| Thiemo Seufer | ba5187d | 2005-04-25 16:36:23 +0000 | [diff] [blame] | 1 | /* |
| 2 | * This file is subject to the terms and conditions of the GNU General Public |
| 3 | * License. See the file "COPYING" in the main directory of this archive |
| 4 | * for more details. |
| 5 | * |
| 6 | * Copyright (C) 2005 Thiemo Seufer |
| 7 | * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved. |
| 8 | * Author: Maciej W. Rozycki <macro@mips.com> |
| 9 | */ |
| 10 | |
| 11 | #include <linux/init.h> |
| 12 | |
| 13 | #include <asm/addrspace.h> |
| 14 | #include <asm/bug.h> |
| 15 | |
| 16 | #ifndef CKSEG2 |
| 17 | #define CKSEG2 CKSSEG |
| 18 | #endif |
| 19 | #ifndef TO_PHYS_MASK |
| 20 | #define TO_PHYS_MASK -1 |
| 21 | #endif |
| 22 | |
| 23 | /* |
| 24 | * FUNC is executed in one of the uncached segments, depending on its |
| 25 | * original address as follows: |
| 26 | * |
| 27 | * 1. If the original address is in CKSEG0 or CKSEG1, then the uncached |
| 28 | * segment used is CKSEG1. |
| 29 | * 2. If the original address is in XKPHYS, then the uncached segment |
| 30 | * used is XKPHYS(2). |
| 31 | * 3. Otherwise it's a bug. |
| 32 | * |
| 33 | * The same remapping is done with the stack pointer. Stack handling |
| 34 | * works because we don't handle stack arguments or more complex return |
| 35 | * values, so we can avoid sharing the same stack area between a cached |
| 36 | * and the uncached mode. |
| 37 | */ |
| 38 | unsigned long __init run_uncached(void *func) |
| 39 | { |
| 40 | register long sp __asm__("$sp"); |
| 41 | register long ret __asm__("$2"); |
| 42 | long lfunc = (long)func, ufunc; |
| 43 | long usp; |
| 44 | |
| 45 | if (sp >= (long)CKSEG0 && sp < (long)CKSEG2) |
| 46 | usp = CKSEG1ADDR(sp); |
| 47 | else if ((long long)sp >= (long long)PHYS_TO_XKPHYS(0LL, 0) && |
| 48 | (long long)sp < (long long)PHYS_TO_XKPHYS(8LL, 0)) |
| 49 | usp = PHYS_TO_XKPHYS((long long)K_CALG_UNCACHED, |
| 50 | XKPHYS_TO_PHYS((long long)sp)); |
| 51 | else { |
| 52 | BUG(); |
| 53 | usp = sp; |
| 54 | } |
| 55 | if (lfunc >= (long)CKSEG0 && lfunc < (long)CKSEG2) |
| 56 | ufunc = CKSEG1ADDR(lfunc); |
| 57 | else if ((long long)lfunc >= (long long)PHYS_TO_XKPHYS(0LL, 0) && |
| 58 | (long long)lfunc < (long long)PHYS_TO_XKPHYS(8LL, 0)) |
| 59 | ufunc = PHYS_TO_XKPHYS((long long)K_CALG_UNCACHED, |
| 60 | XKPHYS_TO_PHYS((long long)lfunc)); |
| 61 | else { |
| 62 | BUG(); |
| 63 | ufunc = lfunc; |
| 64 | } |
| 65 | |
| 66 | __asm__ __volatile__ ( |
| 67 | " move $16, $sp\n" |
| 68 | " move $sp, %1\n" |
| 69 | " jalr %2\n" |
| 70 | " move $sp, $16" |
| 71 | : "=r" (ret) |
| 72 | : "r" (usp), "r" (ufunc) |
| 73 | : "$16", "$31"); |
| 74 | |
| 75 | return ret; |
| 76 | } |