aa6758d486
Implement sys_[gs]et_thread_area and the corresponding ptrace operations for UML. This is the main chunk, additional parts follow. This implementation is now well tested and has run reliably for some time, and we've understood all the previously existing problems. Their implementation saves the new GDT content and then forwards the call to the host when appropriate, i.e. immediately when the target process is running or on context switch otherwise (i.e. on fork and on ptrace() calls). In SKAS mode, we must switch registers on each context switch (because SKAS does not switches tls_array together with current->mm). Also, added get_cpu() locking; this has been done for SKAS mode, since TT does not need it (it does not use smp_processor_id()). Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
425 lines
10 KiB
C
425 lines
10 KiB
C
/*
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* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#include <linux/config.h>
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#include <linux/compiler.h>
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#include "linux/sched.h"
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#include "linux/mm.h"
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#include "asm/elf.h"
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#include "asm/ptrace.h"
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#include "asm/uaccess.h"
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#include "asm/unistd.h"
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#include "sysdep/ptrace.h"
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#include "sysdep/sigcontext.h"
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#include "sysdep/sc.h"
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void arch_switch_to_tt(struct task_struct *from, struct task_struct *to)
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{
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update_debugregs(to->thread.arch.debugregs_seq);
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arch_switch_tls_tt(from, to);
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}
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void arch_switch_to_skas(struct task_struct *from, struct task_struct *to)
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{
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arch_switch_tls_skas(from, to);
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}
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int is_syscall(unsigned long addr)
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{
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unsigned short instr;
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int n;
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n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
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if(n){
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/* access_process_vm() grants access to vsyscall and stub,
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* while copy_from_user doesn't. Maybe access_process_vm is
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* slow, but that doesn't matter, since it will be called only
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* in case of singlestepping, if copy_from_user failed.
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*/
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n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
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if(n != sizeof(instr)) {
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printk("is_syscall : failed to read instruction from "
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"0x%lx\n", addr);
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return(1);
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}
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}
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/* int 0x80 or sysenter */
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return((instr == 0x80cd) || (instr == 0x340f));
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}
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/* determines which flags the user has access to. */
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/* 1 = access 0 = no access */
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#define FLAG_MASK 0x00044dd5
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int putreg(struct task_struct *child, int regno, unsigned long value)
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{
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regno >>= 2;
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switch (regno) {
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case FS:
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if (value && (value & 3) != 3)
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return -EIO;
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PT_REGS_FS(&child->thread.regs) = value;
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return 0;
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case GS:
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if (value && (value & 3) != 3)
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return -EIO;
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PT_REGS_GS(&child->thread.regs) = value;
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return 0;
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case DS:
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case ES:
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if (value && (value & 3) != 3)
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return -EIO;
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value &= 0xffff;
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break;
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case SS:
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case CS:
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if ((value & 3) != 3)
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return -EIO;
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value &= 0xffff;
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break;
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case EFL:
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value &= FLAG_MASK;
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value |= PT_REGS_EFLAGS(&child->thread.regs);
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break;
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}
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PT_REGS_SET(&child->thread.regs, regno, value);
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return 0;
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}
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int poke_user(struct task_struct *child, long addr, long data)
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{
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if ((addr & 3) || addr < 0)
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return -EIO;
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if (addr < MAX_REG_OFFSET)
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return putreg(child, addr, data);
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else if((addr >= offsetof(struct user, u_debugreg[0])) &&
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(addr <= offsetof(struct user, u_debugreg[7]))){
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addr -= offsetof(struct user, u_debugreg[0]);
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addr = addr >> 2;
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if((addr == 4) || (addr == 5)) return -EIO;
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child->thread.arch.debugregs[addr] = data;
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return 0;
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}
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return -EIO;
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}
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unsigned long getreg(struct task_struct *child, int regno)
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{
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unsigned long retval = ~0UL;
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regno >>= 2;
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switch (regno) {
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case FS:
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case GS:
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case DS:
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case ES:
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case SS:
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case CS:
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retval = 0xffff;
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/* fall through */
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default:
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retval &= PT_REG(&child->thread.regs, regno);
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}
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return retval;
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}
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int peek_user(struct task_struct *child, long addr, long data)
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{
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/* read the word at location addr in the USER area. */
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unsigned long tmp;
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if ((addr & 3) || addr < 0)
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return -EIO;
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tmp = 0; /* Default return condition */
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if(addr < MAX_REG_OFFSET){
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tmp = getreg(child, addr);
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}
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else if((addr >= offsetof(struct user, u_debugreg[0])) &&
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(addr <= offsetof(struct user, u_debugreg[7]))){
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addr -= offsetof(struct user, u_debugreg[0]);
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addr = addr >> 2;
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tmp = child->thread.arch.debugregs[addr];
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}
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return put_user(tmp, (unsigned long __user *) data);
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}
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struct i387_fxsave_struct {
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unsigned short cwd;
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unsigned short swd;
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unsigned short twd;
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unsigned short fop;
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long fip;
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long fcs;
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long foo;
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long fos;
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long mxcsr;
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long reserved;
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long st_space[32]; /* 8*16 bytes for each FP-reg = 128 bytes */
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long xmm_space[32]; /* 8*16 bytes for each XMM-reg = 128 bytes */
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long padding[56];
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};
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/*
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* FPU tag word conversions.
