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-rw-r--r--arch/x86/um/signal.c583
1 files changed, 583 insertions, 0 deletions
diff --git a/arch/x86/um/signal.c b/arch/x86/um/signal.c
new file mode 100644
index 000000000..263e1d08f
--- /dev/null
+++ b/arch/x86/um/signal.c
@@ -0,0 +1,583 @@
+/*
+ * Copyright (C) 2003 PathScale, Inc.
+ * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+
+#include <linux/personality.h>
+#include <linux/ptrace.h>
+#include <linux/kernel.h>
+#include <asm/unistd.h>
+#include <linux/uaccess.h>
+#include <asm/ucontext.h>
+#include <frame_kern.h>
+#include <registers.h>
+#include <skas.h>
+
+#ifdef CONFIG_X86_32
+
+/*
+ * FPU tag word conversions.
+ */
+
+static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
+{
+ unsigned int tmp; /* to avoid 16 bit prefixes in the code */
+
+ /* Transform each pair of bits into 01 (valid) or 00 (empty) */
+ tmp = ~twd;
+ tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
+ /* and move the valid bits to the lower byte. */
+ tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
+ tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
+ tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
+ return tmp;
+}
+
+static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
+{
+ struct _fpxreg *st = NULL;
+ unsigned long twd = (unsigned long) fxsave->twd;
+ unsigned long tag;
+ unsigned long ret = 0xffff0000;
+ int i;
+
+#define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16)
+
+ for (i = 0; i < 8; i++) {
+ if (twd & 0x1) {
+ st = (struct _fpxreg *) FPREG_ADDR(fxsave, i);
+
+ switch (st->exponent & 0x7fff) {
+ case 0x7fff:
+ tag = 2; /* Special */
+ break;
+ case 0x0000:
+ if ( !st->significand[0] &&
+ !st->significand[1] &&
+ !st->significand[2] &&
+ !st->significand[3] ) {
+ tag = 1; /* Zero */
+ } else {
+ tag = 2; /* Special */
+ }
+ break;
+ default:
+ if (st->significand[3] & 0x8000) {
+ tag = 0; /* Valid */
+ } else {
+ tag = 2; /* Special */
+ }
+ break;
+ }
+ } else {
+ tag = 3; /* Empty */
+ }
+ ret |= (tag << (2 * i));
+ twd = twd >> 1;
+ }
+ return ret;
+}
+
+static int convert_fxsr_to_user(struct _fpstate __user *buf,
+ struct user_fxsr_struct *fxsave)
+{
+ unsigned long env[7];
+ struct _fpreg __user *to;
+ struct _fpxreg *from;
+ int i;
+
+ env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
+ env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
+ env[2] = twd_fxsr_to_i387(fxsave);
+ env[3] = fxsave->fip;
+ env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
+ env[5] = fxsave->foo;
+ env[6] = fxsave->fos;
+
+ if (__copy_to_user(buf, env, 7 * sizeof(unsigned long)))
+ return 1;
+
+ to = &buf->_st[0];
+ from = (struct _fpxreg *) &fxsave->st_space[0];
+ for (i = 0; i < 8; i++, to++, from++) {
+ unsigned long __user *t = (unsigned long __user *)to;
+ unsigned long *f = (unsigned long *)from;
+
+ if (__put_user(*f, t) ||
+ __put_user(*(f + 1), t + 1) ||
+ __put_user(from->exponent, &to->exponent))
+ return 1;
+ }
+ return 0;
+}
+
+static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave,
+ struct _fpstate __user *buf)
+{
+ unsigned long env[7];
+ struct _fpxreg *to;
+ struct _fpreg __user *from;
+ int i;
+
+ if (copy_from_user( env, buf, 7 * sizeof(long)))
+ return 1;
+
+ fxsave->cwd = (unsigned short)(env[0] & 0xffff);
+ fxsave->swd = (unsigned short)(env[1] & 0xffff);
+ fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
+ fxsave->fip = env[3];
+ fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
+ fxsave->fcs = (env[4] & 0xffff);
+ fxsave->foo = env[5];
+ fxsave->fos = env[6];
