git: e9bb4ce3d0e7 - main - arm64: don't pass user trapframe to kdb_trap()

[Mitchell Horne]

The branch main has been updated by mhorne:

URL: https://cgit.FreeBSD.org/src/commit/?id=e9bb4ce3d0e714d35b12ffdc7ecb56cade01f4a0

commit e9bb4ce3d0e714d35b12ffdc7ecb56cade01f4a0
Author:     mhorne <mhorne at FreeBSD.org>
AuthorDate: 2020-12-18 18:43:52 +0000
Commit:     Mitchell Horne <mhorne at FreeBSD.org>
CommitDate: 2021-01-08 18:53:20 +0000

    arm64: don't pass user trapframe to kdb_trap()
    
    This effectively undoes the changes made in r321571. While useful, it is
    inconsistent with how other architectures pass trapframes to kdb. This
    change is also required to get a working gdb(4) stub on arm64, as
    otherwise the backtrace will begin too early.
    
    As of 088a7eef95b1, this information can still be obtained via
    "show registers/u".
    
    Reviewed by:    jhb (slightly earlier version)
    MFC after:      2 weeks
    Sponsored by:   The FreeBSD Foundation
    Pull Request:   https://reviews.freebsd.org/D27719
---
 sys/arm64/arm64/trap.c | 22 ++--------------------
 1 file changed, 2 insertions(+), 20 deletions(-)

diff --git a/sys/arm64/arm64/trap.c b/sys/arm64/arm64/trap.c
index 1330838148d2..12d10ff1d261 100644
--- a/sys/arm64/arm64/trap.c
+++ b/sys/arm64/arm64/trap.c
@@ -360,7 +360,6 @@ print_registers(struct trapframe *frame)
 void
 do_el1h_sync(struct thread *td, struct trapframe *frame)
 {
-	struct trapframe *oframe;
 	uint32_t exception;
 	uint64_t esr, far;
 	int dfsc;
@@ -378,18 +377,6 @@ do_el1h_sync(struct thread *td, struct trapframe *frame)
 	    "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td,
 	    esr, frame->tf_elr, frame);
 
-	oframe = td->td_frame;
-
-	switch (exception) {
-	case EXCP_BRK:
-	case EXCP_WATCHPT_EL1:
-	case EXCP_SOFTSTP_EL1:
-		break;
-	default:
-		td->td_frame = frame;
-		break;
-	}
-
 	switch (exception) {
 	case EXCP_FP_SIMD:
 	case EXCP_TRAP_FP:
@@ -429,18 +416,15 @@ do_el1h_sync(struct thread *td, struct trapframe *frame)
 		}
 #endif
 #ifdef KDB
-		kdb_trap(exception, 0,
-		    (td->td_frame != NULL) ? td->td_frame : frame);
+		kdb_trap(exception, 0, frame);
 #else
 		panic("No debugger in kernel.\n");
 #endif
-		frame->tf_elr += 4;
 		break;
 	case EXCP_WATCHPT_EL1:
 	case EXCP_SOFTSTP_EL1:
 #ifdef KDB
-		kdb_trap(exception, 0,
-		    (td->td_frame != NULL) ? td->td_frame : frame);
+		kdb_trap(exception, 0, frame);
 #else
 		panic("No debugger in kernel.\n");
 #endif
@@ -455,8 +439,6 @@ do_el1h_sync(struct thread *td, struct trapframe *frame)
 		panic("Unknown kernel exception %x esr_el1 %lx\n", exception,
 		    esr);
 	}
-
-	td->td_frame = oframe;
 }
 
 void