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*/
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static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
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{
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unsigned int tmp; /* to avoid 16 bit prefixes in the code */
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/* Transform each pair of bits into 01 (valid) or 00 (empty) */
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tmp = ~twd;
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tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
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/* and move the valid bits to the lower byte. */
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tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
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tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
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tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
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return tmp;
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}
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static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave )
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{
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struct _fpxreg *st = NULL;
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unsigned long twd = (unsigned long) fxsave->twd;
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unsigned long tag;
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unsigned long ret = 0xffff0000;
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int i;
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#define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16);
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for ( i = 0 ; i < 8 ; i++ ) {
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if ( twd & 0x1 ) {
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st = (struct _fpxreg *) FPREG_ADDR( fxsave, i );
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switch ( st->exponent & 0x7fff ) {
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case 0x7fff:
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tag = 2; /* Special */
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break;
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case 0x0000:
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if ( !st->significand[0] &&
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!st->significand[1] &&
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!st->significand[2] &&
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!st->significand[3] ) {
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tag = 1; /* Zero */
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} else {
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tag = 2; /* Special */
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}
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break;
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default:
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if ( st->significand[3] & 0x8000 ) {
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tag = 0; /* Valid */
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} else {
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tag = 2; /* Special */
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}
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break;
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}
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} else {
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tag = 3; /* Empty */
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}
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ret |= (tag << (2 * i));
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twd = twd >> 1;
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}
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return ret;
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}
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/*
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* FXSR floating point environment conversions.
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*/
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#ifdef CONFIG_MODE_TT
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static inline int convert_fxsr_to_user_tt(struct _fpstate __user *buf,
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struct pt_regs *regs)
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{
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struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
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unsigned long env[7];
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struct _fpreg __user *to;
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struct _fpxreg *from;
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int i;
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env[0] = (unsigned long)fxsave->cwd | 0xffff0000;
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env[1] = (unsigned long)fxsave->swd | 0xffff0000;
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env[2] = twd_fxsr_to_i387(fxsave);
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env[3] = fxsave->fip;
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env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
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env[5] = fxsave->foo;
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env[6] = fxsave->fos;
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if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) )
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return 1;
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to = &buf->_st[0];
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from = (struct _fpxreg *) &fxsave->st_space[0];
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for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
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if ( __copy_to_user( to, from, sizeof(*to) ) )
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return 1;
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}
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return 0;
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}
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#endif
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static inline int convert_fxsr_to_user(struct _fpstate __user *buf,
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struct pt_regs *regs)
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{
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return(CHOOSE_MODE(convert_fxsr_to_user_tt(buf, regs), 0));
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}
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#ifdef CONFIG_MODE_TT
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static inline int convert_fxsr_from_user_tt(struct pt_regs *regs,
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struct _fpstate __user *buf)
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{
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struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
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unsigned long env[7];
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struct _fpxreg *to;
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struct _fpreg __user *from;
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int i;
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if ( __copy_from_user( env, buf, 7 * sizeof(long) ) )
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return 1;
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fxsave->cwd = (unsigned short)(env[0] & 0xffff);
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fxsave->swd = (unsigned short)(env[1] & 0xffff);
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fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
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fxsave->fip = env[3];
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fxsave->fop = (unsigned short)((env[4] & 0xffff0000) >> 16);
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fxsave->fcs = (env[4] & 0xffff);
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fxsave->foo = env[5];
