d853cf56f8
Change the ARMv7 dispatch stubs to use ARM instead of Thumb. There's no difference in size (since either one fits in the 128-byte alignment that we use), but using ARM means that they'll compile and work on an ARMv6 build as well.
154 lines
5.4 KiB
C
154 lines
5.4 KiB
C
/*
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* Copyright (c) 2015, NVIDIA CORPORATION.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and/or associated documentation files (the
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* "Materials"), to deal in the Materials without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Materials, and to
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* permit persons to whom the Materials are furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* unaltered in all copies or substantial portions of the Materials.
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* Any additions, deletions, or changes to the original source files
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* must be clearly indicated in accompanying documentation.
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*
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* THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
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*/
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#include "entry.h"
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#include "entry_common.h"
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#include <string.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <assert.h>
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#include "glapi.h"
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#include "u_macros.h"
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#include "u_current.h"
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#include "utils_misc.h"
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#include "glvnd/GLdispatchABI.h"
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/*
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* See: https://sourceware.org/binutils/docs/as/ARM-Directives.html
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*/
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__asm__(".syntax unified\n\t");
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/*
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* The size of each dispatch stub.
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*/
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#define ENTRY_STUB_ALIGN 128
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#if !defined(GLDISPATCH_PAGE_SIZE)
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#define GLDISPATCH_PAGE_SIZE 4096
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#endif
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/*
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* This runs in ARM mode.
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*
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* On ARMv7, we could use Thumb, with only minor modifications, but using ARM
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* mode means that this code can compile on ARMv6 as well.
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*
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* See: https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html
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*/
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#define STUB_ASM_ENTRY(func) \
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".balign " U_STRINGIFY(ENTRY_STUB_ALIGN) "\n\t" \
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".arm\n\t" \
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".global " func "\n\t" \
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".type " func ", %function\n\t" \
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func ":\n\t"
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/*
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* Looks up the current dispatch table, finds the stub address at the given slot
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* then jumps to it.
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*
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* First tries to find a dispatch table in _glapi_Current[GLAPI_CURRENT_DISPATCH],
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* if not found then it jumps to the 'lookup_dispatch' and calls
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* _glapi_get_current() then jumps back to the 'found_dispatch' label.
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*
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* The 'found_dispatch' section computes the correct offset in the dispatch
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* table then does a branch without link to the function address.
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*
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* This routine preserves the r0-r3 volatile registers as they store the
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* parameters of the entry point that is being looked up.
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*/
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#define STUB_ASM_CODE(slot) \
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"push {r0-r3}\n\t" \
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"ldr r2, 1f\n\t" \
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"12:\n\t" \
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"add r2, pc\n\t" \
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"ldr r3, 1f+4\n\t" \
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"ldr r0, [r2, r3]\n\t" \
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"ldr r0, [r0]\n\t" \
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"cmp r0, #0\n\t" \
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"it eq\n\t" \
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"beq 10f\n\t" \
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"11:\n\t" /* found_dispatch */ \
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"ldr r1, 3f\n\t" \
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"mov r2, #4\n\t" /* sizeof(void *) */ \
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"mul r1, r1, r2\n\t" \
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"ldr ip, [r0, +r1]\n\t" \
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"pop {r0-r3}\n\t" \
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"bx ip\n\t" \
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"10:\n\t" /* lookup_dispatch */ \
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"push {lr}\n\t" \
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"ldr r2, 2f\n\t" \
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"13:\n\t" \
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"add r2, pc\n\t" \
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"ldr r3, 2f+4\n\t" \
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"ldr r0, [r2, r3]\n\t" \
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"blx r0\n\t" \
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"pop {lr}\n\t" \
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"b 11b\n\t" \
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"1:\n\t" \
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".word _GLOBAL_OFFSET_TABLE_-(12b+8)\n\t"\
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".word _glapi_Current(GOT)\n\t" \
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"2:\n\t" \
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".word _GLOBAL_OFFSET_TABLE_-(13b+8)\n\t"\
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".word _glapi_get_current(GOT)\n\t" \
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"3:\n\t" \
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".word " slot "\n\t"
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__asm__(".section wtext,\"ax\"\n"
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".balign " U_STRINGIFY(GLDISPATCH_PAGE_SIZE) "\n"
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".syntax unified\n"
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".globl public_entry_start\n"
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".hidden public_entry_start\n"
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"public_entry_start:\n");
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#define MAPI_TMP_STUB_ASM_GCC
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#include "mapi_tmp.h"
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__asm__(".balign " U_STRINGIFY(GLDISPATCH_PAGE_SIZE) "\n"
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".globl public_entry_end\n"
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".hidden public_entry_end\n"
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"public_entry_end:\n"
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".text\n\t");
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/*
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* If built with -mthumb, let the assembler know that we are done with ARM
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*/
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#if defined(__thumb__)
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__asm__(".thumb\n\t");
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#endif
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const int entry_type = __GLDISPATCH_STUB_ARMV7_ARM;
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const int entry_stub_size = ENTRY_STUB_ALIGN;
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// Note: The rest of these functions could also be used for ARMv7 TLS stubs,
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// once those are implemented.
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mapi_func
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entry_get_public(int index)
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{
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return (mapi_func)(public_entry_start + (index * entry_stub_size));
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}
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