bsd-user/arm/signal.c

   1 /*
   2  *  arm signal functions
   3  *
   4  *  Copyright (c) 2013 Stacey D. Son
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "qemu.h"
  22
  23 /*
  24  * Compare to arm/arm/machdep.c sendsig()
  25  * Assumes that target stack frame memory is locked.
  26  */
  27 abi_long set_sigtramp_args(CPUARMState *env, int sig,
  28                            struct target_sigframe *frame,
  29                            abi_ulong frame_addr,
  30                            struct target_sigaction *ka)
  31 {
  32     /*
  33      * Arguments to signal handler:
  34      *  r0 = signal number
  35      *  r1 = siginfo pointer
  36      *  r2 = ucontext pointer
  37      *  r5 = ucontext pointer
  38      *  pc = signal handler pointer
  39      *  sp = sigframe struct pointer
  40      *  lr = sigtramp at base of user stack
  41      */
  42
  43     env->regs[0] = sig;
  44     env->regs[1] = frame_addr +
  45         offsetof(struct target_sigframe, sf_si);
  46     env->regs[2] = frame_addr +
  47         offsetof(struct target_sigframe, sf_uc);
  48
  49     /* the trampoline uses r5 as the uc address */
  50     env->regs[5] = frame_addr +
  51         offsetof(struct target_sigframe, sf_uc);
  52     env->regs[TARGET_REG_PC] = ka->_sa_handler & ~1;
  53     env->regs[TARGET_REG_SP] = frame_addr;
  54     env->regs[TARGET_REG_LR] = TARGET_PS_STRINGS - TARGET_SZSIGCODE;
  55     /*
  56      * Low bit indicates whether or not we're entering thumb mode.
  57      */
  58     cpsr_write(env, (ka->_sa_handler & 1) * CPSR_T, CPSR_T, CPSRWriteByInstr);
  59
  60     return 0;
  61 }
  62
  63 static abi_long get_vfpcontext(CPUARMState *env, abi_ulong frame_addr,
  64                                struct target_sigframe *frame)
  65 {
  66     /* see sendsig and get_vfpcontext in sys/arm/arm/exec_machdep.c */
  67     target_mcontext_vfp_t *vfp = &frame->sf_vfp;
  68     target_mcontext_t *mcp = &frame->sf_uc.uc_mcontext;
  69
  70     /* Assumes that mcp and vfp are locked */
  71     for (int i = 0; i < 32; i++) {
  72         vfp->mcv_reg[i] = tswap64(*aa32_vfp_dreg(env, i));
  73     }
  74     vfp->mcv_fpscr = tswap32(vfp_get_fpscr(env));
  75     mcp->mc_vfp_size = tswap32(sizeof(*vfp));
  76     mcp->mc_vfp_ptr = tswap32(frame_addr + ((uintptr_t)vfp - (uintptr_t)frame));
  77     return 0;
  78 }
  79
  80 /*
  81  * Compare to arm/arm/exec_machdep.c get_mcontext()
  82  * Assumes that the memory is locked if mcp points to user memory.
  83  */
  84 abi_long get_mcontext(CPUARMState *env, target_mcontext_t *mcp, int flags)
  85 {
  86     uint32_t *gr = mcp->__gregs;
  87
  88     gr[TARGET_REG_CPSR] = tswap32(cpsr_read(env));
  89     if (flags & TARGET_MC_GET_CLEAR_RET) {
  90         gr[TARGET_REG_R0] = 0;
  91         gr[TARGET_REG_CPSR] &= ~CPSR_C;
  92     } else {
  93         gr[TARGET_REG_R0] = tswap32(env->regs[0]);
  94     }
  95
  96     gr[TARGET_REG_R1] = tswap32(env->regs[1]);
  97     gr[TARGET_REG_R2] = tswap32(env->regs[2]);
  98     gr[TARGET_REG_R3] = tswap32(env->regs[3]);
  99     gr[TARGET_REG_R4] = tswap32(env->regs[4]);
 100     gr[TARGET_REG_R5] = tswap32(env->regs[5]);
 101     gr[TARGET_REG_R6] = tswap32(env->regs[6]);
 102     gr[TARGET_REG_R7] = tswap32(env->regs[7]);
 103     gr[TARGET_REG_R8] = tswap32(env->regs[8]);
 104     gr[TARGET_REG_R9] = tswap32(env->regs[9]);
 105     gr[TARGET_REG_R10] = tswap32(env->regs[10]);
 106     gr[TARGET_REG_R11] = tswap32(env->regs[11]);
 107     gr[TARGET_REG_R12] = tswap32(env->regs[12]);
 108
 109     gr[TARGET_REG_SP] = tswap32(env->regs[13]);
 110     gr[TARGET_REG_LR] = tswap32(env->regs[14]);
 111     gr[TARGET_REG_PC] = tswap32(env->regs[15]);
 112
 113     /*
 114      * FreeBSD's get_mcontext doesn't save VFP info, but sets the pointer and
 115      * size to zero.  Applications that need the VFP state use
 116      * sysarch(ARM_GET_VFPSTATE) and are expected to adjust mcontext after that.
