alignment.c
/*
* linux/arch/unicore32/mm/alignment.c
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/*
* TODO:
* FPU ldm/stm not handling
*/
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/sched/debug.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/unaligned.h>
#include "mm.h"
#define CODING_BITS(i) (i & 0xe0000120)
#define LDST_P_BIT(i) (i & (1 << 28)) /* Preindex */
#define LDST_U_BIT(i) (i & (1 << 27)) /* Add offset */
#define LDST_W_BIT(i) (i & (1 << 25)) /* Writeback */
#define LDST_L_BIT(i) (i & (1 << 24)) /* Load */
#define LDST_P_EQ_U(i) ((((i) ^ ((i) >> 1)) & (1 << 27)) == 0)
#define LDSTH_I_BIT(i) (i & (1 << 26)) /* half-word immed */
#define LDM_S_BIT(i) (i & (1 << 26)) /* write ASR from BSR */
#define LDM_H_BIT(i) (i & (1 << 6)) /* select r0-r15 or r16-r31 */
#define RN_BITS(i) ((i >> 19) & 31) /* Rn */
#define RD_BITS(i) ((i >> 14) & 31) /* Rd */
#define RM_BITS(i) (i & 31) /* Rm */
#define REGMASK_BITS(i) (((i & 0x7fe00) >> 3) | (i & 0x3f))
#define OFFSET_BITS(i) (i & 0x03fff)
#define SHIFT_BITS(i) ((i >> 9) & 0x1f)
#define SHIFT_TYPE(i) (i & 0xc0)
#define SHIFT_LSL 0x00
#define SHIFT_LSR 0x40
#define SHIFT_ASR 0x80
#define SHIFT_RORRRX 0xc0
union offset_union {
unsigned long un;
signed long sn;
};
#define TYPE_ERROR 0
#define TYPE_FAULT 1
#define TYPE_LDST 2
#define TYPE_DONE 3
#define TYPE_SWAP 4
#define TYPE_COLS 5 /* Coprocessor load/store */
#define get8_unaligned_check(val, addr, err) \
__asm__( \
"1: ldb.u %1, [%2], #1\n" \
"2:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
"3: mov %0, #1\n" \
" b 2b\n" \
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
" .long 1b, 3b\n" \
" .popsection\n" \
: "=r" (err), "=&r" (val), "=r" (addr) \
: "0" (err), "2" (addr))
#define get8t_unaligned_check(val, addr, err) \
__asm__( \
"1: ldb.u %1, [%2], #1\n" \
"2:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
"3: mov %0, #1\n" \
" b 2b\n" \
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
" .long 1b, 3b\n" \
" .popsection\n" \
: "=r" (err), "=&r" (val), "=r" (addr) \
: "0" (err), "2" (addr))
#define get16_unaligned_check(val, addr) \
do { \
unsigned int err = 0, v, a = addr; \
get8_unaligned_check(val, a, err); \
get8_unaligned_check(v, a, err); \
val |= v << 8; \
if (err) \
goto fault; \
} while (0)
#define put16_unaligned_check(val, addr) \
do { \
unsigned int err = 0, v = val, a = addr; \
__asm__( \
"1: stb.u %1, [%2], #1\n" \
" mov %1, %1 >> #8\n" \
"2: stb.u %1, [%2]\n" \
"3:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
"4: mov %0, #1\n" \
" b 3b\n" \
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
" .long 1b, 4b\n" \
" .long 2b, 4b\n" \
" .popsection\n" \
: "=r" (err), "=&r" (v), "=&r" (a) \
: "0" (err), "1" (v), "2" (a)); \
if (err) \
goto fault; \
} while (0)
#define __put32_unaligned_check(ins, val, addr) \
do { \
unsigned int err = 0, v = val, a = addr; \
__asm__( \
"1: "ins" %1, [%2], #1\n" \
