1 // SPDX-License-Identifier: GPL-2.0
3 * linux/arch/x86_64/ia32/ia32_signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
8 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
9 * 2000-12-* x86-64 compatibility mode signal handling by Andi Kleen
12 #include <linux/sched.h>
13 #include <linux/sched/task_stack.h>
15 #include <linux/smp.h>
16 #include <linux/kernel.h>
17 #include <linux/errno.h>
18 #include <linux/wait.h>
19 #include <linux/unistd.h>
20 #include <linux/stddef.h>
21 #include <linux/personality.h>
22 #include <linux/compat.h>
23 #include <linux/binfmts.h>
24 #include <linux/syscalls.h>
25 #include <asm/ucontext.h>
26 #include <linux/uaccess.h>
27 #include <asm/fpu/signal.h>
28 #include <asm/ptrace.h>
29 #include <asm/ia32_unistd.h>
30 #include <asm/user32.h>
31 #include <uapi/asm/sigcontext.h>
32 #include <asm/proto.h>
34 #include <asm/sigframe.h>
35 #include <asm/sighandling.h>
38 static inline void reload_segments(struct sigcontext_32 *sc)
43 if ((sc->gs | 0x03) != cur)
44 load_gs_index(sc->gs | 0x03);
46 if ((sc->fs | 0x03) != cur)
47 loadsegment(fs, sc->fs | 0x03);
49 if ((sc->ds | 0x03) != cur)
50 loadsegment(ds, sc->ds | 0x03);
52 if ((sc->es | 0x03) != cur)
53 loadsegment(es, sc->es | 0x03);
57 * Do a signal return; undo the signal stack.
59 static bool ia32_restore_sigcontext(struct pt_regs *regs,
60 struct sigcontext_32 __user *usc)
62 struct sigcontext_32 sc;
64 /* Always make any pending restarted system calls return -EINTR */
65 current->restart_block.fn = do_no_restart_syscall;
67 if (unlikely(copy_from_user(&sc, usc, sizeof(sc))))
70 /* Get only the ia32 registers. */
81 /* Get CS/SS and force CPL3 */
82 regs->cs = sc.cs | 0x03;
83 regs->ss = sc.ss | 0x03;
85 regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);
86 /* disable syscall checks */
90 * Reload fs and gs if they have changed in the signal
91 * handler. This does not handle long fs/gs base changes in
92 * the handler, but does not clobber them at least in the
96 return fpu__restore_sig(compat_ptr(sc.fpstate), 1);
99 COMPAT_SYSCALL_DEFINE0(sigreturn)
101 struct pt_regs *regs = current_pt_regs();
102 struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);
105 if (!access_ok(frame, sizeof(*frame)))
107 if (__get_user(set.sig[0], &frame->sc.oldmask)
108 || __get_user(((__u32 *)&set)[1], &frame->extramask[0]))
111 set_current_blocked(&set);
113 if (!ia32_restore_sigcontext(regs, &frame->sc))
118 signal_fault(regs, frame, "32bit sigreturn");
122 COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
124 struct pt_regs *regs = current_pt_regs();
125 struct rt_sigframe_ia32 __user *frame;
128 frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4);
130 if (!access_ok(frame, sizeof(*frame)))
132 if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
135 set_current_blocked(&set);
137 if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext))
140 if (compat_restore_altstack(&frame->uc.uc_stack))
146 signal_fault(regs, frame, "32bit rt sigreturn");
151 * Set up a signal frame.
154 #define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; })
156 static __always_inline int
157 __unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc,
158 void __user *fpstate,
159 struct pt_regs *regs, unsigned int mask)
161 unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault);
162 unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault);
163 unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault);
164 unsafe_put_user(get_user_seg(es), (unsigned int __user *)&sc->es, Efault);
166 unsafe_put_user(regs->di, &sc->di, Efault);
167 unsafe_put_user(regs->si, &sc->si, Efault);
168 unsafe_put_user(regs->bp, &sc->bp, Efault);
169 unsafe_put_user(regs->sp, &sc->sp, Efault);
170 unsafe_put_user(regs->bx, &sc->bx, Efault);
171 unsafe_put_user(regs->dx, &sc->dx, Efault);
172 unsafe_put_user(regs->cx, &sc->cx, Efault);
173 unsafe_put_user(regs->ax, &sc->ax, Efault);
174 unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault);
175 unsafe_put_user(current->thread.error_code, &sc->err, Efault);
176 unsafe_put_user(regs->ip, &sc->ip, Efault);
177 unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault);
178 unsafe_put_user(regs->flags, &sc->flags, Efault);
179 unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault);
180 unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault);
182 unsafe_put_user(ptr_to_compat(fpstate), &sc->fpstate, Efault);
184 /* non-iBCS2 extensions.. */
185 unsafe_put_user(mask, &sc->oldmask, Efault);
186 unsafe_put_user(current->thread.cr2, &sc->cr2, Efault);
193 #define unsafe_put_sigcontext32(sc, fp, regs, set, label) \
195 if (__unsafe_setup_sigcontext32(sc, fp, regs, set->sig[0])) \
200 * Determine which stack to use..
