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8890454
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Enable interrupts after reading CR2 in page fault handler.
author
Ben Pfaff
<blp@cs.stanford.edu>
Thu, 2 Sep 2004 04:03:53 +0000
(
04:03
+0000)
committer
Ben Pfaff
<blp@cs.stanford.edu>
Thu, 2 Sep 2004 04:03:53 +0000
(
04:03
+0000)
src/userprog/exception.c
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diff --git
a/src/userprog/exception.c
b/src/userprog/exception.c
index 79ba7a921b61042e111cce1b0c6231f7ed1cc8ea..24985514aa5882d832e1035afd1effa43b7b61cc 100644
(file)
--- a/
src/userprog/exception.c
+++ b/
src/userprog/exception.c
@@
-116,24
+116,27
@@
page_fault (struct intr_frame *f)
bool not_present, write, user;
uint32_t fault_addr;
bool not_present, write, user;
uint32_t fault_addr;
- /* Determine cause. */
- not_present = (f->error_code & PF_P) == 0;
- write = (f->error_code & PF_W) != 0;
- user = (f->error_code & PF_U) != 0;
-
- /* Obtain faulting address.
+ /* Obtain faulting address, then turn interrupts back on.
+ (Interrupts were only off so that we could be assured of
+ reading CR2 before it changed.)
-
(
The faulting address is not necesarily the address of the
+ The faulting address is not necesarily the address of the
instruction that caused the fault--that's in F's eip
member. Rather, it's the linear address that was accessed
to cause the fault, which is probably an address of data,
instruction that caused the fault--that's in F's eip
member. Rather, it's the linear address that was accessed
to cause the fault, which is probably an address of data,
- not code.
)
*/
+ not code. */
asm ("movl %%cr2, %0" : "=r" (fault_addr));
asm ("movl %%cr2, %0" : "=r" (fault_addr));
+ intr_enable ();
+
+ /* Determine cause. */
+ not_present = (f->error_code & PF_P) == 0;
+ write = (f->error_code & PF_W) != 0;
+ user = (f->error_code & PF_U) != 0;
/* To implement virtual memory, delete the rest of the function
body, and replace it with code that brings in the page to
which fault_addr refers. */
/* To implement virtual memory, delete the rest of the function
body, and replace it with code that brings in the page to
which fault_addr refers. */
- printk ("Page fault
on address %08"PRIx32": %s
%s page in %s context.\n",
+ printk ("Page fault
at %08"PRIx32": %s error
%s page in %s context.\n",
fault_addr,
not_present ? "not present" : "rights violation",
write ? "writing" : "reading",
fault_addr,
not_present ? "not present" : "rights violation",
write ? "writing" : "reading",