Implement makectx(). The makectx() function is used by KDB to create

a PCB from a trapframe for purposes of unwinding the stack. The PCB
is used as the thread context and all but the thread that entered the
debugger has a valid PCB.
This function can also be used to create a context for the threads
running on the CPUs that have been stopped when the debugger got
entered. This however is not done at the time of this commit.

10 files changed, 108 insertions, 1 deletions

diff --git a/sys/alpha/alpha/machdep.c b/sys/alpha/alpha/machdep.c
index 005e56e..82c856d 100644
--- a/sys/alpha/alpha/machdep.c
+++ b/sys/alpha/alpha/machdep.c
@@ -1989,6 +1989,29 @@ alpha_pa_access(vm_offset_t pa)
 #endif
 }
 
+/*
+ * Construct a PCB from a trapframe. This is called from kdb_trap() where
+ * we want to start a backtrace from the function that caused us to enter
+ * the debugger. We have the context in the trapframe, but base the trace
+ * on the PCB. The PCB doesn't have to be perfect, as long as it contains
+ * enough for a backtrace.
+ */
+void
+makectx(struct trapframe *tf, struct pcb *pcb)
+{
+
+	pcb->pcb_context[0] = tf->tf_regs[FRAME_S0];
+	pcb->pcb_context[1] = tf->tf_regs[FRAME_S1];
+	pcb->pcb_context[2] = tf->tf_regs[FRAME_S2];
+	pcb->pcb_context[3] = tf->tf_regs[FRAME_S3];
+	pcb->pcb_context[4] = tf->tf_regs[FRAME_S4];
+	pcb->pcb_context[5] = tf->tf_regs[FRAME_S5];
+	pcb->pcb_context[6] = tf->tf_regs[FRAME_S6];
+	pcb->pcb_context[7] = tf->tf_regs[FRAME_PC];
+	pcb->pcb_context[8] = tf->tf_regs[FRAME_PS];
+	pcb->pcb_hw.apcb_ksp = tf->tf_regs[FRAME_SP];
+}
+
 int
 fill_regs(td, regs)
 	struct thread *td;
diff --git a/sys/alpha/include/pcb.h b/sys/alpha/include/pcb.h
index 982e97b..4375ef2 100644
--- a/sys/alpha/include/pcb.h
+++ b/sys/alpha/include/pcb.h
@@ -58,6 +58,7 @@ struct pcb {
 };
 
 #ifdef _KERNEL
+void	makectx(struct trapframe *, struct pcb *);
 void	savectx(struct pcb *);
 #endif
 
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 2d0fd66..8a107ab 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1265,6 +1265,27 @@ cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
 	pcpu->pc_acpi_id = 0xffffffff;
 }
 
+/*
+ * Construct a PCB from a trapframe. This is called from kdb_trap() where
+ * we want to start a backtrace from the function that caused us to enter
+ * the debugger. We have the context in the trapframe, but base the trace
+ * on the PCB. The PCB doesn't have to be perfect, as long as it contains
+ * enough for a backtrace.
+ */
+void
+makectx(struct trapframe *tf, struct pcb *pcb)
+{
+
+	pcb->pcb_r12 = tf->tf_r12;
+	pcb->pcb_r13 = tf->tf_r13;
+	pcb->pcb_r14 = tf->tf_r14;
+	pcb->pcb_r15 = tf->tf_r15;
+	pcb->pcb_rbp = tf->tf_rbp;
+	pcb->pcb_rbx = tf->tf_rbx;
+	pcb->pcb_rip = tf->tf_rip;
+	pcb->pcb_rsp = (ISPL(tf->tf_cs)) ? tf->tf_rsp : (long)(tf + 1) - 8;
+}
+
 int
 ptrace_set_pc(struct thread *td, unsigned long addr)
 {
diff --git a/sys/amd64/include/pcb.h b/sys/amd64/include/pcb.h
index 73d8aa5..305b7ff 100644
--- a/sys/amd64/include/pcb.h
+++ b/sys/amd64/include/pcb.h
@@ -78,6 +78,9 @@ struct pcb {
 };
 
 #ifdef _KERNEL
+struct trapframe;
+
+void	makectx(struct trapframe *, struct pcb *);
 void	savectx(struct pcb *);
 #endif
 
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 9fbc6f9..b1b388c 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -2206,6 +2206,25 @@ f00f_hack(void *unused)
 }
 #endif /* defined(I586_CPU) && !NO_F00F_HACK */
 
