mips/kernel/signal_o32.c

0001 /*
0002  * This file is subject to the terms and conditions of the GNU General Public
0003  * License.  See the file "COPYING" in the main directory of this archive
0004  * for more details.
0005  *
0006  * Copyright (C) 1991, 1992  Linus Torvalds
0007  * Copyright (C) 1994 - 2000, 2006  Ralf Baechle
0008  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
0009  * Copyright (C) 2016, Imagination Technologies Ltd.
0010  */
0011 #include <linux/compiler.h>
0012 #include <linux/errno.h>
0013 #include <linux/signal.h>
0014 #include <linux/sched/signal.h>
0015 #include <linux/uaccess.h>
0016
0017 #include <asm/abi.h>
0018 #include <asm/compat-signal.h>
0019 #include <asm/dsp.h>
0020 #include <asm/sim.h>
0021 #include <asm/unistd.h>
0022
0023 #include "signal-common.h"
0024
0025 /*
0026  * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
0027  */
0028 #define __NR_O32_restart_syscall    4253
0029
0030 struct sigframe32 {
0031     u32 sf_ass[4];      /* argument save space for o32 */
0032     u32 sf_pad[2];      /* Was: signal trampoline */
0033     struct sigcontext32 sf_sc;
0034     compat_sigset_t sf_mask;
0035 };
0036
0037 struct ucontext32 {
0038     u32         uc_flags;
0039     s32         uc_link;
0040     compat_stack_t      uc_stack;
0041     struct sigcontext32 uc_mcontext;
0042     compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
0043 };
0044
0045 struct rt_sigframe32 {
0046     u32 rs_ass[4];          /* argument save space for o32 */
0047     u32 rs_pad[2];          /* Was: signal trampoline */
0048     compat_siginfo_t rs_info;
0049     struct ucontext32 rs_uc;
0050 };
0051
0052 static int setup_sigcontext32(struct pt_regs *regs,
0053                   struct sigcontext32 __user *sc)
0054 {
0055     int err = 0;
0056     int i;
0057
0058     err |= __put_user(regs->cp0_epc, &sc->sc_pc);
0059
0060     err |= __put_user(0, &sc->sc_regs[0]);
0061     for (i = 1; i < 32; i++)
0062         err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
0063
0064     err |= __put_user(regs->hi, &sc->sc_mdhi);
0065     err |= __put_user(regs->lo, &sc->sc_mdlo);
0066     if (cpu_has_dsp) {
0067         err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
0068         err |= __put_user(mfhi1(), &sc->sc_hi1);
0069         err |= __put_user(mflo1(), &sc->sc_lo1);
0070         err |= __put_user(mfhi2(), &sc->sc_hi2);
0071         err |= __put_user(mflo2(), &sc->sc_lo2);
0072         err |= __put_user(mfhi3(), &sc->sc_hi3);
0073         err |= __put_user(mflo3(), &sc->sc_lo3);
0074     }
0075
0076     /*
0077      * Save FPU state to signal context.  Signal handler
0078      * will "inherit" current FPU state.
0079      */
0080     err |= protected_save_fp_context(sc);
0081
0082     return err;
0083 }
0084
0085 static int restore_sigcontext32(struct pt_regs *regs,
0086                 struct sigcontext32 __user *sc)
0087 {
0088     int err = 0;
0089     s32 treg;
0090     int i;
0091
0092     /* Always make any pending restarted system calls return -EINTR */
0093     current->restart_block.fn = do_no_restart_syscall;
0094
0095     err |= __get_user(regs->cp0_epc, &sc->sc_pc);
0096     err |= __get_user(regs->hi, &sc->sc_mdhi);
0097     err |= __get_user(regs->lo, &sc->sc_mdlo);
0098     if (cpu_has_dsp) {
0099         err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
0100         err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
0101         err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
0102         err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
0103         err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
0104         err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
0105         err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
0106     }
0107
0108     for (i = 1; i < 32; i++)
0109         err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
0110
0111     return err ?: protected_restore_fp_context(sc);
0112 }
0113
0114 static int setup_frame_32(void *sig_return, struct ksignal *ksig,
0115               struct pt_regs *regs, sigset_t *set)
0116 {
0117     struct sigframe32 __user *frame;
0118     int err = 0;
0119
0120     frame = get_sigframe(ksig, regs, sizeof(*frame));
0121     if (!access_ok(frame, sizeof (*frame)))
0122         return -EFAULT;
0123
0124     err |= setup_sigcontext32(regs, &frame->sf_sc);
0125     err |= __copy_conv_sigset_to_user(&frame->sf_mask, set);
0126
0127     if (err)
0128         return -EFAULT;
0129
0130     /*
0131      * Arguments to signal handler:
0132      *
0133      *   a0 = signal number
0134      *   a1 = 0 (should be cause)
0135      *   a2 = pointer to struct sigcontext
0136      *
0137      * $25 and c0_epc point to the signal handler, $29 points to the
0138      * struct sigframe.