" mov %1, %1 >> #8\n" \
"2: "ins" %1, [%2], #1\n" \
" mov %1, %1 >> #8\n" \
"3: "ins" %1, [%2], #1\n" \
" mov %1, %1 >> #8\n" \
"4: "ins" %1, [%2]\n" \
"5:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
"6: mov %0, #1\n" \
" b 5b\n" \
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
" .long 1b, 6b\n" \
" .long 2b, 6b\n" \
" .long 3b, 6b\n" \
" .long 4b, 6b\n" \
" .popsection\n" \
: "=r" (err), "=&r" (v), "=&r" (a) \
: "0" (err), "1" (v), "2" (a)); \
if (err) \
goto fault; \
} while (0)
#define get32_unaligned_check(val, addr) \
do { \
unsigned int err = 0, v, a = addr; \
get8_unaligned_check(val, a, err); \
get8_unaligned_check(v, a, err); \
val |= v << 8; \
get8_unaligned_check(v, a, err); \
val |= v << 16; \
get8_unaligned_check(v, a, err); \
val |= v << 24; \
if (err) \
goto fault; \
} while (0)
#define put32_unaligned_check(val, addr) \
__put32_unaligned_check("stb.u", val, addr)
#define get32t_unaligned_check(val, addr) \
do { \
unsigned int err = 0, v, a = addr; \
get8t_unaligned_check(val, a, err); \
get8t_unaligned_check(v, a, err); \
val |= v << 8; \
get8t_unaligned_check(v, a, err); \
val |= v << 16; \
get8t_unaligned_check(v, a, err); \
val |= v << 24; \
if (err) \
goto fault; \
} while (0)
#define put32t_unaligned_check(val, addr) \
__put32_unaligned_check("stb.u", val, addr)
static void
do_alignment_finish_ldst(unsigned long addr, unsigned long instr,
struct pt_regs *regs, union offset_union offset)
{
if (!LDST_U_BIT(instr))
offset.un = -offset.un;
if (!LDST_P_BIT(instr))
addr += offset.un;
if (!LDST_P_BIT(instr) || LDST_W_BIT(instr))
regs->uregs[RN_BITS(instr)] = addr;
}
static int
do_alignment_ldrhstrh(unsigned long addr, unsigned long instr,
struct pt_regs *regs)
{
unsigned int rd = RD_BITS(instr);
/* old value 0x40002120, can't judge swap instr correctly */
if ((instr & 0x4b003fe0) == 0x40000120)
goto swp;
if (LDST_L_BIT(instr)) {
unsigned long val;
get16_unaligned_check(val, addr);
/* signed half-word? */
if (instr & 0x80)
val = (signed long)((signed short)val);
regs->uregs[rd] = val;
} else
put16_unaligned_check(regs->uregs[rd], addr);
return TYPE_LDST;
swp:
/* only handle swap word
* for swap byte should not active this alignment exception */
get32_unaligned_check(regs->uregs[RD_BITS(instr)], addr);
put32_unaligned_check(regs->uregs[RM_BITS(instr)], addr);
return TYPE_SWAP;
fault:
return TYPE_FAULT;
}
static int
do_alignment_ldrstr(unsigned long addr, unsigned long instr,
struct pt_regs *regs)
{
unsigned int rd = RD_BITS(instr);
if (!LDST_P_BIT(instr) && LDST_W_BIT(instr))
goto trans;
if (LDST_L_BIT(instr))
get32_unaligned_check(regs->uregs[rd], addr);
else
put32_unaligned_check(regs->uregs[rd], addr);
return TYPE_LDST;
trans:
if (LDST_L_BIT(instr))
get32t_unaligned_check(regs->uregs[rd], addr);
else
put32t_unaligned_check(regs->uregs[rd], addr);
return TYPE_LDST;
fault:
return TYPE_FAULT;
}
/*
* LDM/STM alignment handler.
