[PATCH v7 3/5] lib/gpgpu_shader: add inline support for iga64 assembly

Zbigniew Kempczyński zbigniew.kempczynski at intel.com
Wed Jun 19 06:40:44 UTC 2024


On Wed, Jun 12, 2024 at 11:39:01AM +0200, Andrzej Hajda wrote:
> With this patch adding iga64 assembly should be similar to
> adding x86 assembly inline. Simple example:
>     emit_iga64_code(shdr, set_exception, R"ASM(
>         or (1|M0) cr0.1<1>:ud cr0.1<0;1,0>:ud ARG(0):ud
>     )ASM", value);
> Note presence of 'ARG(0)', it will be replaced by 'value' argument,
> multiple arguments are possible.
> More sophisticated examples in following patches.
> How does it works:
> 1. Raw string literals (C++ feature available in gcc as extension):
>    R"ASM(...)ASM" allows to use multiline/unescaped string literals.
>    If for some reason they cannot be used we could always fallback to
>    old ugly way of handling multiline strings with escape characters:
>     emit_iga64_code(shdr, set_exception, "\n\
>         or (1|M0) cr0.1<1>:ud cr0.1<0;1,0>:ud ARG(0):ud\n\
>     ", value);
> 2. emit_iga64_code puts the assembly string into special linker section,
>    and calls __emit_iga64_code with pointer to external variable
>    which will contain code templates generated from the assembly for all
>    supported platforms, remaining arguments are put to temporal array
>    to eventually patch the code with positional arguments.
> 3. During build phase the linker section is scanned for assemblies.
>    Every assembly is preprocessed with cpp, to replace ARG(x) macros with
>    magic numbers, and to provide different code for different platforms
>    if needed. Then output file is compiled with iga64, and then .c file
>    is generated with global variables pointing to hexified iga64 codes.
> 
> v2:
>  - fixed meson paths to script,
>  - added check if compiler supports all platforms,
>  - include assembly names in MD5 calculations,
>  - use more specific name for MD5 sum
> v3:
>  - bump minimal meson version to kill "ERROR:  Expecting eol got id." bug
> v4:
>  - set minimal meson to 0.49.2 - builder uses it
> v5:
>  - revert back minimal ver of meson, instead use old syntax a.contains(b)
> v6:
>  - generate_iga64_codes moved to scripts dir,
>  - added include guards to iga64_macros.h
> v7:
>  - use C++ style comments in generated file,
>  - style fixes
> 
> Signed-off-by: Andrzej Hajda <andrzej.hajda at intel.com>
> ---
>  lib/gpgpu_shader.c           |  39 +++++++++++++++
>  lib/gpgpu_shader.h           |  25 ++++++++++
>  lib/iga64_generated_codes.c  |   6 +++
>  lib/iga64_macros.h           |  18 +++++++
>  lib/meson.build              |  17 +++++++
>  meson.build                  |   9 ++--
>  scripts/generate_iga64_codes | 115 +++++++++++++++++++++++++++++++++++++++++++
>  scripts/meson.build          |   1 +
>  8 files changed, 226 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/gpgpu_shader.c b/lib/gpgpu_shader.c
> index 080eef2445da..98a7ffc151ee 100644
> --- a/lib/gpgpu_shader.c
> +++ b/lib/gpgpu_shader.c
> @@ -11,6 +11,9 @@
>  #include "gpgpu_shader.h"
>  #include "gpu_cmds.h"
>  
> +#define IGA64_ARG0 0xc0ded000
> +#define IGA64_ARG_MASK 0xffffff00
> +
>  #define SUPPORTED_GEN_VER 1200 /* Support TGL and up */
>  
>  #define PAGE_SIZE 4096
> @@ -22,6 +25,42 @@
>  #define GPGPU_CURBE_SIZE 0
>  #define GEN7_VFE_STATE_GPGPU_MODE 1
>  
> +static void gpgpu_shader_extend(struct gpgpu_shader *shdr)
> +{
> +	shdr->max_size <<= 1;
> +	shdr->code = realloc(shdr->code, 4 * shdr->max_size);

Assert in case of unsuccessful realloc.

