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microblaze: fix handling of multiple pending signals
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We need to keep building sigframes until no pending signals remain.
Wrap do_notify_resume() calls into loops; do _not_ allow syscall
restart logics to trigger after the first iteration.

Incidentally, comments about pending signals that should (somehow)
be in r18 are pure BS.  Doesn't work that way and cannot work that
way, sorry...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro committed Feb 3, 2013
1 parent 14203e1 commit e9f9252
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Showing 2 changed files with 42 additions and 29 deletions.
13 changes: 11 additions & 2 deletions arch/microblaze/kernel/entry-nommu.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -124,6 +124,7 @@ ret_from_intr:
lwi r11, r1, PT_MODE
bneid r11, no_intr_resched

3:
lwi r6, r31, TS_THREAD_INFO /* get thread info */
lwi r19, r6, TI_FLAGS /* get flags in thread info */
/* do an extra work if any bits are set */
Expand All @@ -132,11 +133,13 @@ ret_from_intr:
beqi r11, 1f
bralid r15, schedule
nop
bri 3b
1: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
beqid r11, no_intr_resched
addk r5, r1, r0
bralid r15, do_notify_resume
addk r6, r0, r0
bri 3b

no_intr_resched:
/* Disable interrupts, we are now committed to the state restore */
Expand Down Expand Up @@ -486,18 +489,24 @@ ENTRY(ret_from_kernel_thread)
work_pending:
lwi r11, r1, PT_MODE
bneid r11, 2f
3:
enable_irq

andi r11, r19, _TIF_NEED_RESCHED
beqi r11, 1f
bralid r15, schedule
nop
bri 4f
1: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
beqi r11, no_work_pending
addk r5, r30, r0
bralid r15, do_notify_resume
addik r6, r0, 1
bri no_work_pending
addk r30, r0, r0 /* no restarts from now on */
4:
disable_irq
lwi r6, r31, TS_THREAD_INFO /* get thread info */
lwi r19, r6, TI_FLAGS /* get flags in thread info */
bri 3b

ENTRY(ret_to_user)
disable_irq
Expand Down
58 changes: 31 additions & 27 deletions arch/microblaze/kernel/entry.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -402,26 +402,27 @@ C_ENTRY(ret_from_trap):
* trigger rescheduling. */
/* get thread info from current task */
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_NEED_RESCHED;
lwi r19, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f;

bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
bri 1b

/* Maybe handle a signal */
5: /* get thread info from current task*/
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 1f; /* Signals to handle, handle them */
5:
andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 4f; /* Signals to handle, handle them */

addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
add r6, r30, r0; /* Arg 2: int in_syscall */
add r30, r0, r0 /* no more restarts */
bri 1b

/* Finally, return to user state. */
1: set_bip; /* Ints masked for state restore */
4: set_bip; /* Ints masked for state restore */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
Expand Down Expand Up @@ -573,20 +574,20 @@ C_ENTRY(ret_from_exc):

/* We're returning to user mode, so check for various conditions that
trigger rescheduling. */
1:
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_NEED_RESCHED;
lwi r19, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f;

/* Call the scheduler before returning from a syscall/trap. */
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
bri 1b

/* Maybe handle a signal */
5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 1f; /* Signals to handle, handle them */
5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 4f; /* Signals to handle, handle them */

/*
* Handle a signal return; Pending signals should be in r18.
Expand All @@ -602,9 +603,10 @@ C_ENTRY(ret_from_exc):
addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
addi r6, r0, 0; /* Arg 2: int in_syscall */
bri 1b

/* Finally, return to user state. */
1: set_bip; /* Ints masked for state restore */
4: set_bip; /* Ints masked for state restore */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
Expand Down Expand Up @@ -684,22 +686,23 @@ ret_from_irq:
lwi r11, r1, PT_MODE;
bnei r11, 2f;

1:
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */
andi r11, r11, _TIF_NEED_RESCHED;
lwi r19, r11, TI_FLAGS; /* MS: get flags from thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f
bralid r15, schedule;
nop; /* delay slot */
bri 1b

/* Maybe handle a signal */
5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqid r11, no_intr_resched
/* Handle a signal return; Pending signals should be in r18. */
addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
addi r6, r0, 0; /* Arg 2: int in_syscall */
bri 1b

/* Finally, return to user state. */
no_intr_resched:
Expand Down Expand Up @@ -817,28 +820,29 @@ dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
lwi r11, r1, PT_MODE;
bnei r11, 2f;
/* MS: Return to user space - gdb */
1:
/* Get current task ptr into r11 */
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_NEED_RESCHED;
lwi r19, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f;

/* Call the scheduler before returning from a syscall/trap. */
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
bri 1b

/* Maybe handle a signal */
5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 1f; /* Signals to handle, handle them */
5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 4f; /* Signals to handle, handle them */

addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
addi r6, r0, 0; /* Arg 2: int in_syscall */
bri 1b

/* Finally, return to user state. */
1: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
4: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
/* MS: Restore all regs */
Expand Down

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