 117      */
 118     mcp->mc_vfp_size = 0;
 119     mcp->mc_vfp_ptr = 0;
 120     memset(&mcp->mc_spare, 0, sizeof(mcp->mc_spare));
 121
 122     return 0;
 123 }
 124
 125 /*
 126  * Compare to arm/arm/exec_machdep.c sendsig()
 127  * Assumes that the memory is locked if frame points to user memory.
 128  */
 129 abi_long setup_sigframe_arch(CPUARMState *env, abi_ulong frame_addr,
 130                              struct target_sigframe *frame, int flags)
 131 {
 132     target_mcontext_t *mcp = &frame->sf_uc.uc_mcontext;
 133
 134     get_mcontext(env, mcp, flags);
 135     get_vfpcontext(env, frame_addr, frame);
 136     return 0;
 137 }
 138
 139 /* Compare to arm/arm/exec_machdep.c set_mcontext() */
 140 abi_long set_mcontext(CPUARMState *env, target_mcontext_t *mcp, int srflag)
 141 {
 142     int err = 0;
 143     const uint32_t *gr = mcp->__gregs;
 144     uint32_t cpsr, ccpsr = cpsr_read(env);
 145     uint32_t fpscr, mask;
 146
 147     cpsr = tswap32(gr[TARGET_REG_CPSR]);
 148     /*
 149      * Only allow certain bits to change, reject attempted changes to non-user
 150      * bits. In addition, make sure we're headed for user mode and none of the
 151      * interrupt bits are set.
 152      */
 153     if ((ccpsr & ~CPSR_USER) != (cpsr & ~CPSR_USER)) {
 154         return -TARGET_EINVAL;
 155     }
 156     if ((cpsr & CPSR_M) != ARM_CPU_MODE_USR ||
 157         (cpsr & (CPSR_I | CPSR_F)) != 0) {
 158         return -TARGET_EINVAL;
 159     }
 160
 161     /*
 162      * The movs pc,lr instruction that implements the return to userland masks
 163      * these bits out.
 164      */
 165     mask = cpsr & CPSR_T ? 0x1 : 0x3;
 166
 167     /*
 168      * Make sure that we either have no vfp, or it's the correct size.
 169      * FreeBSD just ignores it, though, so maybe we'll need to adjust
 170      * things below instead.
 171      */
 172     if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_size != sizeof(target_mcontext_vfp_t)) {
 173         return -TARGET_EINVAL;
 174     }
 175
 176     env->regs[0] = tswap32(gr[TARGET_REG_R0]);
 177     env->regs[1] = tswap32(gr[TARGET_REG_R1]);
 178     env->regs[2] = tswap32(gr[TARGET_REG_R2]);
 179     env->regs[3] = tswap32(gr[TARGET_REG_R3]);
 180     env->regs[4] = tswap32(gr[TARGET_REG_R4]);
 181     env->regs[5] = tswap32(gr[TARGET_REG_R5]);
 182     env->regs[6] = tswap32(gr[TARGET_REG_R6]);
 183     env->regs[7] = tswap32(gr[TARGET_REG_R7]);
 184     env->regs[8] = tswap32(gr[TARGET_REG_R8]);
 185     env->regs[9] = tswap32(gr[TARGET_REG_R9]);
 186     env->regs[10] = tswap32(gr[TARGET_REG_R10]);
 187     env->regs[11] = tswap32(gr[TARGET_REG_R11]);
 188     env->regs[12] = tswap32(gr[TARGET_REG_R12]);
 189
 190     env->regs[13] = tswap32(gr[TARGET_REG_SP]);
 191     env->regs[14] = tswap32(gr[TARGET_REG_LR]);
 192     env->regs[15] = tswap32(gr[TARGET_REG_PC] & ~mask);
 193     if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_ptr != 0) {
 194         /* see set_vfpcontext in sys/arm/arm/exec_machdep.c */
 195         target_mcontext_vfp_t *vfp;
 196
 197         vfp = lock_user(VERIFY_READ, mcp->mc_vfp_ptr, sizeof(*vfp), 1);
 198         for (int i = 0; i < 32; i++) {
 199             __get_user(*aa32_vfp_dreg(env, i), &vfp->mcv_reg[i]);
 200         }
 201         __get_user(fpscr, &vfp->mcv_fpscr);
 202         vfp_set_fpscr(env, fpscr);
 203         unlock_user(vfp, mcp->mc_vfp_ptr, sizeof(target_ucontext_t));
 204
 205         /*
 206          * linux-user sets fpexc, fpinst and fpinst2, but these aren't in
 207          * FreeBSD's mcontext, what to do?
 208          */
 209     }
 210     cpsr_write(env, cpsr, CPSR_USER | CPSR_EXEC, CPSRWriteByInstr);
 211
 212     return err;
 213 }
 214
 215 /* Compare to arm/arm/machdep.c sys_sigreturn() */
 216 abi_long get_ucontext_sigreturn(CPUARMState *env, abi_ulong target_sf,
 217                                 abi_ulong *target_uc)
 218 {
 219     *target_uc = target_sf;
 220
 221     return 0;
 222 }