+
+ to = (struct _fpxreg *) &fxsave->st_space[0];
+ from = &buf->_st[0];
+ for (i = 0; i < 8; i++, to++, from++) {
+ unsigned long *t = (unsigned long *)to;
+ unsigned long __user *f = (unsigned long __user *)from;
+
+ if (__get_user(*t, f) ||
+ __get_user(*(t + 1), f + 1) ||
+ __get_user(to->exponent, &from->exponent))
+ return 1;
+ }
+ return 0;
+}
+
+extern int have_fpx_regs;
+
+#endif
+
+static int copy_sc_from_user(struct pt_regs *regs,
+ struct sigcontext __user *from)
+{
+ struct sigcontext sc;
+ int err, pid;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current->restart_block.fn = do_no_restart_syscall;
+
+ err = copy_from_user(&sc, from, sizeof(sc));
+ if (err)
+ return err;
+
+#define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
+
+#ifdef CONFIG_X86_32
+ GETREG(GS, gs);
+ GETREG(FS, fs);
+ GETREG(ES, es);
+ GETREG(DS, ds);
+#endif
+ GETREG(DI, di);
+ GETREG(SI, si);
+ GETREG(BP, bp);
+ GETREG(SP, sp);
+ GETREG(BX, bx);
+ GETREG(DX, dx);
+ GETREG(CX, cx);
+ GETREG(AX, ax);
+ GETREG(IP, ip);
+
+#ifdef CONFIG_X86_64
+ GETREG(R8, r8);
+ GETREG(R9, r9);
+ GETREG(R10, r10);
+ GETREG(R11, r11);
+ GETREG(R12, r12);
+ GETREG(R13, r13);
+ GETREG(R14, r14);
+ GETREG(R15, r15);
+#endif
+
+ GETREG(CS, cs);
+ GETREG(EFLAGS, flags);
+#ifdef CONFIG_X86_32
+ GETREG(SS, ss);
+#endif
+
+#undef GETREG
+
+ pid = userspace_pid[current_thread_info()->cpu];
+#ifdef CONFIG_X86_32
+ if (have_fpx_regs) {
+ struct user_fxsr_struct fpx;
+
+ err = copy_from_user(&fpx,
+ &((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0],
+ sizeof(struct user_fxsr_struct));
+ if (err)
+ return 1;
+
+ err = convert_fxsr_from_user(&fpx, (void *)sc.fpstate);
+ if (err)
+ return 1;
+
+ err = restore_fpx_registers(pid, (unsigned long *) &fpx);
+ if (err < 0) {
+ printk(KERN_ERR "copy_sc_from_user - "
+ "restore_fpx_registers failed, errno = %d\n",
+ -err);
+ return 1;
+ }
+ } else
+#endif
+ {
+ err = copy_from_user(regs->regs.fp, (void *)sc.fpstate,
+ sizeof(struct _xstate));
+ if (err)
+ return 1;
+ }
+ return 0;
+}
+
+static int copy_sc_to_user(struct sigcontext __user *to,
+ struct _xstate __user *to_fp, struct pt_regs *regs,
+ unsigned long mask)
+{
+ struct sigcontext sc;
+ struct faultinfo * fi = &current->thread.arch.faultinfo;
+ int err, pid;
+ memset(&sc, 0, sizeof(struct sigcontext));
+
+#define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
+
+#ifdef CONFIG_X86_32
+ PUTREG(GS, gs);
+ PUTREG(FS, fs);
+ PUTREG(ES, es);
+ PUTREG(DS, ds);
+#endif
+ PUTREG(DI, di);
+ PUTREG(SI, si);
+ PUTREG(BP, bp);
+ PUTREG(SP, sp);
+ PUTREG(BX, bx);
+ PUTREG(DX, dx);
+ PUTREG(CX, cx);
+ PUTREG(AX, ax);
+#ifdef CONFIG_X86_64
+ PUTREG(R8, r8);
+ PUTREG(R9, r9);
+ PUTREG(R10, r10);
+ PUTREG(R11, r11);
+ PUTREG(R12, r12);
+ PUTREG(R13, r13);
+ PUTREG(R14, r14);
+ PUTREG(R15, r15);
+#endif
+
+ sc.cr2 = fi->cr2;
+ sc.err = fi->error_code;
+ sc.trapno = fi->trap_no;
+ PUTREG(IP, ip);
+ PUTREG(CS, cs);
+ PUTREG(EFLAGS, flags);
+#ifdef CONFIG_X86_32
+ PUTREG(SP, sp_at_signal);
+ PUTREG(SS, ss);
+#endif
+#undef PUTREG
+ sc.oldmask = mask;
+ sc.fpstate = (unsigned long)to_fp;
+
+ err = copy_to_user(to, &sc, sizeof(struct sigcontext));
+ if (err)
+ return 1;
+
+ pid = userspace_pid[current_thread_info()->cpu];
+
+#ifdef CONFIG_X86_32
+ if (have_fpx_regs) {
+ struct user_fxsr_struct fpx;
+
+ err = save_fpx_registers(pid, (unsigned long *) &fpx);
+ if (err < 0){
+ printk(KERN_ERR "copy_sc_to_user - save_fpx_registers "
+ "failed, errno = %d\n", err);
+ return 1;
+ }
+
+ err = convert_fxsr_to_user(&to_fp->fpstate, &fpx);
