1 files changed, 390 insertions, 0 deletions

diff --git a/arch/sparc/kernel/unaligned_32.c b/arch/sparc/kernel/unaligned_32.c
new file mode 100644
index 000000000000..c2a28c5ad650
--- /dev/null
+++ b/arch/sparc/kernel/unaligned_32.c
@@ -0,0 +1,390 @@
+/*
+ * 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 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/ptrace.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+
+/* #define DEBUG_MNA */
+
+enum direction {
+        load,    /* ld, ldd, ldh, ldsh */
+        store,   /* st, std, sth, stsh */
+        both,    /* Swap, ldstub, etc. */
+        fpload,
+        fpstore,
+        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 {
+                if(((insn>>19)&0x3f) == 15)
+                        return both;
+                else
+                        return store;
+        }
+}
+
+/* 8 = double-word, 4 = word, 2 = half-word */
+static inline int decode_access_size(unsigned int insn)
+{
+        insn = (insn >> 19) & 3;
+
+        if(!insn)
+                return 4;
+        else if(insn == 3)
+                return 8;
+        else if(insn == 2)
+                return 2;
+        else {
+                printk("Impossible unaligned trap. insn=%08x\n", insn);
+                die_if_kernel("Byte sized unaligned access?!?!", current->thread.kregs);
+                return 4; /* just to keep gcc happy. */
+        }
+}
+
+/* 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)
+{
+        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");
+        }
+}
+
+static inline int sign_extend_imm13(int imm)
+{
+        return imm << 19 >> 19;
+}
+
+static inline unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
+{
+        struct reg_window *win;
+
+        if(reg < 16)
+                return (!reg ? 0 : regs->u_regs[reg]);
+
+        /* Ho hum, the slightly complicated case. */
+        win = (struct reg_window *) regs->u_regs[UREG_FP];
+        return win->locals[reg - 16]; /* yes, I know what this does... */
+}
+
+static inline unsigned long safe_fetch_reg(unsigned int reg, struct pt_regs *regs)
+{
+        struct reg_window __user *win;
+        unsigned long ret;
+
+        if (reg < 16)
+                return (!reg ? 0 : regs->u_regs[reg]);
+
+        /* Ho hum, the slightly complicated case. */
+        win = (struct reg_window __user *) regs->u_regs[UREG_FP];
+
+        if ((unsigned long)win & 3)
+                return -1;
+
+        if (get_user(ret, &win->locals[reg - 16]))
+                return -1;
+
+        return ret;
+}
+
+static inline unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
+{
+        struct reg_window *win;
+
+        if(reg < 16)
+                return &regs->u_regs[reg];
+        win = (struct reg_window *) regs->u_regs[UREG_FP];
+        return &win->locals[reg - 16];
+}
+
+static unsigned long compute_effective_address(struct pt_regs *regs,
+                                               unsigned int insn)
+{
+        unsigned int rs1 = (insn >> 14) & 0x1f;
+        unsigned int rs2 = insn & 0x1f;
+        unsigned int rd = (insn >> 25) & 0x1f;
+
+        if(insn & 0x2000) {
+                maybe_flush_windows(rs1, 0, rd);
+                return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
+        } else {
+                maybe_flush_windows(rs1, rs2, rd);
+                return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
+        }
+}
+
+unsigned long safe_compute_effective_address(struct pt_regs *regs,
+                                             unsigned int insn)
+{
+        unsigned int rs1 = (insn >> 14) & 0x1f;
+        unsigned int rs2 = insn & 0x1f;
+        unsigned int rd = (insn >> 25) & 0x1f;
+
+        if(insn & 0x2000) {
+                maybe_flush_windows(rs1, 0, rd);
+                return (safe_fetch_reg(rs1, regs) + sign_extend_imm13(insn));
+        } else {
+                maybe_flush_windows(rs1, rs2, rd);
+                return (safe_fetch_reg(rs1, regs) + safe_fetch_reg(rs2, regs));
+        }
+}
+
+/* This is just to make gcc think panic does return... */
+static void unaligned_panic(char *str)
+{
+        panic(str);
+}
+
+/* una_asm.S */
+extern int do_int_load(unsigned long *dest_reg, int size,
+                       unsigned long *saddr, int is_signed);
+extern int __do_int_store(unsigned long *dst_addr, int size,
+                          unsigned long *src_val);
+
+static int do_int_store(int reg_num, int size, unsigned long *dst_addr,
+                        struct pt_regs *regs)
+{
+        unsigned long zero[2] = { 0, 0 };
+        unsigned long *src_val;
+
+        if (reg_num)
+                src_val = fetch_reg_addr(reg_num, regs);
+        else {
+                src_val = &zero[0];
+                if (size == 8)
+                        zero[1] = fetch_reg(1, regs);
+        }
+        return __do_int_store(dst_addr, size, src_val);
+}
+
+extern void smp_capture(void);
+extern void smp_release(void);
+
+static inline void advance(struct pt_regs *regs)
+{
+        regs->pc   = regs->npc;
+        regs->npc += 4;
+}
+
+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(struct pt_regs *regs, unsigned int insn)
+{
+        unsigned long g2 = regs->u_regs [UREG_G2];
+        unsigned long fixup = search_extables_range(regs->pc, &g2);
+
+        if (!fixup) {
+                unsigned long address = compute_effective_address(regs, insn);
+                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 %08lx\n",address);
+                printk(KERN_ALERT "current->{mm,active_mm}->context = %08lx\n",
+                        (current->mm ? current->mm->context :
+                        current->active_mm->context));
