svn commit: r305807 - in head/sys: amd64/amd64 i386/i386 x86/include
Bruce Evans
bde at FreeBSD.org
Wed Sep 14 12:57:42 UTC 2016
Author: bde
Date: Wed Sep 14 12:57:40 2016
New Revision: 305807
URL: https://svnweb.freebsd.org/changeset/base/305807
Log:
Use the MI macro TRAPF_USERMODE() instead of open-coded checks for
SEL_UPL and sometimes PSL_VM. This is just a style change on amd64,
but on i386 it fixes 1 unimportant place where the PSL_VM check was
missing and starts fixing 1 important place where the PSL_VM check
had a logic error.
Fix logic errors in treating vm86 bioscall mode as kernel mode. The
main place checked all the necessary flags, but put the necessary
parentheses for the PSL_VM and PCB_VM86CALL checks in the wrong
place. The broken case is only reached if a vm86 bioscall uses a
%cs which is nonzero mod 4, but that is unusual -- most bios calls
start with %cs = 0xc000 or 0xf000 and rarely change it. Another
place was missing the check for PCB_VM86CALL, but was only reachable
if there are bugs virtualizing PSL_I.
Add a macro TF_HAS_STACKREGS() and use this instead of converting
open-coded checks of SEL_UPL, etc. to TRAPF_USERMODE() when we only
care about whether the frame has stack registers. This fixes 3
places in my recent fix for register variables in vm86 mode where I
messed up the PSL_VM check and cleans up other places.
Modified:
head/sys/amd64/amd64/trap.c
head/sys/i386/i386/db_trace.c
head/sys/i386/i386/trap.c
head/sys/x86/include/frame.h
Modified: head/sys/amd64/amd64/trap.c
==============================================================================
--- head/sys/amd64/amd64/trap.c Wed Sep 14 12:07:34 2016 (r305806)
+++ head/sys/amd64/amd64/trap.c Wed Sep 14 12:57:40 2016 (r305807)
@@ -236,7 +236,7 @@ trap(struct trapframe *frame)
* interrupts disabled until they are accidentally
* enabled later.
*/
- if (ISPL(frame->tf_cs) == SEL_UPL)
+ if (TRAPF_USERMODE(frame))
uprintf(
"pid %ld (%s): trap %d with interrupts disabled\n",
(long)curproc->p_pid, curthread->td_name, type);
@@ -260,7 +260,7 @@ trap(struct trapframe *frame)
code = frame->tf_err;
- if (ISPL(frame->tf_cs) == SEL_UPL) {
+ if (TRAPF_USERMODE(frame)) {
/* user trap */
td->td_pticks = 0;
@@ -787,7 +787,7 @@ trap_fatal(frame, eva)
else
msg = "UNKNOWN";
printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
- ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
+ TRAPF_USERMODE(frame) ? "user" : "kernel");
#ifdef SMP
/* two separate prints in case of a trap on an unmapped page */
printf("cpuid = %d; ", PCPU_GET(cpuid));
@@ -804,7 +804,7 @@ trap_fatal(frame, eva)
}
printf("instruction pointer = 0x%lx:0x%lx\n",
frame->tf_cs & 0xffff, frame->tf_rip);
- if (ISPL(frame->tf_cs) == SEL_UPL) {
+ if (TF_HAS_STACKREGS(frame)) {
ss = frame->tf_ss & 0xffff;
esp = frame->tf_rsp;
} else {
@@ -934,7 +934,7 @@ amd64_syscall(struct thread *td, int tra
ksiginfo_t ksi;
#ifdef DIAGNOSTIC
- if (ISPL(td->td_frame->tf_cs) != SEL_UPL) {
+ if (!TRAPF_USERMODE(frame)) {
panic("syscall");
/* NOT REACHED */
}
Modified: head/sys/i386/i386/db_trace.c
==============================================================================
--- head/sys/i386/i386/db_trace.c Wed Sep 14 12:07:34 2016 (r305806)
+++ head/sys/i386/i386/db_trace.c Wed Sep 14 12:57:40 2016 (r305807)
@@ -82,8 +82,7 @@ struct db_variable *db_eregs = db_regs +
static __inline int
get_esp(struct trapframe *tf)
{
- return ((ISPL(tf->tf_cs) || kdb_frame->tf_eflags & PSL_VM) ?