+ if (err)
+ return 1;
+
+ err |= __put_user(fpx.swd, &to_fp->fpstate.status);
+ err |= __put_user(X86_FXSR_MAGIC, &to_fp->fpstate.magic);
+ if (err)
+ return 1;
+
+ if (copy_to_user(&to_fp->fpstate._fxsr_env[0], &fpx,
+ sizeof(struct user_fxsr_struct)))
+ return 1;
+ } else
+#endif
+ {
+ if (copy_to_user(to_fp, regs->regs.fp, sizeof(struct _xstate)))
+ return 1;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_X86_32
+static int copy_ucontext_to_user(struct ucontext __user *uc,
+ struct _xstate __user *fp, sigset_t *set,
+ unsigned long sp)
+{
+ int err = 0;
+
+ err |= __save_altstack(&uc->uc_stack, sp);
+ err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, 0);
+ err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
+ return err;
+}
+
+struct sigframe
+{
+ char __user *pretcode;
+ int sig;
+ struct sigcontext sc;
+ struct _xstate fpstate;
+ unsigned long extramask[_NSIG_WORDS-1];
+ char retcode[8];
+};
+
+struct rt_sigframe
+{
+ char __user *pretcode;
+ int sig;
+ struct siginfo __user *pinfo;
+ void __user *puc;
+ struct siginfo info;
+ struct ucontext uc;
+ struct _xstate fpstate;
+ char retcode[8];
+};
+
+int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
+ struct pt_regs *regs, sigset_t *mask)
+{
+ struct sigframe __user *frame;
+ void __user *restorer;
+ int err = 0, sig = ksig->sig;
+
+ /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
+ stack_top = ((stack_top + 4) & -16UL) - 4;
+ frame = (struct sigframe __user *) stack_top - 1;
+ if (!access_ok(frame, sizeof(*frame)))
+ return 1;
+
+ restorer = frame->retcode;
+ if (ksig->ka.sa.sa_flags & SA_RESTORER)
+ restorer = ksig->ka.sa.sa_restorer;
+
+ err |= __put_user(restorer, &frame->pretcode);
+ err |= __put_user(sig, &frame->sig);
+ err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]);
+ if (_NSIG_WORDS > 1)
+ err |= __copy_to_user(&frame->extramask, &mask->sig[1],
+ sizeof(frame->extramask));
+
+ /*
+ * This is popl %eax ; movl $,%eax ; int $0x80
+ *
+ * WE DO NOT USE IT ANY MORE! It's only left here for historical
+ * reasons and because gdb uses it as a signature to notice
+ * signal handler stack frames.
+ */
+ err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
+ err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
+ err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
+
+ if (err)
+ return err;
+
+ PT_REGS_SP(regs) = (unsigned long) frame;
+ PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
+ PT_REGS_AX(regs) = (unsigned long) sig;
+ PT_REGS_DX(regs) = (unsigned long) 0;
+ PT_REGS_CX(regs) = (unsigned long) 0;
+ return 0;
+}
+
+int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
+ struct pt_regs *regs, sigset_t *mask)
+{
+ struct rt_sigframe __user *frame;
+ void __user *restorer;
+ int err = 0, sig = ksig->sig;
+
+ stack_top &= -8UL;
+ frame = (struct rt_sigframe __user *) stack_top - 1;
+ if (!access_ok(frame, sizeof(*frame)))
+ return 1;
+
+ restorer = frame->retcode;
+ if (ksig->ka.sa.sa_flags & SA_RESTORER)
+ restorer = ksig->ka.sa.sa_restorer;
+
+ err |= __put_user(restorer, &frame->pretcode);
+ err |= __put_user(sig, &frame->sig);
+ err |= __put_user(&frame->info, &frame->pinfo);
+ err |= __put_user(&frame->uc, &frame->puc);
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+ err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
+ PT_REGS_SP(regs));
+
+ /*
+ * This is movl $,%eax ; int $0x80
+ *
+ * WE DO NOT USE IT ANY MORE! It's only left here for historical
+ * reasons and because gdb uses it as a signature to notice
+ * signal handler stack frames.
