1 files changed, 411 insertions, 0 deletions

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
new file mode 100644
index 000000000..513ba49c2
--- /dev/null
+++ b/arch/x86/ia32/ia32_signal.c
@@ -0,0 +1,411 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/arch/x86_64/ia32/ia32_signal.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
+ *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
+ *  2000-12-*   x86-64 compatibility mode signal handling by Andi Kleen
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/personality.h>
+#include <linux/compat.h>
+#include <linux/binfmts.h>
+#include <asm/ucontext.h>
+#include <linux/uaccess.h>
+#include <asm/fpu/internal.h>
+#include <asm/fpu/signal.h>
+#include <asm/ptrace.h>
+#include <asm/ia32_unistd.h>
+#include <asm/user32.h>
+#include <uapi/asm/sigcontext.h>
+#include <asm/proto.h>
+#include <asm/vdso.h>
+#include <asm/sigframe.h>
+#include <asm/sighandling.h>
+#include <asm/smap.h>
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+#define loadsegment_gs(v)	load_gs_index(v)
+#define loadsegment_fs(v)	loadsegment(fs, v)
+#define loadsegment_ds(v)	loadsegment(ds, v)
+#define loadsegment_es(v)	loadsegment(es, v)
+
+#define get_user_seg(seg)	({ unsigned int v; savesegment(seg, v); v; })
+#define set_user_seg(seg, v)	loadsegment_##seg(v)
+
+#define COPY(x)			{		\
+	get_user_ex(regs->x, &sc->x);		\
+}
+
+#define GET_SEG(seg)		({			\
+	unsigned short tmp;				\
+	get_user_ex(tmp, &sc->seg);			\
+	tmp;						\
+})
+
+#define COPY_SEG_CPL3(seg)	do {			\
+	regs->seg = GET_SEG(seg) | 3;			\
+} while (0)
+
+#define RELOAD_SEG(seg)		{		\
+	unsigned int pre = (seg) | 3;		\
+	unsigned int cur = get_user_seg(seg);	\
+	if (pre != cur)				\
+		set_user_seg(seg, pre);		\
+}
+
+static int ia32_restore_sigcontext(struct pt_regs *regs,
+				   struct sigcontext_32 __user *sc)
+{
+	unsigned int tmpflags, err = 0;
+	u16 gs, fs, es, ds;
+	void __user *buf;
+	u32 tmp;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	get_user_try {
+		gs = GET_SEG(gs);
+		fs = GET_SEG(fs);
+		ds = GET_SEG(ds);
+		es = GET_SEG(es);
+
+		COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
+		COPY(dx); COPY(cx); COPY(ip); COPY(ax);
+		/* Don't touch extended registers */
+
+		COPY_SEG_CPL3(cs);
+		COPY_SEG_CPL3(ss);
+
+		get_user_ex(tmpflags, &sc->flags);
+		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
+		/* disable syscall checks */
+		regs->orig_ax = -1;
+
+		get_user_ex(tmp, &sc->fpstate);
+		buf = compat_ptr(tmp);
+	} get_user_catch(err);
+
+	/*
+	 * Reload fs and gs if they have changed in the signal
+	 * handler.  This does not handle long fs/gs base changes in
+	 * the handler, but does not clobber them at least in the
+	 * normal case.
