linux/arch/mips/kernel/unaligned.c
Alexey Dobriyan e8edc6e03a Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.

This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
   getting them indirectly

Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
   they don't need sched.h
b) sched.h stops being dependency for significant number of files:
   on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
   after patch it's only 3744 (-8.3%).

Cross-compile tested on

	all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
	alpha alpha-up
	arm
	i386 i386-up i386-defconfig i386-allnoconfig
	ia64 ia64-up
	m68k
	mips
	parisc parisc-up
	powerpc powerpc-up
	s390 s390-up
	sparc sparc-up
	sparc64 sparc64-up
	um-x86_64
	x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig

as well as my two usual configs.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21 09:18:19 -07:00

549 lines
13 KiB
C

/*
* Handle unaligned accesses by emulation.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996, 1998, 1999, 2002 by Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
*
* This file contains exception handler for address error exception with the
* special capability to execute faulting instructions in software. The
* handler does not try to handle the case when the program counter points
* to an address not aligned to a word boundary.
*
* Putting data to unaligned addresses is a bad practice even on Intel where
* only the performance is affected. Much worse is that such code is non-
* portable. Due to several programs that die on MIPS due to alignment
* problems I decided to implement this handler anyway though I originally
* didn't intend to do this at all for user code.
*
* For now I enable fixing of address errors by default to make life easier.
* I however intend to disable this somewhen in the future when the alignment
* problems with user programs have been fixed. For programmers this is the
* right way to go.
*
* Fixing address errors is a per process option. The option is inherited
* across fork(2) and execve(2) calls. If you really want to use the
* option in your user programs - I discourage the use of the software
* emulation strongly - use the following code in your userland stuff:
*
* #include <sys/sysmips.h>
*
* ...
* sysmips(MIPS_FIXADE, x);
* ...
*
* The argument x is 0 for disabling software emulation, enabled otherwise.
*
* Below a little program to play around with this feature.
*
* #include <stdio.h>
* #include <sys/sysmips.h>
*
* struct foo {
* unsigned char bar[8];
* };
*
* main(int argc, char *argv[])
* {
* struct foo x = {0, 1, 2, 3, 4, 5, 6, 7};
* unsigned int *p = (unsigned int *) (x.bar + 3);
* int i;
*
* if (argc > 1)
* sysmips(MIPS_FIXADE, atoi(argv[1]));
*
* printf("*p = %08lx\n", *p);
*
* *p = 0xdeadface;
*
* for(i = 0; i <= 7; i++)
* printf("%02x ", x.bar[i]);
* printf("\n");
* }
*
* Coprocessor loads are not supported; I think this case is unimportant
* in the practice.
*
* TODO: Handle ndc (attempted store to doubleword in uncached memory)
* exception for the R6000.
* A store crossing a page boundary might be executed only partially.
* Undo the partial store in this case.
*/
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/byteorder.h>
#include <asm/inst.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#define STR(x) __STR(x)
#define __STR(x) #x
#ifdef CONFIG_PROC_FS
unsigned long unaligned_instructions;
#endif
static inline int emulate_load_store_insn(struct pt_regs *regs,
void __user *addr, unsigned int __user *pc,
unsigned long **regptr, unsigned long *newvalue)
{
union mips_instruction insn;
unsigned long value;
unsigned int res;
regs->regs[0] = 0;
*regptr=NULL;
/*
* This load never faults.
*/
__get_user(insn.word, pc);
switch (insn.i_format.opcode) {
/*
