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Modules changes for v6.10-rc1 

Finally something fun. Mike Rapoport does some cleanup to allow us to
 take out module_alloc() out of modules into a new paint shedded execmem_alloc()
 and execmem_free() so to make emphasis these helpers are actually used outside
 of modules. It starts with a no-functional changes API rename / placeholders
 to then allow architectures to define their requirements into a new shiny
 struct execmem_info with ranges, and requirements for those ranges. Archs
 now can intitialize this execmem_info as the last part of mm_core_init() if
 they have to diverge from the norm. Each range is a known type clearly
 articulated and spelled out in enum execmem_type.
 
 Although a lot of this is major cleanup and prep work for future enhancements an
 immediate clear gain is we get to enable KPROBES without MODULES now. That is
 ultimately what motiviated to pick this work up again, now with smaller goal as
 concrete stepping stone.
 
 This has been sitting on linux-next for a little less than a month, a few issues
 were found already and fixed, in particular an odd mips boot issue. Arch folks
 reviewed the code too. This is ready for wider exposure and testing.
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Merge tag 'modules-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull modules updates from Luis Chamberlain:
 "Finally something fun. Mike Rapoport does some cleanup to allow us to
  take out module_alloc() out of modules into a new paint shedded
  execmem_alloc() and execmem_free() so to make emphasis these helpers
  are actually used outside of modules.

  It starts with a non-functional changes API rename / placeholders to
  then allow architectures to define their requirements into a new shiny
  struct execmem_info with ranges, and requirements for those ranges.

  Archs now can intitialize this execmem_info as the last part of
  mm_core_init() if they have to diverge from the norm. Each range is a
  known type clearly articulated and spelled out in enum execmem_type.

  Although a lot of this is major cleanup and prep work for future
  enhancements an immediate clear gain is we get to enable KPROBES
  without MODULES now. That is ultimately what motiviated to pick this
  work up again, now with smaller goal as concrete stepping stone"

* tag 'modules-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of
  kprobes: remove dependency on CONFIG_MODULES
  powerpc: use CONFIG_EXECMEM instead of CONFIG_MODULES where appropriate
  x86/ftrace: enable dynamic ftrace without CONFIG_MODULES
  arch: make execmem setup available regardless of CONFIG_MODULES
  powerpc: extend execmem_params for kprobes allocations
  arm64: extend execmem_info for generated code allocations
  riscv: extend execmem_params for generated code allocations
  mm/execmem, arch: convert remaining overrides of module_alloc to execmem
  mm/execmem, arch: convert simple overrides of module_alloc to execmem
  mm: introduce execmem_alloc() and execmem_free()
  module: make module_memory_{alloc,free} more self-contained
  sparc: simplify module_alloc()
  nios2: define virtual address space for modules
  mips: module: rename MODULE_START to MODULES_VADDR
  arm64: module: remove unneeded call to kasan_alloc_module_shadow()
  kallsyms: replace deprecated strncpy with strscpy
  module: allow UNUSED_KSYMS_WHITELIST to be relative against objtree.
This commit is contained in:
Linus Torvalds 2024-05-15 14:05:08 -07:00
parent 8c06da67d0 2c9e5d4a00
commit a49468240e
62 changed files with 907 additions and 585 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/Kconfig
View File

@ -60,9 +60,9 @@ config GENERIC_ENTRY
config KPROBES
bool "Kprobes"
depends on MODULES
depends on HAVE_KPROBES
select KALLSYMS
select EXECMEM
select NEED_TASKS_RCU
help
Kprobes allows you to trap at almost any kernel address and
@ -977,6 +977,14 @@ config ARCH_WANTS_MODULES_DATA_IN_VMALLOC
For architectures like powerpc/32 which have constraints on module
allocation and need to allocate module data outside of module area.
config ARCH_WANTS_EXECMEM_LATE
bool
help
For architectures that do not allocate executable memory early on
boot, but rather require its initialization late when there is
enough entropy for module space randomization, for instance
arm64.
config HAVE_IRQ_EXIT_ON_IRQ_STACK
bool
help

34
arch/arm/kernel/module.c
View File

@ -12,48 +12,14 @@
#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>
#include <asm/sections.h>
#include <asm/smp_plat.h>
#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") ||

45
arch/arm/mm/init.c
View File

@ -22,6 +22,7 @@
#include <linux/sizes.h>
#include <linux/stop_machine.h>
#include <linux/swiotlb.h>
#include <linux/execmem.h>
#include <asm/cp15.h>
#include <asm/mach-types.h>
@ -486,3 +487,47 @@ void free_initrd_mem(unsigned long start, unsigned long end)
free_reserved_area((void *)start, (void *)end, -1, "initrd");
}
#endif
#ifdef CONFIG_EXECMEM
#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
static struct execmem_info execmem_info __ro_after_init;
struct execmem_info __init *execmem_arch_setup(void)
{
unsigned long fallback_start = 0, fallback_end = 0;
if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS)) {
fallback_start = VMALLOC_START;
fallback_end = VMALLOC_END;
}
execmem_info = (struct execmem_info){
.ranges = {
[EXECMEM_DEFAULT] = {
.start = MODULES_VADDR,
.end = MODULES_END,
.pgprot = PAGE_KERNEL_EXEC,
.alignment = 1,
.fallback_start = fallback_start,
.fallback_end = fallback_end,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_MMU */
#endif /* CONFIG_EXECMEM */

1
arch/arm64/Kconfig
View File

@ -105,6 +105,7 @@ config ARM64
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
select ARCH_WANT_LD_ORPHAN_WARN
select ARCH_WANTS_EXECMEM_LATE if EXECMEM
select ARCH_WANTS_NO_INSTR
select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES
select ARCH_HAS_UBSAN

126
arch/arm64/kernel/module.c
View File

@ -12,144 +12,18 @@
#include <linux/bitops.h>
#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,

7
arch/arm64/kernel/probes/kprobes.c
View File

@ -129,13 +129,6 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return 0;
}
void *alloc_insn_page(void)
{
return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS,
NUMA_NO_NODE, __builtin_return_address(0));
}
/* arm kprobe: install breakpoint in text */
void __kprobes arch_arm_kprobe(struct kprobe *p)
{

