Commit 656be92f authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Ralf Baechle
Browse files

[MIPS] Load modules to CKSEG0 if CONFIG_BUILD_ELF64=n 



This is a patch to load 64-bit modules to CKSEG0 so that can be
compiled with -msym32 option.  This makes each module ~10% smaller.

* introduce MODULE_START and MODULE_END
* custom module_alloc()
* PGD for modules
* change XTLB refill handler synthesizer
* enable -msym32 for modules again
  (revert ca78b1a5c6a6e70e052d3ea253828e49b5d07c8a)

New XTLB refill handler looks like this:

80000080 dmfc0   k0,C0_BADVADDR
80000084 bltz    k0,800000e4			# goto l_module_alloc
80000088 lui     k1,0x8046			# %high(pgd_current)
8000008c ld      k1,24600(k1)			# %low(pgd_current)
80000090 dsrl    k0,k0,0x1b			# l_vmalloc_done:
80000094 andi    k0,k0,0x1ff8
80000098 daddu   k1,k1,k0
8000009c dmfc0   k0,C0_BADVADDR
800000a0 ld      k1,0(k1)
800000a4 dsrl    k0,k0,0x12
800000a8 andi    k0,k0,0xff8
800000ac daddu   k1,k1,k0
800000b0 dmfc0   k0,C0_XCONTEXT
800000b4 ld      k1,0(k1)
800000b8 andi    k0,k0,0xff0
800000bc daddu   k1,k1,k0
800000c0 ld      k0,0(k1)
800000c4 ld      k1,8(k1)
800000c8 dsrl    k0,k0,0x6
800000cc mtc0    k0,C0_ENTRYLO0
800000d0 dsrl    k1,k1,0x6
800000d4 mtc0    k1,C0_ENTRYL01
800000d8 nop
800000dc tlbwr
800000e0 eret
800000e4 dsll    k1,k0,0x2			# l_module_alloc:
800000e8 bgez    k1,80000008			# goto l_vmalloc
800000ec lui     k1,0xc000
800000f0 dsubu   k0,k0,k1
800000f4 lui     k1,0x8046			# %high(module_pg_dir)
800000f8 beq     zero,zero,80000000
800000fc nop
80000000 beq     zero,zero,80000090		# goto l_vmalloc_done
80000004 daddiu  k1,k1,0x4000
80000008 dsll32  k1,k1,0x0			# l_vmalloc:
8000000c dsubu   k0,k0,k1
80000010 beq     zero,zero,80000090		# goto l_vmalloc_done
80000014 lui     k1,0x8046			# %high(swapper_pg_dir)

Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 56ae5833

arch/mips/Makefile

+1 −3
Original line number Diff line number Diff line
@@ -63,9 +63,7 @@ cflags-y += -mabi=64 
ifdef CONFIG_BUILD_ELF64

cflags-y		+= $(call cc-option,-mno-explicit-relocs)

else

# -msym32 can not be used for modules since they are loaded into XKSEG

CFLAGS_MODULE		+= $(call cc-option,-mno-explicit-relocs)

CFLAGS_KERNEL		+= $(call cc-option,-msym32)

cflags-y		+= $(call cc-option,-msym32)

endif

endif

arch/mips/kernel/head.S

+3 −0
Original line number Diff line number Diff line
@@ -250,6 +250,9 @@ NESTED(smp_bootstrap, 16, sp) 
	 */

	page	swapper_pg_dir, _PGD_ORDER

#ifdef CONFIG_64BIT

#if defined(CONFIG_MODULES) && !defined(CONFIG_BUILD_ELF64)

	page	module_pg_dir, _PGD_ORDER

#endif

	page	invalid_pmd_table, _PMD_ORDER

#endif

	page	invalid_pte_table, _PTE_ORDER

arch/mips/kernel/module.c

+15 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/spinlock.h>

#include <asm/pgtable.h>	/* MODULE_START */



struct mips_hi16 {

	struct mips_hi16 *next;
@@ -43,9 +44,23 @@ static DEFINE_SPINLOCK(dbe_lock); 


void *module_alloc(unsigned long size)

{

#ifdef MODULE_START

	struct vm_struct *area;



	size = PAGE_ALIGN(size);

	if (!size)

		return NULL;



	area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END);

	if (!area)

		return NULL;



	return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);

#else

	if (size == 0)

		return NULL;

	return vmalloc(size);

#endif

}



/* Free memory returned from module_alloc */

arch/mips/mm/fault.c

+4 −0
Original line number Diff line number Diff line
@@ -60,6 +60,10 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write, 
	 */

	if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))

		goto vmalloc_fault;

#ifdef MODULE_START

	if (unlikely(address >= MODULE_START && address < MODULE_END))

		goto vmalloc_fault;

#endif



	/*

	 * If we're in an interrupt or have no user

arch/mips/mm/pgtable-64.c

+3 −0
Original line number Diff line number Diff line
@@ -58,6 +58,9 @@ void __init pagetable_init(void) 


	/* Initialize the entire pgd.  */

	pgd_init((unsigned long)swapper_pg_dir);

#ifdef MODULE_START

	pgd_init((unsigned long)module_pg_dir);

#endif

	pmd_init((unsigned long)invalid_pmd_table, (unsigned long)invalid_pte_table);



	pgd_base = swapper_pg_dir;

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