2 * unaligned.c: Unaligned load/store trap handling with special
3 * cases for the kernel to do them more quickly.
5 * Copyright (C) 1996,2008 David S. Miller (davem@davemloft.net)
6 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
10 #include <linux/jiffies.h>
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
14 #include <linux/module.h>
16 #include <asm/ptrace.h>
17 #include <asm/pstate.h>
18 #include <asm/processor.h>
19 #include <asm/uaccess.h>
20 #include <linux/smp.h>
21 #include <linux/bitops.h>
22 #include <linux/perf_event.h>
23 #include <linux/ratelimit.h>
24 #include <linux/context_tracking.h>
25 #include <asm/fpumacro.h>
26 #include <asm/cacheflush.h>
31 load, /* ld, ldd, ldh, ldsh */
32 store, /* st, std, sth, stsh */
33 both, /* Swap, ldstub, cas, ... */
39 static inline enum direction decode_direction(unsigned int insn)
41 unsigned long tmp = (insn >> 21) & 1;
46 switch ((insn>>19)&0xf) {
55 /* 16 = double-word, 8 = extra-word, 4 = word, 2 = half-word */
56 static inline int decode_access_size(struct pt_regs *regs, unsigned int insn)
60 tmp = ((insn >> 19) & 0xf);
61 if (tmp == 11 || tmp == 14) /* ldx/stx */
67 return 16; /* ldd/std - Although it is actually 8 */
71 printk("Impossible unaligned trap. insn=%08x\n", insn);
72 die_if_kernel("Byte sized unaligned access?!?!", regs);
74 /* GCC should never warn that control reaches the end
75 * of this function without returning a value because
76 * die_if_kernel() is marked with attribute 'noreturn'.
77 * Alas, some versions do...
84 static inline int decode_asi(unsigned int insn, struct pt_regs *regs)
86 if (insn & 0x800000) {
88 return (unsigned char)(regs->tstate >> 24); /* %asi */
90 return (unsigned char)(insn >> 5); /* imm_asi */
95 /* 0x400000 = signed, 0 = unsigned */
96 static inline int decode_signedness(unsigned int insn)
98 return (insn & 0x400000);
101 static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
102 unsigned int rd, int from_kernel)
104 if (rs2 >= 16 || rs1 >= 16 || rd >= 16) {
105 if (from_kernel != 0)
106 __asm__ __volatile__("flushw");
112 static inline long sign_extend_imm13(long imm)
114 return imm << 51 >> 51;
117 static unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
119 unsigned long value, fp;
122 return (!reg ? 0 : regs->u_regs[reg]);
124 fp = regs->u_regs[UREG_FP];
126 if (regs->tstate & TSTATE_PRIV) {
127 struct reg_window *win;
128 win = (struct reg_window *)(fp + STACK_BIAS);
129 value = win->locals[reg - 16];
130 } else if (!test_thread_64bit_stack(fp)) {
131 struct reg_window32 __user *win32;
132 win32 = (struct reg_window32 __user *)((unsigned long)((u32)fp));
133 get_user(value, &win32->locals[reg - 16]);
135 struct reg_window __user *win;
136 win = (struct reg_window __user *)(fp + STACK_BIAS);
137 get_user(value, &win->locals[reg - 16]);
142 static unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
147 return ®s->u_regs[reg];
149 fp = regs->u_regs[UREG_FP];
151 if (regs->tstate & TSTATE_PRIV) {
152 struct reg_window *win;
153 win = (struct reg_window *)(fp + STACK_BIAS);
154 return &win->locals[reg - 16];
155 } else if (!test_thread_64bit_stack(fp)) {
156 struct reg_window32 *win32;
157 win32 = (struct reg_window32 *)((unsigned long)((u32)fp));
158 return (unsigned long *)&win32->locals[reg - 16];
160 struct reg_window *win;
161 win = (struct reg_window *)(fp + STACK_BIAS);
162 return &win->locals[reg - 16];
166 unsigned long compute_effective_address(struct pt_regs *regs,
167 unsigned int insn, unsigned int rd)
169 unsigned int rs1 = (insn >> 14) & 0x1f;
170 unsigned int rs2 = insn & 0x1f;
171 int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
174 maybe_flush_windows(rs1, 0, rd, from_kernel);
175 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
177 maybe_flush_windows(rs1, rs2, rd, from_kernel);
178 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
182 /* This is just to make gcc think die_if_kernel does return... */
183 static void __used unaligned_panic(char *str, struct pt_regs *regs)
185 die_if_kernel(str, regs);
188 extern int do_int_load(unsigned long *dest_reg, int size,
189 unsigned long *saddr, int is_signed, int asi);
191 extern int __do_int_store(unsigned long *dst_addr, int size,
192 unsigned long src_val, int asi);
194 static inline int do_int_store(int reg_num, int size, unsigned long *dst_addr,
195 struct pt_regs *regs, int asi, int orig_asi)
197 unsigned long zero = 0;
198 unsigned long *src_val_p = &zero;
199 unsigned long src_val;
203 zero = (((long)(reg_num ?
