Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 784 insertions, 0 deletions

diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
new file mode 100644
index 000000000..dad38960d
--- /dev/null
+++ b/arch/sparc/kernel/signal32.c
@@ -0,0 +1,784 @@
+// SPDX-License-Identifier: GPL-2.0
+/*  arch/sparc64/kernel/signal32.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
+ *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
+ *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/ptrace.h>
+#include <linux/unistd.h>
+#include <linux/mm.h>
+#include <linux/tty.h>
+#include <linux/binfmts.h>
+#include <linux/compat.h>
+#include <linux/bitops.h>
+
+#include <linux/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/psrcompat.h>
+#include <asm/fpumacro.h>
+#include <asm/visasm.h>
+#include <asm/compat_signal.h>
+#include <asm/switch_to.h>
+
+#include "sigutil.h"
+#include "kernel.h"
+
+/* This magic should be in g_upper[0] for all upper parts
+ * to be valid.
+ */
+#define SIGINFO_EXTRA_V8PLUS_MAGIC	0x130e269
+typedef struct {
+	unsigned int g_upper[8];
+	unsigned int o_upper[8];
+	unsigned int asi;
+} siginfo_extra_v8plus_t;
+
+struct signal_frame32 {
+	struct sparc_stackf32	ss;
+	__siginfo32_t		info;
+	/* __siginfo_fpu_t * */ u32 fpu_save;
+	unsigned int		insns[2];
+	unsigned int		extramask[_COMPAT_NSIG_WORDS - 1];
+	unsigned int		extra_size; /* Should be sizeof(siginfo_extra_v8plus_t) */
+	/* Only valid if (info.si_regs.psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS */
+	siginfo_extra_v8plus_t	v8plus;
+	/* __siginfo_rwin_t * */u32 rwin_save;
+} __attribute__((aligned(8)));
+
+struct rt_signal_frame32 {
+	struct sparc_stackf32	ss;
+	compat_siginfo_t	info;
+	struct pt_regs32	regs;
+	compat_sigset_t		mask;
+	/* __siginfo_fpu_t * */ u32 fpu_save;
+	unsigned int		insns[2];
+	compat_stack_t		stack;
+	unsigned int		extra_size; /* Should be sizeof(siginfo_extra_v8plus_t) */
+	/* Only valid if (regs.psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS */
+	siginfo_extra_v8plus_t	v8plus;
+	/* __siginfo_rwin_t * */u32 rwin_save;
+} __attribute__((aligned(8)));
+
+/* Checks if the fp is valid.  We always build signal frames which are
+ * 16-byte aligned, therefore we can always enforce that the restore
+ * frame has that property as well.
+ */
+static bool invalid_frame_pointer(void __user *fp, int fplen)
+{
+	if ((((unsigned long) fp) & 15) ||
+	    ((unsigned long)fp) > 0x100000000ULL - fplen)
+		return true;
+	return false;
+}
+
+void do_sigreturn32(struct pt_regs *regs)
+{
+	struct signal_frame32 __user *sf;
+	compat_uptr_t fpu_save;
+	compat_uptr_t rwin_save;
+	unsigned int psr, ufp;
+	unsigned int pc, npc;
+	sigset_t set;
+	compat_sigset_t seta;
+	int err, i;
+	
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	synchronize_user_stack();
+
+	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
+	sf = (struct signal_frame32 __user *) regs->u_regs[UREG_FP];
+
+	/* 1. Make sure we are not getting garbage from the user */
+	if (invalid_frame_pointer(sf, sizeof(*sf)))
+		goto segv;
+
+	if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP]))
+		goto segv;
+
+	if (ufp & 0x7)
+		goto segv;
+
+	if (__get_user(pc, &sf->info.si_regs.pc) ||
+	    __get_user(npc, &sf->info.si_regs.npc))
+		goto segv;
+
+	if ((pc | npc) & 3)
+		goto segv;
+
+	if (test_thread_flag(TIF_32BIT)) {
+		pc &= 0xffffffff;
+		npc &= 0xffffffff;
+	}
+	regs->tpc = pc;
+	regs->tnpc = npc;
+
+	/* 2. Restore the state */
+	err = __get_user(regs->y, &sf->info.si_regs.y);
+	err |= __get_user(psr, &sf->info.si_regs.psr);
+
+	for (i = UREG_G1; i <= UREG_I7; i++)
+		err |= __get_user(regs->u_regs[i], &sf->info.si_regs.u_regs[i]);
+	if ((psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS) {
