diff options
Diffstat (limited to 'arch/sparc/kernel/unaligned_32.c')
| -rw-r--r-- | arch/sparc/kernel/unaligned_32.c | 390 |
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 00000000000..6b1e6cde6ff --- /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_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(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(); +} |