+ */
+ err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
+ err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
+ err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
+
+ if (err)
+ return err;
+
+ PT_REGS_SP(regs) = (unsigned long) frame;
+ PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
+ PT_REGS_AX(regs) = (unsigned long) sig;
+ PT_REGS_DX(regs) = (unsigned long) &frame->info;
+ PT_REGS_CX(regs) = (unsigned long) &frame->uc;
+ return 0;
+}
+
+long sys_sigreturn(void)
+{
+ unsigned long sp = PT_REGS_SP(&current->thread.regs);
+ struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
+ sigset_t set;
+ struct sigcontext __user *sc = &frame->sc;
+ int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
+
+ if (copy_from_user(&set.sig[0], &sc->oldmask, sizeof(set.sig[0])) ||
+ copy_from_user(&set.sig[1], frame->extramask, sig_size))
+ goto segfault;
+
+ set_current_blocked(&set);
+
+ if (copy_sc_from_user(&current->thread.regs, sc))
+ goto segfault;
+
+ /* Avoid ERESTART handling */
+ PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
+ return PT_REGS_SYSCALL_RET(&current->thread.regs);
+
+ segfault:
+ force_sig(SIGSEGV);
+ return 0;
+}
+
+#else
+
+struct rt_sigframe
+{
+ char __user *pretcode;
+ struct ucontext uc;
+ struct siginfo info;
+ struct _xstate fpstate;
+};
+
+int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
+ struct pt_regs *regs, sigset_t *set)
+{
+ struct rt_sigframe __user *frame;
+ int err = 0, sig = ksig->sig;
+ unsigned long fp_to;
+
+ frame = (struct rt_sigframe __user *)
+ round_down(stack_top - sizeof(struct rt_sigframe), 16);
+ /* Subtract 128 for a red zone and 8 for proper alignment */
+ frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
+
+ if (!access_ok(frame, sizeof(*frame)))
+ goto out;
+
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+ if (err)
+ goto out;
+ }
+
+ /* Create the ucontext. */
+ err |= __put_user(0, &frame->uc.uc_flags);
+ err |= __put_user(0, &frame->uc.uc_link);
+ err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
+ err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
+ set->sig[0]);
+
+ fp_to = (unsigned long)&frame->fpstate;
+
+ err |= __put_user(fp_to, &frame->uc.uc_mcontext.fpstate);
+ if (sizeof(*set) == 16) {
+ err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
+ err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
+ }
+ else
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set,
+ sizeof(*set));
+
+ /*
+ * Set up to return from userspace. If provided, use a stub
+ * already in userspace.
+ */
+ /* x86-64 should always use SA_RESTORER. */
+ if (ksig->ka.sa.sa_flags & SA_RESTORER)
+ err |= __put_user((void *)ksig->ka.sa.sa_restorer,
+ &frame->pretcode);
+ else
+ /* could use a vstub here */
+ return err;
+
+ if (err)
+ return err;
+
+ PT_REGS_SP(regs) = (unsigned long) frame;
+ PT_REGS_DI(regs) = sig;
+ /* In case the signal handler was declared without prototypes */
+ PT_REGS_AX(regs) = 0;
+
+ /*
+ * This also works for non SA_SIGINFO handlers because they expect the
+ * next argument after the signal number on the stack.
+ */
+ PT_REGS_SI(regs) = (unsigned long) &frame->info;
+ PT_REGS_DX(regs) = (unsigned long) &frame->uc;
+ PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
+ out:
+ return err;
+}
+#endif
+
+long sys_rt_sigreturn(void)
+{
+ unsigned long sp = PT_REGS_SP(&current->thread.regs);
+ struct rt_sigframe __user *frame =
+ (struct rt_sigframe __user *)(sp - sizeof(long));
+ struct ucontext __user *uc = &frame->uc;
+ sigset_t set;
+
+ if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
+ goto segfault;
+
+ set_current_blocked(&set);
+
+ if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
+ goto segfault;
+
+ /* Avoid ERESTART handling */
+ PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
+ return PT_REGS_SYSCALL_RET(&current->thread.regs);
+
+ segfault:
+ force_sig(SIGSEGV);
+ return 0;
+}
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