140
arch/arm64/mm/init.c
View File

@ -32,6 +32,7 @@
#include <linux/hugetlb.h>
#include <linux/acpi_iort.h>
#include <linux/kmemleak.h>
#include <linux/execmem.h>
#include <asm/boot.h>
#include <asm/fixmap.h>
@ -432,3 +433,142 @@ void dump_mem_limit(void)
pr_emerg("Memory Limit: none\n");
}
}
#ifdef CONFIG_EXECMEM
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;
}
static struct execmem_info execmem_info __ro_after_init;
struct execmem_info __init *execmem_arch_setup(void)
{
unsigned long fallback_start = 0, fallback_end = 0;
unsigned long start = 0, end = 0;
module_init_limits();
/*
* Where possible, prefer to allocate within direct branch range of the
* kernel such that no PLTs are necessary.
*/
if (module_direct_base) {
start = module_direct_base;
end = module_direct_base + SZ_128M;
if (module_plt_base) {
fallback_start = module_plt_base;
fallback_end = module_plt_base + SZ_2G;
}
} else if (module_plt_base) {
start = module_plt_base;
end = module_plt_base + SZ_2G;
}
execmem_info = (struct execmem_info){
.ranges = {
[EXECMEM_DEFAULT] = {
.start = start,
.end = end,
.pgprot = PAGE_KERNEL,
.alignment = 1,
.fallback_start = fallback_start,
.fallback_end = fallback_end,
},
[EXECMEM_KPROBES] = {
.start = VMALLOC_START,
.end = VMALLOC_END,
.pgprot = PAGE_KERNEL_ROX,
.alignment = 1,
},
[EXECMEM_BPF] = {
.start = VMALLOC_START,
.end = VMALLOC_END,
.pgprot = PAGE_KERNEL,
.alignment = 1,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_EXECMEM */

11
arch/arm64/net/bpf_jit_comp.c
View File

@ -1897,17 +1897,6 @@ u64 bpf_jit_alloc_exec_limit(void)
return VMALLOC_END - VMALLOC_START;
}
void *bpf_jit_alloc_exec(unsigned long size)
{
/* Memory is intended to be executable, reset the pointer tag. */
return kasan_reset_tag(vmalloc(size));
}
void bpf_jit_free_exec(void *addr)
{
return vfree(addr);
}
/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
bool bpf_jit_supports_subprog_tailcalls(void)
{

6
arch/loongarch/kernel/module.c
View File

@ -490,12 +490,6 @@ 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)
{

21
arch/loongarch/mm/init.c
View File

@ -24,6 +24,7 @@
#include <linux/gfp.h>
#include <linux/hugetlb.h>
#include <linux/mmzone.h>
#include <linux/execmem.h>
#include <asm/asm-offsets.h>
#include <asm/bootinfo.h>
@ -248,3 +249,23 @@ EXPORT_SYMBOL(invalid_pmd_table);
#endif
pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss;
EXPORT_SYMBOL(invalid_pte_table);
#ifdef CONFIG_EXECMEM
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 /* CONFIG_EXECMEM */

4
arch/mips/include/asm/pgtable-64.h
View File

@ -147,8 +147,8 @@
#if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
VMALLOC_START != CKSSEG
/* Load modules into 32bit-compatible segment. */
#define MODULE_START CKSSEG
#define MODULE_END (FIXADDR_START-2*PAGE_SIZE)
#define MODULES_VADDR CKSSEG
#define MODULES_END (FIXADDR_START-2*PAGE_SIZE)
#endif
#define pte_ERROR(e) \

10
arch/mips/kernel/module.c
View File

@ -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;

4
arch/mips/mm/fault.c
View File

@ -83,8 +83,8 @@ static void __do_page_fault(struct pt_regs *regs, unsigned long write,
if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))
goto VMALLOC_FAULT_TARGET;
#ifdef MODULE_START
if (unlikely(address >= MODULE_START && address < MODULE_END))
#ifdef MODULES_VADDR
if (unlikely(address >= MODULES_VADDR && address < MODULES_END))
goto VMALLOC_FAULT_TARGET;
#endif

23
arch/mips/mm/init.c
View File

@ -31,6 +31,7 @@
#include <linux/gfp.h>
#include <linux/kcore.h>
#include <linux/initrd.h>
#include <linux/execmem.h>
#include <asm/bootinfo.h>
#include <asm/cachectl.h>
@ -576,3 +577,25 @@ EXPORT_SYMBOL_GPL(invalid_pmd_table);
#endif
pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss;
EXPORT_SYMBOL(invalid_pte_table);
#ifdef CONFIG_EXECMEM
#ifdef MODULES_VADDR
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
#endif /* CONFIG_EXECMEM */

5
arch/nios2/include/asm/pgtable.h
View File

@ -25,7 +25,10 @@
#include <asm-generic/pgtable-nopmd.h>
#define VMALLOC_START CONFIG_NIOS2_KERNEL_MMU_REGION_BASE
#define VMALLOC_END (CONFIG_NIOS2_KERNEL_REGION_BASE - 1)
#define VMALLOC_END (CONFIG_NIOS2_KERNEL_REGION_BASE - SZ_32M - 1)
#define MODULES_VADDR (CONFIG_NIOS2_KERNEL_REGION_BASE - SZ_32M)
#define MODULES_END (CONFIG_NIOS2_KERNEL_REGION_BASE - 1)
struct mm_struct;

20
arch/nios2/kernel/module.c
View File

@ -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)

21
arch/nios2/mm/init.c
View File

@ -26,6 +26,7 @@
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/execmem.h>
#include <asm/setup.h>
#include <asm/page.h>
@ -143,3 +144,23 @@ static const pgprot_t protection_map[16] = {
[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = MKP(1, 1, 1)
};
DECLARE_VM_GET_PAGE_PROT
#ifdef CONFIG_EXECMEM
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_EXEC,
.alignment = 1,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_EXECMEM */

12
arch/parisc/kernel/module.c
View File

@ -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)
{

23
arch/parisc/mm/init.c
View File

@ -24,6 +24,7 @@
#include <linux/nodemask.h> /* for node_online_map */
#include <linux/pagemap.h> /* for release_pages */
#include <linux/compat.h>
#include <linux/execmem.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
@ -481,7 +482,7 @@ void free_initmem(void)
/* finally dump all the instructions which were cached, since the
* pages are no-longer executable */
flush_icache_range(init_begin, init_end);
free_initmem_default(POISON_FREE_INITMEM);
/* set up a new led state on systems shipped LED State panel */
@ -992,3 +993,23 @@ static const pgprot_t protection_map[16] = {
[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_RWX
};
DECLARE_VM_GET_PAGE_PROT
#ifdef CONFIG_EXECMEM
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 = VMALLOC_START,
.end = VMALLOC_END,
.pgprot = PAGE_KERNEL_RWX,
.alignment = 1,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_EXECMEM */

