Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e1088430626b2ec4cd64f2fb7d9fd7c6df5d5824
Commit: e1088430626b2ec4cd64f2fb7d9fd7c6df5d5824
Parent: 9f8fcf38e8928cccf8c7b32668d146e457f2ccf2
Author: Chris Zankel <[EMAIL PROTECTED]>
AuthorDate: Tue Jan 22 00:45:25 2008 -0800
Committer: Chris Zankel <[EMAIL PROTECTED]>
CommitDate: Wed Feb 13 17:43:54 2008 -0800
[XTENSA] Fix register corruption for certain processor configurations
For processor configurations that have optional registers
(compiler-used but non-coprocessor), user space registers
might get corrupted when there are only 4 registers in
the current window-frame, ie. register a4 belongs to the
oldest frame in the register file.
Signed-off-by: Chris Zankel <[EMAIL PROTECTED]>
---
arch/xtensa/kernel/entry.S | 44 +++++++++++++++-----------------------------
1 files changed, 15 insertions(+), 29 deletions(-)
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 24770b6..dfd35dc 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -395,55 +395,49 @@ common_exception_return:
/* Jump if we are returning from kernel exceptions. */
1: l32i a3, a1, PT_PS
- _bbsi.l a3, PS_UM_BIT, 2f
- j kernel_exception_exit
+ _bbci.l a3, PS_UM_BIT, 4f
/* Specific to a user exception exit:
* We need to check some flags for signal handling and rescheduling,
* and have to restore WB and WS, extra states, and all registers
* in the register file that were in use in the user task.
- */
-
-2: wsr a3, PS /* disable interrupts */
-
- /* Check for signals (keep interrupts disabled while we read TI_FLAGS)
- * Note: PS.INTLEVEL = 0, PS.EXCM = 1
+ * Note that we don't disable interrupts here.
*/
GET_THREAD_INFO(a2,a1)
l32i a4, a2, TI_FLAGS
- /* Enable interrupts again.
- * Note: When we get here, we certainly have handled any interrupts.
- * (Hint: There is only one user exception frame on stack)
- */
-
- movi a3, 1 << PS_WOE_BIT
-
_bbsi.l a4, TIF_NEED_RESCHED, 3f
_bbci.l a4, TIF_SIGPENDING, 4f
l32i a4, a1, PT_DEPC
bgeui a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 4f
- /* Reenable interrupts and call do_signal() */
- wsr a3, PS
+ /* Call do_signal() */
+
movi a4, do_signal # int do_signal(struct pt_regs*, sigset_t*)
mov a6, a1
movi a7, 0
callx4 a4
j 1b
-3: /* Reenable interrupts and reschedule */
+3: /* Reschedule */
- wsr a3, PS
movi a4, schedule # void schedule (void)
callx4 a4
j 1b
- /* Restore the state of the task and return from the exception. */
+4: /* Restore optional registers. */
+
+ load_xtregs_opt a1 a2 a4 a5 a6 a7 PT_XTREGS_OPT
-4: /* a2 holds GET_CURRENT(a2,a1) */
+ wsr a3, PS /* disable interrupts */
+
+ _bbci.l a3, PS_UM_BIT, kernel_exception_exit
+
+user_exception_exit:
+
+ /* Restore the state of the task and return from the exception. */
/* Switch to the user thread WINDOWBASE. Save SP temporarily in DEPC */
@@ -509,10 +503,6 @@ common_exception_return:
kernel_exception_exit:
- /* Disable interrupts (a3 holds PT_PS) */
-
- wsr a3, PS
-
#ifdef PREEMPTIBLE_KERNEL
#ifdef CONFIG_PREEMPT
@@ -591,10 +581,6 @@ kernel_exception_exit:
common_exception_exit:
- /* Restore optional registers. */
-
- load_xtregs_opt a1 a3 a4 a5 a6 a7 PT_XTREGS_OPT
-
/* Restore address registers. */
_bbsi.l a2, 1, 1f
-
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