+                printk(KERN_ALERT "current->{mm,active_mm}->pgd = %08lx\n",
+                        (current->mm ? (unsigned long) current->mm->pgd :
+                        (unsigned long) current->active_mm->pgd));
+                die_if_kernel("Oops", regs);
+                /* Not reached */
+        }
+        regs->pc = fixup;
+        regs->npc = regs->pc + 4;
+        regs->u_regs [UREG_G2] = g2;
+}
+
+asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
+{
+        enum direction dir = decode_direction(insn);
+        int size = decode_access_size(insn);
+
+        if(!ok_for_kernel(insn) || dir == both) {
+                printk("Unsupported unaligned load/store trap for kernel at <%08lx>.\n",
+                       regs->pc);
+                unaligned_panic("Wheee. Kernel does fpu/atomic unaligned load/store.");
+        } else {
+                unsigned long addr = compute_effective_address(regs, insn);
+                int err;
+
+#ifdef DEBUG_MNA
+                printk("KMNA: pc=%08lx [dir=%s addr=%08lx size=%d] retpc[%08lx]\n",
+                       regs->pc, dirstrings[dir], addr, size, regs->u_regs[UREG_RETPC]);
+#endif
+                switch (dir) {
+                case load:
+                        err = do_int_load(fetch_reg_addr(((insn>>25)&0x1f),
+                                                         regs),
+                                          size, (unsigned long *) addr,
+                                          decode_signedness(insn));
+                        break;
+
+                case store:
+                        err = do_int_store(((insn>>25)&0x1f), size,
+                                           (unsigned long *) addr, regs);
+                        break;
+                default:
+                        panic("Impossible kernel unaligned trap.");
+                        /* Not reached... */
+                }
+                if (err)
+                        kernel_mna_trap_fault(regs, insn);
+                else
+                        advance(regs);
+        }
+}
+
+static inline int ok_for_user(struct pt_regs *regs, unsigned int insn,
+                              enum direction dir)
+{
+        unsigned int reg;
+        int check = (dir == load) ? VERIFY_READ : VERIFY_WRITE;
+        int size = ((insn >> 19) & 3) == 3 ? 8 : 4;
+
+        if ((regs->pc | regs->npc) & 3)
+                return 0;
+
+        /* Must access_ok() in all the necessary places. */
+#define WINREG_ADDR(regnum) \
+        ((void __user *)(((unsigned long *)regs->u_regs[UREG_FP])+(regnum)))
+
+        reg = (insn >> 25) & 0x1f;
+        if (reg >= 16) {
+                if (!access_ok(check, WINREG_ADDR(reg - 16), size))
+                        return -EFAULT;
+        }
+        reg = (insn >> 14) & 0x1f;
+        if (reg >= 16) {
+                if (!access_ok(check, WINREG_ADDR(reg - 16), size))
+                        return -EFAULT;
+        }
+        if (!(insn & 0x2000)) {
+                reg = (insn & 0x1f);
+                if (reg >= 16) {
+                        if (!access_ok(check, WINREG_ADDR(reg - 16), size))
+                                return -EFAULT;
+                }
+        }
+#undef WINREG_ADDR
+        return 0;
+}
+
+static void user_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
+{
+        siginfo_t info;
+
+        info.si_signo = SIGBUS;
+        info.si_errno = 0;
+        info.si_code = BUS_ADRALN;
+        info.si_addr = (void __user *)safe_compute_effective_address(regs, insn);
+        info.si_trapno = 0;
+        send_sig_info(SIGBUS, &info, current);
+}
+
+asmlinkage void user_unaligned_trap(struct pt_regs *regs, unsigned int insn)
+{
+        enum direction dir;
+
+        lock_kernel();
+        if(!(current->thread.flags & SPARC_FLAG_UNALIGNED) ||
+           (((insn >> 30) & 3) != 3))
+                goto kill_user;
+        dir = decode_direction(insn);
+        if(!ok_for_user(regs, insn, dir)) {
+                goto kill_user;
+        } else {
+                int err, size = decode_access_size(insn);
+                unsigned long addr;
+
+                if(floating_point_load_or_store_p(insn)) {
+                        printk("User FPU load/store unaligned unsupported.\n");
+                        goto kill_user;
+                }
+
+                addr = compute_effective_address(regs, insn);
+                switch(dir) {
+                case load:
+                        err = do_int_load(fetch_reg_addr(((insn>>25)&0x1f),
+                                                         regs),
+                                          size, (unsigned long *) addr,
+                                          decode_signedness(insn));
+                        break;
+
+                case store:
+                        err = do_int_store(((insn>>25)&0x1f), size,
+                                           (unsigned long *) addr, regs);
+                        break;
+
+                case both:
+                        /*
+                         * This was supported in 2.4. However, we question
+                         * the value of SWAP instruction across word boundaries.
+                         */
+                        printk("Unaligned SWAP unsupported.\n");
+                        err = -EFAULT;
+                        break;
+
+                default:
+                        unaligned_panic("Impossible user unaligned trap.");
+                        goto out;
+                }
+                if (err)
+                        goto kill_user;
+                else
+                        advance(regs);
+                goto out;
+        }
+
+kill_user:
+        user_mna_trap_fault(regs, insn);
+out:
+        unlock_kernel();
+}