+		err |= __get_user(i, &sf->v8plus.g_upper[0]);
+		if (i == SIGINFO_EXTRA_V8PLUS_MAGIC) {
+			unsigned long asi;
+
+			for (i = UREG_G1; i <= UREG_I7; i++)
+				err |= __get_user(((u32 *)regs->u_regs)[2*i], &sf->v8plus.g_upper[i]);
+			err |= __get_user(asi, &sf->v8plus.asi);
+			regs->tstate &= ~TSTATE_ASI;
+			regs->tstate |= ((asi & 0xffUL) << 24UL);
+		}
+	}
+
+	/* User can only change condition codes in %tstate. */
+	regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
+	regs->tstate |= psr_to_tstate_icc(psr);
+
+	/* Prevent syscall restart.  */
+	pt_regs_clear_syscall(regs);
+
+	err |= __get_user(fpu_save, &sf->fpu_save);
+	if (!err && fpu_save)
+		err |= restore_fpu_state(regs, compat_ptr(fpu_save));
+	err |= __get_user(rwin_save, &sf->rwin_save);
+	if (!err && rwin_save) {
+		if (restore_rwin_state(compat_ptr(rwin_save)))
+			goto segv;
+	}
+	err |= __get_user(seta.sig[0], &sf->info.si_mask);
+	err |= copy_from_user(&seta.sig[1], &sf->extramask,
+			      (_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));
+	if (err)
+	    	goto segv;
+
+	set.sig[0] = seta.sig[0] + (((long)seta.sig[1]) << 32);
+	set_current_blocked(&set);
+	return;
+
+segv:
+	force_sig(SIGSEGV);
+}
+
+asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
+{
+	struct rt_signal_frame32 __user *sf;
+	unsigned int psr, pc, npc, ufp;
+	compat_uptr_t fpu_save;
+	compat_uptr_t rwin_save;
+	sigset_t set;
+	int err, i;
+	
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	synchronize_user_stack();
+	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
+	sf = (struct rt_signal_frame32 __user *) regs->u_regs[UREG_FP];
+
+	/* 1. Make sure we are not getting garbage from the user */
+	if (invalid_frame_pointer(sf, sizeof(*sf)))
+		goto segv;
+
+	if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
+		goto segv;
+
+	if (ufp & 0x7)
+		goto segv;
+
+	if (__get_user(pc, &sf->regs.pc) || 
+	    __get_user(npc, &sf->regs.npc))
+		goto segv;
+
+	if ((pc | npc) & 3)
+		goto segv;
+
+	if (test_thread_flag(TIF_32BIT)) {
+		pc &= 0xffffffff;
+		npc &= 0xffffffff;
+	}
+	regs->tpc = pc;
+	regs->tnpc = npc;
+
+	/* 2. Restore the state */
+	err = __get_user(regs->y, &sf->regs.y);
+	err |= __get_user(psr, &sf->regs.psr);
+	
+	for (i = UREG_G1; i <= UREG_I7; i++)
+		err |= __get_user(regs->u_regs[i], &sf->regs.u_regs[i]);
+	if ((psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS) {
+		err |= __get_user(i, &sf->v8plus.g_upper[0]);
+		if (i == SIGINFO_EXTRA_V8PLUS_MAGIC) {
+			unsigned long asi;
+
+			for (i = UREG_G1; i <= UREG_I7; i++)
+				err |= __get_user(((u32 *)regs->u_regs)[2*i], &sf->v8plus.g_upper[i]);
+			err |= __get_user(asi, &sf->v8plus.asi);
+			regs->tstate &= ~TSTATE_ASI;
+			regs->tstate |= ((asi & 0xffUL) << 24UL);
+		}
+	}
+
+	/* User can only change condition codes in %tstate. */
+	regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
+	regs->tstate |= psr_to_tstate_icc(psr);
+
+	/* Prevent syscall restart.  */
+	pt_regs_clear_syscall(regs);
+
+	err |= __get_user(fpu_save, &sf->fpu_save);
+	if (!err && fpu_save)
+		err |= restore_fpu_state(regs, compat_ptr(fpu_save));
+	err |= get_compat_sigset(&set, &sf->mask);
+	err |= compat_restore_altstack(&sf->stack);
+	if (err)
+		goto segv;
+		
+	err |= __get_user(rwin_save, &sf->rwin_save);
+	if (!err && rwin_save) {
+		if (restore_rwin_state(compat_ptr(rwin_save)))
+			goto segv;
+	}
+
+	set_current_blocked(&set);
+	return;
+segv:
+	force_sig(SIGSEGV);
+}
+
+static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
+{
+	unsigned long sp;
+	
+	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
+	sp = regs->u_regs[UREG_FP];
+	
+	/*
+	 * If we are on the alternate signal stack and would overflow it, don't.
