[PATCH v2 03/12] mm/execmem, arch: convert simple overrides of module_alloc to execmem

From: Mike Rapoport
Date: Fri Jun 16 2023 - 04:51:58 EST

From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>

Several architectures override module_alloc() only to define address
range for code allocations different than VMALLOC address space.

Provide a generic implementation in execmem that uses the parameters
for address space ranges, required alignment and page protections
provided by architectures.

The architecures must fill execmem_params structure and implement
execmem_arch_params() that returns a pointer to that structure. This
way the execmem initialization won't be called from every architecure,
but rather from a central place, namely initialization of the core
memory management.

The execmem provides execmem_text_alloc() API that wraps
__vmalloc_node_range() with the parameters defined by the architecures.
If an architeture does not implement execmem_arch_params(),
execmem_text_alloc() will fall back to module_alloc().

The name execmem_text_alloc() emphasizes that the allocated memory is
for executable code, the allocations of the associated data, like data
sections of a module will use execmem_data_alloc() interface that will
be added later.

Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
---
arch/loongarch/kernel/module.c | 18 ++++++++++--
arch/mips/kernel/module.c | 18 +++++++++---
arch/nios2/kernel/module.c | 19 +++++++++----
arch/parisc/kernel/module.c | 23 +++++++++------
arch/riscv/kernel/module.c | 20 +++++++++----
arch/sparc/kernel/module.c | 44 +++++++++++++---------------
include/linux/execmem.h | 52 ++++++++++++++++++++++++++++++++++
mm/execmem.c | 52 +++++++++++++++++++++++++++++++---
mm/mm_init.c | 2 ++
9 files changed, 195 insertions(+), 53 deletions(-)

diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index b8b86088b2dd..32b167722c2b 100644
--- a/arch/loongarch/kernel/module.c
+++ b/arch/loongarch/kernel/module.c
@@ -18,6 +18,7 @@
#include <linux/ftrace.h>
#include <linux/string.h>
#include <linux/kernel.h>
+#include <linux/execmem.h>
#include <asm/alternative.h>
#include <asm/inst.h>

@@ -469,10 +470,21 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
return 0;
}

-void *module_alloc(unsigned long size)
+static struct execmem_params execmem_params = {
+ .modules = {
+ .text = {
+ .pgprot = PAGE_KERNEL,
+ .alignment = 1,
+ },
+ },
+};
+
+struct execmem_params __init *execmem_arch_params(void)
{
- return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
- GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0));
+ execmem_params.modules.text.start = MODULES_VADDR;
+ execmem_params.modules.text.end = MODULES_END;
+
+ return &execmem_params;
}

static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
index 0c936cbf20c5..2d370de67383 100644
--- a/arch/mips/kernel/module.c
+++ b/arch/mips/kernel/module.c
@@ -20,6 +20,7 @@
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/jump_label.h>
+#include <linux/execmem.h>

extern void jump_label_apply_nops(struct module *mod);

@@ -33,11 +34,20 @@ static LIST_HEAD(dbe_list);
static DEFINE_SPINLOCK(dbe_lock);

#ifdef MODULE_START
-void *module_alloc(unsigned long size)
+static struct execmem_params execmem_params = {
+ .modules = {
+ .text = {
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL,
+ .alignment = 1,
+ },
+ },
+};
+
+struct execmem_params __init *execmem_arch_params(void)
{
- return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
- GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
- __builtin_return_address(0));
+ return &execmem_params;
}
#endif

diff --git a/arch/nios2/kernel/module.c b/arch/nios2/kernel/module.c
index 9c97b7513853..3cf5723e3c70 100644
--- a/arch/nios2/kernel/module.c
+++ b/arch/nios2/kernel/module.c
@@ -18,15 +18,24 @@
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
+#include <linux/execmem.h>

