diff options
| author | Chris Zankel <chris@zankel.net> | 2008-01-22 00:45:25 -0800 |
|---|---|---|
| committer | Chris Zankel <chris@zankel.net> | 2008-02-13 17:43:54 -0800 |
| commit | e1088430626b2ec4cd64f2fb7d9fd7c6df5d5824 (patch) | |
| tree | ce563e0400ad22974ae65e25d2534432f5d4e76b /arch/xtensa/kernel | |
| parent | 9f8fcf38e8928cccf8c7b32668d146e457f2ccf2 (diff) | |
[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 <chris@zankel.net>
Diffstat (limited to 'arch/xtensa/kernel')
| -rw-r--r-- | 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 24770b6a5e4..dfd35dcc1cb 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 |