parisc: Add vDSO support

Add minimal vDSO support, which provides the signal trampoline helpers,
but none of the userspace syscall helpers like time wrappers.

The big benefit of this vDSO implementation is, that we now don't need
an executeable stack any longer. PA-RISC is one of the last
architectures where an executeable stack was needed in oder to implement
the signal trampolines by putting assembly instructions on the stack
which then gets executed. Instead the kernel will provide the relevant
code in the vDSO page and only put the pointers to the signal
information on the stack.

By dropping the need for executable stacks we avoid running into issues
with applications which want non executable stacks for security reasons.
Additionally, alternative stacks on memory areas without exec
permissions are supported too.

This code is based on an initial implementation by Randolph Chung from 2006:
https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/

I did the porting and lifted the code to current code base. Dave fixed
the unwind code so that gdb and glibc are able to backtrace through the
code. An additional patch to gdb will be pushed upstream by Dave.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Cc: Randolph Chung <randolph@tausq.org>
Signed-off-by: Helge Deller <deller@gmx.de>

20 files changed, 1051 insertions, 138 deletions

diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index 8fb819bbbb17..d579243edc2f 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -39,3 +39,8 @@ obj-$(CONFIG_KGDB)			+= kgdb.o
 obj-$(CONFIG_KPROBES)			+= kprobes.o
 obj-$(CONFIG_KEXEC_CORE)		+= kexec.o relocate_kernel.o
 obj-$(CONFIG_KEXEC_FILE)		+= kexec_file.o
+
+# vdso
+obj-y			+= vdso.o
+obj-$(CONFIG_64BIT)	+= vdso64/
+obj-y			+= vdso32/
diff --git a/arch/parisc/kernel/asm-offsets.c b/arch/parisc/kernel/asm-offsets.c
index 2a83ef36d216..2673d57eeb00 100644
--- a/arch/parisc/kernel/asm-offsets.c
+++ b/arch/parisc/kernel/asm-offsets.c
@@ -26,7 +26,11 @@
 #include <asm/ptrace.h>
 #include <asm/processor.h>
 #include <asm/pdc.h>
+#include <uapi/asm/sigcontext.h>
+#include <asm/ucontext.h>
+#include <asm/rt_sigframe.h>
 #include <linux/uaccess.h>
+#include "signal32.h"
 
 /* Add FRAME_SIZE to the size x and align it to y. All definitions
  * that use align_frame will include space for a frame.
@@ -218,6 +222,11 @@ int main(void)
 	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
 	DEFINE(TI_PRE_COUNT, offsetof(struct task_struct, thread_info.preempt_count));
 	BLANK();
+	DEFINE(ASM_SIGFRAME_SIZE, PARISC_RT_SIGFRAME_SIZE);
+	DEFINE(SIGFRAME_CONTEXT_REGS, offsetof(struct rt_sigframe, uc.uc_mcontext) - PARISC_RT_SIGFRAME_SIZE);
+	DEFINE(ASM_SIGFRAME_SIZE32, PARISC_RT_SIGFRAME_SIZE32);
+	DEFINE(SIGFRAME_CONTEXT_REGS32, offsetof(struct compat_rt_sigframe, uc.uc_mcontext) - PARISC_RT_SIGFRAME_SIZE32);
+	BLANK();
 	DEFINE(ICACHE_BASE, offsetof(struct pdc_cache_info, ic_base));
 	DEFINE(ICACHE_STRIDE, offsetof(struct pdc_cache_info, ic_stride));
 	DEFINE(ICACHE_COUNT, offsetof(struct pdc_cache_info, ic_count));
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index bce71cefe572..00dc82658856 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -566,7 +566,7 @@ void flush_cache_mm(struct mm_struct *mm)
 	   rp3440, etc.  So, avoid it if the mm isn't too big.  */
 	if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
 	    mm_total_size(mm) >= parisc_cache_flush_threshold) {
-		if (mm->context)
+		if (mm->context.space_id)
 			flush_tlb_all();
 		flush_cache_all();
 		return;
@@ -581,7 +581,7 @@ void flush_cache_range(struct vm_area_struct *vma,
 {
 	if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
 	    end - start >= parisc_cache_flush_threshold) {
-		if (vma->vm_mm->context)
+		if (vma->vm_mm->context.space_id)
 			flush_tlb_range(vma, start, end);
 		flush_cache_all();
 		return;
@@ -594,7 +594,7 @@ void
 flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn)
 {
 	if (pfn_valid(pfn)) {
-		if (likely(vma->vm_mm->context)) {
+		if (likely(vma->vm_mm->context.space_id)) {
 			flush_tlb_page(vma, vmaddr);
 			__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
 		} else {
diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
index 46b1050640b8..24443908f905 100644
--- a/arch/parisc/kernel/signal.c
+++ b/arch/parisc/kernel/signal.c
@@ -1,16 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- *  linux/arch/parisc/kernel/signal.c: Architecture-specific signal
- *  handling support.
+ *  PA-RISC architecture-specific signal handling support.
  *
  *  Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
  *  Copyright (C) 2000 Linuxcare, Inc.
+ *  Copyright (C) 2000-2022 Helge Deller <deller@gmx.de>
+ *  Copyright (C) 2022 John David Anglin <dave.anglin@bell.net>
  *
  *  Based on the ia64, i386, and alpha versions.
- *
- *  Like the IA-64, we are a recent enough port (we are *starting*
- *  with glibc2.2) that we do not need to support the old non-realtime
- *  Linux signals.  Therefore we don't.
  */
 
