[PATCH v6 07/16] mm/execmem, arch: convert simple overrides of module_alloc to execmem

Mike Rapoport
2024-04-26T08:30:32Z

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 architectures must fill execmem_info structure and implement
execmem_arch_setup() that returns a pointer to that structure. This way the
execmem initialization won't be called from every architecture, but rather
from a central place, namely a core_initcall() in execmem.

The execmem provides execmem_alloc() API that wraps __vmalloc_node_range()
with the parameters defined by the architectures. If an architecture does
not implement execmem_arch_setup(), execmem_alloc() will fall back to
module_alloc().

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
arch/loongarch/kernel/module.c | 19 ++++++++--
arch/mips/kernel/module.c | 20 ++++++++--
arch/nios2/kernel/module.c | 21 ++++++++---
arch/parisc/kernel/module.c | 24 ++++++++----
arch/riscv/kernel/module.c | 24 ++++++++----
arch/sparc/kernel/module.c | 20 ++++++++--
include/linux/execmem.h | 47 ++++++++++++++++++++++++
mm/execmem.c | 67 ++++++++++++++++++++++++++++++++--
mm/mm_init.c | 2 +
9 files changed, 210 insertions(+), 34 deletions(-)

diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index c7d0338d12c1..ca6dd7ea1610 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>
#include <asm/unwind.h>
@@ -490,10 +491,22 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
return 0;
}

-void *module_alloc(unsigned long size)
+static struct execmem_info execmem_info __ro_after_init;
+
+struct execmem_info __init *execmem_arch_setup(void)
{
- return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
- GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0));
+ execmem_info = (struct execmem_info){
+ .ranges = {
+ [EXECMEM_DEFAULT] = {
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL,
+ .alignment = 1,
+ },
+ },
+ };
+
+ return &execmem_info;
}

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 9a6c96014904..59225a3cf918 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>
#include <asm/jump_label.h>

struct mips_hi16 {
@@ -32,11 +33,22 @@ static LIST_HEAD(dbe_list);
static DEFINE_SPINLOCK(dbe_lock);

#ifdef MODULES_VADDR
-void *module_alloc(unsigned long size)
+static struct execmem_info execmem_info __ro_after_init;
+
+struct execmem_info __init *execmem_arch_setup(void)
{
- return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
- GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
- __builtin_return_address(0));
+ execmem_info = (struct execmem_info){
+ .ranges = {
+ [EXECMEM_DEFAULT] = {
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL,
+ .alignment = 1,
+ },
+ },
+ };
+
+ return &execmem_info;
}
#endif

diff --git a/arch/nios2/kernel/module.c b/arch/nios2/kernel/module.c
index 9c97b7513853..0d1ee86631fc 100644
--- a/arch/nios2/kernel/module.c
+++ b/arch/nios2/kernel/module.c
@@ -18,15 +18,26 @@
#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_info execmem_info __ro_after_init;
+
+struct execmem_info __init *execmem_arch_setup(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));
+ execmem_info = (struct execmem_info){
+ .ranges = {
+ [EXECMEM_DEFAULT] = {
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL_EXEC,
+ .alignment = 1,
+ },
+ },
+ };
+
+ return &execmem_info;
}

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 d214bbe3c2af..bdfa85e10c1b 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 +174,22 @@ static inline int reassemble_22(int as22)
((as22 & 0x0003ff) << 3));
}

-void *module_alloc(unsigned long size)
+static struct execmem_info execmem_info __ro_after_init;
+
+struct execmem_info __init *execmem_arch_setup(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_info = (struct execmem_info){
+ .ranges = {
+ [EXECMEM_DEFAULT] = {
+ .start = VMALLOC_START,
+ .end = VMALLOC_END,
+ .pgprot = PAGE_KERNEL_RWX,
+ .alignment = 1,
+ },
+ },
+ };
+
+ return &execmem_info;
}

#ifndef CONFIG_64BIT
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 5e5a82644451..182904127ba0 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -14,6 +14,7 @@
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/pgtable.h>
+#include <linux/execmem.h>
#include <asm/alternative.h>
#include <asm/sections.h>

@@ -906,13 +907,22 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
}

#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));
+static struct execmem_info execmem_info __ro_after_init;
+
+struct execmem_info __init *execmem_arch_setup(void)
+{
+ execmem_info = (struct execmem_info){
+ .ranges = {
+ [EXECMEM_DEFAULT] = {
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL,
+ .alignment = 1,
+ },
+ },
+ };
+
+ return &execmem_info;
}
#endif

diff --git a/arch/sparc/kernel/module.c b/arch/sparc/kernel/module.c
index d37adb2a0b54..8b7ee45defc3 100644
--- a/arch/sparc/kernel/module.c
+++ b/arch/sparc/kernel/module.c
@@ -14,6 +14,7 @@
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/mm.h>
+#include <linux/execmem.h>

#include <asm/processor.h>
#include <asm/spitfire.h>
@@ -21,11 +22,22 @@

#include "entry.h"

