/*
* unaligned.c: Unaligned load/store trap handling with special
* cases for the kernel to do them more quickly.
*
* Copyright (C) 1996,2008 David S. Miller (davem@davemloft.net)
* Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
*/
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <asm/asi.h>
#include <asm/ptrace.h>
#include <asm/pstate.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <linux/smp.h>
#include <linux/bitops.h>
#include <linux/perf_event.h>
#include <linux/ratelimit.h>
#include <asm/fpumacro.h>
#include <asm/cacheflush.h>
enum direction {
load, /* ld, ldd, ldh, ldsh */
store, /* st, std, sth, stsh */
both, /* Swap, ldstub, cas, ... */
fpld,
fpst,
invalid,
};
static inline enum direction decode_direction(unsigned int insn)
{
unsigned long tmp = (insn >> 21) & 1;
if (!tmp)
return load;
else {
switch ((insn>>19)&0xf) {
case 15: /* swap* */
return both;
default:
return store;
}
}
}
/* 16 = double-word, 8 = extra-word, 4 = word, 2 = half-word */
static inline int decode_access_size(struct pt_regs *regs, unsigned int insn)
{
unsigned int tmp;
tmp = ((insn >> 19) & 0xf);
if (tmp == 11 || tmp == 14) /* ldx/stx */
return 8;
tmp &= 3;
if (!tmp)
return 4;
else if (tmp == 3)
return 16; /* ldd/std - Although it is actually 8 */
else if (tmp == 2)
return 2;
else {
printk("Impossible unaligned trap. insn=%08x\n", insn);
die_if_kernel("Byte sized unaligned access?!?!", regs);
/* GCC should never warn that control reaches the end
* of this function without returning a value because
* die_if_kernel() is marked with attribute 'noreturn'.
* Alas, some versions do...
*/
return 0;
}
}
static inline int decode_asi(unsigned int insn, struct pt_regs *regs)
{
if (insn & 0x800000) {
if (insn & 0x2000)
return (unsigned char)(regs->tstate >> 24); /* %asi */
else
return (unsigned char)(insn >> 5); /* imm_asi */
} else
return ASI_P;
}
/* 0x400000 = signed, 0 = unsigned */
static inline int decode_signedness(unsigned int insn)
{
return (insn & 0x400000);
}
static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
unsigned int rd, int from_kernel)
{
if (rs2 >= 16 || rs1 >= 16 || rd >= 16) {
if (from_kernel != 0)
__asm__ __volatile__("flushw");
else
flushw_user();
}
}
static inline long sign_extend_imm13(long imm)
{
return imm << 51 >> 51;
}
static unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
{
unsigned long value, fp;
if (reg < 16)
return (!reg ? 0 : regs->u_regs[reg]);
fp = regs->u_regs[UREG_FP];
if (regs->tstate & TSTATE_PRIV) {
struct reg_window *win;
win = (struct reg_window *)(fp + STACK_BIAS);
value = win->locals[reg - 16];
} else if (!test_thread_64bit_stack(fp)) {
struct reg_window32 __user *win32;
win32 = (struct reg_window32 __user *)((unsigned long)((u32)fp));
get_user(value, &win32->locals[reg - 16]);
} else {
struct reg_window __user *win;
win = (struct reg_window __user *)(fp + STACK_BIAS);
get_user(value, &win->locals[reg - 16]);
}
return value;
}
static unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
{
unsigned long fp;
if (reg < 16)
return ®s->u_regs[reg];
fp = regs->u_regs[UREG_FP];
if (regs->tstate & TSTATE_PRIV) {
struct reg_window *win;
win = (struct reg_window *)(fp + STACK_BIAS);
return &win->locals[reg - 16];
} else if (!test_thread_64bit_stack(fp)) {
struct reg_window32 *win32;
win32 = (struct reg_window32 *)((unsigned long)((u32)fp));
return (unsigned long *)&win32->locals[reg - 16];
} else {
struct reg_window *win;
win = (struct reg_window *)(fp + STACK_BIAS);
return &win->locals[reg - 16];
}
}
unsigned long compute_effective_address(struct pt_regs *regs,
unsigned int insn, unsigned int rd)
{
unsigned int rs1 = (insn >> 14) & 0x1f;
unsigned int rs2 = insn & 0x1f;
int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
if (insn & 0x2000) {
maybe_flush_windows(rs1, 0, rd, from_kernel);
return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
} else {
maybe_flush_windows(rs1, rs2, rd, from_kernel);
return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
}
}
/* This is just to make gcc think die_if_kernel does return... */
static void __used unaligned_panic(char *str, struct pt_regs *regs)
{
die_if_kernel(str, regs);
}
extern int do_int_load(unsigned long *dest_reg, int size,
unsigned long *saddr, int is_signed, int asi);
extern int __do_int_store(unsigned long *dst_addr, int size,
unsigned long src_val, int asi);
static inline int do_int_store(int reg_num, int size, unsigned long *dst_addr,
struct pt_regs *regs, int asi, int orig_asi)
{
unsigned long zero = 0;
unsigned long *src_val_p = &zero;
unsigned long src_val;
if (size == 16) {
size = 8;
zero = (((long)(reg_num ?