+/*
+ * Construct a PCB from a trapframe. This is called from kdb_trap() where
+ * we want to start a backtrace from the function that caused us to enter
+ * the debugger. We have the context in the trapframe, but base the trace
+ * on the PCB. The PCB doesn't have to be perfect, as long as it contains
+ * enough for a backtrace.
+ */
+void
+makectx(struct trapframe *tf, struct pcb *pcb)
+{
+
+	pcb->pcb_edi = tf->tf_edi;
+	pcb->pcb_esi = tf->tf_esi;
+	pcb->pcb_ebp = tf->tf_ebp;
+	pcb->pcb_ebx = tf->tf_ebx;
+	pcb->pcb_eip = tf->tf_eip;
+	pcb->pcb_esp = (ISPL(tf->tf_cs)) ? tf->tf_esp : (int)(tf + 1) - 8;
+}
+
 int
 ptrace_set_pc(struct thread *td, u_long addr)
 {
diff --git a/sys/i386/include/pcb.h b/sys/i386/include/pcb.h
index c88823a..3f32340 100644
--- a/sys/i386/include/pcb.h
+++ b/sys/i386/include/pcb.h
@@ -74,6 +74,9 @@ struct pcb {
 };
 
 #ifdef _KERNEL
+struct trapframe;
+
+void	makectx(struct trapframe *, struct pcb *);
 void	savectx(struct pcb *);
 #endif
 
diff --git a/sys/ia64/ia64/machdep.c b/sys/ia64/ia64/machdep.c
index ca75d2c..5c39d05 100644
--- a/sys/ia64/ia64/machdep.c
+++ b/sys/ia64/ia64/machdep.c
@@ -1017,6 +1017,23 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 }
 #endif
 
+/*
+ * Construct a PCB from a trapframe. This is called from kdb_trap() where
+ * we want to start a backtrace from the function that caused us to enter
+ * the debugger. We have the context in the trapframe, but base the trace
+ * on the PCB. The PCB doesn't have to be perfect, as long as it contains
+ * enough for a backtrace.
+ */
+void
+makectx(struct trapframe *tf, struct pcb *pcb)
+{
+
+	pcb->pcb_special = tf->tf_special;
+	pcb->pcb_special.__spare = ~0UL;	/* XXX see unwind.c */
+	save_callee_saved(&pcb->pcb_preserved);
+	save_callee_saved_fp(&pcb->pcb_preserved_fp);
+}
+
 int
 get_mcontext(struct thread *td, mcontext_t *mc, int flags)
 {
diff --git a/sys/ia64/include/pcb.h b/sys/ia64/include/pcb.h
index 23d7e50..d018127 100644
--- a/sys/ia64/include/pcb.h
+++ b/sys/ia64/include/pcb.h
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2003 Doug Rabson
+ * Copyright (c) 2003,2004 Marcel Moolenaar
  * Copyright (c) 2000 Doug Rabson
  * All rights reserved.
  *
@@ -59,6 +59,10 @@ struct pcb {
 #ifdef _KERNEL
 
 #define	savectx(p)	swapctx(p, NULL)
+
+struct trapframe;
+
+void makectx(struct trapframe *, struct pcb *);
 void restorectx(struct pcb *) __dead2;
 int swapctx(struct pcb *old, struct pcb *new);
 
diff --git a/sys/sparc64/include/pcb.h b/sys/sparc64/include/pcb.h
index 38578d2..1f1e8dc 100644
--- a/sys/sparc64/include/pcb.h
+++ b/sys/sparc64/include/pcb.h
@@ -49,6 +49,7 @@ struct pcb {
 } __aligned(64);
 
 #ifdef _KERNEL
+void	makectx(struct trapframe *, struct pcb *);
 int	savectx(struct pcb *pcb);
 #endif
 
diff --git a/sys/sparc64/sparc64/machdep.c b/sys/sparc64/sparc64/machdep.c
index 3db2dd8..2bc8329 100644
--- a/sys/sparc64/sparc64/machdep.c
+++ b/sys/sparc64/sparc64/machdep.c
@@ -564,6 +564,21 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 }
 #endif
 
+/*
+ * Construct a PCB from a trapframe. This is called from kdb_trap() where
+ * we want to start a backtrace from the function that caused us to enter
+ * the debugger. We have the context in the trapframe, but base the trace
+ * on the PCB. The PCB doesn't have to be perfect, as long as it contains
+ * enough for a backtrace.
+ */
+void
+makectx(struct trapframe *tf, struct pcb *pcb)
+{
+
+	pcb->pcb_pc = tf->tf_tpc;
+	pcb->pcb_sp = tf->tf_sp;
+}
+
 int
 get_mcontext(struct thread *td, mcontext_t *mc, int flags)
 {