-void *module_alloc(unsigned long size)
+static struct execmem_info execmem_info __ro_after_init;
+
+struct execmem_info __init *execmem_arch_setup(void)
{
- return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
- GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
- __builtin_return_address(0));
+ execmem_info = (struct execmem_info){
+ .ranges = {
+ [EXECMEM_DEFAULT] = {
+ .start = MODULES_VADDR,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL,
+ .alignment = 1,
+ },
+ },
+ };
+
+ return &execmem_info;
}

/* Make generic code ignore STT_REGISTER dummy undefined symbols. */
diff --git a/include/linux/execmem.h b/include/linux/execmem.h
index 8eebc8ef66e7..96fc59258467 100644
--- a/include/linux/execmem.h
+++ b/include/linux/execmem.h
@@ -33,6 +33,47 @@ enum execmem_type {
EXECMEM_TYPE_MAX,
};

+/**
+ * struct execmem_range - definition of an address space suitable for code and
+ * related data allocations
+ * @start: address space start
+ * @end: address space end (inclusive)
+ * @pgprot: permissions 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_info - architecture parameters for code allocations
+ * @ranges: array of parameter sets defining architecture specific
+ * parameters for executable memory allocations. The ranges that are not
+ * explicitly initialized by an architecture use parameters defined for
+ * @EXECMEM_DEFAULT.
+ */
+struct execmem_info {
+ struct execmem_range ranges[EXECMEM_TYPE_MAX];
+};
+
+/**
+ * execmem_arch_setup - define parameters for allocations of executable memory
+ *
+ * A hook for architectures to define parameters for allocations of
+ * executable memory. These parameters should be filled into the
+ * @execmem_info structure.
+ *
+ * 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_info *execmem_arch_setup(void);
+
/**
* execmem_alloc - allocate executable memory
* @type: type of the allocation
@@ -54,4 +95,10 @@ void *execmem_alloc(enum execmem_type type, size_t size);
*/
void execmem_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 480adc69b20d..80e61c1e7319 100644
--- a/mm/execmem.c
+++ b/mm/execmem.c
@@ -11,14 +11,30 @@
#include <linux/execmem.h>
#include <linux/moduleloader.h>

-static void *__execmem_alloc(size_t size)
+static struct execmem_info *execmem_info __ro_after_init;
+
+static void *__execmem_alloc(struct execmem_range *range, size_t size)
{
- return module_alloc(size);
+ unsigned long start = range->start;
+ unsigned long end = range->end;
+ unsigned int align = range->alignment;
+ pgprot_t pgprot = range->pgprot;
+
+ return __vmalloc_node_range(size, align, start, end,
+ GFP_KERNEL, pgprot, VM_FLUSH_RESET_PERMS,
+ NUMA_NO_NODE, __builtin_return_address(0));
}

void *execmem_alloc(enum execmem_type type, size_t size)
{
- return __execmem_alloc(size);
+ struct execmem_range *range;
+
+ if (!execmem_info)
+ return module_alloc(size);
+
+ range = &execmem_info->ranges[type];
+
+ return __execmem_alloc(range, size);
}

void execmem_free(void *ptr)
@@ -30,3 +46,48 @@ void execmem_free(void *ptr)
WARN_ON(in_interrupt());
vfree(ptr);
}
+
+static bool execmem_validate(struct execmem_info *info)
+{
+ struct execmem_range *r = &info->ranges[EXECMEM_DEFAULT];
+
+ if (!r->alignment || !r->start || !r->end || !pgprot_val(r->pgprot)) {
+ pr_crit("Invalid parameters for execmem allocator, module loading will fail");
+ return false;
+ }
+
+ return true;
+}
+
+static void execmem_init_missing(struct execmem_info *info)
+{
+ struct execmem_range *default_range = &info->ranges[EXECMEM_DEFAULT];
+
+ for (int i = EXECMEM_DEFAULT + 1; i < EXECMEM_TYPE_MAX; i++) {
+ struct execmem_range *r = &info->ranges[i];
+
+ if (!r->start) {
+ r->pgprot = default_range->pgprot;
+ r->alignment = default_range->alignment;
+ r->start = default_range->start;
+ r->end = default_range->end;
+ }
+ }
+}
+
+struct execmem_info * __weak execmem_arch_setup(void)
+{
+ return NULL;
+}
+
+void __init execmem_init(void)
+{
+ struct execmem_info *info = execmem_arch_setup();
+
+ if (!info || !execmem_validate(info))
+ return;
+
+ execmem_init_missing(info);
+
+ execmem_info = info;
+}
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 549e76af8f82..b6a1fcf6e13a 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -27,6 +27,7 @@
#include <linux/swap.h>
#include <linux/cma.h>
#include <linux/crash_dump.h>
+#include <linux/execmem.h>
#include "internal.h"
#include "slab.h"
#include "shuffle.h"
@@ -2793,4 +2794,5 @@ void __init mm_core_init(void)
pti_init();
kmsan_init_runtime();
mm_cache_init();
+ execmem_init();
}
--
2.43.0