202 static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
204 void __user **fpstate)
206 unsigned long sp, fx_aligned, math_size;
208 /* Default to using normal stack */
211 /* This is the X/Open sanctioned signal stack switching. */
212 if (ksig->ka.sa.sa_flags & SA_ONSTACK)
213 sp = sigsp(sp, ksig);
214 /* This is the legacy signal stack switching. */
215 else if (regs->ss != __USER32_DS &&
216 !(ksig->ka.sa.sa_flags & SA_RESTORER) &&
217 ksig->ka.sa.sa_restorer)
218 sp = (unsigned long) ksig->ka.sa.sa_restorer;
220 sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
221 *fpstate = (struct _fpstate_32 __user *) sp;
222 if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
224 return (void __user *) -1L;
227 /* Align the stack pointer according to the i386 ABI,
228 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
229 sp = ((sp + 4) & -16ul) - 4;
230 return (void __user *) sp;
233 int ia32_setup_frame(int sig, struct ksignal *ksig,
234 compat_sigset_t *set, struct pt_regs *regs)
236 struct sigframe_ia32 __user *frame;
237 void __user *restorer;
238 void __user *fp = NULL;
240 /* copy_to_user optimizes that into a single 8 byte store */
241 static const struct {
245 } __attribute__((packed)) code = {
246 0xb858, /* popl %eax ; movl $...,%eax */
248 0x80cd, /* int $0x80 */
251 frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);
253 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
254 restorer = ksig->ka.sa.sa_restorer;
256 /* Return stub is in 32bit vsyscall page */
257 if (current->mm->context.vdso)
258 restorer = current->mm->context.vdso +
259 vdso_image_32.sym___kernel_sigreturn;
261 restorer = &frame->retcode;
264 if (!user_access_begin(frame, sizeof(*frame)))
267 unsafe_put_user(sig, &frame->sig, Efault);
268 unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault);
269 unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
270 unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
272 * These are actually not used anymore, but left because some
273 * gdb versions depend on them as a marker.
275 unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);
278 /* Set up registers for signal handler */
279 regs->sp = (unsigned long) frame;
280 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
282 /* Make -mregparm=3 work */
287 loadsegment(ds, __USER32_DS);
288 loadsegment(es, __USER32_DS);
290 regs->cs = __USER32_CS;
291 regs->ss = __USER32_DS;
299 int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
300 compat_sigset_t *set, struct pt_regs *regs)
302 struct rt_sigframe_ia32 __user *frame;
303 void __user *restorer;
304 void __user *fp = NULL;
306 /* unsafe_put_user optimizes that into a single 8 byte store */
307 static const struct {
312 } __attribute__((packed)) code = {
314 __NR_ia32_rt_sigreturn,
319 frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);
321 if (!user_access_begin(frame, sizeof(*frame)))
324 unsafe_put_user(sig, &frame->sig, Efault);
325 unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault);
326 unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault);
328 /* Create the ucontext. */
329 if (static_cpu_has(X86_FEATURE_XSAVE))
330 unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault);
332 unsafe_put_user(0, &frame->uc.uc_flags, Efault);
333 unsafe_put_user(0, &frame->uc.uc_link, Efault);
334 unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
336 if (ksig->ka.sa.sa_flags & SA_RESTORER)
337 restorer = ksig->ka.sa.sa_restorer;
339 restorer = current->mm->context.vdso +
340 vdso_image_32.sym___kernel_rt_sigreturn;
341 unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
344 * Not actually used anymore, but left because some gdb
347 unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);
348 unsafe_put_sigcontext32(&frame->uc.uc_mcontext, fp, regs, set, Efault);
349 unsafe_put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask, Efault);
352 if (__copy_siginfo_to_user32(&frame->info, &ksig->info))
355 /* Set up registers for signal handler */
356 regs->sp = (unsigned long) frame;
357 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
359 /* Make -mregparm=3 work */
361 regs->dx = (unsigned long) &frame->info;
362 regs->cx = (unsigned long) &frame->uc;
364 loadsegment(ds, __USER32_DS);
365 loadsegment(es, __USER32_DS);
367 regs->cs = __USER32_CS;
368 regs->ss = __USER32_DS;