2
arch/powerpc/Kconfig
View File

@ -286,7 +286,7 @@ config PPC
select IOMMU_HELPER if PPC64
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
select KASAN_VMALLOC if KASAN && MODULES
select KASAN_VMALLOC if KASAN && EXECMEM
select LOCK_MM_AND_FIND_VMA
select MMU_GATHER_PAGE_SIZE
select MMU_GATHER_RCU_TABLE_FREE

2
arch/powerpc/include/asm/kasan.h
View File

@ -19,7 +19,7 @@
#define KASAN_SHADOW_SCALE_SHIFT 3
#if defined(CONFIG_MODULES) && defined(CONFIG_PPC32)
#if defined(CONFIG_EXECMEM) && defined(CONFIG_PPC32)
#define KASAN_KERN_START ALIGN_DOWN(PAGE_OFFSET - SZ_256M, SZ_256M)
#else
#define KASAN_KERN_START PAGE_OFFSET

4
arch/powerpc/kernel/head_8xx.S
View File

@ -199,12 +199,12 @@ instruction_counter:
mfspr r10, SPRN_SRR0 /* Get effective address of fault */
INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11)
mtspr SPRN_MD_EPN, r10
#ifdef CONFIG_MODULES
#ifdef CONFIG_EXECMEM
mfcr r11
compare_to_kernel_boundary r10, r10
#endif
mfspr r10, SPRN_M_TWB /* Get level 1 table */
#ifdef CONFIG_MODULES
#ifdef CONFIG_EXECMEM
blt+ 3f
rlwinm r10, r10, 0, 20, 31
oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha

6
arch/powerpc/kernel/head_book3s_32.S
View File

@ -419,14 +419,14 @@ InstructionTLBMiss:
*/
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_IMISS
#ifdef CONFIG_MODULES
#ifdef CONFIG_EXECMEM
lis r1, TASK_SIZE@h /* check if kernel address */
cmplw 0,r1,r3
#endif
mfspr r2, SPRN_SDR1
li r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
rlwinm r2, r2, 28, 0xfffff000
#ifdef CONFIG_MODULES
#ifdef CONFIG_EXECMEM
li r0, 3
bgt- 112f
lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */
@ -442,7 +442,7 @@ InstructionTLBMiss:
andc. r1,r1,r2 /* check access & ~permission */
bne- InstructionAddressInvalid /* return if access not permitted */
/* Convert linux-style PTE to low word of PPC-style PTE */
#ifdef CONFIG_MODULES
#ifdef CONFIG_EXECMEM
rlwimi r2, r0, 0, 31, 31 /* userspace ? -> PP lsb */
#endif
ori r1, r1, 0xe06 /* clear out reserved bits */

22
arch/powerpc/kernel/kprobes.c
View File

@ -19,8 +19,8 @@
#include <linux/extable.h>
#include <linux/kdebug.h>
#include <linux/slab.h>
#include <linux/moduleloader.h>
#include <linux/set_memory.h>
#include <linux/execmem.h>
#include <asm/code-patching.h>
#include <asm/cacheflush.h>
#include <asm/sstep.h>
@ -126,26 +126,6 @@ kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offse
return (kprobe_opcode_t *)(addr + offset);
}
void *alloc_insn_page(void)
{
void *page;
page = module_alloc(PAGE_SIZE);
if (!page)
return NULL;
if (strict_module_rwx_enabled()) {
int err = set_memory_rox((unsigned long)page, 1);
if (err)
goto error;
}
return page;
error:
module_memfree(page);
return NULL;
}
int arch_prepare_kprobe(struct kprobe *p)
{
int ret = 0;

38
arch/powerpc/kernel/module.c
View File

@ -7,7 +7,6 @@
#include <linux/elf.h>
#include <linux/moduleloader.h>
#include <linux/err.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/bug.h>
#include <asm/module.h>
@ -88,40 +87,3 @@ 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
}

2
arch/powerpc/lib/code-patching.c
View File

@ -225,7 +225,7 @@ void __init poking_init(void)
static unsigned long get_patch_pfn(void *addr)
{
if (IS_ENABLED(CONFIG_MODULES) && is_vmalloc_or_module_addr(addr))
if (IS_ENABLED(CONFIG_EXECMEM) && is_vmalloc_or_module_addr(addr))
return vmalloc_to_pfn(addr);
else
return __pa_symbol(addr) >> PAGE_SHIFT;

2
arch/powerpc/mm/book3s32/mmu.c
View File

@ -184,7 +184,7 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
static bool is_module_segment(unsigned long addr)
{
if (!IS_ENABLED(CONFIG_MODULES))
if (!IS_ENABLED(CONFIG_EXECMEM))
return false;
if (addr < ALIGN_DOWN(MODULES_VADDR, SZ_256M))
return false;

64
arch/powerpc/mm/mem.c
View File

@ -16,6 +16,7 @@
#include <linux/highmem.h>
#include <linux/suspend.h>
#include <linux/dma-direct.h>
#include <linux/execmem.h>
#include <asm/swiotlb.h>
#include <asm/machdep.h>
@ -406,3 +407,66 @@ int devmem_is_allowed(unsigned long pfn)
* the EHEA driver. Drop this when drivers/net/ethernet/ibm/ehea is removed.
*/
EXPORT_SYMBOL_GPL(walk_system_ram_range);
#ifdef CONFIG_EXECMEM
static struct execmem_info execmem_info __ro_after_init;
struct execmem_info __init *execmem_arch_setup(void)
{
pgprot_t kprobes_prot = strict_module_rwx_enabled() ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL : PAGE_KERNEL_EXEC;
unsigned long fallback_start = 0, fallback_end = 0;
unsigned long start, end;
/*
* BOOK3S_32 and 8xx define MODULES_VADDR for text allocations and
* allow allocating data in the entire vmalloc space
*/
#ifdef MODULES_VADDR
unsigned long limit = (unsigned long)_etext - SZ_32M;
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) {
start = limit;
fallback_start = MODULES_VADDR;
fallback_end = MODULES_END;
} else {
start = MODULES_VADDR;
}
end = MODULES_END;
#else
start = VMALLOC_START;
end = VMALLOC_END;
#endif
execmem_info = (struct execmem_info){
.ranges = {
[EXECMEM_DEFAULT] = {
.start = start,
.end = end,
.pgprot = prot,
.alignment = 1,
.fallback_start = fallback_start,
.fallback_end = fallback_end,
},
[EXECMEM_KPROBES] = {
.start = VMALLOC_START,
.end = VMALLOC_END,
.pgprot = kprobes_prot,
.alignment = 1,
},
[EXECMEM_MODULE_DATA] = {
.start = VMALLOC_START,
.end = VMALLOC_END,
.pgprot = PAGE_KERNEL,
.alignment = 1,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_EXECMEM */