(unsigned)fetch_reg(reg_num, regs) : 0)) << 32) |
(unsigned)fetch_reg(reg_num + 1, regs);
} else if (reg_num) {
src_val_p = fetch_reg_addr(reg_num, regs);
}
src_val = *src_val_p;
if (unlikely(asi != orig_asi)) {
switch (size) {
case 2:
src_val = swab16(src_val);
break;
case 4:
src_val = swab32(src_val);
break;
case 8:
src_val = swab64(src_val);
break;
case 16:
default:
BUG();
break;
}
}
return __do_int_store(dst_addr, size, src_val, asi);
}
static inline void advance(struct pt_regs *regs)
{
regs->tpc = regs->tnpc;
regs->tnpc += 4;
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
}
static inline int floating_point_load_or_store_p(unsigned int insn)
{
return (insn >> 24) & 1;
}
static inline int ok_for_kernel(unsigned int insn)
{
return !floating_point_load_or_store_p(insn);
}
static void kernel_mna_trap_fault(int fixup_tstate_asi)
{
struct pt_regs *regs = current_thread_info()->kern_una_regs;
unsigned int insn = current_thread_info()->kern_una_insn;
const struct exception_table_entry *entry;
entry = search_exception_tables(regs->tpc);
if (!entry) {
unsigned long address;
address = compute_effective_address(regs, insn,
((insn >> 25) & 0x1f));
if (address < PAGE_SIZE) {
printk(KERN_ALERT "Unable to handle kernel NULL "
"pointer dereference in mna handler");
} else
printk(KERN_ALERT "Unable to handle kernel paging "
"request in mna handler");
printk(KERN_ALERT " at virtual address %016lx\n",address);
printk(KERN_ALERT "current->{active_,}mm->context = %016lx\n",
(current->mm ? CTX_HWBITS(current->mm->context) :
CTX_HWBITS(current->active_mm->context)));
printk(KERN_ALERT "current->{active_,}mm->pgd = %016lx\n",
(current->mm ? (unsigned long) current->mm->pgd :
(unsigned long) current->active_mm->pgd));
die_if_kernel("Oops", regs);
/* Not reached */
}
regs->tpc = entry->fixup;
regs->tnpc = regs->tpc + 4;
if (fixup_tstate_asi) {
regs->tstate &= ~TSTATE_ASI;
regs->tstate |= (ASI_AIUS << 24UL);
}
}
static void log_unaligned(struct pt_regs *regs)
{
static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
if (__ratelimit(&ratelimit)) {
printk("Kernel unaligned access at TPC[%lx] %pS\n",
regs->tpc, (void *) regs->tpc);
}
}
asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
{
enum direction dir = decode_direction(insn);
int size = decode_access_size(regs, insn);
int orig_asi, asi;
current_thread_info()->kern_una_regs = regs;
current_thread_info()->kern_una_insn = insn;
orig_asi = asi = decode_asi(insn, regs);
/* If this is a {get,put}_user() on an unaligned userspace pointer,
* just signal a fault and do not log the event.