+	 */
+	RELOAD_SEG(gs);
+	RELOAD_SEG(fs);
+	RELOAD_SEG(ds);
+	RELOAD_SEG(es);
+
+	err |= fpu__restore_sig(buf, 1);
+
+	force_iret();
+
+	return err;
+}
+
+asmlinkage long sys32_sigreturn(void)
+{
+	struct pt_regs *regs = current_pt_regs();
+	struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);
+	sigset_t set;
+
+	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__get_user(set.sig[0], &frame->sc.oldmask)
+	    || (_COMPAT_NSIG_WORDS > 1
+		&& __copy_from_user((((char *) &set.sig) + 4),
+				    &frame->extramask,
+				    sizeof(frame->extramask))))
+		goto badframe;
+
+	set_current_blocked(&set);
+
+	if (ia32_restore_sigcontext(regs, &frame->sc))
+		goto badframe;
+	return regs->ax;
+
+badframe:
+	signal_fault(regs, frame, "32bit sigreturn");
+	return 0;
+}
+
+asmlinkage long sys32_rt_sigreturn(void)
+{
+	struct pt_regs *regs = current_pt_regs();
+	struct rt_sigframe_ia32 __user *frame;
+	sigset_t set;
+
+	frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4);
+
+	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+		goto badframe;
+
+	set_current_blocked(&set);
+
+	if (ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext))
+		goto badframe;
+
+	if (compat_restore_altstack(&frame->uc.uc_stack))
+		goto badframe;
+
+	return regs->ax;
+
+badframe:
+	signal_fault(regs, frame, "32bit rt sigreturn");
+	return 0;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc,
+				 void __user *fpstate,
+				 struct pt_regs *regs, unsigned int mask)
+{
+	int err = 0;
+
+	put_user_try {
+		put_user_ex(get_user_seg(gs), (unsigned int __user *)&sc->gs);
+		put_user_ex(get_user_seg(fs), (unsigned int __user *)&sc->fs);
+		put_user_ex(get_user_seg(ds), (unsigned int __user *)&sc->ds);
+		put_user_ex(get_user_seg(es), (unsigned int __user *)&sc->es);
+
+		put_user_ex(regs->di, &sc->di);
+		put_user_ex(regs->si, &sc->si);
+		put_user_ex(regs->bp, &sc->bp);
+		put_user_ex(regs->sp, &sc->sp);
+		put_user_ex(regs->bx, &sc->bx);
+		put_user_ex(regs->dx, &sc->dx);
+		put_user_ex(regs->cx, &sc->cx);
+		put_user_ex(regs->ax, &sc->ax);
+		put_user_ex(current->thread.trap_nr, &sc->trapno);
+		put_user_ex(current->thread.error_code, &sc->err);
+		put_user_ex(regs->ip, &sc->ip);
+		put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
+		put_user_ex(regs->flags, &sc->flags);
+		put_user_ex(regs->sp, &sc->sp_at_signal);
+		put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
+
+		put_user_ex(ptr_to_compat(fpstate), &sc->fpstate);
+
+		/* non-iBCS2 extensions.. */
+		put_user_ex(mask, &sc->oldmask);
+		put_user_ex(current->thread.cr2, &sc->cr2);
+	} put_user_catch(err);
+
+	return err;
+}
+
+/*
+ * Determine which stack to use..
+ */
+static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
+				 size_t frame_size,
+				 void __user **fpstate)
+{
+	struct fpu *fpu = &current->thread.fpu;
+	unsigned long sp;
+
+	/* Default to using normal stack */
+	sp = regs->sp;
+
+	/* This is the X/Open sanctioned signal stack switching.  */
+	if (ksig->ka.sa.sa_flags & SA_ONSTACK)
+		sp = sigsp(sp, ksig);
+	/* This is the legacy signal stack switching. */
+	else if (regs->ss != __USER32_DS &&
+		!(ksig->ka.sa.sa_flags & SA_RESTORER) &&
+		 ksig->ka.sa.sa_restorer)
+		sp = (unsigned long) ksig->ka.sa.sa_restorer;
+
+	if (fpu->initialized) {
+		unsigned long fx_aligned, math_size;
+
+		sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
+		*fpstate = (struct _fpstate_32 __user *) sp;
+		if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
+				    math_size) < 0)
+			return (void __user *) -1L;
+	}
+
+	sp -= frame_size;
+	/* Align the stack pointer according to the i386 ABI,
+	 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
+	sp = ((sp + 4) & -16ul) - 4;
+	return (void __user *) sp;
+}
+
+int ia32_setup_frame(int sig, struct ksignal *ksig,
+		     compat_sigset_t *set, struct pt_regs *regs)
+{
+	struct sigframe_ia32 __user *frame;
