/*
* Copyright (C) 2010 LunarG Inc.
* Copyright (c) 2017, NVIDIA CORPORATION.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include "entry.h"
#include "entry_common.h"
#include <assert.h>
#include <stdint.h>
#include <sys/mman.h>
#include <unistd.h>
#include <string.h>
#include "utils_misc.h"
#include "u_macros.h"
#include "glapi.h"
#include "glvnd/GLdispatchABI.h"
// NOTE: These must be powers of two:
#define ENTRY_STUB_ALIGN 64
#if !defined(GLDISPATCH_PAGE_SIZE)
#define GLDISPATCH_PAGE_SIZE 65536
#endif
__asm__(".section wtext,\"ax\",@progbits\n");
__asm__(".balign " U_STRINGIFY(GLDISPATCH_PAGE_SIZE) "\n"
".globl public_entry_start\n"
".hidden public_entry_start\n"
"public_entry_start:");
#define STUB_ASM_ENTRY(func) \
".globl " func "\n" \
".type " func ", @function\n" \
".balign " U_STRINGIFY(ENTRY_STUB_ALIGN) "\n" \
func ":\n\t" \
" addis 2, 12, .TOC.-" func "@ha\n\t" \
" addi 2, 2, .TOC.-" func "@l\n\t" \
" .localentry " func ", .-" func "\n\t"
#define STUB_ASM_CODE(slot) \
" addis 11, 2, _glapi_tls_Current@got@tprel@ha\n\t" \
" ld 11, _glapi_tls_Current@got@tprel@l(11)\n\t" \
" add 11, 11,_glapi_tls_Current@tls\n\t" \
" ld 11, 0(11)\n\t" \
" addis 11, 11, (" slot "*8)@ha\n" \
" ld 12, (" slot "*8)@l (11)\n" \
" mtctr 12\n\t" \
" bctr\n" \
// Conceptually, this is:
// {
// void **dispatchTable = _glapi_tls_Current;
// jump_to_address(dispatchTable[slot];
// }
//
// Note that _glapi_tls_Current is a global variable declared with
// __thread.
#define MAPI_TMP_STUB_ASM_GCC
#include "mapi_tmp.h"
__asm__(".balign " U_STRINGIFY(GLDISPATCH_PAGE_SIZE) "\n"
".globl public_entry_end\n"
".hidden public_entry_end\n"
"public_entry_end:");
__asm__(".text\n");
__asm__("ppc64le_current_tls:\n\t"
" addis 3, 2, _glapi_tls_Current@got@tprel@ha\n\t"
" ld 3, _glapi_tls_Current@got@tprel@l(3)\n\t"
" blr\n"
);
extern uint64_t ppc64le_current_tls();
const int entry_type = __GLDISPATCH_STUB_PPC64LE;
const int entry_stub_size = ENTRY_STUB_ALIGN;
static const uint32_t ENTRY_TEMPLATE[] =
{
// This should be functionally the same code as would be generated from
// the STUB_ASM_CODE macro, but defined as a buffer.
// This is used to generate new dispatch stubs. libglvnd will copy this
// data to the dispatch stub, and then it will patch the slot number and
// any addresses that it needs to.
// NOTE!!! NOTE!!! NOTE!!!
// This representation is correct for both little- and big-endian systems.
// However, more work needs to be done for big-endian Linux because it
// adheres to an older, AIX-compatible ABI that uses function descriptors.
// 1000:
0x7C0802A6, // <ENTRY+00>: mflr 0
0xF8010010, // <ENTRY+04>: std 0, 16(1)
0xE96C0028, // <ENTRY+08>: ld 11, 9000f-1000b+0(12)
0x7D6B6A14, // <ENTRY+12>: add 11, 11, 13
0xE96B0000, // <ENTRY+16>: ld 11, 0(11)
0xE80C0030, // <ENTRY+20>: ld 0, 9000f-1000b+8(12)
0x7D8B002A, // <ENTRY+24>: ldx 12, 11, 0
0x7D8903A6, // <ENTRY+28>: mtctr 12
0x4E800420, // <ENTRY+32>: bctr
0x60000000, // <ENTRY+36>: nop
// 9000:
0, 0, // <ENTRY+40>: .quad _glapi_Current
0, 0 // <ENTRY+48>: .quad <slot>*8
};
/*
* These are the offsets in ENTRY_TEMPLATE used in entry_generate_default_code
* to patch the dispatch table index and the slot number in the generated
* function.
*
* TEMPLATE_OFFSET_TLS_ADDR is the offset part of the _glapi_tls_Current
*__thread variable,
* TEMPLATE_OFFSET_SLOT is the dispatch table index.
*/
static const int TEMPLATE_OFFSET_TLS_ADDR = sizeof(ENTRY_TEMPLATE) - 16;
static const int TEMPLATE_OFFSET_SLOT = sizeof(ENTRY_TEMPLATE) - 8;
void entry_generate_default_code(char *entry, int slot)
{
char *writeEntry = u_execmem_get_writable(entry);
STATIC_ASSERT(ENTRY_STUB_ALIGN >= sizeof(ENTRY_TEMPLATE));
assert(slot >= 0);
memcpy(writeEntry, ENTRY_TEMPLATE, sizeof(ENTRY_TEMPLATE));
*((uint64_t *) (writeEntry + TEMPLATE_OFFSET_TLS_ADDR)) = (uintptr_t) ppc64le_current_tls();
*((uint64_t *) (writeEntry + TEMPLATE_OFFSET_SLOT)) = slot * sizeof(mapi_func);
// This sequence is from the PowerISA Version 2.07B book.
// It may be a bigger hammer than we need, but it works;
// note that the __builtin___clear_cache intrinsic for
// PPC does not seem to generate any code.
__asm__ __volatile__(
" dcbst 0, %0\n\t"
" sync\n\t"
" icbi 0, %0\n\t"
" isync\n"
: : "r" (writeEntry)
);
}