204 (unsigned)fetch_reg(reg_num, regs) : 0)) << 32) |
205 (unsigned)fetch_reg(reg_num + 1, regs);
206 } else if (reg_num) {
207 src_val_p = fetch_reg_addr(reg_num, regs);
209 src_val = *src_val_p;
210 if (unlikely(asi != orig_asi)) {
213 src_val = swab16(src_val);
216 src_val = swab32(src_val);
219 src_val = swab64(src_val);
227 return __do_int_store(dst_addr, size, src_val, asi);
230 static inline void advance(struct pt_regs *regs)
232 regs->tpc = regs->tnpc;
234 if (test_thread_flag(TIF_32BIT)) {
235 regs->tpc &= 0xffffffff;
236 regs->tnpc &= 0xffffffff;
240 static inline int floating_point_load_or_store_p(unsigned int insn)
242 return (insn >> 24) & 1;
245 static inline int ok_for_kernel(unsigned int insn)
247 return !floating_point_load_or_store_p(insn);
250 static void kernel_mna_trap_fault(int fixup_tstate_asi)
252 struct pt_regs *regs = current_thread_info()->kern_una_regs;
253 unsigned int insn = current_thread_info()->kern_una_insn;
254 const struct exception_table_entry *entry;
256 entry = search_exception_tables(regs->tpc);
258 unsigned long address;
260 address = compute_effective_address(regs, insn,
261 ((insn >> 25) & 0x1f));
262 if (address < PAGE_SIZE) {
263 printk(KERN_ALERT "Unable to handle kernel NULL "
264 "pointer dereference in mna handler");
266 printk(KERN_ALERT "Unable to handle kernel paging "
267 "request in mna handler");
268 printk(KERN_ALERT " at virtual address %016lx\n",address);
269 printk(KERN_ALERT "current->{active_,}mm->context = %016lx\n",
270 (current->mm ? CTX_HWBITS(current->mm->context) :
271 CTX_HWBITS(current->active_mm->context)));
272 printk(KERN_ALERT "current->{active_,}mm->pgd = %016lx\n",
273 (current->mm ? (unsigned long) current->mm->pgd :
274 (unsigned long) current->active_mm->pgd));
275 die_if_kernel("Oops", regs);
278 regs->tpc = entry->fixup;
279 regs->tnpc = regs->tpc + 4;
281 if (fixup_tstate_asi) {
282 regs->tstate &= ~TSTATE_ASI;
283 regs->tstate |= (ASI_AIUS << 24UL);
287 static void log_unaligned(struct pt_regs *regs)
289 static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
291 if (__ratelimit(&ratelimit)) {
292 printk("Kernel unaligned access at TPC[%lx] %pS\n",
293 regs->tpc, (void *) regs->tpc);
297 asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
299 enum direction dir = decode_direction(insn);
300 int size = decode_access_size(regs, insn);
303 current_thread_info()->kern_una_regs = regs;
304 current_thread_info()->kern_una_insn = insn;
306 orig_asi = asi = decode_asi(insn, regs);
308 /* If this is a {get,put}_user() on an unaligned userspace pointer,
309 * just signal a fault and do not log the event.
