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linux/arch/sparc64/kernel/unaligned.c
David S. Miller 6c52a96e6c [SPARC64]: Revamp Spitfire error trap handling. 
Current uncorrectable error handling was poor enough
that the processor could just loop taking the same
trap over and over again.  Fix things up so that we
at least get a log message and perhaps even some register
state.

In the process, much consolidation became possible,
particularly with the correctable error handler.

Prefix assembler and C function names with "spitfire"
to indicate that these are for Ultra-I/II/IIi/IIe only.

More work is needed to make these routines robust and
featureful to the level of the Ultra-III error handlers.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 12:45:11 -07:00

586 lines
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/* $Id: unaligned.c,v 1.24 2002/02/09 19:49:31 davem Exp $
* unaligned.c: Unaligned load/store trap handling with special
* cases for the kernel to do them more quickly.
*
* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
*/
#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/system.h>
#include <asm/uaccess.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/bitops.h>
#include <asm/fpumacro.h>
/* #define DEBUG_MNA */
enum direction {
load, /* ld, ldd, ldh, ldsh */
store, /* st, std, sth, stsh */
both, /* Swap, ldstub, cas, ... */
fpld,
fpst,
invalid,
};
#ifdef DEBUG_MNA
static char *dirstrings[] = {
"load", "store", "both", "fpload", "fpstore", "invalid"
};
#endif
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(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?!?!", current_thread_info()->kregs);
/* 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;
if (reg < 16)
return (!reg ? 0 : regs->u_regs[reg]);
if (regs->tstate & TSTATE_PRIV) {
struct reg_window *win;
win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
value = win->locals[reg - 16];
} else if (test_thread_flag(TIF_32BIT)) {
struct reg_window32 __user *win32;
win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
get_user(value, &win32->locals[reg - 16]);
} else {
struct reg_window __user *win;
win = (struct reg_window __user *)(regs->u_regs[UREG_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)
{
if (reg < 16)
return &regs->u_regs[reg];
if (regs->tstate & TSTATE_PRIV) {
struct reg_window *win;
win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
return &win->locals[reg - 16];
} else if (test_thread_flag(TIF_32BIT)) {
struct reg_window32 *win32;
win32 = (struct reg_window32 *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
return (unsigned long *)&win32->locals[reg - 16];
} else {
struct reg_window *win;
win = (struct reg_window *)(regs->u_regs[UREG_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 __attribute_used__ unaligned_panic(char *str, struct pt_regs *regs)
{
die_if_kernel(str, regs);
}
extern void do_int_load(unsigned long *dest_reg, int size,
unsigned long *saddr, int is_signed, int asi);
extern void __do_int_store(unsigned long *dst_addr, int size,
unsigned long *src_val, int asi);
static inline void do_int_store(int reg_num, int size, unsigned long *dst_addr,
struct pt_regs *regs, int asi)
{
unsigned long zero = 0;
unsigned long *src_val = &zero;
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 = fetch_reg_addr(reg_num, regs);
}
__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);
}
void kernel_mna_trap_fault(void)
{
struct pt_regs *regs = current_thread_info()->kern_una_regs;
unsigned int insn = current_thread_info()->kern_una_insn;
unsigned long g2 = regs->u_regs[UREG_G2];
unsigned long fixup = search_extables_range(regs->tpc, &g2);
if (!fixup) {
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 = fixup;
regs->tnpc = regs->tpc + 4;
regs->u_regs [UREG_G2] = g2;
regs->tstate &= ~TSTATE_ASI;
regs->tstate |= (ASI_AIUS << 24UL);
}
asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn, unsigned long sfar, unsigned long sfsr)
{
enum direction dir = decode_direction(insn);
int size = decode_access_size(insn);
current_thread_info()->kern_una_regs = regs;
current_thread_info()->kern_una_insn = insn;
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();
} else {
unsigned long addr;
addr = compute_effective_address(regs, insn,
((insn >> 25) & 0x1f));
#ifdef DEBUG_MNA
printk("KMNA: pc=%016lx [dir=%s addr=%016lx size=%d] "
"retpc[%016lx]\n",
regs->tpc, dirstrings[dir], addr, size,
regs->u_regs[UREG_RETPC]);
#endif
switch (dir) {
case load:
do_int_load(fetch_reg_addr(((insn>>25)&0x1f), regs),
size, (unsigned long *) addr,
decode_signedness(insn),
decode_asi(insn, regs));
break;
case store:
do_int_store(((insn>>25)&0x1f), size,
(unsigned long *) addr, regs,
decode_asi(insn, regs));
break;
default:
panic("Impossible kernel unaligned trap.");
/* Not reached... */
}
advance(regs);
}
}
static char popc_helper[] = {
0, 1, 1, 2, 1, 2, 2, 3,
1, 2, 2, 3, 2, 3, 3, 4,
};
int handle_popc(u32 insn, struct pt_regs *regs)
{
u64 value;
int ret, i, rd = ((insn >> 25) & 0x1f);
int from_kernel = (regs->tstate & TSTATE_PRIV) != 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);
}
for (ret = 0, i = 0; i < 16; i++) {
ret += popc_helper[value & 0xf];
value >>= 4;
}
if (rd < 16) {
if (rd)
regs->u_regs[rd] = ret;
} else {
if (test_thread_flag(TIF_32BIT)) {
struct reg_window32 __user *win32;
win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
put_user(ret, &win32->locals[rd - 16]);
} else {
struct reg_window __user *win;
win = (struct reg_window __user *)(regs->u_regs[UREG_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);
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;
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:
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))) {
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) {
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 */)) {
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;
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_flag(TIF_32BIT)) {
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;
u32 first, second;
u64 value;
u8 asi, freg;
int flag;
struct fpustate *f = FPUSTATE;
if (tstate & TSTATE_PRIV)
die_if_kernel("lddfmna from kernel", regs);
if (test_thread_flag(TIF_32BIT))
pc = (u32)pc;
if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
asi = sfsr >> 16;
if ((asi > ASI_SNFL) ||
(asi < ASI_P))
goto daex;
if (get_user(first, (u32 __user *)sfar) ||
get_user(second, (u32 __user *)(sfar + 4))) {
if (asi & 0x2) /* NF */ {
first = 0; second = 0;
} else
goto daex;
}
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: spitfire_data_access_exception(regs, sfsr, sfar);
return;
}
advance(regs);
return;
}
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 asi, freg;
int flag;
struct fpustate *f = FPUSTATE;
if (tstate & TSTATE_PRIV)
die_if_kernel("stdfmna from kernel", regs);
if (test_thread_flag(TIF_32BIT))
pc = (u32)pc;
if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
asi = sfsr >> 16;
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: spitfire_data_access_exception(regs, sfsr, sfar);
return;
}
advance(regs);
return;
}
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