# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID aab3cd33d2ba65340d355ffbfc859ef6e7b64df3
# Parent 3dca5b4add2be8b6da2052aeddffc497920b9ce1
[MINIOS] Fix the pagefault handler to detect recursive faults.
Signed-off-by: Grzegorz Milos <gm281@xxxxxxxxx>
---
extras/mini-os/console/console.c | 10 ++++++++--
extras/mini-os/traps.c | 15 +++++++++++++++
2 files changed, 23 insertions(+), 2 deletions(-)
diff -r 3dca5b4add2b -r aab3cd33d2ba extras/mini-os/console/console.c
--- a/extras/mini-os/console/console.c Tue May 16 14:07:56 2006 +0100
+++ b/extras/mini-os/console/console.c Tue May 16 16:34:27 2006 +0100
@@ -45,6 +45,10 @@
#include <xen/io/console.h>
+/* Copies all print output to the Xen emergency console apart
+ of standard dom0 handled console */
+#define USE_XEN_CONSOLE
+
/* Low level functions defined in xencons_ring.c */
extern int xencons_ring_init(void);
extern int xencons_ring_send(const char *data, unsigned len);
@@ -117,7 +121,9 @@ void print(int direct, const char *fmt,
(void)HYPERVISOR_console_io(CONSOLEIO_write, strlen(buf), buf);
return;
} else {
- if(!console_initialised)
+#ifndef USE_XEN_CONSOLE
+ if(!console_initialised)
+#endif
(void)HYPERVISOR_console_io(CONSOLEIO_write, strlen(buf), buf);
console_print(buf, strlen(buf));
@@ -128,7 +134,7 @@ void printk(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
- print(1, fmt, args);
+ print(0, fmt, args);
va_end(args);
}
diff -r 3dca5b4add2b -r aab3cd33d2ba extras/mini-os/traps.c
--- a/extras/mini-os/traps.c Tue May 16 14:07:56 2006 +0100
+++ b/extras/mini-os/traps.c Tue May 16 16:34:27 2006 +0100
@@ -120,9 +120,21 @@ void page_walk(unsigned long virt_addres
#define read_cr2() \
(HYPERVISOR_shared_info->vcpu_info[smp_processor_id()].arch.cr2)
+static int handling_pg_fault = 0;
+
void do_page_fault(struct pt_regs *regs, unsigned long error_code)
{
unsigned long addr = read_cr2();
+ /* If we are already handling a page fault, and got another one
+ that means we faulted in pagetable walk. Continuing here would cause
+ a recursive fault */
+ if(handling_pg_fault)
+ {
+ printk("Page fault in pagetable walk (access to invalid memory?).\n");
+ do_exit();
+ }
+ handling_pg_fault = 1;
+
#if defined(__x86_64__)
printk("Page fault at linear address %p, rip %p, code %lx\n",
addr, regs->rip, error_code);
@@ -130,9 +142,12 @@ void do_page_fault(struct pt_regs *regs,
printk("Page fault at linear address %p, eip %p, code %lx\n",
addr, regs->eip, error_code);
#endif
+
dump_regs(regs);
page_walk(addr);
do_exit();
+ /* We should never get here ... but still */
+ handling_pg_fault = 0;
}
void do_general_protection(struct pt_regs *regs, long error_code)
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