> +}
> +
> +void
> +__emit_iga64_code(struct gpgpu_shader *shdr, struct iga64_template const *tpls,
> +		  int argc, uint32_t *argv)
> +{
> +	uint32_t *ptr;
> +
> +	igt_require_f(shdr->gen_ver >= SUPPORTED_GEN_VER,
> +		      "No available shader templates for platforms older than XeLP\n");
> +
> +	while (shdr->gen_ver < tpls->gen_ver)
> +		tpls++;
> +
> +	while (shdr->max_size < shdr->size + tpls->size)
> +		gpgpu_shader_extend(shdr);
> +
> +	ptr = shdr->code + shdr->size;
> +	memcpy(ptr, tpls->code, 4 * tpls->size);
> +
> +	/* patch the template */
> +	for (int n, i = 0; i < tpls->size; ++i) {
> +		if ((ptr[i] & IGA64_ARG_MASK) != IGA64_ARG0)
> +			continue;
> +		n = ptr[i] - IGA64_ARG0;
> +		igt_assert(n < argc);
> +		ptr[i] = argv[n];
> +	}

This is the part I'm afraid might be problematic. You've probably
expected this question - how can you be sure, no instruction uses
magic value as a part of instruction and it will be incidentally
patched as well?

I think we can at least protect this in script part, by processing
file twice - first with using some artificial macros file (instead
iga64_macros.h), substitute all ARGs with 0x0 and check if your
selected magic (0xc0ded0XX) doesn't exist. If it exists then it
must be changed to something else. If not process this with
iga64_macros.h and we're fine.

