/module.c
+++ b/arch/sparc/kernel/module.c
@@ -8,7 +8,6 @@
 #include <linux/moduleloader.h>
 #include <linux/kernel.h>
 #include <linux/elf.h>
-#include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/string.h>
@@ -21,36 +20,6 @@
 
 #include "entry.h"
 
-#ifdef CONFIG_SPARC64
-
-#include <linux/jump_label.h>
-
-static void *module_map(unsigned long size)
-{
-	if (PAGE_ALIGN(size) > MODULES_LEN)
-		return NULL;
-	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
-				GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
-				__builtin_return_address(0));
-}
-#else
-static void *module_map(unsigned long size)
-{
-	return vmalloc(size);
-}
-#endif /* CONFIG_SPARC64 */
-
-void *module_alloc(unsigned long size)
-{
-	void *ret;
-
-	ret = module_map(size);
-	if (ret)
-		memset(ret, 0, size);
-
-	return ret;
-}
-
 /* Make generic code ignore STT_REGISTER dummy undefined symbols.  */
 int module_frob_arch_sections(Elf_Ehdr *hdr,
 			      Elf_Shdr *sechdrs,
diff --git a/arch/sparc/mm/Makefile b/arch/sparc/mm/Makefile
index 809d993f6d88..a8e9ba46679a 100644
--- a/arch/sparc/mm/Makefile
+++ b/arch/sparc/mm/Makefile
@@ -14,3 +14,5 @@ obj-$(CONFIG_SPARC32)   += leon_mm.o
 
 # Only used by sparc64
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
+
+obj-$(CONFIG_MODULE_ALLOC) += module_alloc.o
diff --git a/arch/sparc/mm/module_alloc.c b/arch/sparc/mm/module_alloc.c
new file mode 100644
index 000000000000..14aef0f75650
--- /dev/null
+++ b/arch/sparc/mm/module_alloc.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#ifdef CONFIG_SPARC64
+static void *module_map(unsigned long size)
+{
+	if (PAGE_ALIGN(size) > MODULES_LEN)
+		return NULL;
+	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
+				GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
+				__builtin_return_address(0));
+}
+#else
+static void *module_map(unsigned long size)
+{
+	return vmalloc(size);
+}
+#endif /* CONFIG_SPARC64 */
+
+void *module_alloc(unsigned long size)
+{
+	void *ret;
+
+	ret = module_map(size);
+	if (ret)
+		memset(ret, 0, size);
+
+	return ret;
+}
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 12df54ff0e81..99f242e11f88 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -260,7 +260,7 @@ void arch_ftrace_update_code(int command)
 /* Currently only x86_64 supports dynamic trampolines */
 #ifdef CONFIG_X86_64
 
-#ifdef CONFIG_MODULES
+#if IS_ENABLED(CONFIG_MODULE_ALLOC)
 #include <linux/moduleloader.h>
 /* Module allocation simplifies allocating memory for code */
 static inline void *alloc_tramp(unsigned long size)
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index e18914c0e38a..ad7e3968ee8f 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -8,21 +8,14 @@
 
 #include <linux/moduleloader.h>
 #include <linux/elf.h>
-#include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
-#include <linux/kasan.h>
 #include <linux/bug.h>
-#include <linux/mm.h>
-#include <linux/gfp.h>
 #include <linux/jump_label.h>
-#include <linux/random.h>
 #include <linux/memory.h>
 
 #include <asm/text-patching.h>
-#include <asm/page.h>
-#include <asm/setup.h>
 #include <asm/unwind.h>
 
 #if 0
@@ -36,56 +29,7 @@ do {							\
 } while (0)
 #endif
 
-#ifdef CONFIG_RANDOMIZE_BASE
-static unsigned long module_load_offset;
 
