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, 14 insertions, 12 deletions

diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 2d159b32885b..b9dbf0c483ed 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -126,6 +126,7 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 	Elf_Rela *rela;
 	char *strings;
 	int nrela, i, j;
+	struct module_memory *mod_mem;
 
 	/* Find symbol table and string table. */
 	symtab = NULL;
@@ -173,14 +174,15 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 
 	/* Increase core size by size of got & plt and set start
 	   offsets for got and plt. */
-	me->core_layout.size = ALIGN(me->core_layout.size, 4);
-	me->arch.got_offset = me->core_layout.size;
-	me->core_layout.size += me->arch.got_size;
-	me->arch.plt_offset = me->core_layout.size;
+	mod_mem = &me->mem[MOD_TEXT];
+	mod_mem->size = ALIGN(mod_mem->size, 4);
+	me->arch.got_offset = mod_mem->size;
+	mod_mem->size += me->arch.got_size;
+	me->arch.plt_offset = mod_mem->size;
 	if (me->arch.plt_size) {
 		if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable)
 			me->arch.plt_size += PLT_ENTRY_SIZE;
-		me->core_layout.size += me->arch.plt_size;
+		mod_mem->size += me->arch.plt_size;
 	}
 	return 0;
 }
@@ -304,7 +306,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 	case R_390_GOTPLT64:	/* 64 bit offset to jump slot.	*/
 	case R_390_GOTPLTENT:	/* 32 bit rel. offset to jump slot >> 1. */
 		if (info->got_initialized == 0) {
-			Elf_Addr *gotent = me->core_layout.base +
+			Elf_Addr *gotent = me->mem[MOD_TEXT].base +
 					   me->arch.got_offset +
 					   info->got_offset;
 
@@ -329,7 +331,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 			rc = apply_rela_bits(loc, val, 0, 64, 0, write);
 		else if (r_type == R_390_GOTENT ||
 			 r_type == R_390_GOTPLTENT) {
-			val += (Elf_Addr) me->core_layout.base - loc;
+			val += (Elf_Addr) me->mem[MOD_TEXT].base - loc;
 			rc = apply_rela_bits(loc, val, 1, 32, 1, write);
 		}
 		break;
@@ -345,7 +347,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 			char *plt_base;
 			char *ip;
 
-			plt_base = me->core_layout.base + me->arch.plt_offset;
+			plt_base = me->mem[MOD_TEXT].base + me->arch.plt_offset;
 			ip = plt_base + info->plt_offset;
 			*(int *)insn = 0x0d10e310;	/* basr 1,0  */
 			*(int *)&insn[4] = 0x100c0004;	/* lg	1,12(1) */
@@ -375,7 +377,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 			       val - loc + 0xffffUL < 0x1ffffeUL) ||
 			      (r_type == R_390_PLT32DBL &&
 			       val - loc + 0xffffffffULL < 0x1fffffffeULL)))
-				val = (Elf_Addr) me->core_layout.base +
+				val = (Elf_Addr) me->mem[MOD_TEXT].base +
 					me->arch.plt_offset +
 					info->plt_offset;
 			val += rela->r_addend - loc;
@@ -397,7 +399,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 	case R_390_GOTOFF32:	/* 32 bit offset to GOT.  */
 	case R_390_GOTOFF64:	/* 64 bit offset to GOT. */
 		val = val + rela->r_addend -
-			((Elf_Addr) me->core_layout.base + me->arch.got_offset);
+			((Elf_Addr) me->mem[MOD_TEXT].base + me->arch.got_offset);
 		if (r_type == R_390_GOTOFF16)
 			rc = apply_rela_bits(loc, val, 0, 16, 0, write);
 		else if (r_type == R_390_GOTOFF32)
@@ -407,7 +409,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 		break;
 	case R_390_GOTPC:	/* 32 bit PC relative offset to GOT. */
 	case R_390_GOTPCDBL:	/* 32 bit PC rel. off. to GOT shifted by 1. */
-		val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +
+		val = (Elf_Addr) me->mem[MOD_TEXT].base + me->arch.got_offset +
 			rela->r_addend - loc;
 		if (r_type == R_390_GOTPC)
 			rc = apply_rela_bits(loc, val, 1, 32, 0, write);
@@ -515,7 +517,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 	    !nospec_disable && me->arch.plt_size) {
 		unsigned int *ij;
 
-		ij = me->core_layout.base + me->arch.plt_offset +
+		ij = me->mem[MOD_TEXT].base + me->arch.plt_offset +
 			me->arch.plt_size - PLT_ENTRY_SIZE;
 		ij[0] = 0xc6000000;	/* exrl	%r0,.+10	*/
 		ij[1] = 0x0005a7f4;	/* j	.		*/