Linux内核-模块专用地址空间

Memory: 245540K/262144K available (3043K kernel code, 1665K rwdata, 1112K rodata, 176K init, 6356K bss, 16604K reserved, 0K cma-reserved)

Virtual kernel memory layout:

    vector  : 0xffff0000 - 0xffff1000   (   4 kB)

    fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)

    vmalloc : 0xd0800000 - 0xff000000   ( 744 MB)

    lowmem  : 0xc0000000 - 0xd0000000   ( 256 MB)

    modules : 0xbe600000 - 0xc0000000   (  26 MB)   <<< 模块地址空间

      .text : 0xc0018000 - 0xc04272b0   (4157 kB)

      .init : 0xc0428000 - 0xc0454000   ( 176 kB)

      .data : 0xc0454000 - 0xc05f45c0   (1666 kB)

       .bss : 0xc05f45c0 - 0xc0c295ec   (6357 kB)

    void * __weak module_alloc(unsigned long size)

{

  return vmalloc_exec(size);

}

    #ifdef CONFIG_MMU

void *module_alloc(unsigned long size)

{

  return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,

              GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,

              __builtin_return_address(0));

}

#endif

    #define MODULES_END       (PAGE_OFFSET)

#define MODULES_VADDR     (MODULES_END - 16*1048576)

https://patchwork.kernel.org/project/linux-arm-kernel/patch/002001cf07a1$fd4bdc10$f7e39430$@lge.com/

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index c1f1a7e..cf1fb55   100644

--- a/arch/arm/Kconfig

+++ b/arch/arm/Kconfig

@@ -2257,6 +2257,10 @@  config ARM_CPU_SUSPEND

 endmenu

+config MODULES_AREA_SIZE

+       int

+       default 0x1000000

+

 source "net/Kconfig"

 source "drivers/Kconfig"

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h

index 6976b03..3396758 100644

--- a/arch/arm/include/asm/memory.h

+++ b/arch/arm/include/asm/memory.h

@@ -32,13 +32,17 @@ 

 #ifdef CONFIG_MMU

+#if CONFIG_MODULES_AREA_SIZE > SZ_32M

+#error Too much space for modules

+#endif

+

 /*

  * PAGE_OFFSET - the virtual address of the start of the kernel image
  * TASK_SIZE - the maximum size of a user space task.
  * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area
  */
-#define PAGE_OFFSET            UL(CONFIG_PAGE_OFFSET)
-#define TASK_SIZE              (UL(CONFIG_PAGE_OFFSET) - UL(SZ_16M))
+#define PAGE_OFFSET    UL(CONFIG_PAGE_OFFSET)
+#define TASK_SIZE      (UL(CONFIG_PAGE_OFFSET) -
UL(CONFIG_MODULES_AREA_SIZE))
 #define TASK_UNMAPPED_BASE     ALIGN(TASK_SIZE / 3, SZ_16M)

#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