amd/common: add a more powerful runtime linker

Using an explicit linker instead of just concatenating .text
sections will allow us to start using .rodata sections and
explicit descriptions of data on LDS that is shared between
stages.

Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 561 insertions, 0 deletions

diff --git a/src/amd/common/ac_rtld.c b/src/amd/common/ac_rtld.c
new file mode 100644
index 00000000000..996ff045b16
--- /dev/null
+++ b/src/amd/common/ac_rtld.c
@@ -0,0 +1,561 @@
+/*
+ * Copyright 2014-2019 Advanced Micro Devices, Inc.
+ *
+ * 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 (including the next
+ * paragraph) 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 "ac_rtld.h"
+
+#include <gelf.h>
+#include <libelf.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ac_binary.h"
+#include "util/u_math.h"
+
+// Old distributions may not have this enum constant
+#define MY_EM_AMDGPU 224
+
+#ifndef R_AMDGPU_NONE
+#define R_AMDGPU_NONE 0
+#define R_AMDGPU_ABS32_LO 1
+#define R_AMDGPU_ABS32_HI 2
+#define R_AMDGPU_ABS64 3
+#define R_AMDGPU_REL32 4
+#define R_AMDGPU_REL64 5
+#define R_AMDGPU_ABS32 6
+#define R_AMDGPU_GOTPCREL 7
+#define R_AMDGPU_GOTPCREL32_LO 8
+#define R_AMDGPU_GOTPCREL32_HI 9
+#define R_AMDGPU_REL32_LO 10
+#define R_AMDGPU_REL32_HI 11
+#define R_AMDGPU_RELATIVE64 13
+#endif
+
+/* For the UMR disassembler. */
+#define DEBUGGER_END_OF_CODE_MARKER	0xbf9f0000 /* invalid instruction */
+#define DEBUGGER_NUM_MARKERS		5
+
+struct ac_rtld_section {
+	bool is_rx : 1;
+	bool is_pasted_text : 1;
+	uint64_t offset;
+	const char *name;
+};
+
+struct ac_rtld_part {
+	Elf *elf;
+	struct ac_rtld_section *sections;
+	unsigned num_sections;
+};
+
+static void report_erroraf(const char *fmt, va_list va)
+{
+	char *msg;
+	int ret = asprintf(&msg, fmt, va);
+	if (ret < 0)
+		msg = "(asprintf failed)";
+
+	fprintf(stderr, "ac_rtld error: %s\n", msg);
+
+	if (ret >= 0)
+		free(msg);
+}
+
+static void report_errorf(const char *fmt, ...) PRINTFLIKE(1, 2);
+
+static void report_errorf(const char *fmt, ...)
+{
+	va_list va;
+	va_start(va, fmt);
+	report_erroraf(fmt, va);
+	va_end(va);
+}
+
+static void report_elf_errorf(const char *fmt, ...) PRINTFLIKE(1, 2);
+
+static void report_elf_errorf(const char *fmt, ...)
+{
+	va_list va;
+	va_start(va, fmt);
+	report_erroraf(fmt, va);
+	va_end(va);
+
+	fprintf(stderr, "ELF error: %s\n", elf_errmsg(elf_errno()));
+}
+
+/**
+ * Open a binary consisting of one or more shader parts.
+ *
+ * \param binary the uninitialized struct
+ * \param num_parts number of shader parts
+ * \param elf_ptrs pointers to the in-memory ELF objects for each shader part
+ * \param elf_sizes sizes (in bytes) of the in-memory ELF objects
+ */
+bool ac_rtld_open(struct ac_rtld_binary *binary, unsigned num_parts,
+		  const char * const *elf_ptrs,
+		  const size_t *elf_sizes)
+{
+	/* One of the libelf implementations
+	 * (http://www.mr511.de/software/english.htm) requires calling
+	 * elf_version() before elf_memory().
