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#
# Copyright (C) 2005 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#include <arch/arch.h>
#include <arch/regdef.h>
#include <arch/boot/boot.h>
#include <arch/stack.h>
#include <arch/mm/mmu.h>
#include <arch/mm/tlb.h>
#include <arch/mm/tte.h>
#ifdef CONFIG_SMP
#include <arch/context_offset.h>
#endif
.register %g2, #scratch
.register %g3, #scratch
.section K_TEXT_START, "ax"
/*
* Here is where the kernel is passed control
* from the boot loader.
*
* The registers are expected to be in this state:
* - %o0 non-zero for the bootstrap processor, zero for application/secondary processors
* - %o1 bootinfo structure address
* - %o2 bootinfo structure size
*
* Moreover, we depend on boot having established the
* following environment:
* - TLBs are on
* - identity mapping for the kernel image
*/
.global kernel_image_start
kernel_image_start:
mov %o0, %l7
/*
* Setup basic runtime environment.
*/
wrpr %g0, NWINDOWS - 2, %cansave ! set maximum saveable windows
wrpr %g0, 0, %canrestore ! get rid of windows we will never need again
wrpr %g0, 0, %otherwin ! make sure the window state is consistent
wrpr %g0, NWINDOWS - 1, %cleanwin ! prevent needless clean_window traps for kernel
wrpr %g0, 0, %tl ! TL = 0, primary context register is used
wrpr %g0, PSTATE_PRIV_BIT, %pstate ! Disable interrupts and disable 32-bit address masking.
wrpr %g0, 0, %pil ! intialize %pil
/*
* Switch to kernel trap table.
*/
sethi %hi(trap_table), %g1
wrpr %g1, %lo(trap_table), %tba
/*
* Take over the DMMU by installing global locked
* TTE entry identically mapping the first 4M
* of memory.
*
* In case of DMMU, no FLUSH instructions need to be
* issued. Because of that, the old DTLB contents can
* be demapped pretty straightforwardly and without
* causing any traps.
*/
wr %g0, ASI_DMMU, %asi
#define SET_TLB_DEMAP_CMD(r1, context_id) \
set (TLB_DEMAP_CONTEXT<<TLB_DEMAP_TYPE_SHIFT) | (context_id<<TLB_DEMAP_CONTEXT_SHIFT), %r1
! demap context 0
SET_TLB_DEMAP_CMD(g1, TLB_DEMAP_NUCLEUS)
stxa %g0, [%g1] ASI_DMMU_DEMAP
membar #Sync
#define SET_TLB_TAG(r1, context) \
set VMA | (context<<TLB_TAG_ACCESS_CONTEXT_SHIFT), %r1
! write DTLB tag
SET_TLB_TAG(g1, MEM_CONTEXT_KERNEL)
stxa %g1, [VA_DMMU_TAG_ACCESS] %asi
membar #Sync
#define SET_TLB_DATA(r1, r2, imm) \
set TTE_CV | TTE_CP | TTE_P | LMA | imm, %r1; \
set PAGESIZE_4M, %r2; \
sllx %r2, TTE_SIZE_SHIFT, %r2; \
or %r1, %r2, %r1; \
mov 1, %r2; \
sllx %r2, TTE_V_SHIFT, %r2; \
or %r1, %r2, %r1;
! write DTLB data and install the kernel mapping
SET_TLB_DATA(g1, g2, TTE_L | TTE_W) ! use non-global mapping
stxa %g1, [%g0] ASI_DTLB_DATA_IN_REG
membar #Sync
/*
* Because we cannot use global mappings (because we want to
* have separate 64-bit address spaces for both the kernel
* and the userspace), we prepare the identity mapping also in
* context 1. This step is required by the
* code installing the ITLB mapping.
*/
! write DTLB tag of context 1 (i.e. MEM_CONTEXT_TEMP)
SET_TLB_TAG(g1, MEM_CONTEXT_TEMP)
stxa %g1, [VA_DMMU_TAG_ACCESS] %asi
membar #Sync
! write DTLB data and install the kernel mapping in context 1
SET_TLB_DATA(g1, g2, TTE_W) ! use non-global mapping
stxa %g1, [%g0] ASI_DTLB_DATA_IN_REG
membar #Sync
/*
* Now is time to take over the IMMU.
* Unfortunatelly, it cannot be done as easily as the DMMU,
* because the IMMU is mapping the code it executes.
*
* [ Note that brave experiments with disabling the IMMU
* and using the DMMU approach failed after a dozen
* of desparate days with only little success. ]
*
* The approach used here is inspired from OpenBSD.
