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/* $Id: muldiv.c,v 1.5 1997/12/15 20:07:20 ecd Exp $
* muldiv.c: Hardware multiply/division illegal instruction trap
* for sun4c/sun4 (which do not have those instructions)
*
* Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
*
* 2004-12-25 Krzysztof Helt (krzysztof.h1@wp.pl)
* - fixed registers constrains in inline assembly declarations
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
/* #define DEBUG_MULDIV */
static inline int has_imm13(int insn)
{
return (insn & 0x2000);
}
static inline int is_foocc(int insn)
{
return (insn & 0x800000);
}
static inline int sign_extend_imm13(int imm)
{
return imm << 19 >> 19;
}
static inline void advance(struct pt_regs *regs)
{
regs->pc = regs->npc;
regs->npc += 4;
}
static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
unsigned int rd)
{
if(rs2 >= 16 || rs1 >= 16 || rd >= 16) {
/* Wheee... */
__asm__ __volatile__("save %sp, -0x40, %sp\n\t"
"save %sp, -0x40, %sp\n\t"
"save %sp, -0x40, %sp\n\t"
"save %sp, -0x40, %sp\n\t"
"save %sp, -0x40, %sp\n\t"
"save %sp, -0x40, %sp\n\t"
"save %sp, -0x40, %sp\n\t"
"restore; restore; restore; restore;\n\t"
"restore; restore; restore;\n\t");
}
}
#define fetch_reg(reg, regs) ({ \
struct reg_window __user *win; \
register unsigned long ret; \
\
if (!(reg)) ret = 0; \
else if ((reg) < 16) { \
ret = regs->u_regs[(reg)]; \
} else { \
/* Ho hum, the slightly complicated case. */ \
win = (struct reg_window __user *)regs->u_regs[UREG_FP];\
if (get_user (ret, &win->locals[(reg) - 16])) return -1;\
} \
ret; \
})
static inline int
store_reg(unsigned int result, unsigned int reg, struct pt_regs *regs)
{
struct reg_window __user *win;
if (!reg)
return 0;
if (reg < 16) {
regs->u_regs[reg] = result;
return 0;
} else {
/* need to use put_user() in this case: */
win = (struct reg_window __user *) regs->u_regs[UREG_FP];
return (put_user(result, &win->locals[reg - 16]));
}
}
extern void handle_hw_divzero (struct pt_regs *regs, unsigned long pc,
unsigned long npc, unsigned long psr);
/* Should return 0 if mul/div emulation succeeded and SIGILL should
* not be issued.
*/
int do_user_muldiv(struct pt_regs *regs, unsigned long pc)
{
unsigned int insn;
int inst;
unsigned int rs1, rs2, rdv;
if (!pc)
return -1; /* This happens to often, I think */
if (get_user (insn, (unsigned int __user *)pc))
return -1;
if ((insn & 0xc1400000) != 0x80400000)
return -1;
inst = ((insn >> 19) & 0xf);
if ((inst & 0xe) != 10 && (inst & 0xe) != 14)
return -1;
/* Now we know we have to do something with umul, smul, udiv or sdiv */
rs1 = (insn >> 14) & 0x1f;
rs2 = insn & 0x1f;
rdv = (insn >> 25) & 0x1f;
if (has_imm13(insn)) {
maybe_flush_windows(rs1, 0, rdv);
