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kernel_optimize_test/arch/mips/kernel/branch.c
Markos Chandras e9d92d2233 MIPS: Fix branch emulation for BLTC and BGEC instructions 
Commits f1b44067c1 ("MIPS: Emulate the
new MIPS R6 B{L,G}T{Z,}{AL,}C instructions") and commit
a8ff66f52d ("MIPS: Emulate the new MIPS
R6 B{L,G}E{Z,}{AL,}C instructions") added support for emulating various
branch compact instructions. However, it missed the case for those which
use the old BLEZL and BGTZL opcodes leading to random crashes when the R6
emulator is disabled. We fix this by ensuring that the 'rt' field is not
zero which is always true for these branch compact instructions.

Fixes: f1b44067c1 ("MIPS: Emulate the new MIPS R6 B{L,G}T{Z,}{AL,}C instructions")
Fixes: a8ff66f52d ("MIPS: Emulate the new MIPS R6 B{L,G}E{Z,}{AL,}C instructions")
Cc: <stable@vger.kernel.org> # 4.0+
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10582/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-09 11:10:40 +02:00

881 lines
21 KiB
C
Raw Blame History

/*
* 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, 97, 2000, 2001 by Ralf Baechle
* Copyright (C) 2001 MIPS Technologies, Inc.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/module.h>
#include <asm/branch.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
#include <asm/fpu.h>
#include <asm/fpu_emulator.h>
#include <asm/inst.h>
#include <asm/mips-r2-to-r6-emul.h>
#include <asm/ptrace.h>
#include <asm/uaccess.h>
/*
* Calculate and return exception PC in case of branch delay slot
* for microMIPS and MIPS16e. It does not clear the ISA mode bit.
*/
int __isa_exception_epc(struct pt_regs *regs)
{
unsigned short inst;
long epc = regs->cp0_epc;
/* Calculate exception PC in branch delay slot. */
if (__get_user(inst, (u16 __user *) msk_isa16_mode(epc))) {
/* This should never happen because delay slot was checked. */
force_sig(SIGSEGV, current);
return epc;
}
if (cpu_has_mips16) {
union mips16e_instruction inst_mips16e;
inst_mips16e.full = inst;
if (inst_mips16e.ri.opcode == MIPS16e_jal_op)
epc += 4;
else
epc += 2;
} else if (mm_insn_16bit(inst))
epc += 2;
else
epc += 4;
return epc;
}
/* (microMIPS) Convert 16-bit register encoding to 32-bit register encoding. */
static const unsigned int reg16to32map[8] = {16, 17, 2, 3, 4, 5, 6, 7};
int __mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
unsigned long *contpc)
{
union mips_instruction insn = (union mips_instruction)dec_insn.insn;
int bc_false = 0;
unsigned int fcr31;
unsigned int bit;
if (!cpu_has_mmips)
return 0;
switch (insn.mm_i_format.opcode) {
case mm_pool32a_op:
if ((insn.mm_i_format.simmediate & MM_POOL32A_MINOR_MASK) ==
mm_pool32axf_op) {
switch (insn.mm_i_format.simmediate >>
MM_POOL32A_MINOR_SHIFT) {
case mm_jalr_op:
case mm_jalrhb_op:
case mm_jalrs_op:
case mm_jalrshb_op:
if (insn.mm_i_format.rt != 0) /* Not mm_jr */
regs->regs[insn.mm_i_format.rt] =
regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
*contpc = regs->regs[insn.mm_i_format.rs];
return 1;
}
}
break;
case mm_pool32i_op:
switch (insn.mm_i_format.rt) {
case mm_bltzals_op:
case mm_bltzal_op:
regs->regs[31] = regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
/* Fall through */
case mm_bltz_op:
if ((long)regs->regs[insn.mm_i_format.rs] < 0)
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_i_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
return 1;
case mm_bgezals_op:
case mm_bgezal_op:
regs->regs[31] = regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
/* Fall through */
case mm_bgez_op:
if ((long)regs->regs[insn.mm_i_format.rs] >= 0)
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_i_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
return 1;
case mm_blez_op:
if ((long)regs->regs[insn.mm_i_format.rs] <= 0)
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_i_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
return 1;
case mm_bgtz_op:
if ((long)regs->regs[insn.mm_i_format.rs] <= 0)
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_i_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
return 1;
case mm_bc2f_op:
case mm_bc1f_op:
bc_false = 1;
