[PATCH] kprobes: Enable tracing for mololithic kernel images

[Jarkko Sakkinen]

Tracing with kprobes while running a monolithic kernel is currently
impossible because CONFIG_KPROBES is dependent of CONFIG_MODULES.  This
dependency is a result of kprobes code using the module allocator for the
trampoline code.

Detaching kprobes from modules helps to squeeze down the user space,
e.g. when developing new core kernel features, while still having all
the nice tracing capabilities.

For kernel/ and arch/*, move module_alloc() and module_memfree() to
module_alloc.c, and compile as part of vmlinux when either CONFIG_MODULES
or CONFIG_KPROBES is enabled.  In addition, flag kernel module specific
code with CONFIG_MODULES.

As the result, kprobes can be used with a monolithic kernel.

Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxxx>
---
Tested with the help of BuildRoot and QEMU:
- arm (function tracer)
- arm64 (function tracer)
- mips (function tracer)
- powerpc (function tracer)
- riscv (function tracer)
- s390 (function tracer)
- sparc (function tracer)
- x86 (function tracer)
- sh (function tracer, for the "pure" kernel/modules_alloc.c path)
---
 arch/Kconfig                       |  1 -
 arch/arm/kernel/Makefile           |  5 +++
 arch/arm/kernel/module.c           | 32 ----------------
 arch/arm/kernel/module_alloc.c     | 42 ++++++++++++++++++++
 arch/arm64/kernel/Makefile         |  5 +++
 arch/arm64/kernel/module.c         | 47 -----------------------
 arch/arm64/kernel/module_alloc.c   | 57 ++++++++++++++++++++++++++++
 arch/mips/kernel/Makefile          |  5 +++
 arch/mips/kernel/module.c          |  9 -----
 arch/mips/kernel/module_alloc.c    | 18 +++++++++
 arch/parisc/kernel/Makefile        |  5 +++
 arch/parisc/kernel/module.c        | 11 ------
 arch/parisc/kernel/module_alloc.c  | 23 +++++++++++
 arch/powerpc/kernel/Makefile       |  5 +++
 arch/powerpc/kernel/module.c       | 37 ------------------
 arch/powerpc/kernel/module_alloc.c | 47 +++++++++++++++++++++++
 arch/riscv/kernel/Makefile         |  5 +++
 arch/riscv/kernel/module.c         | 10 -----
 arch/riscv/kernel/module_alloc.c   | 19 ++++++++++
 arch/s390/kernel/Makefile          |  5 +++
 arch/s390/kernel/module.c          | 17 ---------
 arch/s390/kernel/module_alloc.c    | 33 ++++++++++++++++
 arch/sparc/kernel/Makefile         |  5 +++
 arch/sparc/kernel/module.c         | 30 ---------------
 arch/sparc/kernel/module_alloc.c   | 39 +++++++++++++++++++
 arch/x86/kernel/Makefile           |  5 +++
 arch/x86/kernel/module.c           | 50 ------------------------
 arch/x86/kernel/module_alloc.c     | 61 ++++++++++++++++++++++++++++++
 kernel/Makefile                    |  5 +++
 kernel/kprobes.c                   | 10 +++++
 kernel/module/main.c               | 17 ---------
 kernel/module_alloc.c              | 26 +++++++++++++
 kernel/trace/trace_kprobe.c        | 10 ++++-
 33 files changed, 434 insertions(+), 262 deletions(-)
 create mode 100644 arch/arm/kernel/module_alloc.c
 create mode 100644 arch/arm64/kernel/module_alloc.c
 create mode 100644 arch/mips/kernel/module_alloc.c
 create mode 100644 arch/parisc/kernel/module_alloc.c
 create mode 100644 arch/powerpc/kernel/module_alloc.c
 create mode 100644 arch/riscv/kernel/module_alloc.c
 create mode 100644 arch/s390/kernel/module_alloc.c
 create mode 100644 arch/sparc/kernel/module_alloc.c
 create mode 100644 arch/x86/kernel/module_alloc.c
 create mode 100644 kernel/module_alloc.c