#include <asm/cacheflush.h>

-void *module_alloc(unsigned long size)
+static struct execmem_params execmem_params = {
+ .modules = {
+ .text = {
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL_EXEC,
+ .alignment = 1,
+ },
+ },
+};
+
+struct execmem_params __init *execmem_arch_params(void)
{
- return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
- GFP_KERNEL, PAGE_KERNEL_EXEC,
- VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
- __builtin_return_address(0));
+ return &execmem_params;
}

int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index f6e38c4d3904..569b8f52a24b 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -49,6 +49,7 @@
#include <linux/bug.h>
#include <linux/mm.h>
#include <linux/slab.h>
+#include <linux/execmem.h>

#include <asm/unwind.h>
#include <asm/sections.h>
@@ -173,15 +174,21 @@ static inline int reassemble_22(int as22)
((as22 & 0x0003ff) << 3));
}

-void *module_alloc(unsigned long size)
+static struct execmem_params execmem_params = {
+ .modules = {
+ .text = {
+ .pgprot = PAGE_KERNEL_RWX,
+ .alignment = 1,
+ },
+ },
+};
+
+struct execmem_params __init *execmem_arch_params(void)
{
- /* 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));
+ execmem_params.modules.text.start = VMALLOC_START;
+ execmem_params.modules.text.end = VMALLOC_END;
+
+ return &execmem_params;
}

#ifndef CONFIG_64BIT
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 7c651d55fcbd..ee5e04cd3f21 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -11,6 +11,7 @@
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/pgtable.h>
+#include <linux/execmem.h>
#include <asm/alternative.h>
#include <asm/sections.h>

@@ -436,12 +437,21 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
}

#if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
-void *module_alloc(unsigned long size)
+static struct execmem_params execmem_params = {
+ .modules = {
+ .text = {
+ .pgprot = PAGE_KERNEL,
+ .alignment = 1,
+ },
+ },
+};
+
+struct execmem_params __init *execmem_arch_params(void)
{
- return __vmalloc_node_range(size, 1, MODULES_VADDR,
- MODULES_END, GFP_KERNEL,
- PAGE_KERNEL, 0, NUMA_NO_NODE,
- __builtin_return_address(0));
+ execmem_params.modules.text.start = MODULES_VADDR;
+ execmem_params.modules.text.end = MODULES_END;
+
+ return &execmem_params;
}
#endif

diff --git a/arch/sparc/kernel/module.c b/arch/sparc/kernel/module.c
index 66c45a2764bc..ab75e3e69834 100644
--- a/arch/sparc/kernel/module.c
+++ b/arch/sparc/kernel/module.c
@@ -14,6 +14,10 @@
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/mm.h>
+#include <linux/execmem.h>
+#ifdef CONFIG_SPARC64
+#include <linux/jump_label.h>
+#endif

#include <asm/processor.h>
#include <asm/spitfire.h>
@@ -21,34 +25,26 @@

#include "entry.h"

+static struct execmem_params execmem_params = {
+ .modules = {
+ .text = {
#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));
-}
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
#else
-static void *module_map(unsigned long size)
-{
- return vmalloc(size);
-}
-#endif /* CONFIG_SPARC64 */
-
-void *module_alloc(unsigned long size)
+ .start = VMALLOC_START,
+ .end = VMALLOC_END,
+#endif
+ .alignment = 1,
+ },
+ },
+};
+
+struct execmem_params __init *execmem_arch_params(void)
{
- void *ret;
-
- ret = module_map(size);
- if (ret)
- memset(ret, 0, size);
+ execmem_params.modules.text.pgprot = PAGE_KERNEL;

- return ret;
+ return &execmem_params;
}

/* Make generic code ignore STT_REGISTER dummy undefined symbols. */
diff --git a/include/linux/execmem.h b/include/linux/execmem.h
index 0d4e5a6985f8..75946f23731e 100644
--- a/include/linux/execmem.h
+++ b/include/linux/execmem.h
@@ -4,6 +4,52 @@