 #include <linux/sched.h>
@@ -32,6 +29,7 @@
 #include <linux/uaccess.h>
 #include <asm/cacheflush.h>
 #include <asm/asm-offsets.h>
+#include <asm/vdso.h>
 
 #ifdef CONFIG_COMPAT
 #include "signal32.h"
@@ -59,14 +57,6 @@
  * Do a signal return - restore sigcontext.
  */
 
-/* Trampoline for calling rt_sigreturn() */
-#define INSN_LDI_R25_0	 0x34190000 /* ldi  0,%r25 (in_syscall=0) */
-#define INSN_LDI_R25_1	 0x34190002 /* ldi  1,%r25 (in_syscall=1) */
-#define INSN_LDI_R20	 0x3414015a /* ldi  __NR_rt_sigreturn,%r20 */
-#define INSN_BLE_SR2_R0  0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
-/* For debugging */
-#define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
-
 static long
 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
 {
@@ -77,9 +67,9 @@ restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
 	err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
 	err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
 	err |= __get_user(regs->sar, &sc->sc_sar);
-	DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n",
-			regs->iaoq[0],regs->iaoq[1]);
-	DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
+	DBG(2, "%s: iaoq is %#lx / %#lx\n",
+			__func__, regs->iaoq[0], regs->iaoq[1]);
+	DBG(2, "%s: r28 is %ld\n", __func__, regs->gr[28]);
 	return err;
 }
 
@@ -102,7 +92,7 @@ sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
 	/* Unwind the user stack to get the rt_sigframe structure. */
 	frame = (struct rt_sigframe __user *)
 		(usp - sigframe_size);
-	DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
+	DBG(2, "%s: frame is %p pid %d\n", __func__, frame, task_pid_nr(current));
 
 	regs->orig_r28 = 1; /* no restarts for sigreturn */
 
@@ -110,7 +100,6 @@ sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
 	compat_frame = (struct compat_rt_sigframe __user *)frame;
 	
