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linux_dsm_epyc7002/arch/mips/kernel/unaligned.c
Christoph Hellwig 3d13f313ce uaccess: add force_uaccess_{begin,end} helpers 
Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS).  There is no real functional benefit, but this
documents the intent of these calls better, and will allow stubbing the
functions out easily for kernels builds that do not allow address space
overrides in the future.

[hch@lst.de: drop two incorrect hunks, fix a commit log typo]
  Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:59 -07:00

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/*
* 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.
* Copyright (C) 2014 Imagination Technologies Ltd.
*
* 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/context_tracking.h>
#include <linux/mm.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <linux/perf_event.h>
#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/byteorder.h>
#include <asm/cop2.h>
#include <asm/debug.h>
#include <asm/fpu.h>
#include <asm/fpu_emulator.h>
#include <asm/inst.h>
#include <asm/unaligned-emul.h>
#include <asm/mmu_context.h>
#include <linux/uaccess.h>
enum {
UNALIGNED_ACTION_QUIET,
UNALIGNED_ACTION_SIGNAL,
UNALIGNED_ACTION_SHOW,
};
#ifdef CONFIG_DEBUG_FS
static u32 unaligned_instructions;
static u32 unaligned_action;
#else
#define unaligned_action UNALIGNED_ACTION_QUIET
#endif
extern void show_registers(struct pt_regs *regs);
static void emulate_load_store_insn(struct pt_regs *regs,
void __user *addr, unsigned int __user *pc)
{
unsigned long origpc, orig31, value;
union mips_instruction insn;
unsigned int res;
#ifdef CONFIG_EVA
mm_segment_t seg;
#endif
origpc = (unsigned long)pc;
orig31 = regs->regs[31];
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
/*
* 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 spec3_op:
if (insn.dsp_format.func == lx_op) {
switch (insn.dsp_format.op) {
case lwx_op:
if (!access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.dsp_format.rd] = value;
break;
case lhx_op:
if (!access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.dsp_format.rd] = value;
break;
default:
goto sigill;
}
}
#ifdef CONFIG_EVA
else {
/*
* we can land here only from kernel accessing user
* memory, so we need to "switch" the address limit to
* user space, so that address check can work properly.
*/
seg = force_uaccess_begin();
switch (insn.spec3_format.func) {
case lhe_op:
if (!access_ok(addr, 2)) {
force_uaccess_end(seg);
goto sigbus;
}
LoadHWE(addr, value, res);
if (res) {
force_uaccess_end(seg);
goto fault;
}
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case lwe_op:
if (!access_ok(addr, 4)) {
force_uaccess_end(seg);
goto sigbus;
}
LoadWE(addr, value, res);
if (res) {
force_uaccess_end(seg);
goto fault;
}
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case lhue_op:
if (!access_ok(addr, 2)) {
force_uaccess_end(seg);
goto sigbus;
}
LoadHWUE(addr, value, res);
if (res) {
force_uaccess_end(seg);
goto fault;
}
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case she_op:
if (!access_ok(addr, 2)) {
force_uaccess_end(seg);
goto sigbus;
}
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreHWE(addr, value, res);
if (res) {
force_uaccess_end(seg);
goto fault;
}
break;
case swe_op:
if (!access_ok(addr, 4)) {
force_uaccess_end(seg);
goto sigbus;
}
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreWE(addr, value, res);
if (res) {
force_uaccess_end(seg);
goto fault;
}
break;
default:
force_uaccess_end(seg);
goto sigill;
}
force_uaccess_end(seg);
}
#endif
break;
case lh_op:
if (!access_ok(addr, 2))
goto sigbus;
if (IS_ENABLED(CONFIG_EVA)) {
if (uaccess_kernel())
LoadHW(addr, value, res);
else
LoadHWE(addr, value, res);
} else {
LoadHW(addr, value, res);
}
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
case lw_op:
if (!access_ok(addr, 4))
goto sigbus;
if (IS_ENABLED(CONFIG_EVA)) {
if (uaccess_kernel())
LoadW(addr, value, res);
else
LoadWE(addr, value, res);
} else {
LoadW(addr, value, res);
}
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