3
arch/riscv/include/asm/pgtable.h
View File

@ -55,6 +55,9 @@
#define MODULES_LOWEST_VADDR (KERNEL_LINK_ADDR - SZ_2G)
#define MODULES_VADDR (PFN_ALIGN((unsigned long)&_end) - SZ_2G)
#define MODULES_END (PFN_ALIGN((unsigned long)&_start))
#else
#define MODULES_VADDR VMALLOC_START
#define MODULES_END VMALLOC_END
#endif
/*

12
arch/riscv/kernel/module.c
View File

@ -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>
@ -905,17 +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,
struct module *me)

10
arch/riscv/kernel/probes/kprobes.c
View File

@ -104,16 +104,6 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return 0;
}
#ifdef CONFIG_MMU
void *alloc_insn_page(void)
{
return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
GFP_KERNEL, PAGE_KERNEL_READ_EXEC,
VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
__builtin_return_address(0));
}
#endif
/* install breakpoint in text */
void __kprobes arch_arm_kprobe(struct kprobe *p)
{

35
arch/riscv/mm/init.c
View File

@ -24,6 +24,7 @@
#include <linux/elf.h>
#endif
#include <linux/kfence.h>
#include <linux/execmem.h>
#include <asm/fixmap.h>
#include <asm/io.h>
@ -1481,3 +1482,37 @@ void __init pgtable_cache_init(void)
preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
}
#endif
#ifdef CONFIG_EXECMEM
#ifdef CONFIG_MMU
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,
},
[EXECMEM_KPROBES] = {
.start = VMALLOC_START,
.end = VMALLOC_END,
.pgprot = PAGE_KERNEL_READ_EXEC,
.alignment = 1,
},
[EXECMEM_BPF] = {
.start = BPF_JIT_REGION_START,
.end = BPF_JIT_REGION_END,
.pgprot = PAGE_KERNEL,
.alignment = PAGE_SIZE,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_MMU */
#endif /* CONFIG_EXECMEM */

13
arch/riscv/net/bpf_jit_core.c
View File

@ -221,19 +221,6 @@ u64 bpf_jit_alloc_exec_limit(void)
return BPF_JIT_REGION_SIZE;
}
void *bpf_jit_alloc_exec(unsigned long size)
{
return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START,
BPF_JIT_REGION_END, GFP_KERNEL,
PAGE_KERNEL, 0, NUMA_NO_NODE,
__builtin_return_address(0));
}
void bpf_jit_free_exec(void *addr)
{
return vfree(addr);
}
void *bpf_arch_text_copy(void *dst, void *src, size_t len)
{
int ret;

4
arch/s390/kernel/ftrace.c
View File

@ -7,13 +7,13 @@
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/moduleloader.h>
#include <linux/hardirq.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/kprobes.h>
#include <linux/execmem.h>
#include <trace/syscall.h>
#include <asm/asm-offsets.h>
#include <asm/text-patching.h>
@ -220,7 +220,7 @@ static int __init ftrace_plt_init(void)
{
const char *start, *end;
ftrace_plt = module_alloc(PAGE_SIZE);
ftrace_plt = execmem_alloc(EXECMEM_FTRACE, PAGE_SIZE);
if (!ftrace_plt)
panic("cannot allocate ftrace plt\n");

4
arch/s390/kernel/kprobes.c
View File

@ -9,7 +9,6 @@
#define pr_fmt(fmt) "kprobes: " fmt
#include <linux/moduleloader.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/preempt.h>
@ -21,6 +20,7 @@
#include <linux/slab.h>
#include <linux/hardirq.h>
#include <linux/ftrace.h>
#include <linux/execmem.h>
#include <asm/set_memory.h>
#include <asm/sections.h>
#include <asm/dis.h>
@ -38,7 +38,7 @@ void *alloc_insn_page(void)
{
void *page;
page = module_alloc(PAGE_SIZE);
page = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
if (!page)
return NULL;
set_memory_rox((unsigned long)page, 1);

42
arch/s390/kernel/module.c
View File

@ -21,6 +21,7 @@
#include <linux/moduleloader.h>
#include <linux/bug.h>
#include <linux/memory.h>
#include <linux/execmem.h>
#include <asm/alternative.h>
#include <asm/nospec-branch.h>
#include <asm/facility.h>
@ -36,47 +37,10 @@
#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)
{
module_memfree(mod->arch.trampolines_start);
execmem_free(mod->arch.trampolines_start);
}
#endif
@ -510,7 +474,7 @@ static int module_alloc_ftrace_hotpatch_trampolines(struct module *me,
size = FTRACE_HOTPATCH_TRAMPOLINES_SIZE(s->sh_size);
numpages = DIV_ROUND_UP(size, PAGE_SIZE);
start = module_alloc(numpages * PAGE_SIZE);
start = execmem_alloc(EXECMEM_FTRACE, numpages * PAGE_SIZE);
if (!start)
return -ENOMEM;
set_memory_rox((unsigned long)start, numpages);

30
arch/s390/mm/init.c
View File

@ -49,6 +49,7 @@
#include <asm/uv.h>
#include <linux/virtio_anchor.h>
#include <linux/virtio_config.h>
#include <linux/execmem.h>
pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(".bss..swapper_pg_dir");
pgd_t invalid_pg_dir[PTRS_PER_PGD] __section(".bss..invalid_pg_dir");
@ -302,3 +303,32 @@ void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
vmem_remove_mapping(start, size);
}
#endif /* CONFIG_MEMORY_HOTPLUG */
#ifdef CONFIG_EXECMEM
static struct execmem_info execmem_info __ro_after_init;
struct execmem_info __init *execmem_arch_setup(void)
{
unsigned long module_load_offset = 0;
unsigned long start;
if (kaslr_enabled())
module_load_offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
start = MODULES_VADDR + module_load_offset;
execmem_info = (struct execmem_info){
.ranges = {
[EXECMEM_DEFAULT] = {
.flags = EXECMEM_KASAN_SHADOW,
.start = start,
.end = MODULES_END,
.pgprot = PAGE_KERNEL,
.alignment = MODULE_ALIGN,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_EXECMEM */

2
arch/sparc/include/asm/pgtable_32.h
View File

@ -432,6 +432,8 @@ static inline int io_remap_pfn_range(struct vm_area_struct *vma,
#define VMALLOC_START _AC(0xfe600000,UL)
#define VMALLOC_END _AC(0xffc00000,UL)
#define MODULES_VADDR VMALLOC_START
#define MODULES_END VMALLOC_END
/* We provide our own get_unmapped_area to cope with VA holes for userland */
#define HAVE_ARCH_UNMAPPED_AREA

