| /* |
| * Early kernel startup code for Hexagon |
| * |
| * Copyright (c) 2010-2013, The Linux Foundation. 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 version 2 and |
| * only version 2 as published by the Free Software Foundation. |
| * |
| * 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. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| * 02110-1301, USA. |
| */ |
| |
| #include <linux/linkage.h> |
| #include <linux/init.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/mem-layout.h> |
| #include <asm/vm_mmu.h> |
| #include <asm/page.h> |
| #include <asm/hexagon_vm.h> |
| |
| #define SEGTABLE_ENTRIES #0x0e0 |
| |
| __INIT |
| ENTRY(stext) |
| /* |
| * VMM will already have set up true vector page, MMU, etc. |
| * To set up initial kernel identity map, we have to pass |
| * the VMM a pointer to some canonical page tables. In |
| * this implementation, we're assuming that we've got |
| * them precompiled. Generate value in R24, as we'll need |
| * it again shortly. |
| */ |
| r24.L = #LO(swapper_pg_dir) |
| r24.H = #HI(swapper_pg_dir) |
| |
| /* |
| * Symbol is kernel segment address, but we need |
| * the logical/physical address. |
| */ |
| r25 = pc; |
| r2.h = #0xffc0; |
| r2.l = #0x0000; |
| r25 = and(r2,r25); /* R25 holds PHYS_OFFSET now */ |
| r1.h = #HI(PAGE_OFFSET); |
| r1.l = #LO(PAGE_OFFSET); |
| r24 = sub(r24,r1); /* swapper_pg_dir - PAGE_OFFSET */ |
| r24 = add(r24,r25); /* + PHYS_OFFSET */ |
| |
| r0 = r24; /* aka __pa(swapper_pg_dir) */ |
| |
| /* |
| * Initialize page dir to make the virtual and physical |
| * addresses where the kernel was loaded be identical. |
| * Done in 4MB chunks. |
| */ |
| #define PTE_BITS ( __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X \ |
| | __HEXAGON_C_WB_L2 << 6 \ |
| | __HVM_PDE_S_4MB) |
| |
| /* |
| * Get number of VA=PA entries; only really needed for jump |
| * to hyperspace; gets blown away immediately after |
| */ |
| |
| { |
| r1.l = #LO(_end); |
| r2.l = #LO(stext); |
| r3 = #1; |
| } |
| { |
| r1.h = #HI(_end); |
| r2.h = #HI(stext); |
| r3 = asl(r3, #22); |
| } |
| { |
| r1 = sub(r1, r2); |
| r3 = add(r3, #-1); |
| } /* r1 = _end - stext */ |
| r1 = add(r1, r3); /* + (4M-1) */ |
| r26 = lsr(r1, #22); /* / 4M = # of entries */ |
| |
| r1 = r25; |
| r2.h = #0xffc0; |
| r2.l = #0x0000; /* round back down to 4MB boundary */ |
| r1 = and(r1,r2); |
| r2 = lsr(r1, #22) /* 4MB page number */ |
| r2 = asl(r2, #2) /* times sizeof(PTE) (4bytes) */ |
| r0 = add(r0,r2) /* r0 = address of correct PTE */ |
| r2 = #PTE_BITS |
| r1 = add(r1,r2) /* r1 = 4MB PTE for the first entry */ |
| r2.h = #0x0040 |
| r2.l = #0x0000 /* 4MB increments */ |
| loop0(1f,r26); |
| 1: |
| memw(r0 ++ #4) = r1 |
| { r1 = add(r1, r2); } :endloop0 |
| |
| /* Also need to overwrite the initial 0xc0000000 entries */ |
| /* PAGE_OFFSET >> (4MB shift - 4 bytes per entry shift) */ |
| R1.H = #HI(PAGE_OFFSET >> (22 - 2)) |
| R1.L = #LO(PAGE_OFFSET >> (22 - 2)) |
| |
| r0 = add(r1, r24); /* advance to 0xc0000000 entry */ |
| r1 = r25; |
| r2.h = #0xffc0; |
| r2.l = #0x0000; /* round back down to 4MB boundary */ |
| r1 = and(r1,r2); /* for huge page */ |