+	 * Return an always-bogus address instead so we will die with SIGSEGV.
+	 */
+	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
+		return (void __user *) -1L;
+
+	/* This is the X/Open sanctioned signal stack switching.  */
+	sp = sigsp(sp, ksig) - framesize;
+
+	/* Always align the stack frame.  This handles two cases.  First,
+	 * sigaltstack need not be mindful of platform specific stack
+	 * alignment.  Second, if we took this signal because the stack
+	 * is not aligned properly, we'd like to take the signal cleanly
+	 * and report that.
+	 */
+	sp &= ~15UL;
+
+	return (void __user *) sp;
+}
+
+/* The I-cache flush instruction only works in the primary ASI, which
+ * right now is the nucleus, aka. kernel space.
+ *
+ * Therefore we have to kick the instructions out using the kernel
+ * side linear mapping of the physical address backing the user
+ * instructions.
+ */
+static void flush_signal_insns(unsigned long address)
+{
+	unsigned long pstate, paddr;
+	pte_t *ptep, pte;
+	pgd_t *pgdp;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp;
+
+	/* Commit all stores of the instructions we are about to flush.  */
+	wmb();
+
+	/* Disable cross-call reception.  In this way even a very wide
+	 * munmap() on another cpu can't tear down the page table
+	 * hierarchy from underneath us, since that can't complete
+	 * until the IPI tlb flush returns.
+	 */
+
+	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
+	__asm__ __volatile__("wrpr %0, %1, %%pstate"
+				: : "r" (pstate), "i" (PSTATE_IE));
+
+	pgdp = pgd_offset(current->mm, address);
+	if (pgd_none(*pgdp))
+		goto out_irqs_on;
+	p4dp = p4d_offset(pgdp, address);
+	if (p4d_none(*p4dp))
+		goto out_irqs_on;
+	pudp = pud_offset(p4dp, address);
+	if (pud_none(*pudp))
+		goto out_irqs_on;
+	pmdp = pmd_offset(pudp, address);
+	if (pmd_none(*pmdp))
+		goto out_irqs_on;
+
+	ptep = pte_offset_map(pmdp, address);
+	pte = *ptep;
+	if (!pte_present(pte))
+		goto out_unmap;
+
+	paddr = (unsigned long) page_address(pte_page(pte));
+
+	__asm__ __volatile__("flush	%0 + %1"
+			     : /* no outputs */
+			     : "r" (paddr),
+			       "r" (address & (PAGE_SIZE - 1))
+			     : "memory");
+
+out_unmap:
+	pte_unmap(ptep);
+out_irqs_on:
+	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
+
+}
+
+static int setup_frame32(struct ksignal *ksig, struct pt_regs *regs,
+			 sigset_t *oldset)
+{
+	struct signal_frame32 __user *sf;
+	int i, err, wsaved;
+	void __user *tail;
+	int sigframe_size;
+	u32 psr;
+	compat_sigset_t seta;
+
+	/* 1. Make sure everything is clean */
+	synchronize_user_stack();
+	save_and_clear_fpu();
+	
+	wsaved = get_thread_wsaved();
+
+	sigframe_size = sizeof(*sf);
+	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
+		sigframe_size += sizeof(__siginfo_fpu_t);
+	if (wsaved)
+		sigframe_size += sizeof(__siginfo_rwin_t);
+
+	sf = (struct signal_frame32 __user *)