30
arch/sparc/kernel/module.c
View File

@ -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,

2
arch/sparc/mm/Makefile
View File

@ -14,3 +14,5 @@ obj-$(CONFIG_SPARC32) += leon_mm.o
# Only used by sparc64
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_EXECMEM) += execmem.o

21
arch/sparc/mm/execmem.c Normal file
View File

@ -0,0 +1,21 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm.h>
#include <linux/execmem.h>
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;
}

8
arch/sparc/net/bpf_jit_comp_32.c
View File

@ -1,10 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/moduleloader.h>
#include <linux/workqueue.h>
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/cache.h>
#include <linux/if_vlan.h>
#include <linux/execmem.h>
#include <asm/cacheflush.h>
#include <asm/ptrace.h>
@ -713,7 +713,7 @@ cond_branch: f_offset = addrs[i + filter[i].jf];
if (unlikely(proglen + ilen > oldproglen)) {
pr_err("bpb_jit_compile fatal error\n");
kfree(addrs);
module_memfree(image);
execmem_free(image);
return;
}
memcpy(image + proglen, temp, ilen);
@ -736,7 +736,7 @@ cond_branch: f_offset = addrs[i + filter[i].jf];
break;
}
if (proglen == oldproglen) {
image = module_alloc(proglen);
image = execmem_alloc(EXECMEM_BPF, proglen);
if (!image)
goto out;
}
@ -758,7 +758,7 @@ out:
void bpf_jit_free(struct bpf_prog *fp)
{
if (fp->jited)
module_memfree(fp->bpf_func);
execmem_free(fp->bpf_func);
bpf_prog_unlock_free(fp);
}

1
arch/x86/Kconfig
View File

@ -34,6 +34,7 @@ config X86_64
select SWIOTLB
select ARCH_HAS_ELFCORE_COMPAT
select ZONE_DMA32
select EXECMEM if DYNAMIC_FTRACE
config FORCE_DYNAMIC_FTRACE
def_bool y

16
arch/x86/kernel/ftrace.c
View File

@ -25,6 +25,7 @@
#include <linux/memory.h>
#include <linux/vmalloc.h>
#include <linux/set_memory.h>
#include <linux/execmem.h>
#include <trace/syscall.h>
@ -260,25 +261,14 @@ void arch_ftrace_update_code(int command)
/* Currently only x86_64 supports dynamic trampolines */
#ifdef CONFIG_X86_64
#ifdef CONFIG_MODULES
#include <linux/moduleloader.h>
/* Module allocation simplifies allocating memory for code */
static inline void *alloc_tramp(unsigned long size)
{
return module_alloc(size);
return execmem_alloc(EXECMEM_FTRACE, size);
}
static inline void tramp_free(void *tramp)
{
module_memfree(tramp);
execmem_free(tramp);
}
#else
/* Trampolines can only be created if modules are supported */
static inline void *alloc_tramp(unsigned long size)
{
return NULL;
}
static inline void tramp_free(void *tramp) { }
#endif
/* Defined as markers to the end of the ftrace default trampolines */
extern void ftrace_regs_caller_end(void);

4
arch/x86/kernel/kprobes/core.c
View File

@ -40,12 +40,12 @@
#include <linux/kgdb.h>
#include <linux/ftrace.h>
#include <linux/kasan.h>
#include <linux/moduleloader.h>
#include <linux/objtool.h>
#include <linux/vmalloc.h>
#include <linux/pgtable.h>
#include <linux/set_memory.h>
#include <linux/cfi.h>
#include <linux/execmem.h>
#include <asm/text-patching.h>
#include <asm/cacheflush.h>
@ -495,7 +495,7 @@ void *alloc_insn_page(void)
{
void *page;
page = module_alloc(PAGE_SIZE);
page = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
if (!page)
return NULL;

51
arch/x86/kernel/module.c
View File

@ -36,57 +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_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,
const char *strtab,

29
arch/x86/mm/init.c
View File

@ -7,6 +7,7 @@
#include <linux/swapops.h>
#include <linux/kmemleak.h>
#include <linux/sched/task.h>
#include <linux/execmem.h>
#include <asm/set_memory.h>
#include <asm/cpu_device_id.h>
@ -1095,3 +1096,31 @@ unsigned long arch_max_swapfile_size(void)
return pages;
}
#endif
#ifdef CONFIG_EXECMEM
static struct execmem_info execmem_info __ro_after_init;
struct execmem_info __init *execmem_arch_setup(void)
{
unsigned long start, offset = 0;
if (kaslr_enabled())
offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
start = MODULES_VADDR + offset;
execmem_info = (struct execmem_info){
.ranges = {
[EXECMEM_DEFAULT] = {
.flags = EXECMEM_KASAN_SHADOW,
.start = start,
.end = MODULES_END,
.pgprot = PAGE_KERNEL,
.alignment = MODULE_ALIGN,
},
},
};
return &execmem_info;
}
#endif /* CONFIG_EXECMEM */

132
include/linux/execmem.h Normal file
View File

@ -0,0 +1,132 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_EXECMEM_ALLOC_H
#define _LINUX_EXECMEM_ALLOC_H
#include <linux/types.h>
#include <linux/moduleloader.h>
#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
!defined(CONFIG_KASAN_VMALLOC)
#include <linux/kasan.h>
#define MODULE_ALIGN (PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
#else
#define MODULE_ALIGN PAGE_SIZE
#endif
/**
* enum execmem_type - types of executable memory ranges
*
* There are several subsystems that allocate executable memory.
* Architectures define different restrictions on placement,
* permissions, alignment and other parameters for memory that can be used
* by these subsystems.
* Types in this enum identify subsystems that allocate executable memory
* and let architectures define parameters for ranges suitable for
* allocations by each subsystem.
*
* @EXECMEM_DEFAULT: default parameters that would be used for types that
* are not explicitly defined.
* @EXECMEM_MODULE_TEXT: parameters for module text sections
* @EXECMEM_KPROBES: parameters for kprobes
* @EXECMEM_FTRACE: parameters for ftrace
* @EXECMEM_BPF: parameters for BPF
* @EXECMEM_MODULE_DATA: parameters for module data sections
* @EXECMEM_TYPE_MAX:
*/
enum execmem_type {
EXECMEM_DEFAULT,
EXECMEM_MODULE_TEXT = EXECMEM_DEFAULT,
EXECMEM_KPROBES,
EXECMEM_FTRACE,
EXECMEM_BPF,
EXECMEM_MODULE_DATA,
EXECMEM_TYPE_MAX,
};
/**
* enum execmem_range_flags - options for executable memory allocations
* @EXECMEM_KASAN_SHADOW: allocate kasan shadow
*/
enum execmem_range_flags {
EXECMEM_KASAN_SHADOW = (1 << 0),
};
/**
* struct execmem_range - definition of an address space suitable for code and
* related data allocations
* @start: address space start
* @end: address space end (inclusive)
* @fallback_start: start of the secondary address space range for fallback
* allocations on architectures that require it
* @fallback_end: start of the secondary address space (inclusive)
* @pgprot: permissions for memory in this address space
* @alignment: alignment required for text allocations
* @flags: options for memory allocations for this range
*/
struct execmem_range {
unsigned long start;
unsigned long end;
unsigned long fallback_start;
unsigned long fallback_end;
pgprot_t pgprot;
unsigned int alignment;
enum execmem_range_flags flags;
};
/**
* 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
* @size: how many bytes of memory are required
*
* Allocates memory that will contain executable code, either generated or
* loaded from kernel modules.
*
* Allocates memory that will contain data coupled with executable code,
* like data sections in kernel modules.
*
* The memory will have protections defined by architecture for executable
* region of the @type.
*
* Return: a pointer to the allocated memory or %NULL
*/
void *execmem_alloc(enum execmem_type type, size_t size);
/**
* execmem_free - free executable memory
* @ptr: pointer to the memory that should be freed
*/
void execmem_free(void *ptr);
#if defined(CONFIG_EXECMEM) && !defined(CONFIG_ARCH_WANTS_EXECMEM_LATE)
void execmem_init(void);
#else
static inline void execmem_init(void) {}
#endif
#endif /* _LINUX_EXECMEM_ALLOC_H */