| r2 = #PTE_BITS |
| r1 = add(r1,r2); |
| r2.h = #0x0040 |
| r2.l = #0x0000 /* 4MB increments */ |
| |
| loop0(1f,SEGTABLE_ENTRIES); |
| 1: |
| memw(r0 ++ #4) = r1; |
| { r1 = add(r1,r2); } :endloop0 |
| |
| r0 = r24; |
| |
| /* |
| * The subroutine wrapper around the virtual instruction touches |
| * no memory, so we should be able to use it even here. |
| * Note that in this version, R1 and R2 get "clobbered"; see |
| * vm_ops.S |
| */ |
| r1 = #VM_TRANS_TYPE_TABLE |
| call __vmnewmap; |
| |
| /* Jump into virtual address range. */ |
| |
| r31.h = #hi(__head_s_vaddr_target) |
| r31.l = #lo(__head_s_vaddr_target) |
| jumpr r31 |
| |
| /* Insert trippy space effects. */ |
| |
| __head_s_vaddr_target: |
| /* |
| * Tear down VA=PA translation now that we are running |
| * in kernel virtual space. |
| */ |
| r0 = #__HVM_PDE_S_INVALID |
| |
| r1.h = #0xffc0; |
| r1.l = #0x0000; |
| r2 = r25; /* phys_offset */ |
| r2 = and(r1,r2); |
| |
| r1.l = #lo(swapper_pg_dir) |
| r1.h = #hi(swapper_pg_dir) |
| r2 = lsr(r2, #22) /* 4MB page number */ |
| r2 = asl(r2, #2) /* times sizeof(PTE) (4bytes) */ |
| r1 = add(r1,r2); |
| loop0(1f,r26) |
| |
| 1: |
| { |
| memw(R1 ++ #4) = R0 |
| }:endloop0 |
| |
| r0 = r24 |
| r1 = #VM_TRANS_TYPE_TABLE |
| call __vmnewmap |
| |
| /* Go ahead and install the trap0 return so angel calls work */ |
| r0.h = #hi(_K_provisional_vec) |
| r0.l = #lo(_K_provisional_vec) |
| call __vmsetvec |
| |
| /* |
| * OK, at this point we should start to be much more careful, |
| * we're going to enter C code and start touching memory |
| * in all sorts of places. |
| * This means: |
| * SGP needs to be OK |
| * Need to lock shared resources |
| * A bunch of other things that will cause |
| * all kinds of painful bugs |
| */ |
| |
| /* |
| * Stack pointer should be pointed at the init task's |
| * thread stack, which should have been declared in arch/init_task.c. |
| * So uhhhhh... |
| * It's accessible via the init_thread_union, which is a union |
| * of a thread_info struct and a stack; of course, the top |
| * of the stack is not for you. The end of the stack |
| * is simply init_thread_union + THREAD_SIZE. |
| */ |
| |
| {r29.H = #HI(init_thread_union); r0.H = #HI(_THREAD_SIZE); } |
| {r29.L = #LO(init_thread_union); r0.L = #LO(_THREAD_SIZE); } |
| |
| /* initialize the register used to point to current_thread_info */ |
| /* Fixme: THREADINFO_REG can't be R2 because of that memset thing. */ |
| {r29 = add(r29,r0); THREADINFO_REG = r29; } |
| |
| /* Hack: zero bss; */ |
| { r0.L = #LO(__bss_start); r1 = #0; r2.l = #LO(__bss_stop); } |
| { r0.H = #HI(__bss_start); r2.h = #HI(__bss_stop); } |
| |
| r2 = sub(r2,r0); |
| call memset; |
| |
| /* Set PHYS_OFFSET; should be in R25 */ |
| #ifdef CONFIG_HEXAGON_PHYS_OFFSET |
| r0.l = #LO(__phys_offset); |
| r0.h = #HI(__phys_offset); |
| memw(r0) = r25; |
| #endif |
| |
| /* Time to make the doughnuts. */ |
| call start_kernel |
| |
| /* |
| * Should not reach here. |
| */ |
| 1: |
| jump 1b |
| |
| .p2align PAGE_SHIFT |
| ENTRY(external_cmdline_buffer) |
| .fill _PAGE_SIZE,1,0 |
| |
| .data |
| .p2align PAGE_SHIFT |
| ENTRY(empty_zero_page) |
| .fill _PAGE_SIZE,1,0 |