*/
if (asi == ASI_AIUS) {
kernel_mna_trap_fault(0);
return;
}
log_unaligned(regs);
if (!ok_for_kernel(insn) || dir == both) {
printk("Unsupported unaligned load/store trap for kernel "
"at <%016lx>.\n", regs->tpc);
unaligned_panic("Kernel does fpu/atomic "
"unaligned load/store.", regs);
kernel_mna_trap_fault(0);
} else {
unsigned long addr, *reg_addr;
int err;
addr = compute_effective_address(regs, insn,
((insn >> 25) & 0x1f));
perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
switch (asi) {
case ASI_NL:
case ASI_AIUPL:
case ASI_AIUSL:
case ASI_PL:
case ASI_SL:
case ASI_PNFL:
case ASI_SNFL:
asi &= ~0x08;
break;
}
switch (dir) {
case load:
reg_addr = fetch_reg_addr(((insn>>25)&0x1f), regs);
err = do_int_load(reg_addr, size,
(unsigned long *) addr,
decode_signedness(insn), asi);
if (likely(!err) && unlikely(asi != orig_asi)) {
unsigned long val_in = *reg_addr;
switch (size) {
case 2:
val_in = swab16(val_in);
break;
case 4:
val_in = swab32(val_in);
break;
case 8:
val_in = swab64(val_in);
break;
case 16:
default:
BUG();
break;
}
*reg_addr = val_in;
}
break;
case store:
err = do_int_store(((insn>>25)&0x1f), size,
(unsigned long *) addr, regs,
asi, orig_asi);
break;
default:
panic("Impossible kernel unaligned trap.");
/* Not reached... */
}
if (unlikely(err))
kernel_mna_trap_fault(1);
else
advance(regs);
}
}
int handle_popc(u32 insn, struct pt_regs *regs)
{
int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
int ret, rd = ((insn >> 25) & 0x1f);
u64 value;
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
if (insn & 0x2000) {
maybe_flush_windows(0, 0, rd, from_kernel);
value = sign_extend_imm13(insn);
} else {
maybe_flush_windows(0, insn & 0x1f, rd, from_kernel);
value = fetch_reg(insn & 0x1f, regs);
}
ret = hweight64(value);
if (rd < 16) {
if (rd)
regs->u_regs[rd] = ret;
} else {
unsigned long fp = regs->u_regs[UREG_FP];
if (!test_thread_64bit_stack(fp)) {
struct reg_window32 __user *win32;
win32 = (struct reg_window32 __user *)((unsigned long)((u32)fp));
put_user(ret, &win32->locals[rd - 16]);
} else {
struct reg_window __user *win;
win = (struct reg_window __user *)(fp + STACK_BIAS);
put_user(ret, &win->locals[rd - 16]);
}
}
advance(regs);
return 1;
}
extern void do_fpother(struct pt_regs *regs);
extern void do_privact(struct pt_regs *regs);
extern void spitfire_data_access_exception(struct pt_regs *regs,
unsigned long sfsr,
unsigned long sfar);
extern void sun4v_data_access_exception(struct pt_regs *regs,
unsigned long addr,
unsigned long type_ctx);
int handle_ldf_stq(u32 insn, struct pt_regs *regs)
{
unsigned long addr = compute_effective_address(regs, insn, 0);
int freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
struct fpustate *f = FPUSTATE;
int asi = decode_asi(insn, regs);
int flag = (freg < 32) ? FPRS_DL : FPRS_DU;
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
save_and_clear_fpu();
current_thread_info()->xfsr[0] &= ~0x1c000;
if (freg & 3) {
current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
do_fpother(regs);
return 0;
}
if (insn & 0x200000) {
/* STQ */
u64 first = 0, second = 0;
if (current_thread_info()->fpsaved[0] & flag) {
first = *(u64 *)&f->regs[freg];
second = *(u64 *)&f->regs[freg+2];
}
if (asi < 0x80) {
do_privact(regs);
return 1;
}
switch (asi) {
case ASI_P:
case ASI_S: break;
case ASI_PL:
case ASI_SL:
{
/* Need to convert endians */
u64 tmp = __swab64p(&first);
first = __swab64p(&second);
second = tmp;
break;
}
default:
if (tlb_type == hypervisor)
sun4v_data_access_exception(regs, addr, 0);
else
spitfire_data_access_exception(regs, 0, addr);
return 1;
}
if (put_user (first >> 32, (u32 __user *)addr) ||
__put_user ((u32)first, (u32 __user *)(addr + 4)) ||
__put_user (second >> 32, (u32 __user *)(addr + 8)) ||
__put_user ((u32)second, (u32 __user *)(addr + 12))) {
if (tlb_type == hypervisor)
sun4v_data_access_exception(regs, addr, 0);
else
spitfire_data_access_exception(regs, 0, addr);
return 1;
}
} else {
/* LDF, LDDF, LDQF */
u32 data[4] __attribute__ ((aligned(8)));
int size, i;
int err;
if (asi < 0x80) {
do_privact(regs);
return 1;
} else if (asi > ASI_SNFL) {
if (tlb_type == hypervisor)
sun4v_data_access_exception(regs, addr, 0);
else
spitfire_data_access_exception(regs, 0, addr);
return 1;
}
switch (insn & 0x180000) {
case 0x000000: size = 1; break;
case 0x100000: size = 4; break;
default: size = 2; break;
}
for (i = 0; i < size; i++)
data[i] = 0;