case lhu_op:
if (!access_ok(addr, 2))
goto sigbus;
if (IS_ENABLED(CONFIG_EVA)) {
if (uaccess_kernel())
LoadHWU(addr, value, res);
else
LoadHWUE(addr, value, res);
} else {
LoadHWU(addr, value, res);
}
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
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(addr, 4))
goto sigbus;
LoadWU(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
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(addr, 8))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case sh_op:
if (!access_ok(addr, 2))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];
if (IS_ENABLED(CONFIG_EVA)) {
if (uaccess_kernel())
StoreHW(addr, value, res);
else
StoreHWE(addr, value, res);
} else {
StoreHW(addr, value, res);
}
if (res)
goto fault;
break;
case sw_op:
if (!access_ok(addr, 4))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];
if (IS_ENABLED(CONFIG_EVA)) {
if (uaccess_kernel())
StoreW(addr, value, res);
else
StoreWE(addr, value, res);
} else {
StoreW(addr, value, res);
}
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(addr, 8))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];
StoreDW(addr, value, res);
if (res)
goto fault;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
#ifdef CONFIG_MIPS_FP_SUPPORT
case lwc1_op:
case ldc1_op:
case swc1_op:
case sdc1_op:
case cop1x_op: {
void __user *fault_addr = NULL;
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
res = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
&fault_addr);
own_fpu(1); /* Restore FPU state. */
/* Signal if something went wrong. */
process_fpemu_return(res, fault_addr, 0);
if (res == 0)
break;
return;
}
#endif /* CONFIG_MIPS_FP_SUPPORT */
#ifdef CONFIG_CPU_HAS_MSA
case msa_op: {
unsigned int wd, preempted;
enum msa_2b_fmt df;
union fpureg *fpr;
if (!cpu_has_msa)
goto sigill;
/*
* If we've reached this point then userland should have taken
* the MSA disabled exception & initialised vector context at
* some point in the past.
*/
BUG_ON(!thread_msa_context_live());
df = insn.msa_mi10_format.df;
wd = insn.msa_mi10_format.wd;
fpr = &current->thread.fpu.fpr[wd];
switch (insn.msa_mi10_format.func) {
case msa_ld_op:
if (!access_ok(addr, sizeof(*fpr)))
goto sigbus;
do {
/*
* If we have live MSA context keep track of
* whether we get preempted in order to avoid
* the register context we load being clobbered
* by the live context as it's saved during
* preemption. If we don't have live context
* then it can't be saved to clobber the value
* we load.
*/
preempted = test_thread_flag(TIF_USEDMSA);
res = __copy_from_user_inatomic(fpr, addr,
sizeof(*fpr));
if (res)
goto fault;
/*
* Update the hardware register if it is in use
* by the task in this quantum, in order to
* avoid having to save & restore the whole
* vector context.
*/
preempt_disable();
if (test_thread_flag(TIF_USEDMSA)) {
write_msa_wr(wd, fpr, df);
preempted = 0;
}
preempt_enable();
} while (preempted);
break;
case msa_st_op:
if (!access_ok(addr, sizeof(*fpr)))
goto sigbus;
/*
* Update from the hardware register if it is in use by
* the task in this quantum, in order to avoid having to
* save & restore the whole vector context.
*/
preempt_disable();
if (test_thread_flag(TIF_USEDMSA))
read_msa_wr(wd, fpr, df);
preempt_enable();
res = __copy_to_user_inatomic(addr, fpr, sizeof(*fpr));
if (res)
goto fault;
break;
default:
goto sigbus;
}
compute_return_epc(regs);
break;
}
#endif /* CONFIG_CPU_HAS_MSA */
#ifndef CONFIG_CPU_MIPSR6
/*
* COP2 is available to implementor for application specific use.
* It's up to applications to register a notifier chain and do
* whatever they have to do, including possible sending of signals.
*
* This instruction has been reallocated in Release 6
*/
case lwc2_op:
cu2_notifier_call_chain(CU2_LWC2_OP, regs);
break;
case ldc2_op:
cu2_notifier_call_chain(CU2_LDC2_OP, regs);
break;
case swc2_op:
cu2_notifier_call_chain(CU2_SWC2_OP, regs);
break;
case sdc2_op:
cu2_notifier_call_chain(CU2_SDC2_OP, regs);
break;
#endif
default:
/*
* Pheeee... We encountered an yet unknown instruction or
* cache coherence problem. Die sucker, die ...
