[Xen-changelog] [xen-unstable] x86: Generalise BUGFRAME_dump mechanism to allow polled UART irq to

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1267008270 0
# Node ID 8cb6e7eff2ba154afa2d1c29cca05989023ab7fe
# Parent  351a34c2fd48a362dc5339db44916c4478c2564d
x86: Generalise BUGFRAME_dump mechanism to allow polled UART irq to
get proper regs argument.

Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
 xen/arch/x86/traps.c                  |   32 ++++++++++++++++++--------------
 xen/drivers/acpi/utilities/utglobal.c |    1 +
 xen/drivers/char/ns16550.c            |   22 +++++++++++++++++-----
 xen/include/asm-x86/bug.h             |    9 +++++----
 xen/include/asm-x86/processor.h       |    1 +
 5 files changed, 42 insertions(+), 23 deletions(-)

diff -r 351a34c2fd48 -r 8cb6e7eff2ba xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c      Wed Feb 24 09:38:35 2010 +0000
+++ b/xen/arch/x86/traps.c      Wed Feb 24 10:44:30 2010 +0000
@@ -892,6 +892,7 @@ asmlinkage void do_invalid_op(struct cpu
 {
     struct bug_frame bug;
     struct bug_frame_str bug_str;
+    const void *p;
     const char *filename, *predicate, *eip = (char *)regs->eip;
     unsigned long fixup;
     int id, lineno;
@@ -913,26 +914,29 @@ asmlinkage void do_invalid_op(struct cpu
         goto die;
     eip += sizeof(bug);
 
-    id = bug.id & 3;
-
-    if ( id == BUGFRAME_dump )
-    {
-        show_execution_state(regs);
-        regs->eip = (unsigned long)eip;
-        return;
-    }
-
-    /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
+    /* Decode first pointer argument. */
     if ( !is_kernel(eip) ||
          __copy_from_user(&bug_str, eip, sizeof(bug_str)) ||
          (bug_str.mov != 0xbc) )
         goto die;
-    filename = bug_str(bug_str, eip);
+    p = bug_str(bug_str, eip);
+    if ( !is_kernel(p) )
+        goto die;
     eip += sizeof(bug_str);
 
-    if ( !is_kernel(filename) )
-        filename = "<unknown>";
-    lineno   = bug.id >> 2;
+    id = bug.id & 3;
+
+    if ( id == BUGFRAME_run_fn )
+    {
+        const void (*fn)(struct cpu_user_regs *) = p;
+        (*fn)(regs);
+        regs->eip = (unsigned long)eip;
+        return;
+    }
+
+    /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
+    filename = p;
+    lineno = bug.id >> 2;
 
     if ( id == BUGFRAME_warn )
     {
diff -r 351a34c2fd48 -r 8cb6e7eff2ba xen/drivers/acpi/utilities/utglobal.c
--- a/xen/drivers/acpi/utilities/utglobal.c     Wed Feb 24 09:38:35 2010 +0000
+++ b/xen/drivers/acpi/utilities/utglobal.c     Wed Feb 24 10:44:30 2010 +0000
@@ -45,6 +45,7 @@
 
 #include <xen/config.h>
 #include <xen/lib.h>
+#include <asm/processor.h>
 #include <acpi/acpi.h>
 #include <acpi/acnamesp.h>
 
diff -r 351a34c2fd48 -r 8cb6e7eff2ba xen/drivers/char/ns16550.c
--- a/xen/drivers/char/ns16550.c        Wed Feb 24 09:38:35 2010 +0000
+++ b/xen/drivers/char/ns16550.c        Wed Feb 24 10:44:30 2010 +0000
@@ -145,11 +145,13 @@ static void ns16550_interrupt(
     }
 }
 
-static void ns16550_poll(void *data)
-{
-    struct serial_port *port = data;
-    struct ns16550 *uart = port->uart;
-    struct cpu_user_regs *regs = guest_cpu_user_regs();
+/* Safe: ns16550_poll() runs in softirq context so not reentrant on a given 
CPU. */
+static DEFINE_PER_CPU(struct serial_port *, poll_port);
+
+static void __ns16550_poll(struct cpu_user_regs *regs)
+{
+    struct serial_port *port = this_cpu(poll_port);
+    struct ns16550 *uart = port->uart;
 
     if ( uart->intr_works )
         return;     /* Interrupts work - no more polling */
@@ -167,6 +169,16 @@ static void ns16550_poll(void *data)
         serial_tx_interrupt(port, regs);
 
     set_timer(&uart->timer, NOW() + MILLISECS(uart->timeout_ms));
+}
+
+static void ns16550_poll(void *data)
+{
+    this_cpu(poll_port) = data;
+#ifdef run_in_exception_handler
+    run_in_exception_handler(__ns16550_poll);
+#else
+    __ns16550_poll(guest_cpu_user_regs());
+#endif
 }
 
 static int ns16550_tx_empty(struct serial_port *port)
diff -r 351a34c2fd48 -r 8cb6e7eff2ba xen/include/asm-x86/bug.h
--- a/xen/include/asm-x86/bug.h Wed Feb 24 09:38:35 2010 +0000
+++ b/xen/include/asm-x86/bug.h Wed Feb 24 10:44:30 2010 +0000
@@ -13,15 +13,16 @@ struct bug_frame {
     unsigned short id; /* BUGFRAME_??? */
 } __attribute__((packed));
 
-#define BUGFRAME_dump   0
+#define BUGFRAME_run_fn 0
 #define BUGFRAME_warn   1
 #define BUGFRAME_bug    2
 #define BUGFRAME_assert 3
 
-#define dump_execution_state()                     \
+#define run_in_exception_handler(fn)               \
     asm volatile (                                 \
-        "ud2 ; ret $0"                             \
-        : : "i" (BUGFRAME_dump) )
+        "ud2 ; ret %0" BUG_STR(1)                  \
+        : : "i" (BUGFRAME_run_fn),                 \
+            "i" (fn) )
 
 #define WARN()                                     \
     asm volatile (                                 \
diff -r 351a34c2fd48 -r 8cb6e7eff2ba xen/include/asm-x86/processor.h
--- a/xen/include/asm-x86/processor.h   Wed Feb 24 09:38:35 2010 +0000
+++ b/xen/include/asm-x86/processor.h   Wed Feb 24 10:44:30 2010 +0000
@@ -535,6 +535,7 @@ void show_stack_overflow(unsigned int cp
 void show_stack_overflow(unsigned int cpu, unsigned long esp);
 void show_registers(struct cpu_user_regs *regs);
 void show_execution_state(struct cpu_user_regs *regs);
+#define dump_execution_state() run_in_exception_handler(show_execution_state)
 void show_page_walk(unsigned long addr);
 asmlinkage void fatal_trap(int trapnr, struct cpu_user_regs *regs);
 

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