* These are instructions that a compiler doesn't generate. We
* can assume therefore that the code is MIPS-aware and
* really buggy. Emulating these instructions would break the
* semantics anyway.
*/
case ll_op:
case lld_op:
case sc_op:
case scd_op:
/*
* For these instructions the only way to create an address
* error is an attempted access to kernel/supervisor address
* space.
*/
case ldl_op:
case ldr_op:
case lwl_op:
case lwr_op:
case sdl_op:
case sdr_op:
case swl_op:
case swr_op:
case lb_op:
case lbu_op:
case sb_op:
goto sigbus;
/*
* The remaining opcodes are the ones that are really of interest.
*/
case lh_op:
if (!access_ok(VERIFY_READ, addr, 2))
goto sigbus;
__asm__ __volatile__ (".set\tnoat\n"
#ifdef __BIG_ENDIAN
"1:\tlb\t%0, 0(%2)\n"
"2:\tlbu\t$1, 1(%2)\n\t"
#endif
#ifdef __LITTLE_ENDIAN
"1:\tlb\t%0, 1(%2)\n"
"2:\tlbu\t$1, 0(%2)\n\t"
#endif
"sll\t%0, 0x8\n\t"
"or\t%0, $1\n\t"
"li\t%1, 0\n"
"3:\t.set\tat\n\t"
".section\t.fixup,\"ax\"\n\t"
"4:\tli\t%1, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=&r" (value), "=r" (res)
: "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
*newvalue = value;
*regptr = &regs->regs[insn.i_format.rt];
break;
case lw_op:
if (!access_ok(VERIFY_READ, addr, 4))
goto sigbus;
__asm__ __volatile__ (
#ifdef __BIG_ENDIAN
"1:\tlwl\t%0, (%2)\n"
"2:\tlwr\t%0, 3(%2)\n\t"
#endif
#ifdef __LITTLE_ENDIAN
"1:\tlwl\t%0, 3(%2)\n"
"2:\tlwr\t%0, (%2)\n\t"
#endif
"li\t%1, 0\n"
"3:\t.section\t.fixup,\"ax\"\n\t"
"4:\tli\t%1, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=&r" (value), "=r" (res)
: "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
*newvalue = value;
*regptr = &regs->regs[insn.i_format.rt];
break;
case lhu_op:
if (!access_ok(VERIFY_READ, addr, 2))
goto sigbus;
__asm__ __volatile__ (
".set\tnoat\n"
#ifdef __BIG_ENDIAN
"1:\tlbu\t%0, 0(%2)\n"
"2:\tlbu\t$1, 1(%2)\n\t"
#endif
#ifdef __LITTLE_ENDIAN
"1:\tlbu\t%0, 1(%2)\n"
"2:\tlbu\t$1, 0(%2)\n\t"
#endif
"sll\t%0, 0x8\n\t"
"or\t%0, $1\n\t"
"li\t%1, 0\n"
"3:\t.set\tat\n\t"
".section\t.fixup,\"ax\"\n\t"
"4:\tli\t%1, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=&r" (value), "=r" (res)
: "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
*newvalue = value;
*regptr = &regs->regs[insn.i_format.rt];
break;
case lwu_op:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (!access_ok(VERIFY_READ, addr, 4))
goto sigbus;
__asm__ __volatile__ (
#ifdef __BIG_ENDIAN
"1:\tlwl\t%0, (%2)\n"
"2:\tlwr\t%0, 3(%2)\n\t"
#endif
#ifdef __LITTLE_ENDIAN
"1:\tlwl\t%0, 3(%2)\n"
"2:\tlwr\t%0, (%2)\n\t"
#endif
"dsll\t%0, %0, 32\n\t"
"dsrl\t%0, %0, 32\n\t"
"li\t%1, 0\n"
"3:\t.section\t.fixup,\"ax\"\n\t"
"4:\tli\t%1, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=&r" (value), "=r" (res)
: "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
*newvalue = value;
*regptr = &regs->regs[insn.i_format.rt];
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case ld_op:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (!access_ok(VERIFY_READ, addr, 8))
goto sigbus;
__asm__ __volatile__ (
#ifdef __BIG_ENDIAN
"1:\tldl\t%0, (%2)\n"
"2:\tldr\t%0, 7(%2)\n\t"
#endif
#ifdef __LITTLE_ENDIAN
"1:\tldl\t%0, 7(%2)\n"
"2:\tldr\t%0, (%2)\n\t"
#endif
"li\t%1, 0\n"
"3:\t.section\t.fixup,\"ax\"\n\t"
"4:\tli\t%1, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=&r" (value), "=r" (res)
: "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
*newvalue = value;
*regptr = &regs->regs[insn.i_format.rt];
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case sh_op:
if (!access_ok(VERIFY_WRITE, addr, 2))
goto sigbus;
value = regs->regs[insn.i_format.rt];
__asm__ __volatile__ (
#ifdef __BIG_ENDIAN
".set\tnoat\n"
"1:\tsb\t%1, 1(%2)\n\t"
"srl\t$1, %1, 0x8\n"
"2:\tsb\t$1, 0(%2)\n\t"
".set\tat\n\t"
#endif
#ifdef __LITTLE_ENDIAN
".set\tnoat\n"
"1:\tsb\t%1, 0(%2)\n\t"
"srl\t$1,%1, 0x8\n"