diff --git a/arch/Kconfig b/arch/Kconfig
index fcf9a41a4ef5..e8e3e7998a2e 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -39,7 +39,6 @@ config GENERIC_ENTRY
 
 config KPROBES
 	bool "Kprobes"
-	depends on MODULES
 	depends on HAVE_KPROBES
 	select KALLSYMS
 	select TASKS_RCU if PREEMPTION
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 553866751e1a..d2bb954cd54f 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -44,6 +44,11 @@ obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o
 obj-$(CONFIG_ISA_DMA_API)	+= dma.o
 obj-$(CONFIG_FIQ)		+= fiq.o fiqasm.o
 obj-$(CONFIG_MODULES)		+= armksyms.o module.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y				+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)		+= module_alloc.o
+endif
 obj-$(CONFIG_ARM_MODULE_PLTS)	+= module-plts.o
 obj-$(CONFIG_ISA_DMA)		+= dma-isa.o
 obj-$(CONFIG_PCI)		+= bios32.o isa.o
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index d59c36dc0494..054e799e7091 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -22,38 +22,6 @@
 #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/kernel/module_alloc.c b/arch/arm/kernel/module_alloc.c
new file mode 100644
index 000000000000..c3cfb2b60575
--- /dev/null
+++ b/arch/arm/kernel/module_alloc.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2002 Russell King.
+ * Modified for nommu by Hyok S. Choi
+ *
+ * Module allocation method suggested by Andi Kleen.
+ */
+
+#include <linux/mm.h>
+#include <linux/vmalloc.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
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index fa7981d0d917..d61c02da857e 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -43,6 +43,11 @@ obj-$(CONFIG_COMPAT)			+= sigreturn32.o
 obj-$(CONFIG_KUSER_HELPERS)		+= kuser32.o
 obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace.o entry-ftrace.o
 obj-$(CONFIG_MODULES)			+= module.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y					+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)			+= module_alloc.o
+endif
 obj-$(CONFIG_ARM64_MODULE_PLTS)		+= module-plts.o
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o perf_callchain.o
 obj-$(CONFIG_HW_PERF_EVENTS)		+= perf_event.o
diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
index f2d4bb14bfab..d2a979746da0 100644
--- a/arch/arm64/kernel/module.c
+++ b/arch/arm64/kernel/module.c
@@ -20,53 +20,6 @@
 #include <asm/insn.h>
 #include <asm/sections.h>
 