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fxsave->fos = env[6];
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to = (struct _fpxreg *) &fxsave->st_space[0];
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from = &buf->_st[0];
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for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
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if ( __copy_from_user( to, from, sizeof(*from) ) )
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return 1;
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}
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return 0;
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}
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#endif
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static inline int convert_fxsr_from_user(struct pt_regs *regs,
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struct _fpstate __user *buf)
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{
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return(CHOOSE_MODE(convert_fxsr_from_user_tt(regs, buf), 0));
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}
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int get_fpregs(unsigned long buf, struct task_struct *child)
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{
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int err;
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err = convert_fxsr_to_user((struct _fpstate __user *) buf,
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&child->thread.regs);
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if(err) return(-EFAULT);
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else return(0);
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}
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int set_fpregs(unsigned long buf, struct task_struct *child)
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{
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int err;
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err = convert_fxsr_from_user(&child->thread.regs,
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(struct _fpstate __user *) buf);
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if(err) return(-EFAULT);
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else return(0);
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}
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#ifdef CONFIG_MODE_TT
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int get_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
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{
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struct pt_regs *regs = &tsk->thread.regs;
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struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
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int err;
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err = __copy_to_user((void __user *) buf, fxsave,
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sizeof(struct user_fxsr_struct));
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if(err) return -EFAULT;
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else return 0;
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}
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#endif
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int get_fpxregs(unsigned long buf, struct task_struct *tsk)
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{
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return(CHOOSE_MODE(get_fpxregs_tt(buf, tsk), 0));
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}
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#ifdef CONFIG_MODE_TT
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int set_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
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{
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struct pt_regs *regs = &tsk->thread.regs;
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struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
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int err;
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err = __copy_from_user(fxsave, (void __user *) buf,
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sizeof(struct user_fxsr_struct) );
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if(err) return -EFAULT;
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else return 0;
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}
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#endif
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int set_fpxregs(unsigned long buf, struct task_struct *tsk)
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{
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return(CHOOSE_MODE(set_fpxregs_tt(buf, tsk), 0));
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}
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#ifdef notdef
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
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{
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fpu->cwd = (((SC_FP_CW(PT_REGS_SC(regs)) & 0xffff) << 16) |
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(SC_FP_SW(PT_REGS_SC(regs)) & 0xffff));
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fpu->swd = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
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fpu->twd = SC_FP_IPOFF(PT_REGS_SC(regs));
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fpu->fip = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
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fpu->fcs = SC_FP_DATAOFF(PT_REGS_SC(regs));
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fpu->foo = SC_FP_DATASEL(PT_REGS_SC(regs));
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fpu->fos = 0;
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memcpy(fpu->st_space, (void *) SC_FP_ST(PT_REGS_SC(regs)),
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sizeof(fpu->st_space));
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return(1);
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}
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#endif
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#ifdef CONFIG_MODE_TT
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static inline void copy_fpu_fxsave_tt(struct pt_regs *regs,
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struct user_i387_struct *buf)
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{
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struct i387_fxsave_struct *fpu = SC_FXSR_ENV(PT_REGS_SC(regs));
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unsigned short *to;
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unsigned short *from;
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int i;
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memcpy( buf, fpu, 7 * sizeof(long) );
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to = (unsigned short *) &buf->st_space[0];
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from = (unsigned short *) &fpu->st_space[0];
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for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) {
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memcpy( to, from, 5 * sizeof(unsigned short) );
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}
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}
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#endif
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static inline void copy_fpu_fxsave(struct pt_regs *regs,
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struct user_i387_struct *buf)
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{
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(void) CHOOSE_MODE(copy_fpu_fxsave_tt(regs, buf), 0);
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}
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu )
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{
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copy_fpu_fxsave(regs, (struct user_i387_struct *) fpu);
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return(1);
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}
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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