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intvec_32.S
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/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* Linux interrupt vectors.
*/
#include <linux/linkage.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/unistd.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/irqflags.h>
#include <asm/atomic.h>
#include <asm/asm-offsets.h>
#include <hv/hypervisor.h>
#include <arch/abi.h>
#include <arch/interrupts.h>
#include <arch/spr_def.h>
#ifdef CONFIG_PREEMPT
# error "No support for kernel preemption currently"
#endif
#if INT_INTCTRL_1 < 32 || INT_INTCTRL_1 >= 48
# error INT_INTCTRL_1 coded to set high interrupt mask
#endif
#define PTREGS_PTR(reg, ptreg) addli reg, sp, C_ABI_SAVE_AREA_SIZE + (ptreg)
#define PTREGS_OFFSET_SYSCALL PTREGS_OFFSET_REG(TREG_SYSCALL_NR)
#if !CHIP_HAS_WH64()
/* By making this an empty macro, we can use wh64 in the code. */
.macro wh64 reg
.endm
#endif
.macro push_reg reg, ptr=sp, delta=-4
{
sw \ptr, \reg
addli \ptr, \ptr, \delta
}
.endm
.macro pop_reg reg, ptr=sp, delta=4
{
lw \reg, \ptr
addli \ptr, \ptr, \delta
}
.endm
.macro pop_reg_zero reg, zreg, ptr=sp, delta=4
{
move \zreg, zero
lw \reg, \ptr
addi \ptr, \ptr, \delta
}
.endm
.macro push_extra_callee_saves reg
PTREGS_PTR(\reg, PTREGS_OFFSET_REG(51))
push_reg r51, \reg
push_reg r50, \reg
push_reg r49, \reg
push_reg r48, \reg
push_reg r47, \reg
push_reg r46, \reg
push_reg r45, \reg
push_reg r44, \reg
push_reg r43, \reg
push_reg r42, \reg
push_reg r41, \reg
push_reg r40, \reg
push_reg r39, \reg
push_reg r38, \reg
push_reg r37, \reg
push_reg r36, \reg
push_reg r35, \reg
push_reg r34, \reg, PTREGS_OFFSET_BASE - PTREGS_OFFSET_REG(34)
.endm
.macro panic str
.pushsection .rodata, "a"
1:
.asciz "\str"
.popsection
{
moveli r0, lo16(1b)
}
{
auli r0, r0, ha16(1b)
jal panic
}
.endm
#ifdef __COLLECT_LINKER_FEEDBACK__
.pushsection .text.intvec_feedback,"ax"
intvec_feedback:
.popsection
#endif
/*
* Default interrupt handler.
*
* vecnum is where we'll put this code.
* c_routine is the C routine we'll call.
*
* The C routine is passed two arguments:
* - A pointer to the pt_regs state.
* - The interrupt vector number.
*
* The "processing" argument specifies the code for processing
* the interrupt. Defaults to "handle_interrupt".
*/
.macro int_hand vecnum, vecname, c_routine, processing=handle_interrupt
.org (\vecnum << 8)
intvec_\vecname:
.ifc \vecnum, INT_SWINT_1
blz TREG_SYSCALL_NR_NAME, sys_cmpxchg
.endif
/* Temporarily save a register so we have somewhere to work. */
mtspr SYSTEM_SAVE_1_1, r0
mfspr r0, EX_CONTEXT_1_1
/* The cmpxchg code clears sp to force us to reset it here on fault. */
{
bz sp, 2f
andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
}
.ifc \vecnum, INT_DOUBLE_FAULT
/*
* For double-faults from user-space, fall through to the normal
* register save and stack setup path. Otherwise, it's the
* hypervisor giving us one last chance to dump diagnostics, and we
* branch to the kernel_double_fault routine to do so.
*/
bz r0, 1f
j _kernel_double_fault
1:
.else
/*
* If we're coming from user-space, then set sp to the top of
* the kernel stack. Otherwise, assume sp is already valid.
*/
{
bnz r0, 0f
move r0, sp
}
.endif
.ifc \c_routine, do_page_fault
/*
* The page_fault handler may be downcalled directly by the
* hypervisor even when Linux is running and has ICS set.