311 if (asi == ASI_AIUS) {
312 kernel_mna_trap_fault(0);
318 if (!ok_for_kernel(insn) || dir == both) {
319 printk("Unsupported unaligned load/store trap for kernel "
320 "at <%016lx>.\n", regs->tpc);
321 unaligned_panic("Kernel does fpu/atomic "
322 "unaligned load/store.", regs);
324 kernel_mna_trap_fault(0);
326 unsigned long addr, *reg_addr;
329 addr = compute_effective_address(regs, insn,
330 ((insn >> 25) & 0x1f));
331 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
345 reg_addr = fetch_reg_addr(((insn>>25)&0x1f), regs);
346 err = do_int_load(reg_addr, size,
347 (unsigned long *) addr,
348 decode_signedness(insn), asi);
349 if (likely(!err) && unlikely(asi != orig_asi)) {
350 unsigned long val_in = *reg_addr;
353 val_in = swab16(val_in);
356 val_in = swab32(val_in);
359 val_in = swab64(val_in);
371 err = do_int_store(((insn>>25)&0x1f), size,
372 (unsigned long *) addr, regs,
377 panic("Impossible kernel unaligned trap.");
381 kernel_mna_trap_fault(1);
387 int handle_popc(u32 insn, struct pt_regs *regs)
389 int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
390 int ret, rd = ((insn >> 25) & 0x1f);
393 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
395 maybe_flush_windows(0, 0, rd, from_kernel);
396 value = sign_extend_imm13(insn);
398 maybe_flush_windows(0, insn & 0x1f, rd, from_kernel);
399 value = fetch_reg(insn & 0x1f, regs);
401 ret = hweight64(value);
404 regs->u_regs[rd] = ret;
406 unsigned long fp = regs->u_regs[UREG_FP];
408 if (!test_thread_64bit_stack(fp)) {
409 struct reg_window32 __user *win32;
410 win32 = (struct reg_window32 __user *)((unsigned long)((u32)fp));
411 put_user(ret, &win32->locals[rd - 16]);
413 struct reg_window __user *win;
414 win = (struct reg_window __user *)(fp + STACK_BIAS);
415 put_user(ret, &win->locals[rd - 16]);
422 extern void do_fpother(struct pt_regs *regs);
423 extern void do_privact(struct pt_regs *regs);
424 extern void sun4v_data_access_exception(struct pt_regs *regs,
426 unsigned long type_ctx);
428 int handle_ldf_stq(u32 insn, struct pt_regs *regs)
430 unsigned long addr = compute_effective_address(regs, insn, 0);
431 int freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
432 struct fpustate *f = FPUSTATE;
433 int asi = decode_asi(insn, regs);
434 int flag = (freg < 32) ? FPRS_DL : FPRS_DU;
436 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
438 save_and_clear_fpu();
439 current_thread_info()->xfsr[0] &= ~0x1c000;
441 current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
445 if (insn & 0x200000) {
447 u64 first = 0, second = 0;
449 if (current_thread_info()->fpsaved[0] & flag) {
450 first = *(u64 *)&f->regs[freg];
451 second = *(u64 *)&f->regs[freg+2];
463 /* Need to convert endians */
464 u64 tmp = __swab64p(&first);
466 first = __swab64p(&second);
471 if (tlb_type == hypervisor)
472 sun4v_data_access_exception(regs, addr, 0);
474 spitfire_data_access_exception(regs, 0, addr);
477 if (put_user (first >> 32, (u32 __user *)addr) ||
478 __put_user ((u32)first, (u32 __user *)(addr + 4)) ||
479 __put_user (second >> 32, (u32 __user *)(addr + 8)) ||
480 __put_user ((u32)second, (u32 __user *)(addr + 12))) {
481 if (tlb_type == hypervisor)
482 sun4v_data_access_exception(regs, addr, 0);
484 spitfire_data_access_exception(regs, 0, addr);
488 /* LDF, LDDF, LDQF */
489 u32 data[4] __attribute__ ((aligned(8)));
496 } else if (asi > ASI_SNFL) {
497 if (tlb_type == hypervisor)
498 sun4v_data_access_exception(regs, addr, 0);
500 spitfire_data_access_exception(regs, 0, addr);
503 switch (insn & 0x180000) {
504 case 0x000000: size = 1; break;
505 case 0x100000: size = 4; break;
506 default: size = 2; break;
508 for (i = 0; i < size; i++)
511 err = get_user (data[0], (u32 __user *) addr);
513 for (i = 1; i < size; i++)
514 err |= __get_user (data[i], (u32 __user *)(addr + 4*i));
516 if (err && !(asi & 0x2 /* NF */)) {
517 if (tlb_type == hypervisor)
518 sun4v_data_access_exception(regs, addr, 0);