err = get_user (data[0], (u32 __user *) addr);
if (!err) {
for (i = 1; i < size; i++)
err |= __get_user (data[i], (u32 __user *)(addr + 4*i));
}
if (err && !(asi & 0x2 /* NF */)) {
if (tlb_type == hypervisor)
sun4v_data_access_exception(regs, addr, 0);
else
spitfire_data_access_exception(regs, 0, addr);
return 1;
}
if (asi & 0x8) /* Little */ {
u64 tmp;
switch (size) {
case 1: data[0] = le32_to_cpup(data + 0); break;
default:*(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 0));
break;
case 4: tmp = le64_to_cpup((u64 *)(data + 0));
*(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 2));
*(u64 *)(data + 2) = tmp;
break;
}
}
if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
current_thread_info()->fpsaved[0] = FPRS_FEF;
current_thread_info()->gsr[0] = 0;
}
if (!(current_thread_info()->fpsaved[0] & flag)) {
if (freg < 32)
memset(f->regs, 0, 32*sizeof(u32));
else
memset(f->regs+32, 0, 32*sizeof(u32));
}
memcpy(f->regs + freg, data, size * 4);
current_thread_info()->fpsaved[0] |= flag;
}
advance(regs);
return 1;
}
void handle_ld_nf(u32 insn, struct pt_regs *regs)
{
int rd = ((insn >> 25) & 0x1f);
int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
unsigned long *reg;
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
maybe_flush_windows(0, 0, rd, from_kernel);
reg = fetch_reg_addr(rd, regs);
if (from_kernel || rd < 16) {
reg[0] = 0;
if ((insn & 0x780000) == 0x180000)
reg[1] = 0;
} else if (!test_thread_64bit_stack(regs->u_regs[UREG_FP])) {
put_user(0, (int __user *) reg);
if ((insn & 0x780000) == 0x180000)
put_user(0, ((int __user *) reg) + 1);
} else {
put_user(0, (unsigned long __user *) reg);
if ((insn & 0x780000) == 0x180000)
put_user(0, (unsigned long __user *) reg + 1);
}
advance(regs);
}
void handle_lddfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
{
unsigned long pc = regs->tpc;
unsigned long tstate = regs->tstate;
u32 insn;
u64 value;
u8 freg;
int flag;
struct fpustate *f = FPUSTATE;
if (tstate & TSTATE_PRIV)
die_if_kernel("lddfmna from kernel", regs);
perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, sfar);
if (test_thread_flag(TIF_32BIT))
pc = (u32)pc;
if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
int asi = decode_asi(insn, regs);
u32 first, second;
int err;
if ((asi > ASI_SNFL) ||
(asi < ASI_P))
goto daex;
first = second = 0;
err = get_user(first, (u32 __user *)sfar);
if (!err)
err = get_user(second, (u32 __user *)(sfar + 4));
if (err) {
if (!(asi & 0x2))
goto daex;
first = second = 0;
}
save_and_clear_fpu();
freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
value = (((u64)first) << 32) | second;
if (asi & 0x8) /* Little */
value = __swab64p(&value);
flag = (freg < 32) ? FPRS_DL : FPRS_DU;
if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
current_thread_info()->fpsaved[0] = FPRS_FEF;
current_thread_info()->gsr[0] = 0;
}
if (!(current_thread_info()->fpsaved[0] & flag)) {
if (freg < 32)
memset(f->regs, 0, 32*sizeof(u32));
else
memset(f->regs+32, 0, 32*sizeof(u32));
}
*(u64 *)(f->regs + freg) = value;
current_thread_info()->fpsaved[0] |= flag;
} else {
daex:
if (tlb_type == hypervisor)
sun4v_data_access_exception(regs, sfar, sfsr);
else
spitfire_data_access_exception(regs, sfsr, sfar);
return;
}
advance(regs);
}
void handle_stdfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
{
unsigned long pc = regs->tpc;
unsigned long tstate = regs->tstate;
u32 insn;
u64 value;
u8 freg;
int flag;
struct fpustate *f = FPUSTATE;
if (tstate & TSTATE_PRIV)
die_if_kernel("stdfmna from kernel", regs);
perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, sfar);
if (test_thread_flag(TIF_32BIT))
pc = (u32)pc;
if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
int asi = decode_asi(insn, regs);
freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
value = 0;
flag = (freg < 32) ? FPRS_DL : FPRS_DU;
if ((asi > ASI_SNFL) ||
(asi < ASI_P))
goto daex;
save_and_clear_fpu();
if (current_thread_info()->fpsaved[0] & flag)
value = *(u64 *)&f->regs[freg];
switch (asi) {
case ASI_P:
case ASI_S: break;
case ASI_PL:
case ASI_SL:
value = __swab64p(&value); break;
default: goto daex;
}
if (put_user (value >> 32, (u32 __user *) sfar) ||
__put_user ((u32)value, (u32 __user *)(sfar + 4)))
goto daex;
} else {
daex:
if (tlb_type == hypervisor)
sun4v_data_access_exception(regs, sfar, sfsr);
else
spitfire_data_access_exception(regs, sfsr, sfar);
return;
}
advance(regs);
}