*
* In this case the contents of EX_CONTEXT_1_1 reflect the
* previous fault and can't be relied on to choose whether or
* not to reinitialize the stack pointer. So we add a test
* to see whether SYSTEM_SAVE_1_2 has the high bit set,
* and if so we don't reinitialize sp, since we must be coming
* from Linux. (In fact the precise case is !(val & ~1),
* but any Linux PC has to have the high bit set.)
*
* Note that the hypervisor *always* sets SYSTEM_SAVE_1_2 for
* any path that turns into a downcall to one of our TLB handlers.
*/
mfspr r0, SYSTEM_SAVE_1_2
{
blz r0, 0f /* high bit in S_S_1_2 is for a PC to use */
move r0, sp
}
.endif
2:
/*
* SYSTEM_SAVE_1_0 holds the cpu number in the low bits, and
* the current stack top in the higher bits. So we recover
* our stack top by just masking off the low bits, then
* point sp at the top aligned address on the actual stack page.
*/
mfspr r0, SYSTEM_SAVE_1_0
mm r0, r0, zero, LOG2_THREAD_SIZE, 31
0:
/*
* Align the stack mod 64 so we can properly predict what
* cache lines we need to write-hint to reduce memory fetch
* latency as we enter the kernel. The layout of memory is
* as follows, with cache line 0 at the lowest VA, and cache
* line 4 just below the r0 value this "andi" computes.
* Note that we never write to cache line 4, and we skip
* cache line 1 for syscalls.
*
* cache line 4: ptregs padding (two words)
* cache line 3: r46...lr, pc, ex1, faultnum, orig_r0, flags, pad
* cache line 2: r30...r45
* cache line 1: r14...r29
* cache line 0: 2 x frame, r0..r13
*/
andi r0, r0, -64
/*
* Push the first four registers on the stack, so that we can set
* them to vector-unique values before we jump to the common code.
*
* Registers are pushed on the stack as a struct pt_regs,
* with the sp initially just above the struct, and when we're
* done, sp points to the base of the struct, minus
* C_ABI_SAVE_AREA_SIZE, so we can directly jal to C code.
*
* This routine saves just the first four registers, plus the
* stack context so we can do proper backtracing right away,
* and defers to handle_interrupt to save the rest.
* The backtracer needs pc, ex1, lr, sp, r52, and faultnum.
*/
addli r0, r0, PTREGS_OFFSET_LR - (PTREGS_SIZE + KSTK_PTREGS_GAP)
wh64 r0 /* cache line 3 */
{
sw r0, lr
addli r0, r0, PTREGS_OFFSET_SP - PTREGS_OFFSET_LR
}
{
sw r0, sp
addli sp, r0, PTREGS_OFFSET_REG(52) - PTREGS_OFFSET_SP
}
{
sw sp, r52
addli sp, sp, PTREGS_OFFSET_REG(1) - PTREGS_OFFSET_REG(52)
}
wh64 sp /* cache line 0 */
{
sw sp, r1
addli sp, sp, PTREGS_OFFSET_REG(2) - PTREGS_OFFSET_REG(1)
}
{
sw sp, r2
addli sp, sp, PTREGS_OFFSET_REG(3) - PTREGS_OFFSET_REG(2)
}
{
sw sp, r3
addli sp, sp, PTREGS_OFFSET_PC - PTREGS_OFFSET_REG(3)
}
mfspr r0, EX_CONTEXT_1_0
.ifc \processing,handle_syscall
/*
* Bump the saved PC by one bundle so that when we return, we won't
* execute the same swint instruction again. We need to do this while
* we're in the critical section.
*/
addi r0, r0, 8
.endif
{
sw sp, r0
addli sp, sp, PTREGS_OFFSET_EX1 - PTREGS_OFFSET_PC
}
mfspr r0, EX_CONTEXT_1_1
{
sw sp, r0
addi sp, sp, PTREGS_OFFSET_FAULTNUM - PTREGS_OFFSET_EX1
/*
* Use r0 for syscalls so it's a temporary; use r1 for interrupts
* so that it gets passed through unchanged to the handler routine.
* Note that the .if conditional confusingly spans bundles.