"2:\tsb\t$1, 1(%2)\n\t"
".set\tat\n\t"
#endif
"li\t%0, 0\n"
"3:\n\t"
".section\t.fixup,\"ax\"\n\t"
"4:\tli\t%0, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=r" (res)
: "r" (value), "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
break;
case sw_op:
if (!access_ok(VERIFY_WRITE, addr, 4))
goto sigbus;
value = regs->regs[insn.i_format.rt];
__asm__ __volatile__ (
#ifdef __BIG_ENDIAN
"1:\tswl\t%1,(%2)\n"
"2:\tswr\t%1, 3(%2)\n\t"
#endif
#ifdef __LITTLE_ENDIAN
"1:\tswl\t%1, 3(%2)\n"
"2:\tswr\t%1, (%2)\n\t"
#endif
"li\t%0, 0\n"
"3:\n\t"
".section\t.fixup,\"ax\"\n\t"
"4:\tli\t%0, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=r" (res)
: "r" (value), "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
break;
case sd_op:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (!access_ok(VERIFY_WRITE, addr, 8))
goto sigbus;
value = regs->regs[insn.i_format.rt];
__asm__ __volatile__ (
#ifdef __BIG_ENDIAN
"1:\tsdl\t%1,(%2)\n"
"2:\tsdr\t%1, 7(%2)\n\t"
#endif
#ifdef __LITTLE_ENDIAN
"1:\tsdl\t%1, 7(%2)\n"
"2:\tsdr\t%1, (%2)\n\t"
#endif
"li\t%0, 0\n"
"3:\n\t"
".section\t.fixup,\"ax\"\n\t"
"4:\tli\t%0, %3\n\t"
"j\t3b\n\t"
".previous\n\t"
".section\t__ex_table,\"a\"\n\t"
STR(PTR)"\t1b, 4b\n\t"
STR(PTR)"\t2b, 4b\n\t"
".previous"
: "=r" (res)
: "r" (value), "r" (addr), "i" (-EFAULT));
if (res)
goto fault;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case lwc1_op:
case ldc1_op:
case swc1_op:
case sdc1_op:
/*
* I herewith declare: this does not happen. So send SIGBUS.
*/
goto sigbus;
case lwc2_op:
case ldc2_op:
case swc2_op:
case sdc2_op:
/*
* These are the coprocessor 2 load/stores. The current
* implementations don't use cp2 and cp2 should always be
* disabled in c0_status. So send SIGILL.
* (No longer true: The Sony Praystation uses cp2 for
* 3D matrix operations. Dunno if that thingy has a MMU ...)
*/
default:
/*
* Pheeee... We encountered an yet unknown instruction or
* cache coherence problem. Die sucker, die ...
*/
goto sigill;
}
#ifdef CONFIG_PROC_FS
unaligned_instructions++;
#endif
return 0;
fault:
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return 1;
die_if_kernel ("Unhandled kernel unaligned access", regs);
send_sig(SIGSEGV, current, 1);
return 0;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
send_sig(SIGBUS, current, 1);
return 0;
sigill:
die_if_kernel("Unhandled kernel unaligned access or invalid instruction", regs);
send_sig(SIGILL, current, 1);
return 0;
}
asmlinkage void do_ade(struct pt_regs *regs)
{
unsigned long *regptr, newval;
extern int do_dsemulret(struct pt_regs *);
unsigned int __user *pc;
mm_segment_t seg;
/*
* Address errors may be deliberately induced by the FPU emulator to
* retake control of the CPU after executing the instruction in the
* delay slot of an emulated branch.
*/
/* Terminate if exception was recognized as a delay slot return */
if (do_dsemulret(regs))
return;
/* Otherwise handle as normal */
/*
* Did we catch a fault trying to load an instruction?
* Or are we running in MIPS16 mode?
*/
if ((regs->cp0_badvaddr == regs->cp0_epc) || (regs->cp0_epc & 0x1))
goto sigbus;
pc = (unsigned int __user *) exception_epc(regs);
if (user_mode(regs) && (current->thread.mflags & MF_FIXADE) == 0)
goto sigbus;
/*
* Do branch emulation only if we didn't forward the exception.
* This is all so but ugly ...
*/
seg = get_fs();
if (!user_mode(regs))
set_fs(KERNEL_DS);
if (!emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc,
&regptr, &newval)) {
compute_return_epc(regs);
/*
* Now that branch is evaluated, update the dest
* register if necessary
*/
if (regptr)
*regptr = newval;
}
set_fs(seg);
return;
sigbus:
die_if_kernel("Kernel unaligned instruction access", regs);
force_sig(SIGBUS, current);
/*
* XXX On return from the signal handler we should advance the epc
*/
}