+		get_sigframe(ksig, regs, sigframe_size);
+	
+	if (invalid_frame_pointer(sf, sigframe_size)) {
+		if (show_unhandled_signals)
+			pr_info("%s[%d] bad frame in setup_frame32: %08lx TPC %08lx O7 %08lx\n",
+				current->comm, current->pid, (unsigned long)sf,
+				regs->tpc, regs->u_regs[UREG_I7]);
+		force_sigsegv(ksig->sig);
+		return -EINVAL;
+	}
+
+	tail = (sf + 1);
+
+	/* 2. Save the current process state */
+	if (test_thread_flag(TIF_32BIT)) {
+		regs->tpc &= 0xffffffff;
+		regs->tnpc &= 0xffffffff;
+	}
+	err  = put_user(regs->tpc, &sf->info.si_regs.pc);
+	err |= __put_user(regs->tnpc, &sf->info.si_regs.npc);
+	err |= __put_user(regs->y, &sf->info.si_regs.y);
+	psr = tstate_to_psr(regs->tstate);
+	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
+		psr |= PSR_EF;
+	err |= __put_user(psr, &sf->info.si_regs.psr);
+	for (i = 0; i < 16; i++)
+		err |= __put_user(regs->u_regs[i], &sf->info.si_regs.u_regs[i]);
+	err |= __put_user(sizeof(siginfo_extra_v8plus_t), &sf->extra_size);
+	err |= __put_user(SIGINFO_EXTRA_V8PLUS_MAGIC, &sf->v8plus.g_upper[0]);
+	for (i = 1; i < 16; i++)
+		err |= __put_user(((u32 *)regs->u_regs)[2*i],
+				  &sf->v8plus.g_upper[i]);
+	err |= __put_user((regs->tstate & TSTATE_ASI) >> 24UL,
+			  &sf->v8plus.asi);
+
+	if (psr & PSR_EF) {
+		__siginfo_fpu_t __user *fp = tail;
+		tail += sizeof(*fp);
+		err |= save_fpu_state(regs, fp);
+		err |= __put_user((u64)fp, &sf->fpu_save);
+	} else {
+		err |= __put_user(0, &sf->fpu_save);
+	}
+	if (wsaved) {
+		__siginfo_rwin_t __user *rwp = tail;
+		tail += sizeof(*rwp);
+		err |= save_rwin_state(wsaved, rwp);
+		err |= __put_user((u64)rwp, &sf->rwin_save);
+		set_thread_wsaved(0);
+	} else {
+		err |= __put_user(0, &sf->rwin_save);
+	}
+
+	/* If these change we need to know - assignments to seta relies on these sizes */
+	BUILD_BUG_ON(_NSIG_WORDS != 1);
+	BUILD_BUG_ON(_COMPAT_NSIG_WORDS != 2);
+	seta.sig[1] = (oldset->sig[0] >> 32);
+	seta.sig[0] = oldset->sig[0];
+
+	err |= __put_user(seta.sig[0], &sf->info.si_mask);
+	err |= __copy_to_user(sf->extramask, &seta.sig[1],
+			      (_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));
+
+	if (!wsaved) {
+		err |= raw_copy_in_user((u32 __user *)sf,
+					(u32 __user *)(regs->u_regs[UREG_FP]),
+					sizeof(struct reg_window32));
+	} else {
+		struct reg_window *rp;
+
+		rp = &current_thread_info()->reg_window[wsaved - 1];
+		for (i = 0; i < 8; i++)
+			err |= __put_user(rp->locals[i], &sf->ss.locals[i]);
+		for (i = 0; i < 6; i++)
+			err |= __put_user(rp->ins[i], &sf->ss.ins[i]);
+		err |= __put_user(rp->ins[6], &sf->ss.fp);
+		err |= __put_user(rp->ins[7], &sf->ss.callers_pc);
+	}	
+	if (err)
+		return err;
+
+	/* 3. signal handler back-trampoline and parameters */
+	regs->u_regs[UREG_FP] = (unsigned long) sf;
+	regs->u_regs[UREG_I0] = ksig->sig;
+	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
+	regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