*/
.ifc \processing,handle_syscall
movei r0, \vecnum
}
{
sw sp, r0
.else
movei r1, \vecnum
}
{
sw sp, r1
.endif
addli sp, sp, PTREGS_OFFSET_REG(0) - PTREGS_OFFSET_FAULTNUM
}
mfspr r0, SYSTEM_SAVE_1_1 /* Original r0 */
{
sw sp, r0
addi sp, sp, -PTREGS_OFFSET_REG(0) - 4
}
{
sw sp, zero /* write zero into "Next SP" frame pointer */
addi sp, sp, -4 /* leave SP pointing at bottom of frame */
}
.ifc \processing,handle_syscall
j handle_syscall
.else
/*
* Capture per-interrupt SPR context to registers.
* We overload the meaning of r3 on this path such that if its bit 31
* is set, we have to mask all interrupts including NMIs before
* clearing the interrupt critical section bit.
* See discussion below at "finish_interrupt_save".
*/
.ifc \c_routine, do_page_fault
mfspr r2, SYSTEM_SAVE_1_3 /* address of page fault */
mfspr r3, SYSTEM_SAVE_1_2 /* info about page fault */
.else
.ifc \vecnum, INT_DOUBLE_FAULT
{
mfspr r2, SYSTEM_SAVE_1_2 /* double fault info from HV */
movei r3, 0
}
.else
.ifc \c_routine, do_trap
{
mfspr r2, GPV_REASON
movei r3, 0
}
.else
.ifc \c_routine, op_handle_perf_interrupt
{
mfspr r2, PERF_COUNT_STS
movei r3, -1 /* not used, but set for consistency */
}
.else
#if CHIP_HAS_AUX_PERF_COUNTERS()
.ifc \c_routine, op_handle_aux_perf_interrupt
{
mfspr r2, AUX_PERF_COUNT_STS
movei r3, -1 /* not used, but set for consistency */
}
.else
#endif
movei r3, 0
#if CHIP_HAS_AUX_PERF_COUNTERS()
.endif
#endif
.endif
.endif
.endif
.endif
/* Put function pointer in r0 */
moveli r0, lo16(\c_routine)
{
auli r0, r0, ha16(\c_routine)
j \processing
}
.endif
ENDPROC(intvec_\vecname)
#ifdef __COLLECT_LINKER_FEEDBACK__
.pushsection .text.intvec_feedback,"ax"
.org (\vecnum << 5)
FEEDBACK_ENTER_EXPLICIT(intvec_\vecname, .intrpt1, 1 << 8)
jrp lr
.popsection
#endif
.endm
/*
* Save the rest of the registers that we didn't save in the actual
* vector itself. We can't use r0-r10 inclusive here.
*/
.macro finish_interrupt_save, function
/* If it's a syscall, save a proper orig_r0, otherwise just zero. */
PTREGS_PTR(r52, PTREGS_OFFSET_ORIG_R0)
{
.ifc \function,handle_syscall
sw r52, r0
.else
sw r52, zero
.endif
PTREGS_PTR(r52, PTREGS_OFFSET_TP)
}
/*
* For ordinary syscalls, we save neither caller- nor callee-
* save registers, since the syscall invoker doesn't expect the
* caller-saves to be saved, and the called kernel functions will
* take care of saving the callee-saves for us.
*
* For interrupts we save just the caller-save registers. Saving
* them is required (since the "caller" can't save them). Again,
* the called kernel functions will restore the callee-save
* registers for us appropriately.
*
* On return, we normally restore nothing special for syscalls,
* and just the caller-save registers for interrupts.
*
* However, there are some important caveats to all this:
*
* - We always save a few callee-save registers to give us
* some scratchpad registers to carry across function calls.
*
* - fork/vfork/etc require us to save all the callee-save
* registers, which we do in PTREGS_SYSCALL_ALL_REGS, below.
*
* - We always save r0..r5 and r10 for syscalls, since we need
* to reload them a bit later for the actual kernel call, and
* since we might need them for -ERESTARTNOINTR, etc.
*
* - Before invoking a signal handler, we save the unsaved
* callee-save registers so they are visible to the
* signal handler or any ptracer.
*
* - If the unsaved callee-save registers are modified, we set
* a bit in pt_regs so we know to reload them from pt_regs
* and not just rely on the kernel function unwinding.
* (Done for ptrace register writes and SA_SIGINFO handler.)