9
include/linux/module.h
View File

@ -605,6 +605,11 @@ static inline bool module_is_live(struct module *mod)
return mod->state != MODULE_STATE_GOING;
}
static inline bool module_is_coming(struct module *mod)
{
return mod->state == MODULE_STATE_COMING;
}
struct module *__module_text_address(unsigned long addr);
struct module *__module_address(unsigned long addr);
bool is_module_address(unsigned long addr);
@ -857,6 +862,10 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr)
return ptr;
}
static inline bool module_is_coming(struct module *mod)
{
return false;
}
#endif /* CONFIG_MODULES */
#ifdef CONFIG_SYSFS

15
include/linux/moduleloader.h
View File

@ -25,13 +25,6 @@ int module_frob_arch_sections(Elf_Ehdr *hdr,
/* Additional bytes needed by arch in front of individual sections */
unsigned int arch_mod_section_prepend(struct module *mod, unsigned int section);
/* Allocator used for allocating struct module, core sections and init
sections. Returns NULL on failure. */
void *module_alloc(unsigned long size);
/* Free memory returned from module_alloc. */
void module_memfree(void *module_region);
/* Determines if the section name is an init section (that is only used during
* module loading).
*/
@ -129,12 +122,4 @@ void module_arch_cleanup(struct module *mod);
/* Any cleanup before freeing mod->module_init */
void module_arch_freeing_init(struct module *mod);
#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
!defined(CONFIG_KASAN_VMALLOC)
#include <linux/kasan.h>
#define MODULE_ALIGN (PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
#else
#define MODULE_ALIGN PAGE_SIZE
#endif
#endif

2
kernel/bpf/Kconfig
View File

@ -43,7 +43,7 @@ config BPF_JIT
bool "Enable BPF Just In Time compiler"
depends on BPF
depends on HAVE_CBPF_JIT || HAVE_EBPF_JIT
depends on MODULES
select EXECMEM
help
BPF programs are normally handled by a BPF interpreter. This option
allows the kernel to generate native code when a program is loaded

6
kernel/bpf/core.c
View File

@ -22,7 +22,6 @@
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/random.h>
#include <linux/moduleloader.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/objtool.h>
@ -38,6 +37,7 @@
#include <linux/nospec.h>
#include <linux/bpf_mem_alloc.h>
#include <linux/memcontrol.h>
#include <linux/execmem.h>
#include <asm/barrier.h>
#include <asm/unaligned.h>
@ -1065,12 +1065,12 @@ void bpf_jit_uncharge_modmem(u32 size)
void *__weak bpf_jit_alloc_exec(unsigned long size)
{
return module_alloc(size);
return execmem_alloc(EXECMEM_BPF, size);
}
void __weak bpf_jit_free_exec(void *addr)
{
module_memfree(addr);
execmem_free(addr);
}
struct bpf_binary_header *

63
kernel/kprobes.c
View File

@ -26,7 +26,6 @@
#include <linux/slab.h>
#include <linux/stddef.h>
#include <linux/export.h>
#include <linux/moduleloader.h>
#include <linux/kallsyms.h>
#include <linux/freezer.h>
#include <linux/seq_file.h>
@ -39,6 +38,7 @@
#include <linux/jump_label.h>
#include <linux/static_call.h>
#include <linux/perf_event.h>
#include <linux/execmem.h>
#include <asm/sections.h>
#include <asm/cacheflush.h>
@ -113,17 +113,17 @@ enum kprobe_slot_state {
void __weak *alloc_insn_page(void)
{
/*
* Use module_alloc() so this page is within +/- 2GB of where the
* Use execmem_alloc() so this page is within +/- 2GB of where the
* kernel image and loaded module images reside. This is required
* for most of the architectures.
* (e.g. x86-64 needs this to handle the %rip-relative fixups.)
*/
return module_alloc(PAGE_SIZE);
return execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
}
static void free_insn_page(void *page)
{
module_memfree(page);
execmem_free(page);
}
struct kprobe_insn_cache kprobe_insn_slots = {
@ -1588,7 +1588,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
}
/* Get module refcount and reject __init functions for loaded modules. */
if (*probed_mod) {
if (IS_ENABLED(CONFIG_MODULES) && *probed_mod) {
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
@ -1603,12 +1603,13 @@ static int check_kprobe_address_safe(struct kprobe *p,
* kprobes in there.
*/
if (within_module_init((unsigned long)p->addr, *probed_mod) &&
(*probed_mod)->state != MODULE_STATE_COMING) {
!module_is_coming(*probed_mod)) {
module_put(*probed_mod);
*probed_mod = NULL;
ret = -ENOENT;
}
}
out:
preempt_enable();
jump_label_unlock();
@ -2488,24 +2489,6 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
return 0;
}
/* Remove all symbols in given area from kprobe blacklist */
static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
{
struct kprobe_blacklist_entry *ent, *n;
list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
if (ent->start_addr < start || ent->start_addr >= end)
continue;
list_del(&ent->list);
kfree(ent);
}
}
static void kprobe_remove_ksym_blacklist(unsigned long entry)
{
kprobe_remove_area_blacklist(entry, entry + 1);
}
int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
char *type, char *sym)
{
@ -2570,6 +2553,25 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
return ret ? : arch_populate_kprobe_blacklist();
}
#ifdef CONFIG_MODULES
/* Remove all symbols in given area from kprobe blacklist */
static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
{
struct kprobe_blacklist_entry *ent, *n;
list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
if (ent->start_addr < start || ent->start_addr >= end)
continue;
list_del(&ent->list);
kfree(ent);
}
}
static void kprobe_remove_ksym_blacklist(unsigned long entry)
{
kprobe_remove_area_blacklist(entry, entry + 1);
}
static void add_module_kprobe_blacklist(struct module *mod)
{
unsigned long start, end;
@ -2672,6 +2674,17 @@ static struct notifier_block kprobe_module_nb = {
.priority = 0
};
static int kprobe_register_module_notifier(void)
{
return register_module_notifier(&kprobe_module_nb);
}
#else
static int kprobe_register_module_notifier(void)
{
return 0;
}
#endif /* CONFIG_MODULES */
void kprobe_free_init_mem(void)
{
void *start = (void *)(&__init_begin);
@ -2731,7 +2744,7 @@ static int __init init_kprobes(void)
if (!err)
err = register_die_notifier(&kprobe_exceptions_nb);
if (!err)
err = register_module_notifier(&kprobe_module_nb);
err = kprobe_register_module_notifier();
kprobes_initialized = (err == 0);
kprobe_sysctls_init();

