Re: [PATCH v4] module: replace module_layout with module_memory

From: Peter Zijlstra
Date: Tue Jan 31 2023 - 04:13:07 EST



I'm seeing a lot of the same code repeated over and over..

On Mon, Jan 30, 2023 at 10:21:09AM -0800, Song Liu wrote:
> diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c
> index af7c322ebed6..17fd0978aee8 100644
> --- a/arch/arm/kernel/module-plts.c
> +++ b/arch/arm/kernel/module-plts.c
> @@ -30,7 +30,10 @@ static const u32 fixed_plts[] = {
>
> static bool in_init(const struct module *mod, unsigned long loc)
> {
> - return loc - (u32)mod->init_layout.base < mod->init_layout.size;
> + const struct module_memory *mod_mem;
> +
> + mod_mem = &mod->mem[MOD_INIT_TEXT];
> + return loc - (u32)mod_mem->base < mod_mem->size;
> }

within_module_mem_type(loc, mod, MOD_INIT_TEXT)

>
> static void prealloc_fixed(struct mod_plt_sec *pltsec, struct plt_entries *plt)
> diff --git a/arch/arm64/kernel/module-plts.c b/arch/arm64/kernel/module-plts.c
> index 5a0a8f552a61..2f9f672a7cbb 100644
> --- a/arch/arm64/kernel/module-plts.c
> +++ b/arch/arm64/kernel/module-plts.c
> @@ -67,7 +67,10 @@ static bool plt_entries_equal(const struct plt_entry *a,
>
> static bool in_init(const struct module *mod, void *loc)
> {
> - return (u64)loc - (u64)mod->init_layout.base < mod->init_layout.size;
> + const struct module_memory *mod_mem;
> +
> + mod_mem = &mod->mem[MOD_INIT_TEXT];
> + return (u64)loc - (u64)mod_mem->base < mod_mem->size;
> }
>

within_module_mem_type((unsigned long)loc, mod, MOD_INIT_TEXT)

> u64 module_emit_plt_entry(struct module *mod, Elf64_Shdr *sechdrs,
> diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c
> index 8f62cf97f691..4268ddb54a33 100644
> --- a/arch/ia64/kernel/module.c
> +++ b/arch/ia64/kernel/module.c
> @@ -485,19 +485,25 @@ module_frob_arch_sections (Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings,
> return 0;
> }
>
> -static inline int
> +static inline bool
> in_init (const struct module *mod, uint64_t addr)
> {
> - return addr - (uint64_t) mod->init_layout.base < mod->init_layout.size;
> + const struct module_memory *mod_mem;
> +
> + mod_mem = &mod->mem[MOD_INIT_TEXT];
> + return addr - (uint64_t)mod_mem->base < mod_mem->size;
> }

within_module_mem_type(loc, mod, MOD_INIT_TEXT)

> -static inline int
> +static inline bool
> in_core (const struct module *mod, uint64_t addr)
> {
> - return addr - (uint64_t) mod->core_layout.base < mod->core_layout.size;
> + const struct module_memory *mod_mem;
> +
> + mod_mem = &mod->mem[MOD_TEXT];
> + return addr - (uint64_t)mod_mem->base < mod_mem->size;
> }
>

within_module_mem_type(loc, mod, MOD_TEXT)

> diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
> index 7df140545b22..e052a5fdd51b 100644
> --- a/arch/parisc/kernel/module.c
> +++ b/arch/parisc/kernel/module.c
> @@ -76,23 +76,18 @@
> * allows us to allocate up to 4095 GOT entries. */
> #define MAX_GOTS 4095
>
> +static inline bool in_local(struct module *me, void *loc)
> {
> + enum mod_mem_type type;
>
> + for (type = MOD_TEXT; type < MOD_MEM_NUM_TYPES; type++) {
> + struct module_memory *mod_mem = &me->mem[type];
>
> + if (loc >= mod_mem->base &&
> + loc <= (mod_mem->base + mod_mem->size))
> + return true;
> + }
> + return false;
> }

(see below)

within_module_mem_types((unsigned long)loc, me, MOD_TEXT, MOD_INIT_RODATA);

>
> #ifndef CONFIG_64BIT

> diff --git a/include/linux/module.h b/include/linux/module.h
> index 8c5909c0076c..61b7cff632f9 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -320,17 +320,22 @@ struct mod_tree_node {
> struct latch_tree_node node;
> };
>
> -struct module_layout {
> - /* The actual code + data. */
> +enum mod_mem_type {
> + MOD_TEXT,
> + MOD_DATA,
> + MOD_RODATA,
> + MOD_RO_AFTER_INIT,
> + MOD_INIT_TEXT,
> + MOD_INIT_DATA,
> + MOD_INIT_RODATA,
> +
> + MOD_MEM_NUM_TYPES,
> + MOD_INVALID = -1,
> +};

> @@ -573,23 +574,33 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr);
> bool is_module_percpu_address(unsigned long addr);
> bool is_module_text_address(unsigned long addr);
>
> +static inline bool within_module_mem_type(unsigned long addr,
> + const struct module *mod,
> + enum mod_mem_type type)
> +{
> + unsigned long base, size;
> +
> + base = (unsigned long)mod->mem[type].base;
> + size = mod->mem[type].size;
> +
> + return base <= addr && addr < base + size;

Possible (as inspired by all the above is_{init,core}() etc..

return addr - base < size;

> +}


static inline bool within_module_mem_types(unsigned long addr,
const struct module *mod,
enum mod_mem_type first,
enum mod_mem_type last)
{
for (enum mod_mem_type type = first; type <= last; type++) {
if (within_module_mem_type(addr, mod, type))
return true;
}
return false;
}

> +
> static inline bool within_module_core(unsigned long addr,
> const struct module *mod)
> {
> -#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
> - if ((unsigned long)mod->data_layout.base <= addr &&
> - addr < (unsigned long)mod->data_layout.base + mod->data_layout.size)
> - return true;
> -#endif
> - return (unsigned long)mod->core_layout.base <= addr &&
> - addr < (unsigned long)mod->core_layout.base + mod->core_layout.size;
> + return within_module_mem_type(addr, mod, MOD_TEXT) ||
> + within_module_mem_type(addr, mod, MOD_DATA) ||
> + within_module_mem_type(addr, mod, MOD_RODATA) ||
> + within_module_mem_type(addr, mod, MOD_RO_AFTER_INIT);
> }

within_module_mem_types(addr, mod, MOD_TEXT, MOD_RO_AFTER_INIT);

> static inline bool within_module_init(unsigned long addr,
> const struct module *mod)
> {
> - return (unsigned long)mod->init_layout.base <= addr &&
> - addr < (unsigned long)mod->init_layout.base + mod->init_layout.size;
> + return within_module_mem_type(addr, mod, MOD_INIT_TEXT) ||
> + within_module_mem_type(addr, mod, MOD_INIT_DATA) ||
> + within_module_mem_type(addr, mod, MOD_INIT_RODATA);
> }

within_module_mem_types(addr, mod, MOD_INIT_TEXT, MOD_INIT_RODATA);