 	if (is_compat_task()) {
-		DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
 		if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
 			goto give_sigsegv;
 	} else
@@ -125,25 +114,25 @@ sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
 	/* Good thing we saved the old gr[30], eh? */
 #ifdef CONFIG_64BIT
 	if (is_compat_task()) {
-		DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
-				&compat_frame->uc.uc_mcontext);
+		DBG(1, "%s: compat_frame->uc.uc_mcontext 0x%p\n",
+				__func__, &compat_frame->uc.uc_mcontext);
 // FIXME: Load upper half from register file
 		if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, 
 					&compat_frame->regs, regs))
 			goto give_sigsegv;
-		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
-				usp, &compat_frame->uc.uc_stack);
+		DBG(1, "%s: usp %#08lx stack 0x%p\n",
+				__func__, usp, &compat_frame->uc.uc_stack);
 		if (compat_restore_altstack(&compat_frame->uc.uc_stack))
 			goto give_sigsegv;
 	} else
 #endif
 	{
-		DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
-				&frame->uc.uc_mcontext);
+		DBG(1, "%s: frame->uc.uc_mcontext 0x%p\n",
+				__func__, &frame->uc.uc_mcontext);
 		if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
 			goto give_sigsegv;
-		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
-				usp, &frame->uc.uc_stack);
+		DBG(1, "%s: usp %#08lx stack 0x%p\n",
+				__func__, usp, &frame->uc.uc_stack);
 		if (restore_altstack(&frame->uc.uc_stack))
 			goto give_sigsegv;
 	}
@@ -155,14 +144,11 @@ sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
 	 */
 	if (in_syscall)
 		regs->gr[31] = regs->iaoq[0];
-#if DEBUG_SIG
-	DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
-	show_regs(regs);
-#endif
+
 	return;
 
 give_sigsegv:
-	DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
+	DBG(1, "%s: Sending SIGSEGV\n", __func__);
 	force_sig(SIGSEGV);
 	return;
 }
@@ -177,15 +163,15 @@ get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 	/*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
 	  don't use the parameter it doesn't matter */
 
-	DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
-			(unsigned long)ka, sp, frame_size);
+	DBG(1, "%s: ka = %#lx, sp = %#lx, frame_size = %zu\n",
+			__func__, (unsigned long)ka, sp, frame_size);
 	
 	/* Align alternate stack and reserve 64 bytes for the signal
 	   handler's frame marker.  */
 	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
 		sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
 
-	DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
+	DBG(1, "%s: Returning sp = %#lx\n", __func__, (unsigned long)sp);
 	return (void __user *) sp; /* Stacks grow up.  Fun. */
 }
 
@@ -205,20 +191,20 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_sysc
 		err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
 		err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
 		err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
-		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
-			regs->gr[31], regs->gr[31]+4);
+		DBG(1, "%s: iaoq %#lx / %#lx (in syscall)\n",
+			__func__, regs->gr[31], regs->gr[31]+4);
 	} else {
 		err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
 		err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
-		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n", 
-			regs->iaoq[0], regs->iaoq[1]);
+		DBG(1, "%s: iaoq %#lx / %#lx (not in syscall)\n",
+			__func__, regs->iaoq[0], regs->iaoq[1]);
 	}
 
 	err |= __put_user(flags, &sc->sc_flags);
 	err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
 	err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
 	err |= __put_user(regs->sar, &sc->sc_sar);
-	DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
+	DBG(1, "%s: r28 is %ld\n", __func__, regs->gr[28]);
 
 	return err;
 }
@@ -230,7 +216,7 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 	struct rt_sigframe __user *frame;
 	unsigned long rp, usp;
 	unsigned long haddr, sigframe_size;
-	unsigned long start, end;
+	unsigned long start;
 	int err = 0;
 #ifdef CONFIG_64BIT
 	struct compat_rt_sigframe __user * compat_frame;
@@ -247,8 +233,7 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 #endif
 	frame = get_sigframe(&ksig->ka, usp, sigframe_size);
 