rs2 = sign_extend_imm13(insn);
} else {
maybe_flush_windows(rs1, rs2, rdv);
rs2 = fetch_reg(rs2, regs);
}
rs1 = fetch_reg(rs1, regs);
switch (inst) {
case 10: /* umul */
#ifdef DEBUG_MULDIV
printk ("unsigned muldiv: 0x%x * 0x%x = ", rs1, rs2);
#endif
__asm__ __volatile__ ("\n\t"
"mov %0, %%o0\n\t"
"call .umul\n\t"
" mov %1, %%o1\n\t"
"mov %%o0, %0\n\t"
"mov %%o1, %1\n\t"
: "=r" (rs1), "=r" (rs2)
: "0" (rs1), "1" (rs2)
: "o0", "o1", "o2", "o3", "o4", "o5", "o7", "cc");
#ifdef DEBUG_MULDIV
printk ("0x%x%08x\n", rs2, rs1);
#endif
if (store_reg(rs1, rdv, regs))
return -1;
regs->y = rs2;
break;
case 11: /* smul */
#ifdef DEBUG_MULDIV
printk ("signed muldiv: 0x%x * 0x%x = ", rs1, rs2);
#endif
__asm__ __volatile__ ("\n\t"
"mov %0, %%o0\n\t"
"call .mul\n\t"
" mov %1, %%o1\n\t"
"mov %%o0, %0\n\t"
"mov %%o1, %1\n\t"
: "=r" (rs1), "=r" (rs2)
: "0" (rs1), "1" (rs2)
: "o0", "o1", "o2", "o3", "o4", "o5", "o7", "cc");
#ifdef DEBUG_MULDIV
printk ("0x%x%08x\n", rs2, rs1);
#endif
if (store_reg(rs1, rdv, regs))
return -1;
regs->y = rs2;
break;
case 14: /* udiv */
#ifdef DEBUG_MULDIV
printk ("unsigned muldiv: 0x%x%08x / 0x%x = ", regs->y, rs1, rs2);
#endif
if (!rs2) {
#ifdef DEBUG_MULDIV
printk ("DIVISION BY ZERO\n");
#endif
handle_hw_divzero (regs, pc, regs->npc, regs->psr);
return 0;
}
__asm__ __volatile__ ("\n\t"
"mov %2, %%o0\n\t"
"mov %0, %%o1\n\t"
"mov %%g0, %%o2\n\t"
"call __udivdi3\n\t"
" mov %1, %%o3\n\t"
"mov %%o1, %0\n\t"
"mov %%o0, %1\n\t"
: "=r" (rs1), "=r" (rs2)
: "r" (regs->y), "0" (rs1), "1" (rs2)
: "o0", "o1", "o2", "o3", "o4", "o5", "o7",
"g1", "g2", "g3", "cc");
#ifdef DEBUG_MULDIV
printk ("0x%x\n", rs1);
#endif
if (store_reg(rs1, rdv, regs))
return -1;
break;
case 15: /* sdiv */
#ifdef DEBUG_MULDIV
printk ("signed muldiv: 0x%x%08x / 0x%x = ", regs->y, rs1, rs2);
#endif
if (!rs2) {
#ifdef DEBUG_MULDIV
printk ("DIVISION BY ZERO\n");
#endif
handle_hw_divzero (regs, pc, regs->npc, regs->psr);
return 0;
}
__asm__ __volatile__ ("\n\t"
"mov %2, %%o0\n\t"
"mov %0, %%o1\n\t"
"mov %%g0, %%o2\n\t"
"call __divdi3\n\t"
" mov %1, %%o3\n\t"
"mov %%o1, %0\n\t"
"mov %%o0, %1\n\t"
: "=r" (rs1), "=r" (rs2)
: "r" (regs->y), "0" (rs1), "1" (rs2)
: "o0", "o1", "o2", "o3", "o4", "o5", "o7",
"g1", "g2", "g3", "cc");
#ifdef DEBUG_MULDIV
printk ("0x%x\n", rs1);
#endif
if (store_reg(rs1, rdv, regs))
return -1;
break;
}
if (is_foocc (insn)) {
regs->psr &= ~PSR_ICC;
if ((inst & 0xe) == 14) {
/* ?div */
if (rs2) regs->psr |= PSR_V;
}
if (!rs1) regs->psr |= PSR_Z;
if (((int)rs1) < 0) regs->psr |= PSR_N;
#ifdef DEBUG_MULDIV
printk ("psr muldiv: %08x\n", regs->psr);
#endif
}
advance(regs);
return 0;
}
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