+	 */
+	elf_version(EV_CURRENT);
+
+	memset(binary, 0, sizeof(*binary));
+	binary->num_parts = num_parts;
+	binary->parts = calloc(sizeof(*binary->parts), num_parts);
+	if (!binary->parts)
+		return false;
+
+	uint64_t pasted_text_size = 0;
+	uint64_t rx_align = 1;
+	uint64_t rx_size = 0;
+
+#define report_if(cond) \
+	do { \
+		if ((cond)) { \
+			report_errorf(#cond); \
+			goto fail; \
+		} \
+	} while (false)
+#define report_elf_if(cond) \
+	do { \
+		if ((cond)) { \
+			report_elf_errorf(#cond); \
+			goto fail; \
+		} \
+	} while (false)
+
+	/* First pass over all parts: open ELFs and determine the placement of
+	 * sections in the memory image. */
+	for (unsigned i = 0; i < num_parts; ++i) {
+		struct ac_rtld_part *part = &binary->parts[i];
+		part->elf = elf_memory((char *)elf_ptrs[i], elf_sizes[i]);
+		report_elf_if(!part->elf);
+
+		const Elf64_Ehdr *ehdr = elf64_getehdr(part->elf);
+		report_elf_if(!ehdr);
+		report_if(ehdr->e_machine != MY_EM_AMDGPU);
+
+		size_t section_str_index;
+		size_t num_shdrs;
+		report_elf_if(elf_getshdrstrndx(part->elf, &section_str_index) < 0);
+		report_elf_if(elf_getshdrnum(part->elf, &num_shdrs) < 0);
+
+		part->num_sections = num_shdrs;
+		part->sections = calloc(sizeof(*part->sections), num_shdrs);
+		report_if(!part->sections);
+
+		Elf_Scn *section = NULL;
+		while ((section = elf_nextscn(part->elf, section))) {
+			Elf64_Shdr *shdr = elf64_getshdr(section);
+			struct ac_rtld_section *s = &part->sections[elf_ndxscn(section)];
+			s->name = elf_strptr(part->elf, section_str_index, shdr->sh_name);
+			report_elf_if(!s->name);
+
+			/* Cannot actually handle linked objects yet */
+			report_elf_if(shdr->sh_addr != 0);
+
+			/* Alignment must be 0 or a power of two */
+			report_elf_if(shdr->sh_addralign & (shdr->sh_addralign - 1));
+			uint64_t sh_align = MAX2(shdr->sh_addralign, 1);
+
+			if (shdr->sh_flags & SHF_ALLOC &&
+			    shdr->sh_type != SHT_NOTE) {
+				report_if(shdr->sh_flags & SHF_WRITE);
+
+				s->is_rx = true;
+
+				if (shdr->sh_flags & SHF_EXECINSTR) {
+					report_elf_if(shdr->sh_size & 3);
+
+					if (!strcmp(s->name, ".text"))
+						s->is_pasted_text = true;
+				}
+
+				if (s->is_pasted_text) {
+					s->offset = pasted_text_size;
+					pasted_text_size += shdr->sh_size;
+				} else {
+					rx_align = align(rx_align, sh_align);
+					rx_size = align(rx_size, sh_align);
+					s->offset = rx_size;
+					rx_size += shdr->sh_size;
+				}
+			}
+		}
+	}
+
+	binary->rx_end_markers = pasted_text_size;
+	pasted_text_size += 4 * DEBUGGER_NUM_MARKERS;
+
+	/* Second pass: Adjust offsets of non-pasted text sections. */
+	binary->rx_size = pasted_text_size;
+	binary->rx_size = align(binary->rx_size, rx_align);
+
+	for (unsigned i = 0; i < num_parts; ++i) {
+		struct ac_rtld_part *part = &binary->parts[i];
+		size_t num_shdrs;
+		elf_getshdrnum(part->elf, &num_shdrs);
+
+		for (unsigned j = 0; j < num_shdrs; ++j) {
+			struct ac_rtld_section *s = &part->sections[j];
+			if (s->is_rx && !s->is_pasted_text)
+				s->offset += binary->rx_size;
+		}
+	}
+
+	binary->rx_size += rx_size;
+
+	return true;
+
+#undef report_if