-	DBG(1,"SETUP_RT_FRAME: START\n");
-	DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
+	DBG(1, "%s: frame %p info %p\n", __func__, frame, &ksig->info);
 
 	start = (unsigned long) frame;
 	if (start >= user_addr_max() - sigframe_size)
@@ -259,11 +244,12 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 	compat_frame = (struct compat_rt_sigframe __user *)frame;
 	
 	if (is_compat_task()) {
-		DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
+		DBG(1, "%s: frame->info = 0x%p\n", __func__, &compat_frame->info);
 		err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
 		err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
-		DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
-		DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
+		DBG(1, "%s: frame->uc = 0x%p\n", __func__, &compat_frame->uc);
+		DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
+			__func__, &compat_frame->uc.uc_mcontext);
 		err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext, 
 					&compat_frame->regs, regs, in_syscall);
 		err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
@@ -271,11 +257,12 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 	} else
 #endif
 	{	
-		DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
+		DBG(1, "%s: frame->info = 0x%p\n", __func__, &frame->info);
 		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 		err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
-		DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
-		DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
+		DBG(1, "%s: frame->uc = 0x%p\n", __func__, &frame->uc);
+		DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
+			__func__, &frame->uc.uc_mcontext);
 		err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
 		/* FIXME: Should probably be converted as well for the compat case */
 		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
@@ -284,32 +271,15 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 	if (err)
 		return -EFAULT;
 
-	/* Set up to return from userspace.  If provided, use a stub
-	   already in userspace. The first words of tramp are used to
-	   save the previous sigrestartblock trampoline that might be
-	   on the stack. We start the sigreturn trampoline at 
-	   SIGRESTARTBLOCK_TRAMP+X. */
-	err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
-			&frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
-	err |= __put_user(INSN_LDI_R20, 
-			&frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
-	err |= __put_user(INSN_BLE_SR2_R0, 
-			&frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
-	err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
-
-	start = (unsigned long) &frame->tramp[0];
-	end = (unsigned long) &frame->tramp[TRAMP_SIZE];
-	flush_user_dcache_range_asm(start, end);
-	flush_user_icache_range_asm(start, end);
-
-	/* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
-	 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
-	 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
-	 */
-	rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
+#ifdef CONFIG_64BIT
+	if (!is_compat_task())
+		rp = VDSO64_SYMBOL(current, sigtramp_rt);
+	else
+#endif
+		rp = VDSO32_SYMBOL(current, sigtramp_rt);
 
-	if (err)
-		return -EFAULT;
+	if (in_syscall)
+		rp += 4*4; /* skip 4 instructions and start at ldi 1,%r25 */
 
 	haddr = A(ksig->ka.sa.sa_handler);
 	/* The sa_handler may be a pointer to a function descriptor */
@@ -340,8 +310,8 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 		
 		haddr = fdesc.addr;
 		regs->gr[19] = fdesc.gp;
-		DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
-		     haddr, regs->gr[19], in_syscall);
+		DBG(1, "%s: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
+		     __func__, haddr, regs->gr[19], in_syscall);
 	}
 #endif
 
@@ -351,7 +321,7 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 		regs->gr[31] = haddr;
 #ifdef CONFIG_64BIT
 		if (!test_thread_flag(TIF_32BIT))
-			sigframe_size |= 1;
+			sigframe_size |= 1; /* XXX ???? */
 #endif
 	} else {
 		unsigned long psw = USER_PSW;
@@ -373,11 +343,11 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 		}
 
 		regs->gr[0] = psw;
-		regs->iaoq[0] = haddr | 3;
+		regs->iaoq[0] = haddr | PRIV_USER;
 		regs->iaoq[1] = regs->iaoq[0] + 4;
 	}
 
-	regs->gr[2]  = rp;                /* userland return pointer */
+	regs->gr[2]  = rp;			/* userland return pointer */
 	regs->gr[26] = ksig->sig;               /* signal number */
 	
 #ifdef CONFIG_64BIT
@@ -391,15 +361,15 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 		regs->gr[24] = A(&frame->uc);   /* ucontext pointer */
 	}
 	
-	DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
+	DBG(1, "%s: making sigreturn frame: %#lx + %#lx = %#lx\n", __func__,
 	       regs->gr[30], sigframe_size,
 	       regs->gr[30] + sigframe_size);
 	/* Raise the user stack pointer to make a proper call frame. */
 	regs->gr[30] = (A(frame) + sigframe_size);
 