3
kernel/module/Kconfig
View File

@ -2,6 +2,7 @@
menuconfig MODULES
bool "Enable loadable module support"
modules
select EXECMEM
help
Kernel modules are small pieces of compiled code which can
be inserted in the running kernel, rather than being
@ -392,7 +393,7 @@ config UNUSED_KSYMS_WHITELIST
exported at all times, even in absence of in-tree users. The value to
set here is the path to a text file containing the list of symbols,
one per line. The path can be absolute, or relative to the kernel
source tree.
source or obj tree.
config MODULES_TREE_LOOKUP
def_bool y

2
kernel/module/kallsyms.c
View File

@ -348,7 +348,7 @@ const char *module_address_lookup(unsigned long addr,
}
/* Make a copy in here where it's safe */
if (ret) {
strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
strscpy(namebuf, ret, KSYM_NAME_LEN);
ret = namebuf;
}
preempt_enable();

107
kernel/module/main.c
View File

@ -57,6 +57,7 @@
#include <linux/audit.h>
#include <linux/cfi.h>
#include <linux/debugfs.h>
#include <linux/execmem.h>
#include <uapi/linux/module.h>
#include "internal.h"
@ -1179,16 +1180,6 @@ 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)
{
}
@ -1197,25 +1188,47 @@ void __weak module_arch_freeing_init(struct module *mod)
{
}
static bool mod_mem_use_vmalloc(enum mod_mem_type type)
static int module_memory_alloc(struct module *mod, enum mod_mem_type type)
{
return IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC) &&
mod_mem_type_is_core_data(type);
}
unsigned int size = PAGE_ALIGN(mod->mem[type].size);
enum execmem_type execmem_type;
void *ptr;
static void *module_memory_alloc(unsigned int size, enum mod_mem_type type)
{
if (mod_mem_use_vmalloc(type))
return vzalloc(size);
return module_alloc(size);
}
mod->mem[type].size = size;
static void module_memory_free(void *ptr, enum mod_mem_type type)
{
if (mod_mem_use_vmalloc(type))
vfree(ptr);
if (mod_mem_type_is_data(type))
execmem_type = EXECMEM_MODULE_DATA;
else
module_memfree(ptr);
execmem_type = EXECMEM_MODULE_TEXT;
ptr = execmem_alloc(execmem_type, size);
if (!ptr)
return -ENOMEM;
/*
* The pointer to these blocks of memory are stored on the module
* structure and we keep that around so long as the module is
* around. We only free that memory when we unload the module.
* Just mark them as not being a leak then. The .init* ELF
* sections *do* get freed after boot so we *could* treat them
* slightly differently with kmemleak_ignore() and only grey
* them out as they work as typical memory allocations which
* *do* eventually get freed, but let's just keep things simple
* and avoid *any* false positives.
*/
kmemleak_not_leak(ptr);
memset(ptr, 0, size);
mod->mem[type].base = ptr;
return 0;
}
static void module_memory_free(struct module *mod, enum mod_mem_type type)
{
void *ptr = mod->mem[type].base;
execmem_free(ptr);
}
static void free_mod_mem(struct module *mod)
@ -1229,12 +1242,12 @@ static void free_mod_mem(struct module *mod)
/* Free lock-classes; relies on the preceding sync_rcu(). */
lockdep_free_key_range(mod_mem->base, mod_mem->size);
if (mod_mem->size)
module_memory_free(mod_mem->base, type);
module_memory_free(mod, type);
}
/* MOD_DATA hosts mod, so free it at last */
lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
module_memory_free(mod->mem[MOD_DATA].base, MOD_DATA);
module_memory_free(mod, MOD_DATA);
}
/* Free a module, remove from lists, etc. */
@ -1610,13 +1623,6 @@ 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");
@ -2225,7 +2231,6 @@ static int find_module_sections(struct module *mod, struct load_info *info)
static int move_module(struct module *mod, struct load_info *info)
{
int i;
void *ptr;
enum mod_mem_type t = 0;
int ret = -ENOMEM;
@ -2234,26 +2239,12 @@ static int move_module(struct module *mod, struct load_info *info)
mod->mem[type].base = NULL;
continue;
}
mod->mem[type].size = PAGE_ALIGN(mod->mem[type].size);
ptr = module_memory_alloc(mod->mem[type].size, type);
/*
* The pointer to these blocks of memory are stored on the module
* structure and we keep that around so long as the module is
* around. We only free that memory when we unload the module.
* Just mark them as not being a leak then. The .init* ELF
* sections *do* get freed after boot so we *could* treat them
* slightly differently with kmemleak_ignore() and only grey
* them out as they work as typical memory allocations which
* *do* eventually get freed, but let's just keep things simple
* and avoid *any* false positives.
*/
kmemleak_not_leak(ptr);
if (!ptr) {
ret = module_memory_alloc(mod, type);
if (ret) {
t = type;
goto out_enomem;
}
memset(ptr, 0, mod->mem[type].size);
mod->mem[type].base = ptr;
}
/* Transfer each section which specifies SHF_ALLOC */
@ -2296,7 +2287,7 @@ static int move_module(struct module *mod, struct load_info *info)
return 0;
out_enomem:
for (t--; t >= 0; t--)
module_memory_free(mod->mem[t].base, t);
module_memory_free(mod, t);
return ret;
}
@ -2482,9 +2473,9 @@ static void do_free_init(struct work_struct *w)
llist_for_each_safe(pos, n, list) {
initfree = container_of(pos, struct mod_initfree, node);
module_memfree(initfree->init_text);
module_memfree(initfree->init_data);
module_memfree(initfree->init_rodata);
execmem_free(initfree->init_text);
execmem_free(initfree->init_data);
execmem_free(initfree->init_rodata);
kfree(initfree);
}
}
@ -2594,10 +2585,10 @@ static noinline int do_init_module(struct module *mod)
* We want to free module_init, but be aware that kallsyms may be
* walking this with preempt disabled. In all the failure paths, we
* call synchronize_rcu(), but we don't want to slow down the success
* path. module_memfree() cannot be called in an interrupt, so do the
* path. execmem_free() cannot be called in an interrupt, so do the
* work and call synchronize_rcu() in a work queue.
*
* Note that module_alloc() on most architectures creates W+X page
* Note that execmem_alloc() on most architectures creates W+X page
* mappings which won't be cleaned up until do_free_init() runs. Any
* code such as mark_rodata_ro() which depends on those mappings to
* be cleaned up needs to sync with the queued work by invoking

