projects / mirror_ubuntu-bionic-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 26025bbf JH |
2 | /* |
| 3 | * Copyright (C) 2010 Imagination Technologies Ltd. | |
| 4 | * | |
| 5 | * This file contains code that can be accessed from userspace and can | |
| 6 | * access certain kernel data structures without the overhead of a system | |
| 7 | * call. | |
| 8 | */ | |
| 9 | ||
| 10 | #include <asm/metag_regs.h> | |
| 11 | #include <asm/user_gateway.h> | |
| 12 | ||
| 13 | /* | |
| 14 | * User helpers. | |
| 15 | * | |
| 16 | * These are segment of kernel provided user code reachable from user space | |
| 17 | * at a fixed address in kernel memory. This is used to provide user space | |
| 18 | * with some operations which require kernel help because of unimplemented | |
| 19 | * native feature and/or instructions in some Meta CPUs. The idea is for | |
| 20 | * this code to be executed directly in user mode for best efficiency but | |
| 21 | * which is too intimate with the kernel counter part to be left to user | |
| 22 | * libraries. The kernel reserves the right to change this code as needed | |
| 23 | * without warning. Only the entry points and their results are guaranteed | |
| 24 | * to be stable. | |
| 25 | * | |
| 26 | * Each segment is 64-byte aligned. This mechanism should be used only for | |
| 27 | * for things that are really small and justified, and not be abused freely. | |
| 28 | */ | |
| 29 | .text | |
| 30 | .global ___user_gateway_start | |
| 31 | ___user_gateway_start: | |
| 32 | ||
| 33 | /* get_tls | |
| 34 | * Offset: 0 | |
| 35 | * Description: Get the TLS pointer for this process. | |
| 36 | */ | |
| 37 | .global ___kuser_get_tls | |
| 38 | .type ___kuser_get_tls,function | |
| 39 | ___kuser_get_tls: | |
| 40 | MOVT D1Ar1,#HI(USER_GATEWAY_PAGE + USER_GATEWAY_TLS) | |
| 41 | ADD D1Ar1,D1Ar1,#LO(USER_GATEWAY_PAGE + USER_GATEWAY_TLS) | |
| 42 | MOV D1Ar3,TXENABLE | |
| 43 | AND D1Ar3,D1Ar3,#(TXENABLE_THREAD_BITS) | |
| 44 | LSR D1Ar3,D1Ar3,#(TXENABLE_THREAD_S - 2) | |
| 45 | GETD D0Re0,[D1Ar1+D1Ar3] | |
| 46 | ___kuser_get_tls_end: /* Beyond this point the read will complete */ | |
| 47 | MOV PC,D1RtP | |
| 48 | .size ___kuser_get_tls,.-___kuser_get_tls | |
| 49 | .global ___kuser_get_tls_end | |
| 50 | ||
| 51 | /* cmpxchg | |
| 52 | * Offset: 64 | |
| 53 | * Description: Replace the value at 'ptr' with 'newval' if the current | |
| 54 | * value is 'oldval'. Return zero if we succeeded, | |
| 55 | * non-zero otherwise. | |
| 56 | * | |
| 57 | * Reference prototype: | |
| 58 | * | |
| 59 | * int __kuser_cmpxchg(int oldval, int newval, unsigned long *ptr) | |
| 60 | * | |
| 61 | */ | |
| 62 | .balign 64 | |
| 63 | .global ___kuser_cmpxchg | |
| 64 | .type ___kuser_cmpxchg,function | |
| 65 | ___kuser_cmpxchg: | |
| 66 | #ifdef CONFIG_SMP | |
| 67 | /* | |
| 68 | * We must use LNKGET/LNKSET with an SMP kernel because the other method | |
| 69 | * does not provide atomicity across multiple CPUs. | |
| 70 | */ | |
| 71 | 0: LNKGETD D0Re0,[D1Ar3] | |
| 72 | CMP D0Re0,D1Ar1 | |
| 73 | LNKSETDZ [D1Ar3],D0Ar2 | |
| 74 | BNZ 1f | |
| 75 | DEFR D0Re0,TXSTAT | |
| 76 | ANDT D0Re0,D0Re0,#HI(0x3f000000) | |
| 77 | CMPT D0Re0,#HI(0x02000000) | |
| 78 | BNE 0b | |
| 79 | #ifdef CONFIG_METAG_LNKGET_AROUND_CACHE | |
| 80 | DCACHE [D1Ar3], D0Re0 | |
| 81 | #endif | |
| 82 | 1: MOV D0Re0,#1 | |
| 83 | XORZ D0Re0,D0Re0,D0Re0 | |
| 84 | MOV PC,D1RtP | |
| 85 | #else | |
| 86 | GETD D0Re0,[D1Ar3] | |
| 87 | CMP D0Re0,D1Ar1 | |
| 88 | SETDZ [D1Ar3],D0Ar2 | |
| 89 | ___kuser_cmpxchg_end: /* Beyond this point the write will complete */ | |
| 90 | MOV D0Re0,#1 | |
| 91 | XORZ D0Re0,D0Re0,D0Re0 | |
| 92 | MOV PC,D1RtP | |
| 93 | #endif /* CONFIG_SMP */ | |
| 94 | .size ___kuser_cmpxchg,.-___kuser_cmpxchg | |
| 95 | .global ___kuser_cmpxchg_end | |
| 96 | ||
| 97 | .global ___user_gateway_end | |
| 98 | ___user_gateway_end: |