module: replace module_layout with module_memory

module_layout manages different types of memory (text, data, rodata, etc.)
in one allocation, which is problematic for some reasons:

1. It is hard to enable CONFIG_STRICT_MODULE_RWX.
2. It is hard to use huge pages in modules (and not break strict rwx).
3. Many archs uses module_layout for arch-specific data, but it is not
   obvious how these data are used (are they RO, RX, or RW?)

Improve the scenario by replacing 2 (or 3) module_layout per module with
up to 7 module_memory per module:

        MOD_TEXT,
        MOD_DATA,
        MOD_RODATA,
        MOD_RO_AFTER_INIT,
        MOD_INIT_TEXT,
        MOD_INIT_DATA,
        MOD_INIT_RODATA,

and allocating them separately. This adds slightly more entries to
mod_tree (from up to 3 entries per module, to up to 7 entries per
module). However, this at most adds a small constant overhead to
__module_address(), which is expected to be fast.

Various archs use module_layout for different data. These data are put
into different module_memory based on their location in module_layout.
IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT;
data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc.

module_memory simplifies quite some of the module code. For example,
ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a
different allocator for the data. kernel/module/strict_rwx.c is also
much cleaner with module_memory.

Signed-off-by: Song Liu <song@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

1 files changed, 5 insertions, 6 deletions

diff --git a/arch/mips/kernel/vpe.c b/arch/mips/kernel/vpe.c
index 13294972707b..ab114c686f9d 100644
--- a/arch/mips/kernel/vpe.c
+++ b/arch/mips/kernel/vpe.c
@@ -199,18 +199,17 @@ static void layout_sections(struct module *mod, const Elf_Ehdr *hdr,
 	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
 		for (i = 0; i < hdr->e_shnum; ++i) {
 			Elf_Shdr *s = &sechdrs[i];
+			struct module_memory *mod_mem;
+
+			mod_mem = &mod->mem[MOD_TEXT];
 
 			if ((s->sh_flags & masks[m][0]) != masks[m][0]
 			    || (s->sh_flags & masks[m][1])
 			    || s->sh_entsize != ~0UL)
 				continue;
 			s->sh_entsize =
-				get_offset((unsigned long *)&mod->core_layout.size, s);
+				get_offset((unsigned long *)&mod_mem->size, s);
 		}
-
-		if (m == 0)
-			mod->core_layout.text_size = mod->core_layout.size;
-
 	}
 }
 
@@ -641,7 +640,7 @@ static int vpe_elfload(struct vpe *v)
 		layout_sections(&mod, hdr, sechdrs, secstrings);
 	}
 
-	v->load_addr = alloc_progmem(mod.core_layout.size);
+	v->load_addr = alloc_progmem(mod.mod_mem[MOD_TEXT].size);
 	if (!v->load_addr)
 		return -ENOMEM;