+
+	/* 4. signal handler */
+	regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
+	regs->tnpc = (regs->tpc + 4);
+	if (test_thread_flag(TIF_32BIT)) {
+		regs->tpc &= 0xffffffff;
+		regs->tnpc &= 0xffffffff;
+	}
+
+	/* 5. return to kernel instructions */
+	if (ksig->ka.ka_restorer) {
+		regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
+	} else {
+		unsigned long address = ((unsigned long)&(sf->insns[0]));
+
+		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
+	
+		err  = __put_user(0x821020d8, &sf->insns[0]); /*mov __NR_sigreturn, %g1*/
+		err |= __put_user(0x91d02010, &sf->insns[1]); /*t 0x10*/
+		if (err)
+			return err;
+		flush_signal_insns(address);
+	}
+	return 0;
+}
+
+static int setup_rt_frame32(struct ksignal *ksig, struct pt_regs *regs,
+			    sigset_t *oldset)
+{
+	struct rt_signal_frame32 __user *sf;
+	int i, err, wsaved;
+	void __user *tail;
+	int sigframe_size;
+	u32 psr;
+
+	/* 1. Make sure everything is clean */
+	synchronize_user_stack();
+	save_and_clear_fpu();
+	
+	wsaved = get_thread_wsaved();
+
+	sigframe_size = sizeof(*sf);
+	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
+		sigframe_size += sizeof(__siginfo_fpu_t);
+	if (wsaved)
+		sigframe_size += sizeof(__siginfo_rwin_t);
+
+	sf = (struct rt_signal_frame32 __user *)
+		get_sigframe(ksig, regs, sigframe_size);
+	
+	if (invalid_frame_pointer(sf, sigframe_size)) {
+		if (show_unhandled_signals)
+			pr_info("%s[%d] bad frame in setup_rt_frame32: %08lx TPC %08lx O7 %08lx\n",
+				current->comm, current->pid, (unsigned long)sf,
+				regs->tpc, regs->u_regs[UREG_I7]);
+		force_sigsegv(ksig->sig);
+		return -EINVAL;
+	}
+
+	tail = (sf + 1);
+
+	/* 2. Save the current process state */
+	if (test_thread_flag(TIF_32BIT)) {
+		regs->tpc &= 0xffffffff;
+		regs->tnpc &= 0xffffffff;
+	}
+	err  = put_user(regs->tpc, &sf->regs.pc);
+	err |= __put_user(regs->tnpc, &sf->regs.npc);
+	err |= __put_user(regs->y, &sf->regs.y);
+	psr = tstate_to_psr(regs->tstate);
+	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
+		psr |= PSR_EF;
+	err |= __put_user(psr, &sf->regs.psr);
+	for (i = 0; i < 16; i++)
+		err |= __put_user(regs->u_regs[i], &sf->regs.u_regs[i]);
+	err |= __put_user(sizeof(siginfo_extra_v8plus_t), &sf->extra_size);
+	err |= __put_user(SIGINFO_EXTRA_V8PLUS_MAGIC, &sf->v8plus.g_upper[0]);
+	for (i = 1; i < 16; i++)
+		err |= __put_user(((u32 *)regs->u_regs)[2*i],
+				  &sf->v8plus.g_upper[i]);
+	err |= __put_user((regs->tstate & TSTATE_ASI) >> 24UL,
+			  &sf->v8plus.asi);
+
+	if (psr & PSR_EF) {
+		__siginfo_fpu_t __user *fp = tail;
+		tail += sizeof(*fp);
+		err |= save_fpu_state(regs, fp);
+		err |= __put_user((u64)fp, &sf->fpu_save);
+	} else {
+		err |= __put_user(0, &sf->fpu_save);
+	}
+	if (wsaved) {
+		__siginfo_rwin_t __user *rwp = tail;
+		tail += sizeof(*rwp);
+		err |= save_rwin_state(wsaved, rwp);
+		err |= __put_user((u64)rwp, &sf->rwin_save);
