git: c0422e6c365e - stable/13 - arm64: clear debug registers after execve(2)

[Mitchell Horne]

The branch stable/13 has been updated by mhorne:

URL: https://cgit.FreeBSD.org/src/commit/?id=c0422e6c365eca801bde5b2f644e3a7e4803dbc8

commit c0422e6c365eca801bde5b2f644e3a7e4803dbc8
Author:     Mitchell Horne <mhorne at FreeBSD.org>
AuthorDate: 2021-04-09 14:13:21 +0000
Commit:     Mitchell Horne <mhorne at FreeBSD.org>
CommitDate: 2021-04-16 13:48:39 +0000

    arm64: clear debug registers after execve(2)
    
    This is both intuitive and required, as any previous breakpoint settings
    may not be applicable to the new process.
    
    Reported by:    arichardson
    Reviewed by:    kib
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit a2a8b582bdc1c8c1f4da3ae727349327f5fc9dd8)
---
 sys/arm64/arm64/elf32_machdep.c |  8 +++++++-
 sys/arm64/arm64/machdep.c       |  5 ++++-
 sys/arm64/linux/linux_sysvec.c  | 12 +++++++++---
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/sys/arm64/arm64/elf32_machdep.c b/sys/arm64/arm64/elf32_machdep.c
index 84b62caf8590..b9669616e1dd 100644
--- a/sys/arm64/arm64/elf32_machdep.c
+++ b/sys/arm64/arm64/elf32_machdep.c
@@ -239,6 +239,7 @@ freebsd32_setregs(struct thread *td, struct image_params *imgp,
    uintptr_t stack)
 {
 	struct trapframe *tf = td->td_frame;
+	struct pcb *pcb = td->td_pcb;
 
 	memset(tf, 0, sizeof(struct trapframe));
 
@@ -256,8 +257,13 @@ freebsd32_setregs(struct thread *td, struct image_params *imgp,
 	tf->tf_spsr = PSR_M_32;
 
 #ifdef VFP
-	vfp_reset_state(td, td->td_pcb);
+	vfp_reset_state(td, pcb);
 #endif
+
+	/*
+	 * Clear debug register state. It is not applicable to the new process.
+	 */
+	bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
 }
 
 void
diff --git a/sys/arm64/arm64/machdep.c b/sys/arm64/arm64/machdep.c
index 8a1e7520aacb..5cc17d2a4612 100644
--- a/sys/arm64/arm64/machdep.c
+++ b/sys/arm64/arm64/machdep.c
@@ -569,7 +569,10 @@ exec_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack)
 	vfp_reset_state(td, pcb);
 #endif
 
-	/* TODO: Shouldn't we also reset pcb_dbg_regs? */
+	/*
+	 * Clear debug register state. It is not applicable to the new process.
+	 */
+	bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
 }
 
 /* Sanity check these are the same size, they will be memcpy'd to and fro */
diff --git a/sys/arm64/linux/linux_sysvec.c b/sys/arm64/linux/linux_sysvec.c
index df16db4040a7..e20e0fd32b91 100644
--- a/sys/arm64/linux/linux_sysvec.c
+++ b/sys/arm64/linux/linux_sysvec.c
@@ -351,6 +351,7 @@ linux_exec_setregs(struct thread *td, struct image_params *imgp,
     uintptr_t stack)
 {
 	struct trapframe *regs = td->td_frame;
+	struct pcb *pcb = td->td_pcb;
 
 	/* LINUXTODO: validate */
 	LIN_SDT_PROBE0(sysvec, linux_exec_setregs, todo);
@@ -365,14 +366,19 @@ linux_exec_setregs(struct thread *td, struct image_params *imgp,
 #endif
         regs->tf_elr = imgp->entry_addr;
 
-	td->td_pcb->pcb_tpidr_el0 = 0;
-	td->td_pcb->pcb_tpidrro_el0 = 0;
+	pcb->pcb_tpidr_el0 = 0;
+	pcb->pcb_tpidrro_el0 = 0;
 	WRITE_SPECIALREG(tpidrro_el0, 0);
 	WRITE_SPECIALREG(tpidr_el0, 0);
 
 #ifdef VFP
-	vfp_reset_state(td, td->td_pcb);
+	vfp_reset_state(td, pcb);
 #endif
+
+	/*
+	 * Clear debug register state. It is not applicable to the new process.
+	 */
+	bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
 }
 
 int