 
-	DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
-	       current->comm, current->pid, frame, regs->gr[30],
+	DBG(1, "%s: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
+	       __func__, current->comm, current->pid, frame, regs->gr[30],
 	       regs->iaoq[0], regs->iaoq[1], rp);
 
 	return 0;
@@ -415,8 +385,8 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
 	int ret;
 	sigset_t *oldset = sigmask_to_save();
 
-	DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
-	       ksig->sig, ksig->ka, ksig->info, oldset, regs);
+	DBG(1, "%s: sig=%d, ka=%p, info=%p, oldset=%p, regs=%p\n",
+	       __func__, ksig->sig, &ksig->ka, &ksig->info, oldset, regs);
 	
 	/* Set up the stack frame */
 	ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
@@ -424,8 +394,8 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
 	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
 			  test_thread_flag(TIF_BLOCKSTEP));
 
-	DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
-		regs->gr[28]);
+	DBG(1, "%s: Exit (success), regs->gr[28] = %ld\n",
+		__func__, regs->gr[28]);
 }
 
 /*
@@ -483,21 +453,27 @@ syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
 	if (regs->orig_r28)
 		return;
 	regs->orig_r28 = 1; /* no more restarts */
+
+	DBG(1, "%s:  orig_r28 = %ld  pid %d  r20 %ld\n",
+		__func__, regs->orig_r28, task_pid_nr(current), regs->gr[20]);
+
 	/* Check the return code */
 	switch (regs->gr[28]) {
 	case -ERESTART_RESTARTBLOCK:
 	case -ERESTARTNOHAND:
-		DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
+		DBG(1, "%s: ERESTARTNOHAND: returning -EINTR\n", __func__);
 		regs->gr[28] = -EINTR;
 		break;
 	case -ERESTARTSYS:
 		if (!(ka->sa.sa_flags & SA_RESTART)) {
-			DBG(1,"ERESTARTSYS: putting -EINTR\n");
+			DBG(1, "%s: ERESTARTSYS: putting -EINTR pid %d\n",
+				__func__, task_pid_nr(current));
 			regs->gr[28] = -EINTR;
 			break;
 		}
 		fallthrough;
 	case -ERESTARTNOINTR:
+		DBG(1, "%s: %ld\n", __func__, regs->gr[28]);
 		check_syscallno_in_delay_branch(regs);
 		break;
 	}
@@ -509,50 +485,52 @@ insert_restart_trampoline(struct pt_regs *regs)
 	if (regs->orig_r28)
 		return;
 	regs->orig_r28 = 1; /* no more restarts */
-	switch(regs->gr[28]) {
+
+	DBG(2, "%s: gr28 = %ld pid %d\n",
+		__func__, regs->gr[28], task_pid_nr(current));
+
+	switch (regs->gr[28]) {
 	case -ERESTART_RESTARTBLOCK: {
 		/* Restart the system call - no handlers present */
 		unsigned int *usp = (unsigned int *)regs->gr[30];
-		unsigned long start = (unsigned long) &usp[2];
-		unsigned long end  = (unsigned long) &usp[5];
+		unsigned long rp;
 		long err = 0;
 
 		/* check that we don't exceed the stack */
 		if (A(&usp[0]) >= user_addr_max() - 5 * sizeof(int))
 			return;
 