#include <linux/types.h>

+/**
+ * struct execmem_range - definition of a memory range suitable for code and
+ * related data allocations
+ * @start: address space start
+ * @end: address space end (inclusive)
+ * @pgprot: permisssions for memory in this address space
+ * @alignment: alignment required for text allocations
+ */
+struct execmem_range {
+ unsigned long start;
+ unsigned long end;
+ pgprot_t pgprot;
+ unsigned int alignment;
+};
+
+/**
+ * struct execmem_modules_range - architecure parameters for modules address
+ * space
+ * @text: address range for text allocations
+ */
+struct execmem_modules_range {
+ struct execmem_range text;
+};
+
+/**
+ * struct execmem_params - architecure parameters for code allocations
+ * @modules: parameters for modules address space
+ */
+struct execmem_params {
+ struct execmem_modules_range modules;
+};
+
+/**
+ * execmem_arch_params - supply parameters for allocations of executable memory
+ *
+ * A hook for architecures to define parameters for allocations of
+ * executable memory described by struct execmem_params
+ *
+ * For architectures that do not implement this method a default set of
+ * parameters will be used
+ *
+ * Return: a structure defining architecture parameters and restrictions
+ * for allocations of executable memory
+ */
+struct execmem_params *execmem_arch_params(void);
+
/**
* execmem_text_alloc - allocate executable memory
* @size: how many bytes of memory are required
@@ -49,4 +95,10 @@ void *jit_text_alloc(size_t size);
*/
void jit_free(void *ptr);

+#ifdef CONFIG_EXECMEM
+void execmem_init(void);
+#else
+static inline void execmem_init(void) {}
+#endif
+
#endif /* _LINUX_EXECMEM_ALLOC_H */
diff --git a/mm/execmem.c b/mm/execmem.c
index eac26234eb38..c92878cf4d1a 100644
--- a/mm/execmem.c
+++ b/mm/execmem.c
@@ -5,14 +5,27 @@
#include <linux/execmem.h>
#include <linux/moduleloader.h>

-static void *execmem_alloc(size_t size)
+struct execmem_params execmem_params;
+
+static void *execmem_alloc(size_t size, unsigned long start, unsigned long end,
+ unsigned int align, pgprot_t pgprot)
{
- return module_alloc(size);
+ return __vmalloc_node_range(size, align, start, end,
+ GFP_KERNEL, pgprot, VM_FLUSH_RESET_PERMS,
+ NUMA_NO_NODE, __builtin_return_address(0));
}

void *execmem_text_alloc(size_t size)
{
- return execmem_alloc(size);
+ unsigned long start = execmem_params.modules.text.start;
+ unsigned long end = execmem_params.modules.text.end;
+ pgprot_t pgprot = execmem_params.modules.text.pgprot;
+ unsigned int align = execmem_params.modules.text.alignment;
+
+ if (!execmem_params.modules.text.start)
+ return module_alloc(size);
+
+ return execmem_alloc(size, start, end, align, pgprot);
}

void execmem_free(void *ptr)
@@ -27,10 +40,41 @@ void execmem_free(void *ptr)

void *jit_text_alloc(size_t size)
{
- return execmem_alloc(size);
+ return execmem_text_alloc(size);
}

void jit_free(void *ptr)
{
execmem_free(ptr);
}
+
+struct execmem_params * __weak execmem_arch_params(void)
+{
+ return NULL;
+}
+
+static bool execmem_validate_params(struct execmem_params *p)
+{
+ struct execmem_modules_range *m = &p->modules;
+ struct execmem_range *t = &m->text;
+
+ if (!t->alignment || !t->start || !t->end || !pgprot_val(t->pgprot)) {
+ pr_crit("Invalid parameters for execmem allocator, module loading will fail");
+ return false;
+ }
+
+ return true;
+}
+
+void __init execmem_init(void)
+{
+ struct execmem_params *p = execmem_arch_params();
+
+ if (!p)
+ return;
+
+ if (!execmem_validate_params(p))
+ return;
+
+ execmem_params = *p;
+}
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 7f7f9c677854..3b11450efe8a 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -26,6 +26,7 @@
#include <linux/pgtable.h>
#include <linux/swap.h>
#include <linux/cma.h>
+#include <linux/execmem.h>
#include "internal.h"
#include "slab.h"
#include "shuffle.h"
@@ -2747,4 +2748,5 @@ void __init mm_core_init(void)
pti_init();
kmsan_init_runtime();
mm_cache_init();
+ execmem_init();
}
--
2.35.1