-void *module_alloc(unsigned long size)
-{
-	u64 module_alloc_end = module_alloc_base + MODULES_VSIZE;
-	gfp_t gfp_mask = GFP_KERNEL;
-	void *p;
-
-	/* Silence the initial allocation */
-	if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))
-		gfp_mask |= __GFP_NOWARN;
-
-	if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
-	    IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-		/* don't exceed the static module region - see below */
-		module_alloc_end = MODULES_END;
-
-	p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
-				module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK,
-				NUMA_NO_NODE, __builtin_return_address(0));
-
-	if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
-	    (IS_ENABLED(CONFIG_KASAN_VMALLOC) ||
-	     (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
-	      !IS_ENABLED(CONFIG_KASAN_SW_TAGS))))
-		/*
-		 * KASAN without KASAN_VMALLOC can only deal with module
-		 * allocations being served from the reserved module region,
-		 * since the remainder of the vmalloc region is already
-		 * backed by zero shadow pages, and punching holes into it
-		 * is non-trivial. Since the module region is not randomized
-		 * when KASAN is enabled without KASAN_VMALLOC, it is even
-		 * less likely that the module region gets exhausted, so we
-		 * can simply omit this fallback in that case.
-		 */
-		p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
-				module_alloc_base + SZ_2G, GFP_KERNEL,
-				PAGE_KERNEL, 0, NUMA_NO_NODE,
-				__builtin_return_address(0));
-
-	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 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/kernel/module_alloc.c b/arch/arm64/kernel/module_alloc.c
new file mode 100644
index 000000000000..0340c8c0b782
--- /dev/null
+++ b/arch/arm64/kernel/module_alloc.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@xxxxxxx>
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+
+void *module_alloc(unsigned long size)
+{
+	u64 module_alloc_end = module_alloc_base + MODULES_VSIZE;
+	gfp_t gfp_mask = GFP_KERNEL;
+	void *p;
+
+	/* Silence the initial allocation */
+	if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))
+		gfp_mask |= __GFP_NOWARN;
+
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
+	    IS_ENABLED(CONFIG_KASAN_SW_TAGS))
+		/* don't exceed the static module region - see below */
+		module_alloc_end = MODULES_END;
+
+	p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
+				module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK,
+				NUMA_NO_NODE, __builtin_return_address(0));
+
+	if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
+	    (IS_ENABLED(CONFIG_KASAN_VMALLOC) ||
+	     (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
+	      !IS_ENABLED(CONFIG_KASAN_SW_TAGS))))
+		/*
+		 * KASAN without KASAN_VMALLOC can only deal with module
+		 * allocations being served from the reserved module region,
+		 * since the remainder of the vmalloc region is already
+		 * backed by zero shadow pages, and punching holes into it
+		 * is non-trivial. Since the module region is not randomized
+		 * when KASAN is enabled without KASAN_VMALLOC, it is even
+		 * less likely that the module region gets exhausted, so we
+		 * can simply omit this fallback in that case.
+		 */
+		p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
+				module_alloc_base + SZ_2G, GFP_KERNEL,
+				PAGE_KERNEL, 0, NUMA_NO_NODE,
+				__builtin_return_address(0));
+
+	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
+		vfree(p);
+		return NULL;
+	}
+
+	/* Memory is intended to be executable, reset the pointer tag. */
+	return kasan_reset_tag(p);
+}
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 7c96282bff2e..cb9297b613a1 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -38,6 +38,11 @@ obj-$(CONFIG_SYNC_R4K)		+= sync-r4k.o
 obj-$(CONFIG_DEBUG_FS)		+= segment.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_MODULES)		+= module.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y				+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)		+= module_alloc.o
+endif
 
