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author | Chris Metcalf <cmetcalf@tilera.com> | 2011-05-02 18:50:06 (GMT) |
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committer | Chris Metcalf <cmetcalf@tilera.com> | 2011-05-02 22:53:35 (GMT) |
commit | 313ce674d3cbc2d48ed34a9462427920ac54f4ad (patch) | |
tree | 7478150a1268c79851f1a366158c59606330e700 /arch/tile/kernel | |
parent | 93013a0f533fb3dd6875ca670d8e0bb4166a796e (diff) | |
download | linux-313ce674d3cbc2d48ed34a9462427920ac54f4ad.tar.xz |
arch/tile: support TIF_NOTIFY_RESUME
This support is required for CONFIG_KEYS, NFSv4 kernel DNS, etc.
The change is slightly more complex than the minimal thing, since
I took advantage of having to go into the assembly code to just
move a bunch of stuff into C code: specifically, the schedule(),
do_async_page_fault(), do_signal(), and single_step_once() support,
in addition to the TIF_NOTIFY_RESUME support.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Diffstat (limited to 'arch/tile/kernel')
-rw-r--r-- | arch/tile/kernel/intvec_32.S | 114 | ||||
-rw-r--r-- | arch/tile/kernel/process.c | 48 | ||||
-rw-r--r-- | arch/tile/kernel/single_step.c | 8 |
3 files changed, 73 insertions, 97 deletions
diff --git a/arch/tile/kernel/intvec_32.S b/arch/tile/kernel/intvec_32.S index fffcfa6..f35c312 100644 --- a/arch/tile/kernel/intvec_32.S +++ b/arch/tile/kernel/intvec_32.S @@ -851,14 +851,27 @@ STD_ENTRY(interrupt_return) /* Check to see if there is any work to do before returning to user. */ { addi r29, r32, THREAD_INFO_FLAGS_OFFSET - moveli r28, lo16(_TIF_ALLWORK_MASK) + moveli r1, lo16(_TIF_ALLWORK_MASK) } { lw r29, r29 - auli r28, r28, ha16(_TIF_ALLWORK_MASK) + auli r1, r1, ha16(_TIF_ALLWORK_MASK) } - and r28, r29, r28 - bnz r28, .Lwork_pending + and r1, r29, r1 + bzt r1, .Lrestore_all + + /* + * Make sure we have all the registers saved for signal + * handling or single-step. Call out to C code to figure out + * exactly what we need to do for each flag bit, then if + * necessary, reload the flags and recheck. + */ + push_extra_callee_saves r0 + { + PTREGS_PTR(r0, PTREGS_OFFSET_BASE) + jal do_work_pending + } + bnz r0, .Lresume_userspace /* * In the NMI case we @@ -1099,99 +1112,6 @@ STD_ENTRY(interrupt_return) pop_reg r50 pop_reg r51, sp, PTREGS_OFFSET_REG(29) - PTREGS_OFFSET_REG(51) j .Lcontinue_restore_regs - -.Lwork_pending: - /* Mask the reschedule flag */ - andi r28, r29, _TIF_NEED_RESCHED - - { - /* - * If the NEED_RESCHED flag is called, we call schedule(), which - * may drop this context right here and go do something else. - * On return, jump back to .Lresume_userspace and recheck. - */ - bz r28, .Lasync_tlb - - /* Mask the async-tlb flag */ - andi r28, r29, _TIF_ASYNC_TLB - } - - jal schedule - FEEDBACK_REENTER(interrupt_return) - - /* Reload the flags and check again */ - j .Lresume_userspace - -.Lasync_tlb: - { - bz r28, .Lneed_sigpending - - /* Mask the sigpending flag */ - andi r28, r29, _TIF_SIGPENDING - } - - PTREGS_PTR(r0, PTREGS_OFFSET_BASE) - jal do_async_page_fault - FEEDBACK_REENTER(interrupt_return) - - /* - * Go restart the "resume userspace" process. We may have - * fired a signal, and we need to disable interrupts again. - */ - j .Lresume_userspace - -.Lneed_sigpending: - /* - * At this point we are either doing signal handling or single-step, - * so either way make sure we have all the registers saved. - */ - push_extra_callee_saves r0 - - { - /* If no signal pending, skip to singlestep check */ - bz r28, .Lneed_singlestep - - /* Mask the singlestep flag */ - andi r28, r29, _TIF_SINGLESTEP - } - - jal do_signal - FEEDBACK_REENTER(interrupt_return) - - /* Reload the flags and check again */ - j .Lresume_userspace - -.Lneed_singlestep: - { - /* Get a pointer to the EX1 field */ - PTREGS_PTR(r29, PTREGS_OFFSET_EX1) - - /* If we get here, our bit must be set. */ - bz r28, .Lwork_confusion - } - /* If we are in priv mode, don't single step */ - lw r28, r29 - andi r28, r28, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ - bnz r28, .Lrestore_all - - /* Allow interrupts within the single step code */ - TRACE_IRQS_ON /* Note: clobbers registers r0-r29 */ - IRQ_ENABLE(r20, r21) - - /* try to single-step the current instruction */ - PTREGS_PTR(r0, PTREGS_OFFSET_BASE) - jal single_step_once - FEEDBACK_REENTER(interrupt_return) - - /* Re-disable interrupts. TRACE_IRQS_OFF in .Lrestore_all. */ - IRQ_DISABLE(r20,r21) - - j .Lrestore_all - -.Lwork_confusion: - move r0, r28 - panic "thread_info allwork flags unhandled on userspace resume: %#x" - STD_ENDPROC(interrupt_return) /* diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c index d006510..8e86334 100644 --- a/arch/tile/kernel/process.c +++ b/arch/tile/kernel/process.c @@ -25,10 +25,13 @@ #include <linux/hardirq.h> #include <linux/syscalls.h> #include <linux/kernel.h> +#include <linux/tracehook.h> +#include <linux/signal.h> #include <asm/system.h> #include <asm/stack.h> #include <asm/homecache.h> #include <asm/syscalls.h> +#include <asm/traps.h> #ifdef CONFIG_HARDWALL #include <asm/hardwall.h> #endif @@ -546,6 +549,51 @@ struct task_struct *__sched _switch_to(struct task_struct *prev, return __switch_to(prev, next, next_current_ksp0(next)); } +/* + * This routine is called on return from interrupt if any of the + * TIF_WORK_MASK flags are set in thread_info->flags. It is + * entered with interrupts disabled so we don't miss an event + * that modified the thread_info flags. If any flag is set, we + * handle it and return, and the calling assembly code will + * re-disable interrupts, reload the thread flags, and call back + * if more flags need to be handled. + * + * We return whether we need to check the thread_info flags again + * or not. Note that we don't clear TIF_SINGLESTEP here, so it's + * important that it be tested last, and then claim that we don't + * need to recheck the flags. + */ +int do_work_pending(struct pt_regs *regs, u32 thread_info_flags) +{ + if (thread_info_flags & _TIF_NEED_RESCHED) { + schedule(); + return 1; + } +#if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC() + if (thread_info_flags & _TIF_ASYNC_TLB) { + do_async_page_fault(regs); + return 1; + } +#endif + if (thread_info_flags & _TIF_SIGPENDING) { + do_signal(regs); + return 1; + } + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + if (current->replacement_session_keyring) + key_replace_session_keyring(); + return 1; + } + if (thread_info_flags & _TIF_SINGLESTEP) { + if ((regs->ex1 & SPR_EX_CONTEXT_1_1__PL_MASK) == 0) + single_step_once(regs); + return 0; + } + panic("work_pending: bad flags %#x\n", thread_info_flags); +} + /* Note there is an implicit fifth argument if (clone_flags & CLONE_SETTLS). */ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, void __user *, parent_tidptr, void __user *, child_tidptr, diff --git a/arch/tile/kernel/single_step.c b/arch/tile/kernel/single_step.c index 84a729e..86df5a23 100644 --- a/arch/tile/kernel/single_step.c +++ b/arch/tile/kernel/single_step.c @@ -318,6 +318,14 @@ void single_step_once(struct pt_regs *regs) " .popsection\n" ); + /* + * Enable interrupts here to allow touching userspace and the like. + * The callers expect this: do_trap() already has interrupts + * enabled, and do_work_pending() handles functions that enable + * interrupts internally. + */ + local_irq_enable(); + if (state == NULL) { /* allocate a page of writable, executable memory */ state = kmalloc(sizeof(struct single_step_state), GFP_KERNEL); |