*
* There are 4 variants of this instruction:
*
* B = rn pointer before instruction, A = rn pointer after instruction
* ------ increasing address ----->
* | | r0 | r1 | ... | rx | |
* PU = 01 B A
* PU = 11 B A
* PU = 00 A B
* PU = 10 A B
*/
static int
do_alignment_ldmstm(unsigned long addr, unsigned long instr,
struct pt_regs *regs)
{
unsigned int rd, rn, pc_correction, reg_correction, nr_regs, regbits;
unsigned long eaddr, newaddr;
if (LDM_S_BIT(instr))
goto bad;
pc_correction = 4; /* processor implementation defined */
/* count the number of registers in the mask to be transferred */
nr_regs = hweight16(REGMASK_BITS(instr)) * 4;
rn = RN_BITS(instr);
newaddr = eaddr = regs->uregs[rn];
if (!LDST_U_BIT(instr))
nr_regs = -nr_regs;
newaddr += nr_regs;
if (!LDST_U_BIT(instr))
eaddr = newaddr;
if (LDST_P_EQ_U(instr)) /* U = P */
eaddr += 4;
/*
* This is a "hint" - we already have eaddr worked out by the
* processor for us.
*/
if (addr != eaddr) {
printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, "
"addr = %08lx, eaddr = %08lx\n",
instruction_pointer(regs), instr, addr, eaddr);
show_regs(regs);
}
if (LDM_H_BIT(instr))
reg_correction = 0x10;
else
reg_correction = 0x00;
for (regbits = REGMASK_BITS(instr), rd = 0; regbits;
regbits >>= 1, rd += 1)
if (regbits & 1) {
if (LDST_L_BIT(instr))
get32_unaligned_check(regs->
uregs[rd + reg_correction], eaddr);
else
put32_unaligned_check(regs->
uregs[rd + reg_correction], eaddr);
eaddr += 4;
}
if (LDST_W_BIT(instr))
regs->uregs[rn] = newaddr;
return TYPE_DONE;
fault:
regs->UCreg_pc -= pc_correction;
return TYPE_FAULT;
bad:
printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n");
return TYPE_ERROR;
}
static int
do_alignment(unsigned long addr, unsigned int error_code, struct pt_regs *regs)
{
union offset_union offset;
unsigned long instr, instrptr;
int (*handler) (unsigned long addr, unsigned long instr,
struct pt_regs *regs);
unsigned int type;
instrptr = instruction_pointer(regs);
if (instrptr >= PAGE_OFFSET)
instr = *(unsigned long *)instrptr;
else {
__asm__ __volatile__(
"ldw.u %0, [%1]\n"
: "=&r"(instr)
: "r"(instrptr));
}
regs->UCreg_pc += 4;
switch (CODING_BITS(instr)) {
case 0x40000120: /* ldrh or strh */
if (LDSTH_I_BIT(instr))
offset.un = (instr & 0x3e00) >> 4 | (instr & 31);
else
offset.un = regs->uregs[RM_BITS(instr)];
handler = do_alignment_ldrhstrh;
break;
case 0x60000000: /* ldr or str immediate */
case 0x60000100: /* ldr or str immediate */
case 0x60000020: /* ldr or str immediate */
case 0x60000120: /* ldr or str immediate */
offset.un = OFFSET_BITS(instr);
handler = do_alignment_ldrstr;
break;
case 0x40000000: /* ldr or str register */
offset.un = regs->uregs[RM_BITS(instr)];
{
unsigned int shiftval = SHIFT_BITS(instr);
switch (SHIFT_TYPE(instr)) {
case SHIFT_LSL:
offset.un <<= shiftval;
break;
case SHIFT_LSR:
offset.un >>= shiftval;
break;
case SHIFT_ASR:
offset.sn >>= shiftval;
break;
case SHIFT_RORRRX:
if (shiftval == 0) {
offset.un >>= 1;
if (regs->UCreg_asr & PSR_C_BIT)
offset.un |= 1 << 31;
} else
offset.un = offset.un >> shiftval |
offset.un << (32 - shiftval);
break;
}
}
handler = do_alignment_ldrstr;
break;
case 0x80000000: /* ldm or stm */
case 0x80000020: /* ldm or stm */
handler = do_alignment_ldmstm;
break;
default:
goto bad;
}
type = handler(addr, instr, regs);
if (type == TYPE_ERROR || type == TYPE_FAULT)
goto bad_or_fault;
if (type == TYPE_LDST)
do_alignment_finish_ldst(addr, instr, regs, offset);
return 0;
bad_or_fault:
if (type == TYPE_ERROR)
goto bad;
regs->UCreg_pc -= 4;
/*
* We got a fault - fix it up, or die.