+	void __user *restorer;
+	int err = 0;
+	void __user *fpstate = NULL;
+
+	/* copy_to_user optimizes that into a single 8 byte store */
+	static const struct {
+		u16 poplmovl;
+		u32 val;
+		u16 int80;
+	} __attribute__((packed)) code = {
+		0xb858,		 /* popl %eax ; movl $...,%eax */
+		__NR_ia32_sigreturn,
+		0x80cd,		/* int $0x80 */
+	};
+
+	frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate);
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		return -EFAULT;
+
+	if (__put_user(sig, &frame->sig))
+		return -EFAULT;
+
+	if (ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
+		return -EFAULT;
+
+	if (_COMPAT_NSIG_WORDS > 1) {
+		if (__copy_to_user(frame->extramask, &set->sig[1],
+				   sizeof(frame->extramask)))
+			return -EFAULT;
+	}
+
+	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
+		restorer = ksig->ka.sa.sa_restorer;
+	} else {
+		/* Return stub is in 32bit vsyscall page */
+		if (current->mm->context.vdso)
+			restorer = current->mm->context.vdso +
+				vdso_image_32.sym___kernel_sigreturn;
+		else
+			restorer = &frame->retcode;
+	}
+
+	put_user_try {
+		put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
+
+		/*
+		 * These are actually not used anymore, but left because some
+		 * gdb versions depend on them as a marker.
+		 */
+		put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
+	} put_user_catch(err);
+
+	if (err)
+		return -EFAULT;
+
+	/* Set up registers for signal handler */
+	regs->sp = (unsigned long) frame;
+	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
+
+	/* Make -mregparm=3 work */
+	regs->ax = sig;
+	regs->dx = 0;
+	regs->cx = 0;
+
+	loadsegment(ds, __USER32_DS);
+	loadsegment(es, __USER32_DS);
+
+	regs->cs = __USER32_CS;
+	regs->ss = __USER32_DS;
+
+	return 0;
+}
+
+int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
+			compat_sigset_t *set, struct pt_regs *regs)
+{
+	struct rt_sigframe_ia32 __user *frame;
+	void __user *restorer;
+	int err = 0;
+	void __user *fpstate = NULL;
+
+	/* __copy_to_user optimizes that into a single 8 byte store */
+	static const struct {
+		u8 movl;
+		u32 val;
+		u16 int80;
+		u8  pad;
+	} __attribute__((packed)) code = {
+		0xb8,
+		__NR_ia32_rt_sigreturn,
+		0x80cd,
+		0,
+	};
+
+	frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate);
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		return -EFAULT;
+
+	put_user_try {
+		put_user_ex(sig, &frame->sig);
+		put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo);
+		put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
+
+		/* Create the ucontext.  */
+		if (boot_cpu_has(X86_FEATURE_XSAVE))
+			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
+		else
+			put_user_ex(0, &frame->uc.uc_flags);
+		put_user_ex(0, &frame->uc.uc_link);
+		compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
+
+		if (ksig->ka.sa.sa_flags & SA_RESTORER)
+			restorer = ksig->ka.sa.sa_restorer;
+		else
+			restorer = current->mm->context.vdso +
+				vdso_image_32.sym___kernel_rt_sigreturn;
+		put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
+
+		/*
+		 * Not actually used anymore, but left because some gdb
+		 * versions need it.
+		 */
+		put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
+	} put_user_catch(err);
+
+	err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false);
+	err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+				     regs, set->sig[0]);
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+	if (err)
+		return -EFAULT;
+
+	/* Set up registers for signal handler */
+	regs->sp = (unsigned long) frame;
+	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
+
+	/* Make -mregparm=3 work */
+	regs->ax = sig;
+	regs->dx = (unsigned long) &frame->info;
+	regs->cx = (unsigned long) &frame->uc;
+
+	loadsegment(ds, __USER32_DS);
+	loadsegment(es, __USER32_DS);
+
+	regs->cs = __USER32_CS;
+	regs->ss = __USER32_DS;
+
+	return 0;
+}