 obj-$(CONFIG_FTRACE_SYSCALLS)	+= ftrace.o
 obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o ftrace.o
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
index 14f46d17500a..214b2d1868a5 100644
--- a/arch/mips/kernel/module.c
+++ b/arch/mips/kernel/module.c
@@ -31,15 +31,6 @@ 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/kernel/module_alloc.c b/arch/mips/kernel/module_alloc.c
new file mode 100644
index 000000000000..582ab5ed8916
--- /dev/null
+++ b/arch/mips/kernel/module_alloc.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2001 Rusty Russell.
+ *  Copyright (C) 2003, 2004 Ralf Baechle (ralf@xxxxxxxxxxxxxx)
+ *  Copyright (C) 2005 Thiemo Seufer
+ */
+
+#include <linux/mm.h>
+#include <linux/vmalloc.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/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index d0bfac89a842..cd38083ae077 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -25,6 +25,11 @@ obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_PA11)	+= pci-dma.o
 obj-$(CONFIG_PCI)	+= pci.o
 obj-$(CONFIG_MODULES)	+= module.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y			+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)	+= module_alloc.o
+endif
 obj-$(CONFIG_64BIT)	+= sys_parisc32.o signal32.o
 obj-$(CONFIG_STACKTRACE)+= stacktrace.o
 obj-$(CONFIG_AUDIT)	+= audit.o
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index 7df140545b22..c81e63e2549b 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -192,17 +192,6 @@ 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/kernel/module_alloc.c b/arch/parisc/kernel/module_alloc.c
new file mode 100644
index 000000000000..4e4e4ce1132e
--- /dev/null
+++ b/arch/parisc/kernel/module_alloc.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux/PA-RISC Project
+ * Copyright (C) 2003 Randolph Chung <tausq at debian . org>
+ * Copyright (C) 2008 Helge Deller <deller@xxxxxx>
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.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/Makefile b/arch/powerpc/kernel/Makefile
index 2e2a2a9bcf43..5a811cdf230b 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -103,6 +103,11 @@ obj-$(CONFIG_HIBERNATION)	+= swsusp_$(BITS).o
 endif
 obj64-$(CONFIG_HIBERNATION)	+= swsusp_asm64.o
 obj-$(CONFIG_MODULES)		+= module.o module_$(BITS).o
+ifeq ($(CONFIG_MODULES),y)
+obj-y				+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)		+= module_alloc.o
+endif
 obj-$(CONFIG_44x)		+= cpu_setup_44x.o
 obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o
 obj-$(CONFIG_PPC_DOORBELL)	+= dbell.o
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index f6d6ae0a1692..b30e00964a60 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -88,40 +88,3 @@ 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/kernel/module_alloc.c b/arch/powerpc/kernel/module_alloc.c
new file mode 100644
index 000000000000..48541c27ce46
--- /dev/null
+++ b/arch/powerpc/kernel/module_alloc.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Kernel module help for powerpc.
+ *  Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
+ *  Copyright (C) 2008 Freescale Semiconductor, Inc.
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.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/Makefile b/arch/riscv/kernel/Makefile
index c71d6591d539..7af346ae575e 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -61,6 +61,11 @@ obj-$(CONFIG_SMP)		+= cpu_ops.o
 
 obj-$(CONFIG_RISCV_BOOT_SPINWAIT) += cpu_ops_spinwait.o
 obj-$(CONFIG_MODULES)		+= module.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y				+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)		+= module_alloc.o
+endif
 obj-$(CONFIG_MODULE_SECTIONS)	+= module-sections.o
 
 obj-$(CONFIG_CPU_PM)		+= suspend_entry.o suspend.o
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 91fe16bfaa07..1621d5e458f7 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -419,16 +419,6 @@ 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, 0, NUMA_NO_NODE,
-				    __builtin_return_address(0));
-}
-#endif
-
 static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
 				    const Elf_Shdr *sechdrs,
 				    const char *name)
diff --git a/arch/riscv/kernel/module_alloc.c b/arch/riscv/kernel/module_alloc.c
new file mode 100644
index 000000000000..ed87ed048713
--- /dev/null
+++ b/arch/riscv/kernel/module_alloc.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2017 Zihao Yu
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.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, 0, NUMA_NO_NODE,
+				    __builtin_return_address(0));
+}
+#endif
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 27d6b3c7aa06..71e73e34b441 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -48,6 +48,11 @@ obj-$(CONFIG_SYSFS)		+= nospec-sysfs.o
 CFLAGS_REMOVE_nospec-branch.o	+= $(CC_FLAGS_EXPOLINE)
 
 obj-$(CONFIG_MODULES)		+= module.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y				+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)		+= module_alloc.o
+endif
 obj-$(CONFIG_SCHED_TOPOLOGY)	+= topology.o
 obj-$(CONFIG_NUMA)		+= numa.o
 obj-$(CONFIG_AUDIT)		+= audit.o
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 26125a9c436d..e15f09fa50e2 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -35,23 +35,6 @@
 