*/
{
sw r52, tp
PTREGS_PTR(r52, PTREGS_OFFSET_REG(33))
}
wh64 r52 /* cache line 2 */
push_reg r33, r52
push_reg r32, r52
push_reg r31, r52
.ifc \function,handle_syscall
push_reg r30, r52, PTREGS_OFFSET_SYSCALL - PTREGS_OFFSET_REG(30)
push_reg TREG_SYSCALL_NR_NAME, r52, \
PTREGS_OFFSET_REG(5) - PTREGS_OFFSET_SYSCALL
.else
push_reg r30, r52, PTREGS_OFFSET_REG(29) - PTREGS_OFFSET_REG(30)
wh64 r52 /* cache line 1 */
push_reg r29, r52
push_reg r28, r52
push_reg r27, r52
push_reg r26, r52
push_reg r25, r52
push_reg r24, r52
push_reg r23, r52
push_reg r22, r52
push_reg r21, r52
push_reg r20, r52
push_reg r19, r52
push_reg r18, r52
push_reg r17, r52
push_reg r16, r52
push_reg r15, r52
push_reg r14, r52
push_reg r13, r52
push_reg r12, r52
push_reg r11, r52
push_reg r10, r52
push_reg r9, r52
push_reg r8, r52
push_reg r7, r52
push_reg r6, r52
.endif
push_reg r5, r52
sw r52, r4
/* Load tp with our per-cpu offset. */
#ifdef CONFIG_SMP
{
mfspr r20, SYSTEM_SAVE_1_0
moveli r21, lo16(__per_cpu_offset)
}
{
auli r21, r21, ha16(__per_cpu_offset)
mm r20, r20, zero, 0, LOG2_THREAD_SIZE-1
}
s2a r20, r20, r21
lw tp, r20
#else
move tp, zero
#endif
/*
* If we will be returning to the kernel, we will need to
* reset the interrupt masks to the state they had before.
* Set DISABLE_IRQ in flags iff we came from PL1 with irqs disabled.
* We load flags in r32 here so we can jump to .Lrestore_regs
* directly after do_page_fault_ics() if necessary.
*/
mfspr r32, EX_CONTEXT_1_1
{
andi r32, r32, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
PTREGS_PTR(r21, PTREGS_OFFSET_FLAGS)
}
bzt r32, 1f /* zero if from user space */
IRQS_DISABLED(r32) /* zero if irqs enabled */
#if PT_FLAGS_DISABLE_IRQ != 1
# error Value of IRQS_DISABLED used to set PT_FLAGS_DISABLE_IRQ; fix
#endif
1:
.ifnc \function,handle_syscall
/* Record the fact that we saved the caller-save registers above. */
ori r32, r32, PT_FLAGS_CALLER_SAVES
.endif
sw r21, r32
#ifdef __COLLECT_LINKER_FEEDBACK__
/*
* Notify the feedback routines that we were in the
* appropriate fixed interrupt vector area. Note that we
* still have ICS set at this point, so we can't invoke any
* atomic operations or we will panic. The feedback
* routines internally preserve r0..r10 and r30 up.
*/
.ifnc \function,handle_syscall
shli r20, r1, 5
.else
moveli r20, INT_SWINT_1 << 5
.endif
addli r20, r20, lo16(intvec_feedback)
auli r20, r20, ha16(intvec_feedback)
jalr r20
/* And now notify the feedback routines that we are here. */
FEEDBACK_ENTER(\function)
#endif
/*
* we've captured enough state to the stack (including in
* particular our EX_CONTEXT state) that we can now release
* the interrupt critical section and replace it with our
* standard "interrupts disabled" mask value. This allows
* synchronous interrupts (and profile interrupts) to punch
* through from this point onwards.
*
* If bit 31 of r3 is set during a non-NMI interrupt, we know we
* are on the path where the hypervisor has punched through our
* ICS with a page fault, so we call out to do_page_fault_ics()
* to figure out what to do with it. If the fault was in
* an atomic op, we unlock the atomic lock, adjust the
* saved register state a little, and return "zero" in r4,
* falling through into the normal page-fault interrupt code.
* If the fault was in a kernel-space atomic operation, then
* do_page_fault_ics() resolves it itself, returns "one" in r4,
* and as a result goes directly to restoring registers and iret,
* without trying to adjust the interrupt masks at all.
* The do_page_fault_ics() API involves passing and returning
* a five-word struct (in registers) to avoid writing the
* save and restore code here.