- tf->tf_esp : (intptr_t)&tf->tf_esp);
+ return (TF_HAS_STACKREGS(tf) ? tf->tf_esp : (intptr_t)&tf->tf_esp);
}
static int
@@ -147,7 +146,7 @@ db_esp(struct db_variable *vp, db_expr_t
if (op == DB_VAR_GET)
*valuep = get_esp(kdb_frame);
- else if (ISPL(kdb_frame->tf_cs))
+ else if (TF_HAS_STACKREGS(kdb_frame))
kdb_frame->tf_esp = *valuep;
return (1);
}
@@ -180,9 +179,9 @@ db_ss(struct db_variable *vp, db_expr_t
return (0);
if (op == DB_VAR_GET)
- *valuep = (ISPL(kdb_frame->tf_cs) ||
- kdb_frame->tf_eflags & PSL_VM) ? kdb_frame->tf_ss : rss();
- else if (ISPL(kdb_frame->tf_cs) || kdb_frame->tf_eflags & PSL_VM)
+ *valuep = TF_HAS_STACKREGS(kdb_frame) ? kdb_frame->tf_ss :
+ rss();
+ else if (TF_HAS_STACKREGS(kdb_frame))
kdb_frame->tf_ss = *valuep;
return (1);
}
@@ -439,7 +438,7 @@ db_backtrace(struct thread *td, struct t
* Find where the trap frame actually ends.
* It won't contain tf_esp or tf_ss unless crossing rings.
*/
- if (ISPL(kdb_frame->tf_cs))
+ if (TF_HAS_STACKREGS(kdb_frame))
instr = (int)(kdb_frame + 1);
else
instr = (int)&kdb_frame->tf_esp;
Modified: head/sys/i386/i386/trap.c
==============================================================================
--- head/sys/i386/i386/trap.c Wed Sep 14 12:07:34 2016 (r305806)
+++ head/sys/i386/i386/trap.c Wed Sep 14 12:57:40 2016 (r305807)
@@ -267,7 +267,8 @@ trap(struct trapframe *frame)
* interrupts disabled until they are accidentally
* enabled later.
*/
- if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM))
+ if (TRAPF_USERMODE(frame) &&
+ (curpcb->pcb_flags & PCB_VM86CALL) == 0)
uprintf(
"pid %ld (%s): trap %d with interrupts disabled\n",
(long)curproc->p_pid, curthread->td_name, type);
@@ -307,9 +308,7 @@ trap(struct trapframe *frame)
enable_intr();
}
- if ((ISPL(frame->tf_cs) == SEL_UPL) ||
- ((frame->tf_eflags & PSL_VM) &&
- !(curpcb->pcb_flags & PCB_VM86CALL))) {
+ if (TRAPF_USERMODE(frame) && (curpcb->pcb_flags & PCB_VM86CALL) == 0) {
/* user trap */
td->td_pticks = 0;
@@ -963,7 +962,7 @@ trap_fatal(frame, eva)
}
printf("instruction pointer = 0x%x:0x%x\n",
frame->tf_cs & 0xffff, frame->tf_eip);
- if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
+ if (TF_HAS_STACKREGS(frame)) {
ss = frame->tf_ss & 0xffff;
esp = frame->tf_esp;
} else {
@@ -1117,7 +1116,8 @@ syscall(struct trapframe *frame)
ksiginfo_t ksi;
#ifdef DIAGNOSTIC
- if (ISPL(frame->tf_cs) != SEL_UPL) {
+ if (!(TRAPF_USERMODE(frame) &&
+ (curpcb->pcb_flags & PCB_VM86CALL) == 0)) {
panic("syscall");
/* NOT REACHED */
}
Modified: head/sys/x86/include/frame.h
==============================================================================
--- head/sys/x86/include/frame.h Wed Sep 14 12:07:34 2016 (r305806)
+++ head/sys/x86/include/frame.h Wed Sep 14 12:57:40 2016 (r305807)
@@ -64,7 +64,7 @@ struct trapframe {
int tf_eip;
int tf_cs;
int tf_eflags;
- /* below only when crossing rings (e.g. user to kernel) */
+ /* below only when crossing rings (user to kernel) */
int tf_esp;
int tf_ss;
};
@@ -89,10 +89,10 @@ struct trapframe_vm86 {
int tf_eip;
int tf_cs;
int tf_eflags;
- /* below only when crossing rings (e.g. user to kernel) */
+ /* below only when crossing rings (user (including vm86) to kernel) */
int tf_esp;
int tf_ss;
- /* below only when switching out of VM86 mode */
+ /* below only when crossing from vm86 mode to kernel */
int tf_vm86_es;
int tf_vm86_ds;
int tf_vm86_fs;
@@ -136,6 +136,7 @@ struct trapframe {
register_t tf_rip;
register_t tf_cs;
register_t tf_rflags;
+ /* below only when crossing rings (user to kernel) */
register_t tf_rsp;
register_t tf_ss;
};
@@ -145,4 +146,13 @@ struct trapframe {
#define TF_HASFPXSTATE 0x4
#endif /* __amd64__ */
+/*
+ * This alias for the MI TRAPF_USERMODE() should be used when we don't
+ * care about user mode itself, but need to know if a frame has stack
+ * registers. The difference is only logical, but on i386 the logic
+ * for using TRAPF_USERMODE() is complicated by sometimes treating vm86
+ * bioscall mode (which is a special ring 3 user mode) as kernel mode.
+ */
+#define TF_HAS_STACKREGS(tf) TRAPF_USERMODE(tf)
+
#endif /* _MACHINE_FRAME_H_ */
More information about the svn-src-head
mailing list