-		/* Setup a trampoline to restart the syscall
-		 * with __NR_restart_syscall
+		/* Call trampoline in vdso to restart the syscall
+		 * with __NR_restart_syscall.
+		 * Original return addresses are on stack like this:
 		 *
 		 *  0: <return address (orig r31)>
 		 *  4: <2nd half for 64-bit>
-		 *  8: ldw 0(%sp), %r31
-		 * 12: be 0x100(%sr2, %r0)
-		 * 16: ldi __NR_restart_syscall, %r20
 		 */
 #ifdef CONFIG_64BIT
-		err |= put_user(regs->gr[31] >> 32, &usp[0]);
-		err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
-		err |= put_user(0x0fc010df, &usp[2]);
-#else
-		err |= put_user(regs->gr[31], &usp[0]);
-		err |= put_user(0x0fc0109f, &usp[2]);
+		if (!is_compat_task()) {
+			err |= put_user(regs->gr[31] >> 32, &usp[0]);
+			err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
+			rp = VDSO64_SYMBOL(current, restart_syscall);
+		} else
 #endif
-		err |= put_user(0xe0008200, &usp[3]);
-		err |= put_user(0x34140000, &usp[4]);
-
+		{
+			err |= put_user(regs->gr[31], &usp[0]);
+			rp = VDSO32_SYMBOL(current, restart_syscall);
+		}
 		WARN_ON(err);
 
-		/* flush data/instruction cache for new insns */
-		flush_user_dcache_range_asm(start, end);
-		flush_user_icache_range_asm(start, end);
-
-		regs->gr[31] = regs->gr[30] + 8;
+		regs->gr[31] = rp;
+		DBG(1, "%s: ERESTART_RESTARTBLOCK\n", __func__);
 		return;
 	}
+	case -EINTR:
+		/* ok, was handled before and should be returned. */
+		break;
 	case -ERESTARTNOHAND:
 	case -ERESTARTSYS:
 	case -ERESTARTNOINTR:
+		DBG(1, "%s: Type %ld\n", __func__, regs->gr[28]);
 		check_syscallno_in_delay_branch(regs);
 		return;
 	default:
@@ -567,30 +545,35 @@ insert_restart_trampoline(struct pt_regs *regs)
  * registers).  As noted below, the syscall number gets restored for
  * us due to the magic of delayed branching.
  */
-asmlinkage void
-do_signal(struct pt_regs *regs, long in_syscall)
+static void do_signal(struct pt_regs *regs, long in_syscall)
 {
 	struct ksignal ksig;
+	int restart_syscall;
+	bool has_handler;
 
-	DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
-	       regs, regs->sr[7], in_syscall);
+	has_handler = get_signal(&ksig);
 
-	if (get_signal(&ksig)) {
-		DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
+	restart_syscall = 0;
+	if (in_syscall)
+		restart_syscall = 1;
+
+	if (has_handler) {
 		/* Restart a system call if necessary. */
-		if (in_syscall)
+		if (restart_syscall)
 			syscall_restart(regs, &ksig.ka);
 
 		handle_signal(&ksig, regs, in_syscall);
+		DBG(1, "%s: Handled signal pid %d\n",
+			__func__, task_pid_nr(current));
 		return;
 	}
 
-	/* Did we come from a system call? */
-	if (in_syscall)
+	/* Do we need to restart the system call? */
+	if (restart_syscall)
 		insert_restart_trampoline(regs);
 	
-	DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n", 
-		regs->gr[28]);
+	DBG(1, "%s: Exit (not delivered), regs->gr[28] = %ld  orig_r28 = %ld  pid %d\n",
+		__func__, regs->gr[28], regs->orig_r28, task_pid_nr(current));
 
 	restore_saved_sigmask();
 }
diff --git a/arch/parisc/kernel/signal32.h b/arch/parisc/kernel/signal32.h
index f166250f2d06..c03eb1ed4c53 100644
--- a/arch/parisc/kernel/signal32.h
+++ b/arch/parisc/kernel/signal32.h
@@ -36,21 +36,12 @@ struct compat_regfile {
         compat_int_t rf_sar;
 };
 
-#define COMPAT_SIGRETURN_TRAMP 4
-#define COMPAT_SIGRESTARTBLOCK_TRAMP 5
-#define COMPAT_TRAMP_SIZE (COMPAT_SIGRETURN_TRAMP + \
-				COMPAT_SIGRESTARTBLOCK_TRAMP)
-
 struct compat_rt_sigframe {
-        /* XXX: Must match trampoline size in arch/parisc/kernel/signal.c
-                Secondary to that it must protect the ERESTART_RESTARTBLOCK
-                trampoline we left on the stack (we were bad and didn't
-                change sp so we could run really fast.) */
-        compat_uint_t tramp[COMPAT_TRAMP_SIZE];
-        compat_siginfo_t info;
-        struct compat_ucontext uc;
-        /* Hidden location of truncated registers, *must* be last. */
-        struct compat_regfile regs;
+	unsigned int tramp[2]; /* holds original return address */
+	compat_siginfo_t info;
+	struct compat_ucontext uc;
+	/* Hidden location of truncated registers, *must* be last. */
+	struct compat_regfile regs;
 };
 