*/
.ifc \function,handle_nmi
IRQ_DISABLE_ALL(r20)
.else
.ifnc \function,handle_syscall
bgezt r3, 1f
{
PTREGS_PTR(r0, PTREGS_OFFSET_BASE)
jal do_page_fault_ics
}
FEEDBACK_REENTER(\function)
bzt r4, 1f
j .Lrestore_regs
1:
.endif
IRQ_DISABLE(r20, r21)
.endif
mtspr INTERRUPT_CRITICAL_SECTION, zero
#if CHIP_HAS_WH64()
/*
* Prepare the first 256 stack bytes to be rapidly accessible
* without having to fetch the background data. We don't really
* know how far to write-hint, but kernel stacks generally
* aren't that big, and write-hinting here does take some time.
*/
addi r52, sp, -64
{
wh64 r52
addi r52, r52, -64
}
{
wh64 r52
addi r52, r52, -64
}
{
wh64 r52
addi r52, r52, -64
}
wh64 r52
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
.ifnc \function,handle_nmi
/*
* We finally have enough state set up to notify the irq
* tracing code that irqs were disabled on entry to the handler.
* The TRACE_IRQS_OFF call clobbers registers r0-r29.
* For syscalls, we already have the register state saved away
* on the stack, so we don't bother to do any register saves here,
* and later we pop the registers back off the kernel stack.
* For interrupt handlers, save r0-r3 in callee-saved registers.
*/
.ifnc \function,handle_syscall
{ move r30, r0; move r31, r1 }
{ move r32, r2; move r33, r3 }
.endif
TRACE_IRQS_OFF
.ifnc \function,handle_syscall
{ move r0, r30; move r1, r31 }
{ move r2, r32; move r3, r33 }
.endif
.endif
#endif
.endm
.macro check_single_stepping, kind, not_single_stepping
/*
* Check for single stepping in user-level priv
* kind can be "normal", "ill", or "syscall"
* At end, if fall-thru
* r29: thread_info->step_state
* r28: &pt_regs->pc
* r27: pt_regs->pc
* r26: thread_info->step_state->buffer
*/
/* Check for single stepping */
GET_THREAD_INFO(r29)
{
/* Get pointer to field holding step state */
addi r29, r29, THREAD_INFO_STEP_STATE_OFFSET
/* Get pointer to EX1 in register state */
PTREGS_PTR(r27, PTREGS_OFFSET_EX1)
}
{
/* Get pointer to field holding PC */
PTREGS_PTR(r28, PTREGS_OFFSET_PC)
/* Load the pointer to the step state */
lw r29, r29
}
/* Load EX1 */
lw r27, r27
{
/* Points to flags */
addi r23, r29, SINGLESTEP_STATE_FLAGS_OFFSET
/* No single stepping if there is no step state structure */
bzt r29, \not_single_stepping
}
{
/* mask off ICS and any other high bits */
andi r27, r27, SPR_EX_CONTEXT_1_1__PL_MASK
/* Load pointer to single step instruction buffer */
lw r26, r29
}
/* Check priv state */
bnz r27, \not_single_stepping
/* Get flags */
lw r22, r23
{
/* Branch if single-step mode not enabled */
bbnst r22, \not_single_stepping
/* Clear enabled flag */
andi r22, r22, ~SINGLESTEP_STATE_MASK_IS_ENABLED
}
.ifc \kind,normal
{
/* Load PC */
lw r27, r28
/* Point to the entry containing the original PC */
addi r24, r29, SINGLESTEP_STATE_ORIG_PC_OFFSET
}
{
/* Disable single stepping flag */
sw r23, r22
}
{
/* Get the original pc */
lw r24, r24
/* See if the PC is at the start of the single step buffer */
seq r25, r26, r27
}
/*
* NOTE: it is really expected that the PC be in the single step buffer
* at this point
*/
bzt r25, \not_single_stepping
/* Restore the original PC */
sw r28, r24
.else
.ifc \kind,syscall
{
/* Load PC */
lw r27, r28
/* Point to the entry containing the next PC */
addi r24, r29, SINGLESTEP_STATE_NEXT_PC_OFFSET
}
{
/* Increment the stopped PC by the bundle size */
addi r26, r26, 8
/* Disable single stepping flag */
sw r23, r22
}
{
/* Get the next pc */
lw r24, r24
/*
* See if the PC is one bundle past the start of the
* single step buffer
*/
seq r25, r26, r27
}
{
/*
* NOTE: it is really expected that the PC be in the
* single step buffer at this point
*/
bzt r25, \not_single_stepping
}
/* Set to the next PC */
sw r28, r24
.else
{
/* Point to 3rd bundle in buffer */
addi r25, r26, 16
/* Load PC */
lw r27, r28
}
{
/* Disable single stepping flag */
sw r23, r22
/* See if the PC is in the single step buffer */
slte_u r24, r26, r27
}
{
slte_u r25, r27, r25
/*
* NOTE: it is really expected that the PC be in the
* single step buffer at this point
*/
bzt r24, \not_single_stepping
}
bzt r25, \not_single_stepping
.endif
.endif
.endm
/*
* Redispatch a downcall.