0139      */
0140     regs->regs[ 4] = ksig->sig;
0141     regs->regs[ 5] = 0;
0142     regs->regs[ 6] = (unsigned long) &frame->sf_sc;
0143     regs->regs[29] = (unsigned long) frame;
0144     regs->regs[31] = (unsigned long) sig_return;
0145     regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
0146
0147     DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
0148            current->comm, current->pid,
0149            frame, regs->cp0_epc, regs->regs[31]);
0150
0151     return 0;
0152 }
0153
0154 asmlinkage void sys32_rt_sigreturn(void)
0155 {
0156     struct rt_sigframe32 __user *frame;
0157     struct pt_regs *regs;
0158     sigset_t set;
0159     int sig;
0160
0161     regs = current_pt_regs();
0162     frame = (struct rt_sigframe32 __user *)regs->regs[29];
0163     if (!access_ok(frame, sizeof(*frame)))
0164         goto badframe;
0165     if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
0166         goto badframe;
0167
0168     set_current_blocked(&set);
0169
0170     sig = restore_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
0171     if (sig < 0)
0172         goto badframe;
0173     else if (sig)
0174         force_sig(sig);
0175
0176     if (compat_restore_altstack(&frame->rs_uc.uc_stack))
0177         goto badframe;
0178
0179     /*
0180      * Don't let your children do this ...
0181      */
0182     __asm__ __volatile__(
0183         "move\t$29, %0\n\t"
0184         "j\tsyscall_exit"
0185         : /* no outputs */
0186         : "r" (regs));
0187     /* Unreached */
0188
0189 badframe:
0190     force_sig(SIGSEGV);
0191 }
0192
0193 static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
0194                  struct pt_regs *regs, sigset_t *set)
0195 {
0196     struct rt_sigframe32 __user *frame;
0197     int err = 0;
0198
0199     frame = get_sigframe(ksig, regs, sizeof(*frame));
0200     if (!access_ok(frame, sizeof (*frame)))
0201         return -EFAULT;
0202
0203     /* Convert (siginfo_t -> compat_siginfo_t) and copy to user. */
0204     err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
0205
0206     /* Create the ucontext.  */
0207     err |= __put_user(0, &frame->rs_uc.uc_flags);
0208     err |= __put_user(0, &frame->rs_uc.uc_link);
0209     err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
0210     err |= setup_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
0211     err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
0212
0213     if (err)
0214         return -EFAULT;
0215
0216     /*
0217      * Arguments to signal handler:
0218      *
0219      *   a0 = signal number
0220      *   a1 = 0 (should be cause)
0221      *   a2 = pointer to ucontext
0222      *
0223      * $25 and c0_epc point to the signal handler, $29 points to
0224      * the struct rt_sigframe32.
0225      */
0226     regs->regs[ 4] = ksig->sig;
0227     regs->regs[ 5] = (unsigned long) &frame->rs_info;
0228     regs->regs[ 6] = (unsigned long) &frame->rs_uc;
0229     regs->regs[29] = (unsigned long) frame;
0230     regs->regs[31] = (unsigned long) sig_return;
0231     regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
0232
0233     DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
0234            current->comm, current->pid,
0235            frame, regs->cp0_epc, regs->regs[31]);
0236
0237     return 0;
0238 }
0239
0240 /*
0241  * o32 compatibility on 64-bit kernels, without DSP ASE
0242  */
0243 struct mips_abi mips_abi_32 = {
0244     .setup_frame    = setup_frame_32,
0245     .setup_rt_frame = setup_rt_frame_32,
0246     .restart    = __NR_O32_restart_syscall,
0247
0248     .off_sc_fpregs = offsetof(struct sigcontext32, sc_fpregs),
0249     .off_sc_fpc_csr = offsetof(struct sigcontext32, sc_fpc_csr),
0250     .off_sc_used_math = offsetof(struct sigcontext32, sc_used_math),
0251
0252     .vdso       = &vdso_image_o32,
0253 };
0254
0255
0256 asmlinkage void sys32_sigreturn(void)
0257 {
0258     struct sigframe32 __user *frame;
0259     struct pt_regs *regs;
0260     sigset_t blocked;
0261     int sig;
0262
0263     regs = current_pt_regs();
0264     frame = (struct sigframe32 __user *)regs->regs[29];
0265     if (!access_ok(frame, sizeof(*frame)))
0266         goto badframe;
0267     if (__copy_conv_sigset_from_user(&blocked, &frame->sf_mask))
0268         goto badframe;
0269
0270     set_current_blocked(&blocked);
0271
0272     sig = restore_sigcontext32(regs, &frame->sf_sc);
0273     if (sig < 0)
0274         goto badframe;
0275     else if (sig)
0276         force_sig(sig);
0277
0278     /*
0279      * Don't let your children do this ...
0280      */
0281     __asm__ __volatile__(
0282         "move\t$29, %0\n\t"
0283         "j\tsyscall_exit"
0284         : /* no outputs */
0285         : "r" (regs));
0286     /* Unreached */
0287
0288 badframe:
0289     force_sig(SIGSEGV);
0290 }