Clear BTYPE bits when setting up a signal handler and when handling a

PT_CONTINUE ptrace(2) request.  Otherwise we would trap if userland was
interrupted at a point where it is doing an indirect branch that has set
the bits but before it has executed the BTI instruction at the branch
target.

The PT_SETREGS request may need similar treatment, at least when the
PC is changed.  But Linux doesn't do this and debuggers might want full
control over the BTYPE bits.  So leave this alone for now.

ok guenther@

diff --git a/sys/arch/arm64/arm64/process_machdep.c b/sys/arch/arm64/arm64/process_machdep.c
index 8703a91..26671a7 100644 (file)
--- a/sys/arch/arm64/arm64/process_machdep.c
+++ b/sys/arch/arm64/arm64/process_machdep.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: process_machdep.c,v 1.6 2022/01/01 18:52:36 kettenis Exp $ */
+/* $OpenBSD: process_machdep.c,v 1.7 2023/04/16 10:14:59 kettenis Exp $ */
 /*
  * Copyright (c) 2014 Patrick Wildt <patrick@blueri.se>
  *
@@ -128,7 +128,10 @@ int
 process_set_pc(struct proc *p, caddr_t addr)
 {
        struct trapframe *tf = p->p_addr->u_pcb.pcb_tf;
+
        tf->tf_elr = (uint64_t)addr;
+       tf->tf_spsr &= ~PSR_BTYPE;
+
        return (0);
 }
 

diff --git a/sys/arch/arm64/arm64/sig_machdep.c b/sys/arch/arm64/arm64/sig_machdep.c
index 69006f7..e0368ff 100644 (file)
--- a/sys/arch/arm64/arm64/sig_machdep.c
+++ b/sys/arch/arm64/arm64/sig_machdep.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: sig_machdep.c,v 1.8 2021/10/06 15:46:03 claudio Exp $ */
+/*     $OpenBSD: sig_machdep.c,v 1.9 2023/04/16 10:14:59 kettenis Exp $ */
 
 /*
  * Copyright (c) 1990 The Regents of the University of California.
@@ -157,6 +157,7 @@ sendsig(sig_t catcher, int sig, sigset_t mask, const siginfo_t *ksip,
        tf->tf_sp = (register_t)fp;
 
        tf->tf_elr = p->p_p->ps_sigcode;
+       tf->tf_spsr &= ~PSR_BTYPE;
 
        return 0;
 }

diff --git a/sys/arch/arm64/include/armreg.h b/sys/arch/arm64/include/armreg.h
index bffe8cc..7c5be0c 100644 (file)
--- a/sys/arch/arm64/include/armreg.h
+++ b/sys/arch/arm64/include/armreg.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: armreg.h,v 1.27 2023/03/27 19:02:48 kettenis Exp $ */
+/* $OpenBSD: armreg.h,v 1.28 2023/04/16 10:14:59 kettenis Exp $ */
 /*-
  * Copyright (c) 2013, 2014 Andrew Turner
  * Copyright (c) 2015 The FreeBSD Foundation
@@ -673,6 +673,7 @@
 #define        PSR_I           0x00000080
 #define        PSR_A           0x00000100
 #define        PSR_D           0x00000200
+#define        PSR_BTYPE       0x00000c00
 #define        PSR_SSBS        0x00001000
 #define        PSR_IL          0x00100000
 #define        PSR_SS          0x00200000