/* Fall through */
case mm_bc2t_op:
case mm_bc1t_op:
preempt_disable();
if (is_fpu_owner())
fcr31 = read_32bit_cp1_register(CP1_STATUS);
else
fcr31 = current->thread.fpu.fcr31;
preempt_enable();
if (bc_false)
fcr31 = ~fcr31;
bit = (insn.mm_i_format.rs >> 2);
bit += (bit != 0);
bit += 23;
if (fcr31 & (1 << bit))
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_i_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc + dec_insn.next_pc_inc;
return 1;
}
break;
case mm_pool16c_op:
switch (insn.mm_i_format.rt) {
case mm_jalr16_op:
case mm_jalrs16_op:
regs->regs[31] = regs->cp0_epc +
dec_insn.pc_inc + dec_insn.next_pc_inc;
/* Fall through */
case mm_jr16_op:
*contpc = regs->regs[insn.mm_i_format.rs];
return 1;
}
break;
case mm_beqz16_op:
if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] == 0)
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_b1_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc + dec_insn.next_pc_inc;
return 1;
case mm_bnez16_op:
if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] != 0)
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_b1_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc + dec_insn.next_pc_inc;
return 1;
case mm_b16_op:
*contpc = regs->cp0_epc + dec_insn.pc_inc +
(insn.mm_b0_format.simmediate << 1);
return 1;
case mm_beq32_op:
if (regs->regs[insn.mm_i_format.rs] ==
regs->regs[insn.mm_i_format.rt])
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_i_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
dec_insn.next_pc_inc;
return 1;
case mm_bne32_op:
if (regs->regs[insn.mm_i_format.rs] !=
regs->regs[insn.mm_i_format.rt])
*contpc = regs->cp0_epc +
dec_insn.pc_inc +
(insn.mm_i_format.simmediate << 1);
else
*contpc = regs->cp0_epc +
dec_insn.pc_inc + dec_insn.next_pc_inc;
return 1;
case mm_jalx32_op:
regs->regs[31] = regs->cp0_epc +
dec_insn.pc_inc + dec_insn.next_pc_inc;
*contpc = regs->cp0_epc + dec_insn.pc_inc;
*contpc >>= 28;
*contpc <<= 28;
*contpc |= (insn.j_format.target << 2);
return 1;
case mm_jals32_op:
case mm_jal32_op:
regs->regs[31] = regs->cp0_epc +
dec_insn.pc_inc + dec_insn.next_pc_inc;
/* Fall through */
case mm_j32_op:
*contpc = regs->cp0_epc + dec_insn.pc_inc;
*contpc >>= 27;
*contpc <<= 27;
*contpc |= (insn.j_format.target << 1);
set_isa16_mode(*contpc);
return 1;
}
return 0;
}
/*
* Compute return address and emulate branch in microMIPS mode after an
* exception only. It does not handle compact branches/jumps and cannot
* be used in interrupt context. (Compact branches/jumps do not cause
* exceptions.)
*/
int __microMIPS_compute_return_epc(struct pt_regs *regs)
{
u16 __user *pc16;
u16 halfword;
unsigned int word;
unsigned long contpc;
struct mm_decoded_insn mminsn = { 0 };
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 sigsegv;
mminsn.next_pc_inc = 2;
word = ((unsigned int)halfword << 16);
if (!mm_insn_16bit(halfword)) {
pc16++;
if (get_user(halfword, pc16))
goto sigsegv;
mminsn.next_pc_inc = 4;
word |= halfword;
}
mminsn.next_insn = word;
mm_isBranchInstr(regs, mminsn, &contpc);
regs->cp0_epc = contpc;
return 0;
sigsegv:
force_sig(SIGSEGV, current);
return -EFAULT;
}
/*
* Compute return address and emulate branch in MIPS16e mode after an
* exception only. It does not handle compact branches/jumps and cannot
* be used in interrupt context. (Compact branches/jumps do not cause
* exceptions.)
*/
int __MIPS16e_compute_return_epc(struct pt_regs *regs)
{
u16 __user *addr;
union mips16e_instruction inst;
u16 inst2;
u32 fullinst;
long epc;
epc = regs->cp0_epc;
/* Read the instruction. */
addr = (u16 __user *)msk_isa16_mode(epc);
if (__get_user(inst.full, addr)) {
force_sig(SIGSEGV, current);
return -EFAULT;
}
switch (inst.ri.opcode) {
case MIPS16e_extend_op:
regs->cp0_epc += 4;
return 0;
/*
* JAL and JALX in MIPS16e mode
*/
case MIPS16e_jal_op:
addr += 1;
if (__get_user(inst2, addr)) {
force_sig(SIGSEGV, current);
return -EFAULT;
}
fullinst = ((unsigned)inst.full << 16) | inst2;
regs->regs[31] = epc + 6;
epc += 4;
epc >>= 28;
epc <<= 28;
/*
* JAL:5 X:1 TARGET[20-16]:5 TARGET[25:21]:5 TARGET[15:0]:16
*
* ......TARGET[15:0].................TARGET[20:16]...........