20
kernel/trace/trace_kprobe.c
View File

@ -111,6 +111,7 @@ static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
}
#ifdef CONFIG_MODULES
static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
{
char *p;
@ -129,6 +130,12 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
return ret;
}
#else
static inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
{
return false;
}
#endif
static bool trace_kprobe_is_busy(struct dyn_event *ev)
{
@ -670,6 +677,7 @@ end:
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)
@ -704,6 +712,16 @@ static struct notifier_block trace_kprobe_module_nb = {
.notifier_call = trace_kprobe_module_callback,
.priority = 1 /* Invoked after kprobe module callback */
};
static int trace_kprobe_register_module_notifier(void)
{
return register_module_notifier(&trace_kprobe_module_nb);
}
#else
static int trace_kprobe_register_module_notifier(void)
{
return 0;
}
#endif /* CONFIG_MODULES */
static int count_symbols(void *data, unsigned long unused)
{
@ -1933,7 +1951,7 @@ static __init int init_kprobe_trace_early(void)
if (ret)
return ret;
if (register_module_notifier(&trace_kprobe_module_nb))
if (trace_kprobe_register_module_notifier())
return -EINVAL;
return 0;

3
mm/Kconfig
View File

@ -1240,6 +1240,9 @@ config LOCK_MM_AND_FIND_VMA
config IOMMU_MM_DATA
bool
config EXECMEM
bool
source "mm/damon/Kconfig"
endmenu

1
mm/Makefile
View File

@ -133,3 +133,4 @@ 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_EXECMEM) += execmem.o

143
mm/execmem.c Normal file
View File

@ -0,0 +1,143 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2002 Richard Henderson
* Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
* Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
* Copyright (C) 2024 Mike Rapoport IBM.
*/
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/execmem.h>
#include <linux/moduleloader.h>
static struct execmem_info *execmem_info __ro_after_init;
static struct execmem_info default_execmem_info __ro_after_init;
static void *__execmem_alloc(struct execmem_range *range, size_t size)
{
bool kasan = range->flags & EXECMEM_KASAN_SHADOW;
unsigned long vm_flags = VM_FLUSH_RESET_PERMS;
gfp_t gfp_flags = GFP_KERNEL | __GFP_NOWARN;
unsigned long start = range->start;
unsigned long end = range->end;
unsigned int align = range->alignment;
pgprot_t pgprot = range->pgprot;
void *p;
if (kasan)
vm_flags |= VM_DEFER_KMEMLEAK;
p = __vmalloc_node_range(size, align, start, end, gfp_flags,
pgprot, vm_flags, NUMA_NO_NODE,
__builtin_return_address(0));
if (!p && range->fallback_start) {
start = range->fallback_start;
end = range->fallback_end;
p = __vmalloc_node_range(size, align, start, end, gfp_flags,
pgprot, vm_flags, NUMA_NO_NODE,
__builtin_return_address(0));
}
if (!p) {
pr_warn_ratelimited("execmem: unable to allocate memory\n");
return NULL;
}
if (kasan && (kasan_alloc_module_shadow(p, size, GFP_KERNEL) < 0)) {
vfree(p);
return NULL;
}
return kasan_reset_tag(p);
}
void *execmem_alloc(enum execmem_type type, size_t size)
{
struct execmem_range *range = &execmem_info->ranges[type];
return __execmem_alloc(range, size);
}
void execmem_free(void *ptr)
{
/*
* This memory may be RO, and freeing RO memory in an interrupt is not
* supported by vmalloc.
*/
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) {
if (i == EXECMEM_MODULE_DATA)
r->pgprot = PAGE_KERNEL;
else
r->pgprot = default_range->pgprot;
r->alignment = default_range->alignment;
r->start = default_range->start;
r->end = default_range->end;
r->flags = default_range->flags;
r->fallback_start = default_range->fallback_start;
r->fallback_end = default_range->fallback_end;
}
}
}
struct execmem_info * __weak execmem_arch_setup(void)
{
return NULL;
}
static void __init __execmem_init(void)
{
struct execmem_info *info = execmem_arch_setup();
if (!info) {
info = execmem_info = &default_execmem_info;
info->ranges[EXECMEM_DEFAULT].start = VMALLOC_START;
info->ranges[EXECMEM_DEFAULT].end = VMALLOC_END;
info->ranges[EXECMEM_DEFAULT].pgprot = PAGE_KERNEL_EXEC;
info->ranges[EXECMEM_DEFAULT].alignment = 1;
}
if (!execmem_validate(info))
return;
execmem_init_missing(info);
execmem_info = info;
}
#ifdef CONFIG_ARCH_WANTS_EXECMEM_LATE
static int __init execmem_late_init(void)
{
__execmem_init();
return 0;
}
core_initcall(execmem_late_init);
#else
void __init execmem_init(void)
{
__execmem_init();
}
#endif

2
mm/mm_init.c
View File

@ -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
scripts/Makefile.modpost
View File

@ -94,7 +94,7 @@ targets += .vmlinux.objs
ifdef CONFIG_TRIM_UNUSED_KSYMS
ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST)
ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(srctree)/)$(ksym-wl)
ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(if $(wildcard $(ksym-wl)),,$(srctree)/))$(ksym-wl)
modpost-args += -t $(addprefix -u , $(ksym-wl))
modpost-deps += $(ksym-wl)
endif