+#undef report_elf_if
+
+fail:
+	ac_rtld_close(binary);
+	return false;
+}
+
+void ac_rtld_close(struct ac_rtld_binary *binary)
+{
+	for (unsigned i = 0; i < binary->num_parts; ++i) {
+		struct ac_rtld_part *part = &binary->parts[i];
+		free(part->sections);
+		elf_end(part->elf);
+	}
+
+	free(binary->parts);
+	binary->parts = NULL;
+	binary->num_parts = 0;
+}
+
+static bool get_section_by_name(struct ac_rtld_part *part, const char *name,
+				const char **data, size_t *nbytes)
+{
+	for (unsigned i = 0; i < part->num_sections; ++i) {
+		struct ac_rtld_section *s = &part->sections[i];
+		if (s->name && !strcmp(name, s->name)) {
+			Elf_Scn *target_scn = elf_getscn(part->elf, i);
+			Elf_Data *target_data = elf_getdata(target_scn, NULL);
+			if (!target_data) {
+				report_elf_errorf("ac_rtld: get_section_by_name: elf_getdata");
+				return false;
+			}
+
+			*data = target_data->d_buf;
+			*nbytes = target_data->d_size;
+			return true;
+		}
+	}
+	return false;
+}
+
+bool ac_rtld_get_section_by_name(struct ac_rtld_binary *binary, const char *name,
+				 const char **data, size_t *nbytes)
+{
+	assert(binary->num_parts == 1);
+	return get_section_by_name(&binary->parts[0], name, data, nbytes);
+}
+
+bool ac_rtld_read_config(struct ac_rtld_binary *binary,
+			 struct ac_shader_config *config)
+{
+	for (unsigned i = 0; i < binary->num_parts; ++i) {
+		struct ac_rtld_part *part = &binary->parts[i];
+		const char *config_data;
+		size_t config_nbytes;
+
+		if (!get_section_by_name(part, ".AMDGPU.config",
+					 &config_data, &config_nbytes))
+			return false;
+
+		/* TODO: be precise about scratch use? */
+		struct ac_shader_config c = {};
+		ac_parse_shader_binary_config(config_data, config_nbytes, true, &c);
+
+		config->num_sgprs = MAX2(config->num_sgprs, c.num_sgprs);
+		config->num_vgprs = MAX2(config->num_vgprs, c.num_vgprs);
+		config->spilled_sgprs = MAX2(config->spilled_sgprs, c.spilled_sgprs);
+		config->spilled_vgprs = MAX2(config->spilled_vgprs, c.spilled_vgprs);
+		config->scratch_bytes_per_wave = MAX2(config->scratch_bytes_per_wave,
+						      c.scratch_bytes_per_wave);
+
+		assert(i == 0 || config->float_mode == c.float_mode);
+		config->float_mode = c.float_mode;
+
+		/* SPI_PS_INPUT_ENA/ADDR can't be combined. Only the value from
+		 * the main shader part is used. */
+		assert(config->spi_ps_input_ena == 0 &&
+		       config->spi_ps_input_addr == 0);
+		config->spi_ps_input_ena = c.spi_ps_input_ena;
+		config->spi_ps_input_addr = c.spi_ps_input_addr;
+
+		/* TODO: consistently use LDS symbols for this */
+		config->lds_size = MAX2(config->lds_size, c.lds_size);
+
+		/* TODO: Should we combine these somehow? It's currently only
+		 * used for radeonsi's compute, where multiple parts aren't used. */
+		assert(config->rsrc1 == 0 && config->rsrc2 == 0);
+		config->rsrc1 = c.rsrc1;
+		config->rsrc2 = c.rsrc2;
+	}
+
+	return true;
+}
+
+static bool resolve_symbol(const struct ac_rtld_upload_info *u,
+			   unsigned part_idx, const Elf64_Sym *sym,
+			   const char *name, uint64_t *value)
+{
+	if (sym->st_shndx == SHN_UNDEF) {
+		/* TODO: resolve from other parts */