*/
.macro dc_dispatch vecnum, vecname
.org (\vecnum << 8)
intvec_\vecname:
j hv_downcall_dispatch
ENDPROC(intvec_\vecname)
.endm
/*
* Common code for most interrupts. The C function we're eventually
* going to is in r0, and the faultnum is in r1; the original
* values for those registers are on the stack.
*/
.pushsection .text.handle_interrupt,"ax"
handle_interrupt:
finish_interrupt_save handle_interrupt
/*
* Check for if we are single stepping in user level. If so, then
* we need to restore the PC.
*/
check_single_stepping normal, .Ldispatch_interrupt
.Ldispatch_interrupt:
/* Jump to the C routine; it should enable irqs as soon as possible. */
{
jalr r0
PTREGS_PTR(r0, PTREGS_OFFSET_BASE)
}
FEEDBACK_REENTER(handle_interrupt)
{
movei r30, 0 /* not an NMI */
j interrupt_return
}
STD_ENDPROC(handle_interrupt)
/*
* This routine takes a boolean in r30 indicating if this is an NMI.
* If so, we also expect a boolean in r31 indicating whether to
* re-enable the oprofile interrupts.
*/
STD_ENTRY(interrupt_return)
/* If we're resuming to kernel space, don't check thread flags. */
{
bnz r30, .Lrestore_all /* NMIs don't special-case user-space */
PTREGS_PTR(r29, PTREGS_OFFSET_EX1)
}
lw r29, r29
andi r29, r29, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
{
bzt r29, .Lresume_userspace
PTREGS_PTR(r29, PTREGS_OFFSET_PC)
}
/* If we're resuming to _cpu_idle_nap, bump PC forward by 8. */
{
lw r28, r29
moveli r27, lo16(_cpu_idle_nap)
}
{
auli r27, r27, ha16(_cpu_idle_nap)
}
{
seq r27, r27, r28
}
{
bbns r27, .Lrestore_all
addi r28, r28, 8
}
sw r29, r28
j .Lrestore_all
.Lresume_userspace:
FEEDBACK_REENTER(interrupt_return)
/*
* Disable interrupts so as to make sure we don't
* miss an interrupt that sets any of the thread flags (like
* need_resched or sigpending) between sampling and the iret.
* Routines like schedule() or do_signal() may re-enable
* interrupts before returning.
*/
IRQ_DISABLE(r20, r21)
TRACE_IRQS_OFF /* Note: clobbers registers r0-r29 */
/* Get base of stack in r32; note r30/31 are used as arguments here. */
GET_THREAD_INFO(r32)
/* 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)
}
{
lw r29, r29
auli r28, r28, ha16(_TIF_ALLWORK_MASK)
}
and r28, r29, r28
bnz r28, .Lwork_pending
/*
* In the NMI case we
* omit the call to single_process_check_nohz, which normally checks
* to see if we should start or stop the scheduler tick, because
* we can't call arbitrary Linux code from an NMI context.
* We always call the homecache TLB deferral code to re-trigger
* the deferral mechanism.
*
* The other chunk of responsibility this code has is to reset the
* interrupt masks appropriately to reset irqs and NMIs. We have
* to call TRACE_IRQS_OFF and TRACE_IRQS_ON to support all the
* lockdep-type stuff, but we can't set ICS until afterwards, since
* ICS can only be used in very tight chunks of code to avoid
* tripping over various assertions that it is off.