-/* Mutex protects the module_load_offset. */
-static DEFINE_MUTEX(module_kaslr_mutex);
-
-static unsigned long int get_module_load_offset(void)
-{
-	if (kaslr_enabled()) {
-		mutex_lock(&module_kaslr_mutex);
-		/*
-		 * Calculate the module_load_offset the first time this
-		 * code is called. Once calculated it stays the same until
-		 * reboot.
-		 */
-		if (module_load_offset == 0)
-			module_load_offset =
-				get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
-		mutex_unlock(&module_kaslr_mutex);
-	}
-	return module_load_offset;
-}
-#else
-static unsigned long int get_module_load_offset(void)
-{
-	return 0;
-}
-#endif
-
-void *module_alloc(unsigned long size)
-{
-	gfp_t gfp_mask = GFP_KERNEL;
-	void *p;
-
-	if (PAGE_ALIGN(size) > MODULES_LEN)
-		return NULL;
-
-	p = __vmalloc_node_range(size, MODULE_ALIGN,
-				 MODULES_VADDR + get_module_load_offset(),
-				 MODULES_END, gfp_mask, PAGE_KERNEL,
-				 VM_FLUSH_RESET_PERMS | VM_DEFER_KMEMLEAK,
-				 NUMA_NO_NODE, __builtin_return_address(0));
-
-	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
-		vfree(p);
-		return NULL;
-	}
-
-	return p;
-}
 
 #ifdef CONFIG_X86_32
 int apply_relocate(Elf32_Shdr *sechdrs,
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index c80febc44cd2..b9e42770a002 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -67,3 +67,5 @@ obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= mem_encrypt_amd.o
 
 obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= mem_encrypt_identity.o
 obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= mem_encrypt_boot.o
+
+obj-$(CONFIG_MODULE_ALLOC)	+= module_alloc.o
diff --git a/arch/x86/mm/module_alloc.c b/arch/x86/mm/module_alloc.c
new file mode 100644
index 000000000000..00391c15e1eb
--- /dev/null
+++ b/arch/x86/mm/module_alloc.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/kasan.h>
+#include <linux/random.h>
+#include <linux/mutex.h>
+#include <asm/setup.h>
+
+#ifdef CONFIG_RANDOMIZE_BASE
+static unsigned long module_load_offset;
+
+/* Mutex protects the module_load_offset. */
+static DEFINE_MUTEX(module_kaslr_mutex);
+
+static unsigned long int get_module_load_offset(void)
+{
+	if (kaslr_enabled()) {
+		mutex_lock(&module_kaslr_mutex);
+		/*
+		 * Calculate the module_load_offset the first time this
+		 * code is called. Once calculated it stays the same until
+		 * reboot.
+		 */
+		if (module_load_offset == 0)
+			module_load_offset =
+				get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
+		mutex_unlock(&module_kaslr_mutex);
+	}
+	return module_load_offset;
+}
+#else
+static unsigned long int get_module_load_offset(void)
+{
+	return 0;
+}
+#endif
+
+void *module_alloc(unsigned long size)
+{
+	gfp_t gfp_mask = GFP_KERNEL;
+	void *p;
+
+	if (PAGE_ALIGN(size) > MODULES_LEN)
+		return NULL;
+
+	p = __vmalloc_node_range(size, MODULE_ALIGN,
+				 MODULES_VADDR + get_module_load_offset(),
+				 MODULES_END, gfp_mask, PAGE_KERNEL,
+				 VM_FLUSH_RESET_PERMS | VM_DEFER_KMEMLEAK,
+				 NUMA_NO_NODE, __builtin_return_address(0));
+
+	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
+		vfree(p);
+		return NULL;
+	}
+
+	return p;
+}
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 6422e569b080..b8f4dcf92a89 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -668,7 +668,7 @@ static void __init proc_kcore_text_init(void)
 }
 #endif
 
-#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
+#if defined(CONFIG_MODULE_ALLOC) && defined(MODULES_VADDR)
 /*
  * MODULES_VADDR has no intersection with VMALLOC_ADDR.
  */
diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
index 0ea1b2970a23..a49460022350 100644
--- a/kernel/module/Kconfig
+++ b/kernel/module/Kconfig
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 menuconfig MODULES
 	bool "Enable loadable module support"
+	select MODULE_ALLOC
 	modules
 	help
 	  Kernel modules are small pieces of compiled code which can
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 36681911c05a..085bc6e75b3f 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1179,16 +1179,6 @@ resolve_symbol_wait(struct module *mod,
 	return ksym;
 }
 
-void __weak module_memfree(void *module_region)
-{
-	/*
-	 * This memory may be RO, and freeing RO memory in an interrupt is not
-	 * supported by vmalloc.
-	 */
-	WARN_ON(in_interrupt());
-	vfree(module_region);
-}
-
 void __weak module_arch_cleanup(struct module *mod)
 {
 }
@@ -1610,13 +1600,6 @@ static void free_modinfo(struct module *mod)
 	}
 }
 
