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-rw-r--r--arch/sparc/kernel/muldiv.c240
1 files changed, 240 insertions, 0 deletions
diff --git a/arch/sparc/kernel/muldiv.c b/arch/sparc/kernel/muldiv.c
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+++ b/arch/sparc/kernel/muldiv.c
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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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