--
Zbigniew



> +
> +	shdr->size += tpls->size;
> +}
> +
>  static uint32_t fill_sip(struct intel_bb *ibb,
>  			 const uint32_t sip[][4],
>  			 const size_t size)
> diff --git a/lib/gpgpu_shader.h b/lib/gpgpu_shader.h
> index 02f6f1aad1e3..255f93b4dd81 100644
> --- a/lib/gpgpu_shader.h
> +++ b/lib/gpgpu_shader.h
> @@ -23,6 +23,27 @@ struct gpgpu_shader {
>  	};
>  };
>  
> +struct iga64_template {
> +	uint32_t gen_ver;
> +	uint32_t size;
> +	const uint32_t *code;
> +};
> +
> +#pragma GCC diagnostic ignored "-Wnested-externs"
> +
> +void
> +__emit_iga64_code(struct gpgpu_shader *shdr, const struct iga64_template *tpls,
> +		  int argc, uint32_t *argv);
> +
> +#define emit_iga64_code(__shdr, __name, __txt, __args...) \
> +({ \
> +	static const char t[] __attribute__ ((section(".iga64_assembly"), used)) =\
> +		"iga64_assembly_" #__name ":" __txt "\n"; \
> +	extern struct iga64_template const iga64_code_ ## __name[]; \
> +	u32 args[] = { __args }; \
> +	__emit_iga64_code(__shdr, iga64_code_ ## __name, ARRAY_SIZE(args), args); \
> +})
> +
>  struct gpgpu_shader *gpgpu_shader_create(int fd);
>  void gpgpu_shader_destroy(struct gpgpu_shader *shdr);
>  
> @@ -35,4 +56,8 @@ void gpgpu_shader_exec(struct intel_bb *ibb,
>  		       struct gpgpu_shader *sip,
>  		       uint64_t ring, bool explicit_engine);
>  
> +void gpgpu_shader__eot(struct gpgpu_shader *shdr);
> +void gpgpu_shader__write_dword(struct gpgpu_shader *shdr, uint32_t value,
> +			       uint32_t y_offset);
> +
>  #endif /* GPGPU_SHADER_H */
> diff --git a/lib/iga64_generated_codes.c b/lib/iga64_generated_codes.c
> new file mode 100644
> index 000000000000..452d4b3dae53
> --- /dev/null
> +++ b/lib/iga64_generated_codes.c
> @@ -0,0 +1,6 @@
> +// SPDX-License-Identifier: MIT
> +// Generated using Intel Graphics Assembler 1.1.0-int
> +
> +#include "gpgpu_shader.h"
> +
> +#define MD5_SUM_IGA64_ASMS 68b329da9893e34099c7d8ad5cb9c940
> diff --git a/lib/iga64_macros.h b/lib/iga64_macros.h
> new file mode 100644
> index 000000000000..394e95a21039
> --- /dev/null
> +++ b/lib/iga64_macros.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: MIT */
> +/* Copyright © 2024 Intel Corporation */
> +
> +/* Header used during pre-process phase of iga64 assembly. */
> +
> +#ifndef IGA64_MACROS_H
> +#define IGA64_MACROS_H
> +
> +#define ARG(n) (0xc0ded000 + (n))
> +
> +/* send instruction for DG2+ requires 0 length in case src1 is null, BSpec: 47443 */
> +#if GEN_VER < 1271
> +#define src1_null null
> +#else
> +#define src1_null null:0
> +#endif
> +
> +#endif
> diff --git a/lib/meson.build b/lib/meson.build
> index 0a3084f8aea2..82e7dacad153 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -216,7 +216,10 @@ lib_version = vcs_tag(input : 'version.h.in', output : 'version.h',
>  		      fallback : 'NO-GIT',
>  		      command : vcs_command )
>  
> +iga64_assembly_sources = [ 'gpgpu_shader.c' ]
> +
>  lib_intermediates = []
> +iga64_assembly_libs = []
>  foreach f: lib_sources
>      name = f.underscorify()
>      lib = static_library('igt-' + name,
> @@ -230,8 +233,22 @@ foreach f: lib_sources
>  	])
>  
>      lib_intermediates += lib
> +    if iga64_assembly_sources.contains(f)
> +	iga64_assembly_libs += lib
> +    endif
>  endforeach
>  
> +iga64_generated_codes = custom_target(
> +    'iga64_generated_codes.c',
> +    input : [ 'iga64_generated_codes.c' ] + iga64_assembly_libs,
> +    output : 'iga64_generated_codes.c',
> +    command : [ generate_iga64_codes, '-o', '@OUTPUT@', '-i', '@INPUT@' ]
> +)
> +
> +lib_intermediates += static_library('igt-iga64_generated_codes.c',
> +			[ iga64_generated_codes, lib_version ]
> +		     )
> +
>  lib_igt_build = shared_library('igt',
>      ['dummy.c'],
>      link_whole: lib_intermediates,
> diff --git a/meson.build b/meson.build
> index ab44aadb1fdf..716a4d7bde85 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -341,6 +341,11 @@ else
>  	vmwgfx_rpathdir = ''
>  endif
>  
> +build_testplan = get_option('testplan')
> +build_sphinx = get_option('sphinx')
> +
> +subdir('scripts')
> +
>  subdir('lib')
>  if build_tests
>  	subdir('tests')
> @@ -349,9 +354,6 @@ else
>  endif
>  build_info += 'Build tests: @0@'.format(build_tests)
>  
> -build_testplan = get_option('testplan')
> -build_sphinx = get_option('sphinx')
> -
>  subdir('benchmarks')
>  subdir('tools')
>  subdir('runner')
> @@ -360,7 +362,6 @@ if libdrm_intel.found()
>  endif
>  subdir('overlay')
>  subdir('man')
> -subdir('scripts')
>  subdir('docs')
>  
>  message('Build options')
> diff --git a/scripts/generate_iga64_codes b/scripts/generate_iga64_codes
> new file mode 100755
> index 000000000000..8abfdc4c2009