 /*
diff --git a/arch/parisc/kernel/vdso.c b/arch/parisc/kernel/vdso.c
new file mode 100644
index 000000000000..63dc44c4c246
--- /dev/null
+++ b/arch/parisc/kernel/vdso.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (c) 2022 Helge Deller <deller@gmx.de>
+ *
+ *  based on arch/s390/kernel/vdso.c which is
+ *  Copyright IBM Corp. 2008
+ *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/elf.h>
+#include <linux/timekeeper_internal.h>
+#include <linux/compat.h>
+#include <linux/nsproxy.h>
+#include <linux/time_namespace.h>
+#include <linux/random.h>
+
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <asm/vdso.h>
+#include <asm/cacheflush.h>
+
+extern char vdso32_start, vdso32_end;
+extern char vdso64_start, vdso64_end;
+
+static int vdso_mremap(const struct vm_special_mapping *sm,
+		       struct vm_area_struct *vma)
+{
+	current->mm->context.vdso_base = vma->vm_start;
+	return 0;
+}
+
+#ifdef CONFIG_64BIT
+static struct vm_special_mapping vdso64_mapping = {
+	.name = "[vdso]",
+	.mremap = vdso_mremap,
+};
+#endif
+
+static struct vm_special_mapping vdso32_mapping = {
+	.name = "[vdso]",
+	.mremap = vdso_mremap,
+};
+
+/*
+ * This is called from binfmt_elf, we create the special vma for the
+ * vDSO and insert it into the mm struct tree
+ */
+int arch_setup_additional_pages(struct linux_binprm *bprm,
+				int executable_stack)
+{
+
+	unsigned long vdso_text_start, vdso_text_len, map_base;
+	struct vm_special_mapping *vdso_mapping;
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	int rc;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+#ifdef CONFIG_64BIT
+	if (!is_compat_task()) {
+		vdso_text_len = &vdso64_end - &vdso64_start;
+		vdso_mapping = &vdso64_mapping;
+	} else
+#endif
+	{
+		vdso_text_len = &vdso32_end - &vdso32_start;
+		vdso_mapping = &vdso32_mapping;
+	}
+
+	map_base = mm->mmap_base;
+	if (current->flags & PF_RANDOMIZE)
+		map_base -= (get_random_int() & 0x1f) * PAGE_SIZE;
+
+	vdso_text_start = get_unmapped_area(NULL, map_base, vdso_text_len, 0, 0);
+
+	/* VM_MAYWRITE for COW so gdb can set breakpoints */
+	vma = _install_special_mapping(mm, vdso_text_start, vdso_text_len,
+				       VM_READ|VM_EXEC|
+				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+				       vdso_mapping);
+	if (IS_ERR(vma)) {
+		do_munmap(mm, vdso_text_start, PAGE_SIZE, NULL);
+		rc = PTR_ERR(vma);
+	} else {
+		current->mm->context.vdso_base = vdso_text_start;
+		rc = 0;
+	}
+
+	mmap_write_unlock(mm);
+	return rc;
+}
+
+static struct page ** __init vdso_setup_pages(void *start, void *end)
+{
+	int pages = (end - start) >> PAGE_SHIFT;
+	struct page **pagelist;
+	int i;
+
+	pagelist = kcalloc(pages + 1, sizeof(struct page *), GFP_KERNEL);
+	if (!pagelist)
+		panic("%s: Cannot allocate page list for VDSO", __func__);
