--- /dev/null
+/*
+ * 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 <asm/ptrace.h>
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+#include <linux/smp.h>
+#include <linux/perf_event.h>
+
+#include <asm/setup.h>
+
+#include "kernel.h"
+
+enum direction {
+ load, /* ld, ldd, ldh, ldsh */
+ store, /* st, std, sth, stsh */
+ both, /* Swap, ldstub, etc. */
+ fpload,
+ fpstore,
+ invalid,
+};
+
+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_window32 *win;
+
+ if(reg < 16)
+ return (!reg ? 0 : regs->u_regs[reg]);
+
+ /* Ho hum, the slightly complicated case. */
+ win = (struct reg_window32 *) 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_window32 __user *win;
+ unsigned long ret;
+
+ if (reg < 16)
+ return (!reg ? 0 : regs->u_regs[reg]);
+
+ /* Ho hum, the slightly complicated case. */
+ win = (struct reg_window32 __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_window32 *win;
+
+ if(reg < 16)
+ return ®s->u_regs[reg];
+ win = (struct reg_window32 *) 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("%s", 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;
+
+ perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
+ 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;
+
+ 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);
+ perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
+ 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:
+ ;
+}
Code Review / kvmfornfv.git / blobdiff