* ......TARGET[25:21]
*/
epc |=
((fullinst & 0xffff) << 2) | ((fullinst & 0x3e00000) >> 3) |
((fullinst & 0x1f0000) << 7);
if (!inst.jal.x)
set_isa16_mode(epc); /* Set ISA mode bit. */
regs->cp0_epc = epc;
return 0;
/*
* J(AL)R(C)
*/
case MIPS16e_rr_op:
if (inst.rr.func == MIPS16e_jr_func) {
if (inst.rr.ra)
regs->cp0_epc = regs->regs[31];
else
regs->cp0_epc =
regs->regs[reg16to32[inst.rr.rx]];
if (inst.rr.l) {
if (inst.rr.nd)
regs->regs[31] = epc + 2;
else
regs->regs[31] = epc + 4;
}
return 0;
}
break;
}
/*
* All other cases have no branch delay slot and are 16-bits.
* Branches do not cause an exception.
*/
regs->cp0_epc += 2;
return 0;
}
/**
* __compute_return_epc_for_insn - Computes the return address and do emulate
* branch simulation, if required.
*
* @regs: Pointer to pt_regs
* @insn: branch instruction to decode
* @returns: -EFAULT on error and forces SIGBUS, and on success
* returns 0 or BRANCH_LIKELY_TAKEN as appropriate after
* evaluating the branch.
*
* MIPS R6 Compact branches and forbidden slots:
* Compact branches do not throw exceptions because they do
* not have delay slots. The forbidden slot instruction ($PC+4)
* is only executed if the branch was not taken. Otherwise the
* forbidden slot is skipped entirely. This means that the
* only possible reason to be here because of a MIPS R6 compact
* branch instruction is that the forbidden slot has thrown one.
* In that case the branch was not taken, so the EPC can be safely
* set to EPC + 8.
*/
int __compute_return_epc_for_insn(struct pt_regs *regs,
union mips_instruction insn)
{
unsigned int bit, fcr31, dspcontrol, reg;
long epc = regs->cp0_epc;
int ret = 0;
switch (insn.i_format.opcode) {
/*
* jr and jalr are in r_format format.
*/
case spec_op:
switch (insn.r_format.func) {
case jalr_op:
regs->regs[insn.r_format.rd] = epc + 8;
/* Fall through */
case jr_op:
if (NO_R6EMU && insn.r_format.func == jr_op)
goto sigill_r6;
regs->cp0_epc = regs->regs[insn.r_format.rs];
break;
}
break;
/*
* This group contains:
* bltz_op, bgez_op, bltzl_op, bgezl_op,
* bltzal_op, bgezal_op, bltzall_op, bgezall_op.
*/
case bcond_op:
switch (insn.i_format.rt) {
case bltzl_op:
if (NO_R6EMU)
goto sigill_r6;
case bltz_op:
if ((long)regs->regs[insn.i_format.rs] < 0) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.rt == bltzl_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case bgezl_op:
if (NO_R6EMU)
goto sigill_r6;
case bgez_op:
if ((long)regs->regs[insn.i_format.rs] >= 0) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.rt == bgezl_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case bltzal_op:
case bltzall_op:
if (NO_R6EMU && (insn.i_format.rs ||
insn.i_format.rt == bltzall_op)) {
ret = -SIGILL;
break;
}
regs->regs[31] = epc + 8;
/*
* OK we are here either because we hit a NAL
* instruction or because we are emulating an
* old bltzal{,l} one. Lets figure out what the
* case really is.
*/
if (!insn.i_format.rs) {
/*
* NAL or BLTZAL with rs == 0
* Doesn't matter if we are R6 or not. The
* result is the same
*/
regs->cp0_epc += 4 +
(insn.i_format.simmediate << 2);
break;
}
/* Now do the real thing for non-R6 BLTZAL{,L} */
if ((long)regs->regs[insn.i_format.rs] < 0) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.rt == bltzall_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case bgezal_op:
case bgezall_op:
if (NO_R6EMU && (insn.i_format.rs ||
insn.i_format.rt == bgezall_op)) {
ret = -SIGILL;
break;
}
regs->regs[31] = epc + 8;
/*
* OK we are here either because we hit a BAL
* instruction or because we are emulating an
* old bgezal{,l} one. Lets figure out what the
* case really is.