*/
goto sigill;
}
#ifdef CONFIG_DEBUG_FS
unaligned_instructions++;
#endif
return;
fault:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return;
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return;
sigill:
die_if_kernel
("Unhandled kernel unaligned access or invalid instruction", regs);
force_sig(SIGILL);
}
/* Recode table from 16-bit register notation to 32-bit GPR. */
const int reg16to32[] = { 16, 17, 2, 3, 4, 5, 6, 7 };
/* Recode table from 16-bit STORE register notation to 32-bit GPR. */
static const int reg16to32st[] = { 0, 17, 2, 3, 4, 5, 6, 7 };
static void emulate_load_store_microMIPS(struct pt_regs *regs,
void __user *addr)
{
unsigned long value;
unsigned int res;
int i;
unsigned int reg = 0, rvar;
unsigned long orig31;
u16 __user *pc16;
u16 halfword;
unsigned int word;
unsigned long origpc, contpc;
union mips_instruction insn;
struct mm_decoded_insn mminsn;
origpc = regs->cp0_epc;
orig31 = regs->regs[31];
mminsn.micro_mips_mode = 1;
/*
* This load never faults.
*/
pc16 = (unsigned short __user *)msk_isa16_mode(regs->cp0_epc);
__get_user(halfword, pc16);
pc16++;
contpc = regs->cp0_epc + 2;
word = ((unsigned int)halfword << 16);
mminsn.pc_inc = 2;
if (!mm_insn_16bit(halfword)) {
__get_user(halfword, pc16);
pc16++;
contpc = regs->cp0_epc + 4;
mminsn.pc_inc = 4;
word |= halfword;
}
mminsn.insn = word;
if (get_user(halfword, pc16))
goto fault;
mminsn.next_pc_inc = 2;
word = ((unsigned int)halfword << 16);
if (!mm_insn_16bit(halfword)) {
pc16++;
if (get_user(halfword, pc16))
goto fault;
mminsn.next_pc_inc = 4;
word |= halfword;
}
mminsn.next_insn = word;
insn = (union mips_instruction)(mminsn.insn);
if (mm_isBranchInstr(regs, mminsn, &contpc))
insn = (union mips_instruction)(mminsn.next_insn);
/* Parse instruction to find what to do */
switch (insn.mm_i_format.opcode) {
case mm_pool32a_op:
switch (insn.mm_x_format.func) {
case mm_lwxs_op:
reg = insn.mm_x_format.rd;
goto loadW;
}
goto sigbus;
case mm_pool32b_op:
switch (insn.mm_m_format.func) {
case mm_lwp_func:
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (!access_ok(addr, 8))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
addr += 4;
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[reg + 1] = value;
goto success;
case mm_swp_func:
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (!access_ok(addr, 8))
goto sigbus;
value = regs->regs[reg];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
value = regs->regs[reg + 1];
StoreW(addr, value, res);
if (res)
goto fault;
goto success;
case mm_ldp_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (!access_ok(addr, 16))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
addr += 8;
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[reg + 1] = value;
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
case mm_sdp_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (!access_ok(addr, 16))
goto sigbus;
value = regs->regs[reg];
StoreDW(addr, value, res);
if (res)
goto fault;
addr += 8;
value = regs->regs[reg + 1];
StoreDW(addr, value, res);
if (res)
goto fault;
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
case mm_lwm32_func:
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (!access_ok(addr, 4 * (rvar + 1)))
goto sigbus;
} else {
if (!access_ok(addr, 4 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
LoadW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[i] = value;
}
if ((reg & 0xf) == 9) {
LoadW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[30] = value;
}
if (reg & 0x10) {
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[31] = value;
}
goto success;
case mm_swm32_func:
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (!access_ok(addr, 4 * (rvar + 1)))
goto sigbus;
} else {