 #define PLT_ENTRY_SIZE 22
 
-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, MODULES_END,
-				 gfp_mask, PAGE_KERNEL_EXEC, 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/kernel/module_alloc.c b/arch/s390/kernel/module_alloc.c
new file mode 100644
index 000000000000..e4c4175fb759
--- /dev/null
+++ b/arch/s390/kernel/module_alloc.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Kernel module help for s390.
+ *
+ *  S390 version
+ *    Copyright IBM Corp. 2002, 2003
+ *    Author(s): Arnd Bergmann (arndb@xxxxxxxxxx)
+ *		 Martin Schwidefsky (schwidefsky@xxxxxxxxxx)
+ *
+ *  based on i386 version
+ *    Copyright (C) 2001 Rusty Russell.
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+
+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, MODULES_END,
+				 gfp_mask, PAGE_KERNEL_EXEC, 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/Makefile b/arch/sparc/kernel/Makefile
index d3a0e072ebe8..53905c00a094 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -89,6 +89,11 @@ obj-$(CONFIG_SUN_PM)      += apc.o pmc.o
 
 obj-$(CONFIG_MODULES)     += module.o
 obj-$(CONFIG_MODULES)     += sparc_ksyms.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y                     += module_alloc.o
+else
+obj-$(CONFIG_KPROBES)     += module_alloc.o
+endif
 obj-$(CONFIG_SPARC_LED)   += led.o
 obj-$(CONFIG_KGDB)        += kgdb_$(BITS).o
 
diff --git a/arch/sparc/kernel/module.c b/arch/sparc/kernel/module.c
index df39580f398d..f2babc69f189 100644
--- a/arch/sparc/kernel/module.c
+++ b/arch/sparc/kernel/module.c
@@ -21,36 +21,6 @@
 
 #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/kernel/module_alloc.c b/arch/sparc/kernel/module_alloc.c
new file mode 100644
index 000000000000..4bacf8cff012
--- /dev/null
+++ b/arch/sparc/kernel/module_alloc.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Kernel module help for sparc64.
+ *
+ * Copyright (C) 2001 Rusty Russell.
+ * Copyright (C) 2002 David S. Miller.
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.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;
+}
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 03364dc40d8d..1f0304140f44 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -108,6 +108,11 @@ obj-$(CONFIG_KEXEC_FILE)	+= kexec-bzimage64.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump_$(BITS).o
 obj-y				+= kprobes/
 obj-$(CONFIG_MODULES)		+= module.o
+ifeq ($(CONFIG_MODULES),y)
+obj-y				+= module_alloc.o
+else
+obj-$(CONFIG_KPROBES)		+= module_alloc.o
+endif
 obj-$(CONFIG_X86_32)		+= doublefault_32.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index b98ffcf4d250..40bb10b5a68d 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -36,56 +36,6 @@ 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_int() % 1024 + 1) * 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_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,
 		   const char *strtab,
diff --git a/arch/x86/kernel/module_alloc.c b/arch/x86/kernel/module_alloc.c
new file mode 100644
index 000000000000..a7df2af1467a
--- /dev/null
+++ b/arch/x86/kernel/module_alloc.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Kernel module help for x86.
+ *  Copyright (C) 2001 Rusty Russell.
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/random.h>
+#include <linux/vmalloc.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 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_int() % 1024 + 1) * PAGE_SIZE;
+		mutex_unlock(&module_kaslr_mutex);
+	}
+	return module_load_offset;
+}
+#else
+static unsigned long 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_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/kernel/Makefile b/kernel/Makefile
index 318789c728d3..2981fe42060d 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -53,6 +53,11 @@ obj-y += livepatch/
 obj-y += dma/
 obj-y += entry/
 obj-$(CONFIG_MODULES) += module/
+ifeq ($(CONFIG_MODULES),y)
+obj-y += module_alloc.o
+else
+obj-$(CONFIG_KPROBES) += module_alloc.o
+endif
 
 obj-$(CONFIG_KCMP) += kcmp.o
 obj-$(CONFIG_FREEZER) += freezer.o
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f214f8c088ed..3f9876374cd3 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1569,6 +1569,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
 		goto out;
 	}
 
+#ifdef CONFIG_MODULES
 	/* Check if 'p' is probing a module. */
 	*probed_mod = __module_text_address((unsigned long) p->addr);
 	if (*probed_mod) {
@@ -1592,6 +1593,8 @@ static int check_kprobe_address_safe(struct kprobe *p,
 			ret = -ENOENT;
 		}
 	}
+#endif
+
 out:
 	preempt_enable();
 	jump_label_unlock();
@@ -2475,6 +2478,7 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
 	return 0;
 }
 