*/
if (!insn.i_format.rs) {
/*
* BAL or BGEZAL with rs == 0
* Doesn't matter if we are R6 or not. The
* result is the same
*/
regs->cp0_epc += 4 +
(insn.i_format.simmediate << 2);
break;
}
/* Now do the real thing for non-R6 BGEZAL{,L} */
if ((long)regs->regs[insn.i_format.rs] >= 0) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.rt == bgezall_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case bposge32_op:
if (!cpu_has_dsp)
goto sigill_dsp;
dspcontrol = rddsp(0x01);
if (dspcontrol >= 32) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
} else
epc += 8;
regs->cp0_epc = epc;
break;
}
break;
/*
* These are unconditional and in j_format.
*/
case jal_op:
regs->regs[31] = regs->cp0_epc + 8;
case j_op:
epc += 4;
epc >>= 28;
epc <<= 28;
epc |= (insn.j_format.target << 2);
regs->cp0_epc = epc;
if (insn.i_format.opcode == jalx_op)
set_isa16_mode(regs->cp0_epc);
break;
/*
* These are conditional and in i_format.
*/
case beql_op:
if (NO_R6EMU)
goto sigill_r6;
case beq_op:
if (regs->regs[insn.i_format.rs] ==
regs->regs[insn.i_format.rt]) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.opcode == beql_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case bnel_op:
if (NO_R6EMU)
goto sigill_r6;
case bne_op:
if (regs->regs[insn.i_format.rs] !=
regs->regs[insn.i_format.rt]) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.opcode == bnel_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case blezl_op: /* not really i_format */
if (!insn.i_format.rt && NO_R6EMU)
goto sigill_r6;
case blez_op:
/*
* Compact branches for R6 for the
* blez and blezl opcodes.
* BLEZ | rs = 0 | rt != 0 == BLEZALC
* BLEZ | rs = rt != 0 == BGEZALC
* BLEZ | rs != 0 | rt != 0 == BGEUC
* BLEZL | rs = 0 | rt != 0 == BLEZC
* BLEZL | rs = rt != 0 == BGEZC
* BLEZL | rs != 0 | rt != 0 == BGEC
*
* For real BLEZ{,L}, rt is always 0.
*/
if (cpu_has_mips_r6 && insn.i_format.rt) {
if ((insn.i_format.opcode == blez_op) &&
((!insn.i_format.rs && insn.i_format.rt) ||
(insn.i_format.rs == insn.i_format.rt)))
regs->regs[31] = epc + 4;
regs->cp0_epc += 8;
break;
}
/* rt field assumed to be zero */
if ((long)regs->regs[insn.i_format.rs] <= 0) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.opcode == blezl_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case bgtzl_op:
if (!insn.i_format.rt && NO_R6EMU)
goto sigill_r6;
case bgtz_op:
/*
* Compact branches for R6 for the
* bgtz and bgtzl opcodes.
* BGTZ | rs = 0 | rt != 0 == BGTZALC
* BGTZ | rs = rt != 0 == BLTZALC
* BGTZ | rs != 0 | rt != 0 == BLTUC
* BGTZL | rs = 0 | rt != 0 == BGTZC
* BGTZL | rs = rt != 0 == BLTZC
* BGTZL | rs != 0 | rt != 0 == BLTC
*
* *ZALC varint for BGTZ &&& rt != 0
* For real GTZ{,L}, rt is always 0.
*/
if (cpu_has_mips_r6 && insn.i_format.rt) {
if ((insn.i_format.opcode == blez_op) &&
((!insn.i_format.rs && insn.i_format.rt) ||
(insn.i_format.rs == insn.i_format.rt)))
regs->regs[31] = epc + 4;
regs->cp0_epc += 8;
break;
}
/* rt field assumed to be zero */
if ((long)regs->regs[insn.i_format.rs] > 0) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
if (insn.i_format.opcode == bgtzl_op)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
/*
* And now the FPA/cp1 branch instructions.