> --- /dev/null
> +++ b/scripts/generate_iga64_codes
> @@ -0,0 +1,115 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: MIT
> +# Copyright © 2024 Intel Corporation
> +# Author: Andrzej Hajda <andrzej.hajda at intel.com>
> +
> +# List of supported platforms, in format gen100:platform, where gen100 equals
> +# to minimal GPU generation supported by platform multiplied by 100 and platform
> +# is one of platforms supported by -p switch of iga64.
> +#
> +# Must be in decreasing order, the last one must have gen100 equal 0"
> +GEN_VERSIONS="2000:2 1272:12p72 1250:12p5 0:12p1"
> +
> +warn() {
> +    echo -e "$1" >/dev/stderr
> +}
> +
> +die() {
> +    warn "DIE: $1"
> +    exit 1
> +}
> +
> +# parse args
> +while getopts ':i:o:' opt; do
> +    case $opt in
> +    i) INPUT=$OPTARG;;
> +    o) OUTPUT=$OPTARG;;
> +    ?) die "Usage: $0 -i pre-generated-iga64-file -o generated-iga64-file libs-with-iga64-assembly [...]"
> +    esac
> +done
> +LIBS=${@:OPTIND}
> +
> +# read all assemblies into ASMS array
> +ASMS=()
> +while  read -d $'\0' asm; do
> +    test -z "$asm" && continue
> +    ASMS+=( "$asm" )
> +done < <(for f in $LIBS; do objcopy --dump-section .iga64_assembly=/dev/stdout $f.p/*.o; done)
> +
> +# check if we need to recompile - checksum difference and compiler present
> +MD5_ASMS="$(md5sum <<< "${ASMS[@]}" | cut -b1-32)"
> +MD5_PRE="$(grep -Po '(?<=^#define MD5_SUM_IGA64_ASMS )\S{32,32}' $INPUT 2>/dev/null)"
> +
> +if [ "$MD5_ASMS" = "$MD5_PRE" ]; then
> +    echo "iga64 assemblies not changed, reusing pre-compiled file $INPUT."
> +    cp $INPUT $OUTPUT
> +    exit 0
> +fi
> +
> +type iga64 >/dev/null || {
> +    warn "WARNING: iga64 assemblies changed, but iga64 compiler not present, CHANGES will have no effect. Install iga64 (libigc-tools package) to re-compile code."
> +    cp $INPUT $OUTPUT
> +    exit 0
> +}
> +
> +# generate code file
> +WD=$OUTPUT.d
> +mkdir -p $WD
> +
> +# check if all required platforms are supported
> +touch $WD/empty
> +for gen in $GEN_VERSIONS; do
> +    gen_name="${gen#*:}"
> +    iga64 -p=$gen_name -d $WD/empty 2>/dev/null || {
> +        warn "WARNING: iga64 assemblies changed, but iga64 compiler does not support platform '$gen_name', CHANGES will have no effect. Update iga64 (libigc-tools package) to re-compile code."
> +        cp $INPUT $OUTPUT
> +        exit 0
> +    }
> +done
> +
> +# returns count of numbers in strings of format "0x1234, 0x23434, ..."
> +dword_count() {
> +    n=${1//[^x]}
> +    echo ${#n}
> +}
> +
> +echo "Generating new $OUTPUT"
> +
> +cat <<-EOF >$OUTPUT
> +// SPDX-License-Identifier: MIT
> +// Generated using $(iga64 |& head -1)
> +
> +#include "gpgpu_shader.h"
> +
> +#define MD5_SUM_IGA64_ASMS $MD5_ASMS
> +EOF
> +
> +for asm in "${ASMS[@]}"; do
> +    asm_name="${asm%%:*}"
> +    asm_code="${asm_name/assembly/code}"
> +    asm_body="${asm#*:}"
> +    cur_code=""
> +    cur_ver=""
> +    echo -e "\nstruct iga64_template const $asm_code[] = {" >>$OUTPUT
> +    for gen in $GEN_VERSIONS; do
> +        gen_ver="${gen%%:*}"
> +        gen_name="${gen#*:}"
> +        warn "Generating $asm_code for platform $gen_name"
> +        cmd="cpp -P - -o $WD/$asm_name.$gen_name.asm"
> +        cmd+=" -DGEN_VER=$gen_ver -imacros ../lib/iga64_macros.h"
> +        eval "$cmd" <<<"$asm_body" || die "cpp error for $asm_name.$gen_name\ncmd: $cmd"
> +        cmd="iga64 -Xauto-deps -Wall -p=$gen_name"
> +        cmd+=" $WD/$asm_name.$gen_name.asm -o $WD/$asm_name.$gen_name.bin"
> +        eval "$cmd" || die "iga64 error for $asm_name.$gen_name\ncmd: $cmd"
> +        code="$(hexdump -e '"\t\t" 4/4 "0x%08x, " "\n"' $WD/$asm_name.$gen_name.bin)"
> +        [ -z "$cur_code" ] && cur_code="$code"
> +        [ "$cur_code" != "$code" ] && {
> +            echo -e "\t{ .gen_ver = $cur_ver, .size = $(dword_count "$cur_code"), .code = (const uint32_t []) {\n$cur_code\n\t}}," >>$OUTPUT
> +            cur_code="$code"
> +        }
> +        cur_ver=$gen_ver
> +    done
> +    echo -e "\t{ .gen_ver = $cur_ver, .size = $(dword_count "$cur_code"), .code = (const uint32_t []) {\n$cur_code\n\t}}\n};" >>$OUTPUT
> +done
> +
> +cp $OUTPUT $INPUT
> diff --git a/scripts/meson.build b/scripts/meson.build
> index 98783222b6fc..6e64065c5ee7 100644
> --- a/scripts/meson.build
> +++ b/scripts/meson.build
> @@ -14,3 +14,4 @@ endif
>  
>  igt_doc_script = find_program('igt_doc.py', required : build_testplan)
>  gen_rst_index = find_program('gen_rst_index', required : build_sphinx)
> +generate_iga64_codes = find_program('generate_iga64_codes')
> 
> -- 
> 2.34.1
> 


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