-void * __weak module_alloc(unsigned long size)
-{
-	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
-			GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
-			NUMA_NO_NODE, __builtin_return_address(0));
-}
-
 bool __weak module_init_section(const char *name)
 {
 	return strstarts(name, ".init");
diff --git a/mm/Kconfig b/mm/Kconfig
index ffc3a2ba3a8c..92bfb5ae2e95 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1261,6 +1261,9 @@ config LOCK_MM_AND_FIND_VMA
 config IOMMU_MM_DATA
 	bool
 
+config MODULE_ALLOC
+	def_bool n
+
 source "mm/damon/Kconfig"
 
 endmenu
diff --git a/mm/Makefile b/mm/Makefile
index e4b5b75aaec9..731bd2c20ceb 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -134,3 +134,4 @@ obj-$(CONFIG_IO_MAPPING) += io-mapping.o
 obj-$(CONFIG_HAVE_BOOTMEM_INFO_NODE) += bootmem_info.o
 obj-$(CONFIG_GENERIC_IOREMAP) += ioremap.o
 obj-$(CONFIG_SHRINKER_DEBUG) += shrinker_debug.o
+obj-$(CONFIG_MODULE_ALLOC) += module_alloc.o
diff --git a/mm/module_alloc.c b/mm/module_alloc.c
new file mode 100644
index 000000000000..821af49e9a7c
--- /dev/null
+++ b/mm/module_alloc.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+void * __weak module_alloc(unsigned long size)
+{
+	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
+			GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
+			NUMA_NO_NODE, __builtin_return_address(0));
+}
+
+void __weak module_memfree(void *module_region)
+{
+	/*
+	 * This memory may be RO, and freeing RO memory in an interrupt is not
+	 * supported by vmalloc.
+	 */
+	WARN_ON(in_interrupt());
+	vfree(module_region);
+}
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d12a17fc0c17..b7d963fe0707 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -642,7 +642,7 @@ int is_vmalloc_or_module_addr(const void *x)
 	 * and fall back on vmalloc() if that fails. Others
 	 * just put it in the vmalloc space.
 	 */
-#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
+#if defined(CONFIG_MODULE_ALLOC) && defined(MODULES_VADDR)
 	unsigned long addr = (unsigned long)kasan_reset_tag(x);
 	if (addr >= MODULES_VADDR && addr < MODULES_END)
 		return 1;
-- 
2.43.0


  reply	other threads:[~2024-03-06 20:05 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-06 20:05 [RFC][PATCH 0/4] Make bpf_jit and kprobes work with CONFIG_MODULES=n Calvin Owens
2024-03-06 20:05 ` Calvin Owens [this message]
2024-03-07 14:43   ` [RFC][PATCH 1/4] module: mm: Make module_alloc() generally available Christophe Leroy
2024-03-08 20:53     ` Calvin Owens
2024-03-08  2:16   ` Masami Hiramatsu
2024-03-08 20:43     ` Calvin Owens
2024-03-06 20:05 ` [RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n Calvin Owens
2024-03-07 22:09   ` Christophe Leroy
2024-03-08 21:04     ` Calvin Owens
2024-03-06 20:05 ` [RFC][PATCH 3/4] kprobes: Allow kprobes " Calvin Owens
2024-03-07  7:22   ` Mike Rapoport
2024-03-08  2:46     ` Masami Hiramatsu
2024-03-08 20:36     ` Calvin Owens
2024-03-07 22:16   ` Christophe Leroy
2024-03-08 21:02     ` Calvin Owens
2024-03-08  2:46   ` Masami Hiramatsu
2024-03-08 20:57     ` Calvin Owens
2024-03-06 20:05 ` [RFC][PATCH 4/4] selftests/bpf: Support testing the !MODULES case Calvin Owens
2024-03-06 21:34 ` [RFC][PATCH 0/4] Make bpf_jit and kprobes work with CONFIG_MODULES=n Luis Chamberlain
2024-03-06 23:23   ` Calvin Owens
2024-03-07  1:58     ` Song Liu
2024-03-08  2:50       ` Masami Hiramatsu
2024-03-08  2:55         ` Luis Chamberlain
2024-03-08 20:27           ` Calvin Owens
2024-03-07  7:13     ` Mike Rapoport
2024-03-08  2:45   ` Masami Hiramatsu
2024-03-25 22:46 ` Jarkko Sakkinen

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