+		set_thread_wsaved(0);
+	} else {
+		err |= __put_user(0, &sf->rwin_save);
+	}
+
+	/* Update the siginfo structure.  */
+	err |= copy_siginfo_to_user32(&sf->info, &ksig->info);
+	
+	/* Setup sigaltstack */
+	err |= __compat_save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
+
+	err |= put_compat_sigset(&sf->mask, oldset, sizeof(compat_sigset_t));
+
+	if (!wsaved) {
+		err |= raw_copy_in_user((u32 __user *)sf,
+					(u32 __user *)(regs->u_regs[UREG_FP]),
+					sizeof(struct reg_window32));
+	} else {
+		struct reg_window *rp;
+
+		rp = &current_thread_info()->reg_window[wsaved - 1];
+		for (i = 0; i < 8; i++)
+			err |= __put_user(rp->locals[i], &sf->ss.locals[i]);
+		for (i = 0; i < 6; i++)
+			err |= __put_user(rp->ins[i], &sf->ss.ins[i]);
+		err |= __put_user(rp->ins[6], &sf->ss.fp);
+		err |= __put_user(rp->ins[7], &sf->ss.callers_pc);
+	}
+	if (err)
+		return err;
+	
+	/* 3. signal handler back-trampoline and parameters */
+	regs->u_regs[UREG_FP] = (unsigned long) sf;
+	regs->u_regs[UREG_I0] = ksig->sig;
+	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
+	regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
+
+	/* 4. signal handler */
+	regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
+	regs->tnpc = (regs->tpc + 4);
+	if (test_thread_flag(TIF_32BIT)) {
+		regs->tpc &= 0xffffffff;
+		regs->tnpc &= 0xffffffff;
+	}
+
+	/* 5. return to kernel instructions */
+	if (ksig->ka.ka_restorer)
+		regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
+	else {
+		unsigned long address = ((unsigned long)&(sf->insns[0]));
+
+		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
+	
+		/* mov __NR_rt_sigreturn, %g1 */
+		err |= __put_user(0x82102065, &sf->insns[0]);
+
+		/* t 0x10 */
+		err |= __put_user(0x91d02010, &sf->insns[1]);
+		if (err)
+			return err;
+
+		flush_signal_insns(address);
+	}
+	return 0;
+}
+
+static inline void handle_signal32(struct ksignal *ksig, 
+				  struct pt_regs *regs)
+{
+	sigset_t *oldset = sigmask_to_save();
+	int err;
+
+	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+		err = setup_rt_frame32(ksig, regs, oldset);
+	else
+		err = setup_frame32(ksig, regs, oldset);
+
+	signal_setup_done(err, ksig, 0);
+}
+
+static inline void syscall_restart32(unsigned long orig_i0, struct pt_regs *regs,
+				     struct sigaction *sa)
+{
+	switch (regs->u_regs[UREG_I0]) {
+	case ERESTART_RESTARTBLOCK:
+	case ERESTARTNOHAND:
+	no_system_call_restart:
+		regs->u_regs[UREG_I0] = EINTR;
+		regs->tstate |= TSTATE_ICARRY;
+		break;
+	case ERESTARTSYS:
+		if (!(sa->sa_flags & SA_RESTART))
+			goto no_system_call_restart;
+		fallthrough;
+	case ERESTARTNOINTR:
+		regs->u_regs[UREG_I0] = orig_i0;
+		regs->tpc -= 4;
+		regs->tnpc -= 4;
+	}
+}
+
+/* Note that 'init' is a special process: it doesn't get signals it doesn't
+ * want to handle. Thus you cannot kill init even with a SIGKILL even by
+ * mistake.