*/
case cop1_op:
if (cpu_has_mips_r6 &&
((insn.i_format.rs == bc1eqz_op) ||
(insn.i_format.rs == bc1nez_op))) {
if (!used_math()) { /* First time FPU user */
ret = init_fpu();
if (ret && NO_R6EMU) {
ret = -ret;
break;
}
ret = 0;
set_used_math();
}
lose_fpu(1); /* Save FPU state for the emulator. */
reg = insn.i_format.rt;
bit = 0;
switch (insn.i_format.rs) {
case bc1eqz_op:
/* Test bit 0 */
if (get_fpr32(&current->thread.fpu.fpr[reg], 0)
& 0x1)
bit = 1;
break;
case bc1nez_op:
/* Test bit 0 */
if (!(get_fpr32(&current->thread.fpu.fpr[reg], 0)
& 0x1))
bit = 1;
break;
}
own_fpu(1);
if (bit)
epc = epc + 4 +
(insn.i_format.simmediate << 2);
else
epc += 8;
regs->cp0_epc = epc;
break;
} else {
preempt_disable();
if (is_fpu_owner())
fcr31 = read_32bit_cp1_register(CP1_STATUS);
else
fcr31 = current->thread.fpu.fcr31;
preempt_enable();
bit = (insn.i_format.rt >> 2);
bit += (bit != 0);
bit += 23;
switch (insn.i_format.rt & 3) {
case 0: /* bc1f */
case 2: /* bc1fl */
if (~fcr31 & (1 << bit)) {
epc = epc + 4 +
(insn.i_format.simmediate << 2);
if (insn.i_format.rt == 2)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
case 1: /* bc1t */
case 3: /* bc1tl */
if (fcr31 & (1 << bit)) {
epc = epc + 4 +
(insn.i_format.simmediate << 2);
if (insn.i_format.rt == 3)
ret = BRANCH_LIKELY_TAKEN;
} else
epc += 8;
regs->cp0_epc = epc;
break;
}
break;
}
#ifdef CONFIG_CPU_CAVIUM_OCTEON
case lwc2_op: /* This is bbit0 on Octeon */
if ((regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt))
== 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
regs->cp0_epc = epc;
break;
case ldc2_op: /* This is bbit032 on Octeon */
if ((regs->regs[insn.i_format.rs] &
(1ull<<(insn.i_format.rt+32))) == 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
regs->cp0_epc = epc;
break;
case swc2_op: /* This is bbit1 on Octeon */
if (regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt))
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
regs->cp0_epc = epc;
break;
case sdc2_op: /* This is bbit132 on Octeon */
if (regs->regs[insn.i_format.rs] &
(1ull<<(insn.i_format.rt+32)))
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
regs->cp0_epc = epc;
break;
#else
case bc6_op:
/* Only valid for MIPS R6 */
if (!cpu_has_mips_r6) {
ret = -SIGILL;
break;
}
regs->cp0_epc += 8;
break;
case balc6_op:
if (!cpu_has_mips_r6) {
ret = -SIGILL;
break;
}
/* Compact branch: BALC */
regs->regs[31] = epc + 4;
epc += 4 + (insn.i_format.simmediate << 2);
regs->cp0_epc = epc;
break;
case beqzcjic_op:
if (!cpu_has_mips_r6) {
ret = -SIGILL;
break;
}
/* Compact branch: BEQZC || JIC */
regs->cp0_epc += 8;
break;
case bnezcjialc_op:
if (!cpu_has_mips_r6) {
ret = -SIGILL;
break;
}
/* Compact branch: BNEZC || JIALC */
if (insn.i_format.rs)
regs->regs[31] = epc + 4;
regs->cp0_epc += 8;
break;
#endif
case cbcond0_op:
case cbcond1_op:
/* Only valid for MIPS R6 */
if (!cpu_has_mips_r6) {
ret = -SIGILL;
break;
}
/*
* Compact branches:
* bovc, beqc, beqzalc, bnvc, bnec, bnezlac
*/
if (insn.i_format.rt && !insn.i_format.rs)
regs->regs[31] = epc + 4;
regs->cp0_epc += 8;
break;
}
return ret;
sigill_dsp:
printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm);
force_sig(SIGBUS, current);
return -EFAULT;
sigill_r6:
pr_info("%s: R2 branch but r2-to-r6 emulator is not preset - sending SIGILL.\n",
current->comm);
force_sig(SIGILL, current);
return -EFAULT;
}
EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);
int __compute_return_epc(struct pt_regs *regs)
{
unsigned int __user *addr;
long epc;
union mips_instruction insn;
epc = regs->cp0_epc;
if (epc & 3)
goto unaligned;
/*
* Read the instruction
*/
addr = (unsigned int __user *) epc;
if (__get_user(insn.word, addr)) {
force_sig(SIGSEGV, current);
return -EFAULT;
}
return __compute_return_epc_for_insn(regs, insn);
unaligned:
printk("%s: unaligned epc - sending SIGBUS.\n", current->comm);
force_sig(SIGBUS, current);
return -EFAULT;
}
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