+	for (i = 0; i < pages; i++)
+		pagelist[i] = virt_to_page(start + i * PAGE_SIZE);
+	return pagelist;
+}
+
+static int __init vdso_init(void)
+{
+#ifdef CONFIG_64BIT
+	vdso64_mapping.pages = vdso_setup_pages(&vdso64_start, &vdso64_end);
+#endif
+	if (IS_ENABLED(CONFIG_COMPAT) || !IS_ENABLED(CONFIG_64BIT))
+		vdso32_mapping.pages = vdso_setup_pages(&vdso32_start, &vdso32_end);
+	return 0;
+}
+arch_initcall(vdso_init);
diff --git a/arch/parisc/kernel/vdso32/Makefile b/arch/parisc/kernel/vdso32/Makefile
new file mode 100644
index 000000000000..85b1c6d261d1
--- /dev/null
+++ b/arch/parisc/kernel/vdso32/Makefile
@@ -0,0 +1,53 @@
+# List of files in the vdso, has to be asm only for now
+
+obj-vdso32 = note.o sigtramp.o restart_syscall.o
+
+# Build rules
+
+targets := $(obj-vdso32) vdso32.so
+obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
+
+ccflags-y := -shared -fno-common -fbuiltin -mno-fast-indirect-calls -O2 -mno-long-calls
+#  -march=1.1 -mschedule=7100LC
+ccflags-y += -nostdlib -Wl,-soname=linux-vdso32.so.1 \
+		$(call ld-option, -Wl$(comma)--hash-style=sysv)
+asflags-y := -D__VDSO32__ -s
+
+KBUILD_AFLAGS += -DBUILD_VDSO
+KBUILD_CFLAGS += -DBUILD_VDSO -DDISABLE_BRANCH_PROFILING
+
+VDSO_LIBGCC := $(shell $(CROSS32CC) -print-libgcc-file-name)
+
+obj-y += vdso32_wrapper.o
+extra-y += vdso32.lds
+CPPFLAGS_vdso32.lds += -P -C  #  -U$(ARCH)
+
+$(obj)/vdso32_wrapper.o : $(obj)/vdso32.so FORCE
+
+# Force dependency (incbin is bad)
+# link rule for the .so file, .lds has to be first
+$(obj)/vdso32.so: $(src)/vdso32.lds $(obj-vdso32) $(obj-cvdso32) $(VDSO_LIBGCC)
+	$(call if_changed,vdso32ld)
+
+# assembly rules for the .S files
+$(obj-vdso32): %.o: %.S FORCE
+	$(call if_changed_dep,vdso32as)
+
+$(obj-cvdso32): %.o: %.c FORCE
+	$(call if_changed_dep,vdso32cc)
+
+# actual build commands
+quiet_cmd_vdso32ld = VDSO32L $@
+      cmd_vdso32ld = $(CROSS32CC) $(c_flags) -Wl,-T $^ -o $@
+quiet_cmd_vdso32as = VDSO32A $@
+      cmd_vdso32as = $(CROSS32CC) $(a_flags) -c -o $@ $<
+quiet_cmd_vdso32cc = VDSO32C $@
+      cmd_vdso32cc = $(CROSS32CC) $(c_flags) -c -fPIC -mno-fast-indirect-calls -o $@ $<
+
+# Generate VDSO offsets using helper script
+gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
+quiet_cmd_vdsosym = VDSOSYM $@
+	cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
+
+include/generated/vdso32-offsets.h: $(obj)/vdso32.so FORCE
+	$(call if_changed,vdsosym)
diff --git a/arch/parisc/kernel/vdso32/gen_vdso_offsets.sh b/arch/parisc/kernel/vdso32/gen_vdso_offsets.sh
new file mode 100755
index 000000000000..da39d6cff7f1
--- /dev/null
+++ b/arch/parisc/kernel/vdso32/gen_vdso_offsets.sh
@@ -0,0 +1,15 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+#
+# Match symbols in the DSO that look like VDSO_*; produce a header file
+# of constant offsets i