+ */
+void do_signal32(struct pt_regs * regs)
+{
+	struct ksignal ksig;
+	unsigned long orig_i0 = 0;
+	int restart_syscall = 0;
+	bool has_handler = get_signal(&ksig);
+
+	if (pt_regs_is_syscall(regs) &&
+	    (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
+		restart_syscall = 1;
+		orig_i0 = regs->u_regs[UREG_G6];
+	}
+
+	if (has_handler) {
+		if (restart_syscall)
+			syscall_restart32(orig_i0, regs, &ksig.ka.sa);
+		handle_signal32(&ksig, regs);
+	} else {
+		if (restart_syscall) {
+			switch (regs->u_regs[UREG_I0]) {
+			case ERESTARTNOHAND:
+	     		case ERESTARTSYS:
+			case ERESTARTNOINTR:
+				/* replay the system call when we are done */
+				regs->u_regs[UREG_I0] = orig_i0;
+				regs->tpc -= 4;
+				regs->tnpc -= 4;
+				pt_regs_clear_syscall(regs);
+				fallthrough;
+			case ERESTART_RESTARTBLOCK:
+				regs->u_regs[UREG_G1] = __NR_restart_syscall;
+				regs->tpc -= 4;
+				regs->tnpc -= 4;
+				pt_regs_clear_syscall(regs);
+			}
+		}
+		restore_saved_sigmask();
+	}
+}
+
+struct sigstack32 {
+	u32 the_stack;
+	int cur_status;
+};
+
+asmlinkage int do_sys32_sigstack(u32 u_ssptr, u32 u_ossptr, unsigned long sp)
+{
+	struct sigstack32 __user *ssptr =
+		(struct sigstack32 __user *)((unsigned long)(u_ssptr));
+	struct sigstack32 __user *ossptr =
+		(struct sigstack32 __user *)((unsigned long)(u_ossptr));
+	int ret = -EFAULT;
+
+	/* First see if old state is wanted. */
+	if (ossptr) {
+		if (put_user(current->sas_ss_sp + current->sas_ss_size,
+			     &ossptr->the_stack) ||
+		    __put_user(on_sig_stack(sp), &ossptr->cur_status))
+			goto out;
+	}
+	
+	/* Now see if we want to update the new state. */
+	if (ssptr) {
+		u32 ss_sp;
+
+		if (get_user(ss_sp, &ssptr->the_stack))
+			goto out;
+
+		/* If the current stack was set with sigaltstack, don't
+		 * swap stacks while we are on it.
+		 */
+		ret = -EPERM;
+		if (current->sas_ss_sp && on_sig_stack(sp))
+			goto out;
+			
+		/* Since we don't know the extent of the stack, and we don't
+		 * track onstack-ness, but rather calculate it, we must
+		 * presume a size.  Ho hum this interface is lossy.
+		 */
+		current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
+		current->sas_ss_size = SIGSTKSZ;
+	}
+	
+	ret = 0;
+out:
+	return ret;
+}
+
+/*
+ * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
+ * changes likely come with new fields that should be added below.
+ */
+static_assert(NSIGILL	== 11);
+static_assert(NSIGFPE	== 15);
+static_assert(NSIGSEGV	== 9);
+static_assert(NSIGBUS	== 5);
+static_assert(NSIGTRAP	== 6);
+static_assert(NSIGCHLD	== 6);
+static_assert(NSIGSYS	== 2);
+static_assert(sizeof(compat_siginfo_t) == 128);
+static_assert(__alignof__(compat_siginfo_t) == 4);
+static_assert(offsetof(compat_siginfo_t, si_signo)	== 0x00);
+static_assert(offsetof(compat_siginfo_t, si_errno)	== 0x04);
+static_assert(offsetof(compat_siginfo_t, si_code)	== 0x08);
+static_assert(offsetof(compat_siginfo_t, si_pid)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_uid)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_tid)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_overrun)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_status)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_utime)	== 0x18);
+static_assert(offsetof(compat_siginfo_t, si_stime)	== 0x1c);
+static_assert(offsetof(compat_siginfo_t, si_value)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_int)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_ptr)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_addr)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_trapno)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_addr_lsb)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_lower)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_upper)	== 0x18);
+static_assert(offsetof(compat_siginfo_t, si_pkey)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_perf_data)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_perf_type)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_perf_flags)	== 0x18);
+static_assert(offsetof(compat_siginfo_t, si_band)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_fd)		== 0x10);