if (!access_ok(addr, 4 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
value = regs->regs[i];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
}
if ((reg & 0xf) == 9) {
value = regs->regs[30];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
}
if (reg & 0x10) {
value = regs->regs[31];
StoreW(addr, value, res);
if (res)
goto fault;
}
goto success;
case mm_ldm_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (!access_ok(addr, 8 * (rvar + 1)))
goto sigbus;
} else {
if (!access_ok(addr, 8 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
LoadDW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[i] = value;
}
if ((reg & 0xf) == 9) {
LoadDW(addr, value, res);
if (res)
goto fault;
addr += 8;
regs->regs[30] = value;
}
if (reg & 0x10) {
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[31] = value;
}
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
case mm_sdm_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (!access_ok(addr, 8 * (rvar + 1)))
goto sigbus;
} else {
if (!access_ok(addr, 8 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
value = regs->regs[i];
StoreDW(addr, value, res);
if (res)
goto fault;
addr += 8;
}
if ((reg & 0xf) == 9) {
value = regs->regs[30];
StoreDW(addr, value, res);
if (res)
goto fault;
addr += 8;
}
if (reg & 0x10) {
value = regs->regs[31];
StoreDW(addr, value, res);
if (res)
goto fault;
}
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
/* LWC2, SWC2, LDC2, SDC2 are not serviced */
}
goto sigbus;
case mm_pool32c_op:
switch (insn.mm_m_format.func) {
case mm_lwu_func:
reg = insn.mm_m_format.rd;
goto loadWU;
}
/* LL,SC,LLD,SCD are not serviced */
goto sigbus;
#ifdef CONFIG_MIPS_FP_SUPPORT
case mm_pool32f_op:
switch (insn.mm_x_format.func) {
case mm_lwxc1_func:
case mm_swxc1_func:
case mm_ldxc1_func:
case mm_sdxc1_func:
goto fpu_emul;
}
goto sigbus;
case mm_ldc132_op:
case mm_sdc132_op:
case mm_lwc132_op:
case mm_swc132_op: {
void __user *fault_addr = NULL;
fpu_emul:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
BUG_ON(!is_fpu_owner());
res = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
&fault_addr);
own_fpu(1); /* restore FPU state */
/* If something went wrong, signal */
process_fpemu_return(res, fault_addr, 0);
if (res == 0)
goto success;
return;
}
#endif /* CONFIG_MIPS_FP_SUPPORT */
case mm_lh32_op:
reg = insn.mm_i_format.rt;
goto loadHW;
case mm_lhu32_op:
reg = insn.mm_i_format.rt;
goto loadHWU;
case mm_lw32_op:
reg = insn.mm_i_format.rt;
goto loadW;
case mm_sh32_op:
reg = insn.mm_i_format.rt;
goto storeHW;
case mm_sw32_op:
reg = insn.mm_i_format.rt;
goto storeW;
case mm_ld32_op:
reg = insn.mm_i_format.rt;
goto loadDW;
case mm_sd32_op:
reg = insn.mm_i_format.rt;
goto storeDW;
case mm_pool16c_op:
switch (insn.mm16_m_format.func) {
case mm_lwm16_op:
reg = insn.mm16_m_format.rlist;
rvar = reg + 1;
if (!access_ok(addr, 4 * rvar))
goto sigbus;
for (i = 16; rvar; rvar--, i++) {
LoadW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[i] = value;
}
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[31] = value;
goto success;
case mm_swm16_op:
reg = insn.mm16_m_format.rlist;
rvar = reg + 1;
if (!access_ok(addr, 4 * rvar))
goto sigbus;
for (i = 16; rvar; rvar--, i++) {
value = regs->regs[i];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
}
value = regs->regs[31];
StoreW(addr, value, res);
if (res)
goto fault;
goto success;
}
goto sigbus;
case mm_lhu16_op:
reg = reg16to32[insn.mm16_rb_format.rt];
goto loadHWU;
case mm_lw16_op:
reg = reg16to32[insn.mm16_rb_format.rt];
goto loadW;
case mm_sh16_op:
reg = reg16to32st[insn.mm16_rb_format.rt];
goto storeHW;
case mm_sw16_op:
reg = reg16to32st[insn.mm16_rb_format.rt];
goto storeW;
case mm_lwsp16_op:
reg = insn.mm16_r5_format.rt;
goto loadW;
case mm_swsp16_op:
reg = insn.mm16_r5_format.rt;
goto storeW;
case mm_lwgp16_op:
reg = reg16to32[insn.mm16_r3_format.rt];
goto loadW;
default:
goto sigill;
}
loadHW:
if (!access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
loadHWU:
if (!access_ok(addr, 2))
goto sigbus;
LoadHWU(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
loadW:
if (!access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
loadWU:
#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(addr, 4))
goto sigbus;
LoadWU(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
loadDW:
#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(addr, 8))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
storeHW:
if (!access_ok(addr, 2))
goto sigbus;
value = regs->regs[reg];
StoreHW(addr, value, res);
if (res)
goto fault;
goto success;
storeW:
if (!access_ok(addr, 4))
goto sigbus;
value = regs->regs[reg];
StoreW(addr, value, res);
if (res)
goto fault;
goto success;
storeDW:
#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(addr, 8))
goto sigbus;
value = regs->regs[reg];
StoreDW(addr, value, res);
if (res)
goto fault;
goto success;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
success:
regs->cp0_epc = contpc; /* advance or branch */
#ifdef CONFIG_DEBUG_FS
unaligned_instructions++;
#endif
return;
fault:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return;
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return;
sigill:
die_if_kernel
("Unhandled kernel unaligned access or invalid instruction", regs);
force_sig(SIGILL);
}
static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
{
unsigned long value;
unsigned int res;
int reg;
unsigned long orig31;
u16 __user *pc16;
unsigned long origpc;
union mips16e_instruction mips16inst, oldinst;
unsigned int opcode;
int extended = 0;
origpc = regs->cp0_epc;
orig31 = regs->regs[31];
pc16 = (unsigned short __user *)msk_isa16_mode(origpc);
/*
* This load never faults.
*/
__get_user(mips16inst.full, pc16);
oldinst = mips16inst;
/* skip EXTEND instruction */
if (mips16inst.ri.opcode == MIPS16e_extend_op) {
extended = 1;
pc16++;
__get_user(mips16inst.full, pc16);
} else if (delay_slot(regs)) {
/* skip jump instructions */
/* JAL/JALX are 32 bits but have OPCODE in first short int */
if (mips16inst.ri.opcode == MIPS16e_jal_op)
pc16++;
pc16++;
if (get_user(mips16inst.full, pc16))
goto sigbus;
}
opcode = mips16inst.ri.opcode;
switch (opcode) {
case MIPS16e_i64_op: /* I64 or RI64 instruction */
switch (mips16inst.i64.func) { /* I64/RI64 func field check */
case MIPS16e_ldpc_func:
case MIPS16e_ldsp_func:
reg = reg16to32[mips16inst.ri64.ry];
goto loadDW;
case MIPS16e_sdsp_func:
reg = reg16to32[mips16inst.ri64.ry];
goto writeDW;
case MIPS16e_sdrasp_func:
reg = 29; /* GPRSP */
goto writeDW;
}
goto sigbus;
case MIPS16e_swsp_op:
reg = reg16to32[mips16inst.ri.rx];
if (extended && cpu_has_mips16e2)
switch (mips16inst.ri.imm >> 5) {
case 0: /* SWSP */
case 1: /* SWGP */
break;
case 2: /* SHGP */
opcode = MIPS16e_sh_op;
break;
default:
goto sigbus;
}
break;
case MIPS16e_lwpc_op:
reg = reg16to32[mips16inst.ri.rx];
break;
case MIPS16e_lwsp_op:
reg = reg16to32[mips16inst.ri.rx];
if (extended && cpu_has_mips16e2)
switch (mips16inst.ri.imm >> 5) {
case 0: /* LWSP */
case 1: /* LWGP */
break;
case 2: /* LHGP */
opcode = MIPS16e_lh_op;
break;
case 4: /* LHUGP */
opcode = MIPS16e_lhu_op;
break;
default:
goto sigbus;
}
break;
case MIPS16e_i8_op:
if (mips16inst.i8.func != MIPS16e_swrasp_func)
goto sigbus;
reg = 29; /* GPRSP */
break;
default:
reg = reg16to32[mips16inst.rri.ry];
break;
}
switch (opcode) {
case MIPS16e_lb_op:
case MIPS16e_lbu_op:
case MIPS16e_sb_op:
goto sigbus;
case MIPS16e_lh_op:
if (!access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
case MIPS16e_lhu_op:
if (!access_ok(addr, 2))
goto sigbus;
LoadHWU(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
case MIPS16e_lw_op:
case MIPS16e_lwpc_op:
case MIPS16e_lwsp_op:
if (!access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
case MIPS16e_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(addr, 4))
goto sigbus;
LoadWU(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case MIPS16e_ld_op:
loadDW:
#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(addr, 8))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case MIPS16e_sh_op:
if (!access_ok(addr, 2))
goto sigbus;
MIPS16e_compute_return_epc(regs, &oldinst);
value = regs->regs[reg];
StoreHW(addr, value, res);
if (res)
goto fault;
break;
case MIPS16e_sw_op:
case MIPS16e_swsp_op:
case MIPS16e_i8_op: /* actually - MIPS16e_swrasp_func */
if (!access_ok(addr, 4))
goto sigbus;
MIPS16e_compute_return_epc(regs, &oldinst);
value = regs->regs[reg];
StoreW(addr, value, res);
if (res)
goto fault;
break;
case MIPS16e_sd_op:
writeDW:
#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(addr, 8))
goto sigbus;
MIPS16e_compute_return_epc(regs, &oldinst);
value = regs->regs[reg];
StoreDW(addr, value, res);
if (res)
goto fault;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
default:
/*
* Pheeee... We encountered an yet unknown instruction or
* cache coherence problem. Die sucker, die ...
*/
goto sigill;
}
#ifdef CONFIG_DEBUG_FS
unaligned_instructions++;
#endif
return;
fault:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return;
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return;
sigill:
die_if_kernel
("Unhandled kernel unaligned access or invalid instruction", regs);
force_sig(SIGILL);
}
asmlinkage void do_ade(struct pt_regs *regs)
{
enum ctx_state prev_state;
unsigned int __user *pc;
mm_segment_t seg;
prev_state = exception_enter();
perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS,
1, regs, regs->cp0_badvaddr);
/*
* Did we catch a fault trying to load an instruction?
*/
if (regs->cp0_badvaddr == regs->cp0_epc)
goto sigbus;
if (user_mode(regs) && !test_thread_flag(TIF_FIXADE))
goto sigbus;
if (unaligned_action == UNALIGNED_ACTION_SIGNAL)
goto sigbus;
/*
* Do branch emulation only if we didn't forward the exception.
* This is all so but ugly ...
*/
/*
* Are we running in microMIPS mode?
*/
if (get_isa16_mode(regs->cp0_epc)) {
/*
* Did we catch a fault trying to load an instruction in
* 16-bit mode?
*/
if (regs->cp0_badvaddr == msk_isa16_mode(regs->cp0_epc))
goto sigbus;
if (unaligned_action == UNALIGNED_ACTION_SHOW)
show_registers(regs);
if (cpu_has_mmips) {
seg = get_fs();
if (!user_mode(regs))
set_fs(KERNEL_DS);
emulate_load_store_microMIPS(regs,
(void __user *)regs->cp0_badvaddr);
set_fs(seg);
return;
}
if (cpu_has_mips16) {
seg = get_fs();
if (!user_mode(regs))
set_fs(KERNEL_DS);
emulate_load_store_MIPS16e(regs,
(void __user *)regs->cp0_badvaddr);
set_fs(seg);
return;
}
goto sigbus;
}
if (unaligned_action == UNALIGNED_ACTION_SHOW)
show_registers(regs);
pc = (unsigned int __user *)exception_epc(regs);
seg = get_fs();
if (!user_mode(regs))
set_fs(KERNEL_DS);
emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc);
set_fs(seg);
return;
sigbus:
die_if_kernel("Kernel unaligned instruction access", regs);
force_sig(SIGBUS);
/*
* XXX On return from the signal handler we should advance the epc
*/
exception_exit(prev_state);
}
#ifdef CONFIG_DEBUG_FS
static int __init debugfs_unaligned(void)
{
debugfs_create_u32("unaligned_instructions", S_IRUGO, mips_debugfs_dir,
&unaligned_instructions);
debugfs_create_u32("unaligned_action", S_IRUGO | S_IWUSR,
mips_debugfs_dir, &unaligned_action);
return 0;
}
arch_initcall(debugfs_unaligned);
#endif
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