*
* (There is what looks like a window of vulnerability here since
* we might take a profile interrupt between the two SPR writes
* that set the mask, but since we write the low SPR word first,
* and our interrupt entry code checks the low SPR word, any
* profile interrupt will actually disable interrupts in both SPRs
* before returning, which is OK.)
*/
.Lrestore_all:
PTREGS_PTR(r0, PTREGS_OFFSET_EX1)
{
lw r0, r0
PTREGS_PTR(r32, PTREGS_OFFSET_FLAGS)
}
{
andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK
lw r32, r32
}
bnz r0, 1f
j 2f
#if PT_FLAGS_DISABLE_IRQ != 1
# error Assuming PT_FLAGS_DISABLE_IRQ == 1 so we can use bbnst below
#endif
1: bbnst r32, 2f
IRQ_DISABLE(r20,r21)
TRACE_IRQS_OFF
movei r0, 1
mtspr INTERRUPT_CRITICAL_SECTION, r0
bzt r30, .Lrestore_regs
j 3f
2: TRACE_IRQS_ON
movei r0, 1
mtspr INTERRUPT_CRITICAL_SECTION, r0
IRQ_ENABLE(r20, r21)
bzt r30, .Lrestore_regs
3:
/*
* We now commit to returning from this interrupt, since we will be
* doing things like setting EX_CONTEXT SPRs and unwinding the stack
* frame. No calls should be made to any other code after this point.
* This code should only be entered with ICS set.
* r32 must still be set to ptregs.flags.
* We launch loads to each cache line separately first, so we can
* get some parallelism out of the memory subsystem.
* We start zeroing caller-saved registers throughout, since
* that will save some cycles if this turns out to be a syscall.
*/
.Lrestore_regs:
FEEDBACK_REENTER(interrupt_return) /* called from elsewhere */
/*
* Rotate so we have one high bit and one low bit to test.
* - low bit says whether to restore all the callee-saved registers,
* or just r30-r33, and r52 up.
* - high bit (i.e. sign bit) says whether to restore all the
* caller-saved registers, or just r0.
*/
#if PT_FLAGS_CALLER_SAVES != 2 || PT_FLAGS_RESTORE_REGS != 4
# error Rotate trick does not work :-)
#endif
{
rli r20, r32, 30
PTREGS_PTR(sp, PTREGS_OFFSET_REG(0))
}
/*
* Load cache lines 0, 2, and 3 in that order, then use
* the last loaded value, which makes it likely that the other
* cache lines have also loaded, at which point we should be
* able to safely read all the remaining words on those cache
* lines without waiting for the memory subsystem.
*/
pop_reg_zero r0, r1, sp, PTREGS_OFFSET_REG(30) - PTREGS_OFFSET_REG(0)
pop_reg_zero r30, r2, sp, PTREGS_OFFSET_PC - PTREGS_OFFSET_REG(30)
pop_reg_zero r21, r3, sp, PTREGS_OFFSET_EX1 - PTREGS_OFFSET_PC
pop_reg_zero lr, r4, sp, PTREGS_OFFSET_REG(52) - PTREGS_OFFSET_EX1
{
mtspr EX_CONTEXT_1_0, r21
move r5, zero
}
{
mtspr EX_CONTEXT_1_1, lr
andi lr, lr, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
}
/* Restore callee-saveds that we actually use. */
pop_reg_zero r52, r6, sp, PTREGS_OFFSET_REG(31) - PTREGS_OFFSET_REG(52)
pop_reg_zero r31, r7
pop_reg_zero r32, r8
pop_reg_zero r33, r9, sp, PTREGS_OFFSET_REG(29) - PTREGS_OFFSET_REG(33)
/*
* If we modified other callee-saveds, restore them now.
* This is rare, but could be via ptrace or signal handler.
*/
{
move r10, zero
bbs r20, .Lrestore_callees
}
.Lcontinue_restore_regs:
/* Check if we're returning from a syscall. */
{
move r11, zero
blzt r20, 1f /* no, so go restore callee-save registers */
}
/*
* Check if we're returning to userspace.
* Note that if we're not, we don't worry about zeroing everything.
*/
{
addli sp, sp, PTREGS_OFFSET_LR - PTREGS_OFFSET_REG(29)
bnz lr, .Lkernel_return
}
/*
* On return from syscall, we've restored r0 from pt_regs, but we