+
+		if (u->get_external_symbol(u->cb_data, name, value))
+			return true;
+
+		report_errorf("symbol %s: unknown", name);
+		return false;
+	}
+
+	struct ac_rtld_part *part = &u->binary->parts[part_idx];
+	if (sym->st_shndx >= part->num_sections) {
+		report_errorf("symbol %s: section out of bounds", name);
+		return false;
+	}
+
+	struct ac_rtld_section *s = &part->sections[sym->st_shndx];
+	if (!s->is_rx) {
+		report_errorf("symbol %s: bad section", name);
+		return false;
+	}
+
+	uint64_t section_base = u->rx_va + s->offset;
+
+	*value = section_base + sym->st_value;
+	return true;
+}
+
+static bool apply_relocs(const struct ac_rtld_upload_info *u,
+			 unsigned part_idx, const Elf64_Shdr *reloc_shdr,
+			 const Elf_Data *reloc_data)
+{
+#define report_if(cond) \
+	do { \
+		if ((cond)) { \
+			report_errorf(#cond); \
+			return false; \
+		} \
+	} while (false)
+#define report_elf_if(cond) \
+	do { \
+		if ((cond)) { \
+			report_elf_errorf(#cond); \
+			return false; \
+		} \
+	} while (false)
+
+	struct ac_rtld_part *part = &u->binary->parts[part_idx];
+	Elf_Scn *target_scn = elf_getscn(part->elf, reloc_shdr->sh_info);
+	report_elf_if(!target_scn);
+
+	Elf_Data *target_data = elf_getdata(target_scn, NULL);
+	report_elf_if(!target_data);
+
+	Elf_Scn *symbols_scn = elf_getscn(part->elf, reloc_shdr->sh_link);
+	report_elf_if(!symbols_scn);
+
+	Elf64_Shdr *symbols_shdr = elf64_getshdr(symbols_scn);
+	report_elf_if(!symbols_shdr);
+	uint32_t strtabidx = symbols_shdr->sh_link;
+
+	Elf_Data *symbols_data = elf_getdata(symbols_scn, NULL);
+	report_elf_if(!symbols_data);
+
+	const Elf64_Sym *symbols = symbols_data->d_buf;
+	size_t num_symbols = symbols_data->d_size / sizeof(Elf64_Sym);
+
+	struct ac_rtld_section *s = &part->sections[reloc_shdr->sh_info];
+	report_if(!s->is_rx);
+
+	const char *orig_base = target_data->d_buf;
+	char *dst_base = u->rx_ptr + s->offset;
+	uint64_t va_base = u->rx_va + s->offset;
+
+	Elf64_Rel *rel = reloc_data->d_buf;
+	size_t num_relocs = reloc_data->d_size / sizeof(*rel);
+	for (size_t i = 0; i < num_relocs; ++i, ++rel) {
+		size_t r_sym = ELF64_R_SYM(rel->r_info);
+		unsigned r_type = ELF64_R_TYPE(rel->r_info);
+
+		const char *orig_ptr = orig_base + rel->r_offset;
+		char *dst_ptr = dst_base + rel->r_offset;
+		uint64_t va = va_base + rel->r_offset;
+
+		uint64_t symbol;
+		uint64_t addend;
+
+		if (r_sym == STN_UNDEF) {
+			symbol = 0;
+		} else {
+			report_elf_if(r_sym >= num_symbols);
+
+			const Elf64_Sym *sym = &symbols[r_sym];
+			const char *symbol_name =
+				elf_strptr(part->elf, strtabidx, sym->st_name);
+			report_elf_if(!symbol_name);
+
+			if (!resolve_symbol(u, part_idx, sym, symbol_name, &symbol))
+				return false;
+		}
+
+		/* TODO: Should we also support .rela sections, where the
+		 * addend is part of the relocation record? */
+
+		/* Load the addend from the ELF instead of the destination,
+		 * because the destination may be in VRAM. */
+		switch (r_type) {
+		case R_AMDGPU_ABS32:
+		case R_AMDGPU_ABS32_LO:
+		case R_AMDGPU_ABS32_HI:
+		case R_AMDGPU_REL32:
+		case R_AMDGPU_REL32_LO:
+		case R_AMDGPU_REL32_HI:
+			addend = *(const uint32_t *)orig_ptr;
+			break;
+		case R_AMDGPU_ABS64:
+		case R_AMDGPU_REL64:
+			addend = *(const uint64_t *)orig_ptr;
+			break;
+		default:
+			report_errorf("unsupported r_type == %u", r_type);
+			return false;
+		}
+
+		uint64_t abs = symbol + addend;
+
+		switch (r_type) {
+		case R_AMDGPU_ABS32:
+			assert((uint32_t)abs == abs);
+		case R_AMDGPU_ABS32_LO:
+			*(uint32_t *)dst_ptr = util_cpu_to_le32(abs);
+			break;
+		case R_AMDGPU_ABS32_HI:
+			*(uint32_t *)dst_ptr = util_cpu_to_le32(abs >> 32);
+			break;
+		case R_AMDGPU_ABS64:
+			*(uint64_t *)dst_ptr = util_cpu_to_le64(abs);
+			break;
+		case R_AMDGPU_REL32:
+			assert((int64_t)(int32_t)(abs - va) == (int64_t)(abs - va));
+		case R_AMDGPU_REL32_LO:
+			*(uint32_t *)dst_ptr = util_cpu_to_le32(abs - va);
+			break;
+		case R_AMDGPU_REL32_HI:
+			*(uint32_t *)dst_ptr = util_cpu_to_le32((abs - va) >> 32);
+			break;
+		case R_AMDGPU_REL64:
+			*(uint64_t *)dst_ptr = util_cpu_to_le64(abs - va);
+			break;
+		default:
+			unreachable("bad r_type");
+		}
+	}
+
+	return true;
+
+#undef report_if
+#undef report_elf_if
+}
+
+/**
+ * Upload the binary or binaries to the provided GPU buffers, including
+ * relocations.
+ */
+bool ac_rtld_upload(struct ac_rtld_upload_info *u)
+{
+#define report_if(cond) \
+	do { \
+		if ((cond)) { \
+			report_errorf(#cond); \
+			return false; \
+		} \
+	} while (false)
+#define report_elf_if(cond) \
+	do { \
+		if ((cond)) { \
+			report_errorf(#cond); \
+			return false; \
+		} \
+	} while (false)
+
+	/* First pass: upload raw section data. */
+	for (unsigned i = 0; i < u->binary->num_parts; ++i) {
+		struct ac_rtld_part *part = &u->binary->parts[i];
+		Elf_Scn *section = NULL;
+		while ((section = elf_nextscn(part->elf, section))) {
+			Elf64_Shdr *shdr = elf64_getshdr(section);
+			struct ac_rtld_section *s = &part->sections[elf_ndxscn(section)];
+
+			if (!s->is_rx)
+				continue;
+
+			report_if(shdr->sh_type != SHT_PROGBITS);
+
+			Elf_Data *data = elf_getdata(section, NULL);
+			report_elf_if(!data || data->d_size != shdr->sh_size);
+			memcpy(u->rx_ptr + s->offset, data->d_buf, shdr->sh_size);
+		}
+	}
+
+	if (u->binary->rx_end_markers) {
+		uint32_t *dst = (uint32_t *)(u->rx_ptr + u->binary->rx_end_markers);
+		for (unsigned i = 0; i < DEBUGGER_NUM_MARKERS; ++i)
+			*dst++ = util_cpu_to_le32(DEBUGGER_END_OF_CODE_MARKER);
+	}
+
+	/* Second pass: handle relocations, overwriting uploaded data where
+	 * appropriate. */
+	for (unsigned i = 0; i < u->binary->num_parts; ++i) {
+		struct ac_rtld_part *part = &u->binary->parts[i];
+		Elf_Scn *section = NULL;
+		while ((section = elf_nextscn(part->elf, section))) {
+			Elf64_Shdr *shdr = elf64_getshdr(section);
+			if (shdr->sh_type == SHT_REL) {
+				Elf_Data *relocs = elf_getdata(section, NULL);
+				report_elf_if(!relocs || relocs->d_size != shdr->sh_size);
+				if (!apply_relocs(u, i, shdr, relocs))
+					return false;
+			} else if (shdr->sh_type == SHT_RELA) {
+				report_errorf("SHT_RELA not supported");
+				return false;
+			}
+		}
+	}
+
+	return true;
+
+#undef report_if
+#undef report_elf_if
+}