520 spitfire_data_access_exception(regs, 0, addr);
523 if (asi & 0x8) /* Little */ {
527 case 1: data[0] = le32_to_cpup(data + 0); break;
528 default:*(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 0));
530 case 4: tmp = le64_to_cpup((u64 *)(data + 0));
531 *(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 2));
532 *(u64 *)(data + 2) = tmp;
536 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
537 current_thread_info()->fpsaved[0] = FPRS_FEF;
538 current_thread_info()->gsr[0] = 0;
540 if (!(current_thread_info()->fpsaved[0] & flag)) {
542 memset(f->regs, 0, 32*sizeof(u32));
544 memset(f->regs+32, 0, 32*sizeof(u32));
546 memcpy(f->regs + freg, data, size * 4);
547 current_thread_info()->fpsaved[0] |= flag;
553 void handle_ld_nf(u32 insn, struct pt_regs *regs)
555 int rd = ((insn >> 25) & 0x1f);
556 int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
559 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
561 maybe_flush_windows(0, 0, rd, from_kernel);
562 reg = fetch_reg_addr(rd, regs);
563 if (from_kernel || rd < 16) {
565 if ((insn & 0x780000) == 0x180000)
567 } else if (!test_thread_64bit_stack(regs->u_regs[UREG_FP])) {
568 put_user(0, (int __user *) reg);
569 if ((insn & 0x780000) == 0x180000)
570 put_user(0, ((int __user *) reg) + 1);
572 put_user(0, (unsigned long __user *) reg);
573 if ((insn & 0x780000) == 0x180000)
574 put_user(0, (unsigned long __user *) reg + 1);
579 void handle_lddfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
581 enum ctx_state prev_state = exception_enter();
582 unsigned long pc = regs->tpc;
583 unsigned long tstate = regs->tstate;
588 struct fpustate *f = FPUSTATE;
590 if (tstate & TSTATE_PRIV)
591 die_if_kernel("lddfmna from kernel", regs);
592 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, sfar);
593 if (test_thread_flag(TIF_32BIT))
595 if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
596 int asi = decode_asi(insn, regs);
600 if ((asi > ASI_SNFL) ||
604 err = get_user(first, (u32 __user *)sfar);
606 err = get_user(second, (u32 __user *)(sfar + 4));
612 save_and_clear_fpu();
613 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
614 value = (((u64)first) << 32) | second;
615 if (asi & 0x8) /* Little */
616 value = __swab64p(&value);
617 flag = (freg < 32) ? FPRS_DL : FPRS_DU;
618 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
619 current_thread_info()->fpsaved[0] = FPRS_FEF;
620 current_thread_info()->gsr[0] = 0;
622 if (!(current_thread_info()->fpsaved[0] & flag)) {
624 memset(f->regs, 0, 32*sizeof(u32));
626 memset(f->regs+32, 0, 32*sizeof(u32));
628 *(u64 *)(f->regs + freg) = value;
629 current_thread_info()->fpsaved[0] |= flag;
632 if (tlb_type == hypervisor)
633 sun4v_data_access_exception(regs, sfar, sfsr);
635 spitfire_data_access_exception(regs, sfsr, sfar);
640 exception_exit(prev_state);
643 void handle_stdfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
645 enum ctx_state prev_state = exception_enter();
646 unsigned long pc = regs->tpc;
647 unsigned long tstate = regs->tstate;
652 struct fpustate *f = FPUSTATE;
654 if (tstate & TSTATE_PRIV)
655 die_if_kernel("stdfmna from kernel", regs);
656 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, sfar);
657 if (test_thread_flag(TIF_32BIT))
659 if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
660 int asi = decode_asi(insn, regs);
661 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
663 flag = (freg < 32) ? FPRS_DL : FPRS_DU;
664 if ((asi > ASI_SNFL) ||
667 save_and_clear_fpu();
668 if (current_thread_info()->fpsaved[0] & flag)
669 value = *(u64 *)&f->regs[freg];
675 value = __swab64p(&value); break;
678 if (put_user (value >> 32, (u32 __user *) sfar) ||
679 __put_user ((u32)value, (u32 __user *)(sfar + 4)))
683 if (tlb_type == hypervisor)
684 sun4v_data_access_exception(regs, sfar, sfsr);
686 spitfire_data_access_exception(regs, sfsr, sfar);
691 exception_exit(prev_state);