*/
do_bad_area(addr, error_code, regs);
return 0;
bad:
/*
* Oops, we didn't handle the instruction.
* However, we must handle fpu instr firstly.
*/
#ifdef CONFIG_UNICORE_FPU_F64
/* handle co.load/store */
#define CODING_COLS 0xc0000000
#define COLS_OFFSET_BITS(i) (i & 0x1FF)
#define COLS_L_BITS(i) (i & (1<<24))
#define COLS_FN_BITS(i) ((i>>14) & 31)
if ((instr & 0xe0000000) == CODING_COLS) {
unsigned int fn = COLS_FN_BITS(instr);
unsigned long val = 0;
if (COLS_L_BITS(instr)) {
get32t_unaligned_check(val, addr);
switch (fn) {
#define ASM_MTF(n) case n: \
__asm__ __volatile__("MTF %0, F" __stringify(n) \
: : "r"(val)); \
break;
ASM_MTF(0); ASM_MTF(1); ASM_MTF(2); ASM_MTF(3);
ASM_MTF(4); ASM_MTF(5); ASM_MTF(6); ASM_MTF(7);
ASM_MTF(8); ASM_MTF(9); ASM_MTF(10); ASM_MTF(11);
ASM_MTF(12); ASM_MTF(13); ASM_MTF(14); ASM_MTF(15);
ASM_MTF(16); ASM_MTF(17); ASM_MTF(18); ASM_MTF(19);
ASM_MTF(20); ASM_MTF(21); ASM_MTF(22); ASM_MTF(23);
ASM_MTF(24); ASM_MTF(25); ASM_MTF(26); ASM_MTF(27);
ASM_MTF(28); ASM_MTF(29); ASM_MTF(30); ASM_MTF(31);
#undef ASM_MTF
}
} else {
switch (fn) {
#define ASM_MFF(n) case n: \
__asm__ __volatile__("MFF %0, F" __stringify(n) \
: : "r"(val)); \
break;
ASM_MFF(0); ASM_MFF(1); ASM_MFF(2); ASM_MFF(3);
ASM_MFF(4); ASM_MFF(5); ASM_MFF(6); ASM_MFF(7);
ASM_MFF(8); ASM_MFF(9); ASM_MFF(10); ASM_MFF(11);
ASM_MFF(12); ASM_MFF(13); ASM_MFF(14); ASM_MFF(15);
ASM_MFF(16); ASM_MFF(17); ASM_MFF(18); ASM_MFF(19);
ASM_MFF(20); ASM_MFF(21); ASM_MFF(22); ASM_MFF(23);
ASM_MFF(24); ASM_MFF(25); ASM_MFF(26); ASM_MFF(27);
ASM_MFF(28); ASM_MFF(29); ASM_MFF(30); ASM_MFF(31);
#undef ASM_MFF
}
put32t_unaligned_check(val, addr);
}
return TYPE_COLS;
}
fault:
return TYPE_FAULT;
#endif
printk(KERN_ERR "Alignment trap: not handling instruction "
"%08lx at [<%08lx>]\n", instr, instrptr);
return 1;
}
/*
* This needs to be done after sysctl_init, otherwise sys/ will be
* overwritten. Actually, this shouldn't be in sys/ at all since
* it isn't a sysctl, and it doesn't contain sysctl information.
*/
static int __init alignment_init(void)
{
hook_fault_code(1, do_alignment, SIGBUS, BUS_ADRALN,
"alignment exception");
return 0;
}
fs_initcall(alignment_init);