* First, the kernel creates IMMU mapping for itself
* in context 1 (MEM_CONTEXT_TEMP) and switches to
* it. Context 0 (MEM_CONTEXT_KERNEL) can be demapped
* afterwards and replaced with the kernel permanent
* mapping. Finally, the kernel switches back to
* context 0 and demaps context 1.
*
* Moreover, the IMMU requires use of the FLUSH instructions.
* But that is OK because we always use operands with
* addresses already mapped by the taken over DTLB.
*/
set kernel_image_start, %g5
! write ITLB tag of context 1
SET_TLB_TAG(g1, MEM_CONTEXT_TEMP)
mov VA_DMMU_TAG_ACCESS, %g2
stxa %g1, [%g2] ASI_IMMU
flush %g5
! write ITLB data and install the temporary mapping in context 1
SET_TLB_DATA(g1, g2, 0) ! use non-global mapping
stxa %g1, [%g0] ASI_ITLB_DATA_IN_REG
flush %g5
! switch to context 1
mov MEM_CONTEXT_TEMP, %g1
stxa %g1, [VA_PRIMARY_CONTEXT_REG] %asi ! ASI_DMMU is correct here !!!
flush %g5
! demap context 0
SET_TLB_DEMAP_CMD(g1, TLB_DEMAP_NUCLEUS)
stxa %g0, [%g1] ASI_IMMU_DEMAP
flush %g5
! write ITLB tag of context 0
SET_TLB_TAG(g1, MEM_CONTEXT_KERNEL)
mov VA_DMMU_TAG_ACCESS, %g2
stxa %g1, [%g2] ASI_IMMU
flush %g5
! write ITLB data and install the permanent kernel mapping in context 0
SET_TLB_DATA(g1, g2, TTE_L) ! use non-global mapping
stxa %g1, [%g0] ASI_ITLB_DATA_IN_REG
flush %g5
! enter nucleus - using context 0
wrpr %g0, 1, %tl
! demap context 1
SET_TLB_DEMAP_CMD(g1, TLB_DEMAP_PRIMARY)
stxa %g0, [%g1] ASI_IMMU_DEMAP
flush %g5
! set context 0 in the primary context register
stxa %g0, [VA_PRIMARY_CONTEXT_REG] %asi ! ASI_DMMU is correct here !!!
flush %g5
! leave nucleus - using primary context, i.e. context 0
wrpr %g0, 0, %tl
brz %l7, 1f ! skip if you are not the bootstrap CPU
nop
/*
* So far, we have not touched the stack.
* It is a good idead to set the kernel stack to a known state now.
*/
sethi %hi(temporary_boot_stack), %sp
or %sp, %lo(temporary_boot_stack), %sp
sub %sp, STACK_BIAS, %sp
sethi %hi(bootinfo), %o0
call memcpy ! copy bootinfo
or %o0, %lo(bootinfo), %o0
call arch_pre_main
nop
call main_bsp
nop
/* Not reached. */
0:
ba 0b
nop
/*
* Read MID from the processor.
*/
1:
ldxa [%g0] ASI_UPA_CONFIG, %g1
srlx %g1, UPA_CONFIG_MID_SHIFT, %g1
and %g1, UPA_CONFIG_MID_MASK, %g1
#ifdef CONFIG_SMP
/*
* Active loop for APs until the BSP picks them up.
* A processor cannot leave the loop until the
* global variable 'waking_up_mid' equals its
* MID.
*/
set waking_up_mid, %g2
2:
ldx [%g2], %g3
cmp %g3, %g1
bne 2b
nop
/*
* Configure stack for the AP.
* The AP is expected to use the stack saved
* in the ctx global variable.
*/
set ctx, %g1
add %g1, OFFSET_SP, %g1
ldx [%g1], %o6
call main_ap
nop
/* Not reached. */
#endif
0:
ba 0b
nop
.section K_DATA_START, "aw", @progbits
/*
* Create small stack to be used by the bootstrap processor.
* It is going to be used only for a very limited period of
* time, but we switch to it anyway, just to be sure we are
* properly initialized.
*
* What is important is that this piece of memory is covered
* by the 4M DTLB locked entry and therefore there will be
* no surprises like deadly combinations of spill trap and
* and TLB miss on the stack address.
*/
#define INITIAL_STACK_SIZE 1024
.align STACK_ALIGNMENT
.space INITIAL_STACK_SIZE
.align STACK_ALIGNMENT
temporary_boot_stack:
.space STACK_WINDOW_SAVE_AREA_SIZE