+#ifdef CONFIG_MODULES
 /* Remove all symbols in given area from kprobe blacklist */
 static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
 {
@@ -2492,6 +2496,7 @@ static void kprobe_remove_ksym_blacklist(unsigned long entry)
 {
 	kprobe_remove_area_blacklist(entry, entry + 1);
 }
+#endif /* CONFIG_MODULES */
 
 int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
 				   char *type, char *sym)
@@ -2557,6 +2562,7 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
 	return ret ? : arch_populate_kprobe_blacklist();
 }
 
+#ifdef CONFIG_MODULES
 static void add_module_kprobe_blacklist(struct module *mod)
 {
 	unsigned long start, end;
@@ -2658,6 +2664,7 @@ static struct notifier_block kprobe_module_nb = {
 	.notifier_call = kprobes_module_callback,
 	.priority = 0
 };
+#endif /* CONFIG_MODULES */
 
 void kprobe_free_init_mem(void)
 {
@@ -2717,8 +2724,11 @@ static int __init init_kprobes(void)
 	err = arch_init_kprobes();
 	if (!err)
 		err = register_die_notifier(&kprobe_exceptions_nb);
+
+#ifdef CONFIG_MODULES
 	if (!err)
 		err = register_module_notifier(&kprobe_module_nb);
+#endif
 
 	kprobes_initialized = (err == 0);
 	kprobe_sysctls_init();
diff --git a/kernel/module/main.c b/kernel/module/main.c
index fed58d30725d..7fa182b78550 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1121,16 +1121,6 @@ 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)
 {
 }
@@ -1606,13 +1596,6 @@ static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)
 		ddebug_remove_module(mod->name);
 }
 
-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/kernel/module_alloc.c b/kernel/module_alloc.c
new file mode 100644
index 000000000000..26a4c60998ad
--- /dev/null
+++ b/kernel/module_alloc.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2002 Richard Henderson
+ * Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
+ */
+
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.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/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 93507330462c..050b2975332e 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -101,6 +101,7 @@ static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
 	return kprobe_gone(&tk->rp.kp);
 }
 
+#ifdef CONFIG_MODULES
 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
 						 struct module *mod)
 {
@@ -109,11 +110,13 @@ static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
 
 	return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
 }
+#endif /* CONFIG_MODULES */
 
 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 {
+	bool ret = false;
+#ifdef CONFIG_MODULES
 	char *p;
-	bool ret;
 
 	if (!tk->symbol)
 		return false;
@@ -125,6 +128,7 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 	ret = !!find_module(tk->symbol);
 	rcu_read_unlock_sched();
 	*p = ':';
+#endif /* CONFIG_MODULES */
 
 	return ret;
 }
@@ -668,6 +672,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
 	return ret;
 }
 
+#ifdef CONFIG_MODULES
 /* Module notifier call back, checking event on the module */
 static int trace_kprobe_module_callback(struct notifier_block *nb,
 				       unsigned long val, void *data)
@@ -702,6 +707,7 @@ static struct notifier_block trace_kprobe_module_nb = {
 	.notifier_call = trace_kprobe_module_callback,
 	.priority = 1	/* Invoked after kprobe module callback */
 };
+#endif /* CONFIG_MODULES */
 
 static int __trace_kprobe_create(int argc, const char *argv[])
 {
@@ -1896,8 +1902,10 @@ static __init int init_kprobe_trace_early(void)
 	if (ret)
 		return ret;
 
+#ifdef CONFIG_MODULES
 	if (register_module_notifier(&trace_kprobe_module_nb))
 		return -EINVAL;
+#endif /* CONFIG_MODULES */
 
 	return 0;
 }
-- 
2.36.1