[Xen-devel] [RFC XEN PATCH v2 10/15] tools/libacpi: add a simple AML builder

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

It is used by libacpi to generate SSDTs from ACPI namespace devices
built by the device model.

Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: ross.philipson@xxxxxxxxxxxx

Changes in v2:
 * Add code comment for what is built by each function.
 * Change the license to LGPL.
---
 tools/firmware/hvmloader/Makefile |   3 +-
 tools/libacpi/aml_build.c         | 326 ++++++++++++++++++++++++++++++++++++++
 tools/libacpi/aml_build.h         | 116 ++++++++++++++
 tools/libxl/Makefile              |   3 +-
 4 files changed, 446 insertions(+), 2 deletions(-)
 create mode 100644 tools/libacpi/aml_build.c
 create mode 100644 tools/libacpi/aml_build.h

diff --git a/tools/firmware/hvmloader/Makefile 
b/tools/firmware/hvmloader/Makefile
index 80d7b448a5..abbdaaeb40 100644
--- a/tools/firmware/hvmloader/Makefile
+++ b/tools/firmware/hvmloader/Makefile
@@ -76,11 +76,12 @@ smbios.o: CFLAGS += 
-D__SMBIOS_DATE__="\"$(SMBIOS_REL_DATE)\""
 
 ACPI_PATH = ../../libacpi
 DSDT_FILES = dsdt_anycpu.c dsdt_15cpu.c dsdt_anycpu_qemu_xen.c
-ACPI_OBJS = $(patsubst %.c,%.o,$(DSDT_FILES)) build.o static_tables.o
+ACPI_OBJS = $(patsubst %.c,%.o,$(DSDT_FILES)) build.o static_tables.o 
aml_build.o
 $(ACPI_OBJS): CFLAGS += -I. -DLIBACPI_STDUTILS=\"$(CURDIR)/util.h\"
 CFLAGS += -I$(ACPI_PATH)
 vpath build.c $(ACPI_PATH)
 vpath static_tables.c $(ACPI_PATH)
+vpath aml_build.c $(ACPI_PATH)
 OBJS += $(ACPI_OBJS)
 
 hvmloader: $(OBJS)
diff --git a/tools/libacpi/aml_build.c b/tools/libacpi/aml_build.c
new file mode 100644
index 0000000000..9b4e28ad95
--- /dev/null
+++ b/tools/libacpi/aml_build.c
@@ -0,0 +1,326 @@
+/*
+ * tools/libacpi/aml_build.c
+ *
+ * Copyright (C) 2017, Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License, version 2.1, as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include LIBACPI_STDUTILS
+#include "libacpi.h"
+#include "aml_build.h"
+
+#define AML_OP_SCOPE     0x10
+#define AML_OP_EXT       0x5B
+#define AML_OP_DEVICE    0x82
+
+#define ACPI_NAMESEG_LEN 4
+
+struct aml_build_alloctor {
+    struct acpi_ctxt *ctxt;
+    uint8_t *buf;
+    uint32_t capacity;
+    uint32_t used;
+};
+static struct aml_build_alloctor alloc;
+
+static uint8_t *aml_buf_alloc(uint32_t size)
+{
+    uint8_t *buf = NULL;
+    struct acpi_ctxt *ctxt = alloc.ctxt;
+    uint32_t alloc_size, alloc_align = ctxt->min_alloc_byte_align;
+    uint32_t length = alloc.used + size;
+
+    /* Overflow ... */
+    if ( length < alloc.used )
+        return NULL;
+
+    if ( length <= alloc.capacity )
+    {
+        buf = alloc.buf + alloc.used;
+        alloc.used += size;
+    }
+    else
+    {
+        alloc_size = length - alloc.capacity;
+        alloc_size = (alloc_size + alloc_align) & ~(alloc_align - 1);
+        buf = ctxt->mem_ops.alloc(ctxt, alloc_size, alloc_align);
+
+        if ( buf &&
+             buf == alloc.buf + alloc.capacity /* cont to existing buf */ )
+        {
+            alloc.capacity += alloc_size;
+            buf = alloc.buf + alloc.used;
+            alloc.used += size;
+        }
+        else
+            buf = NULL;
+    }
+
+    return buf;
+}
+
+static uint32_t get_package_length(uint8_t *pkg)
+{
+    uint32_t len;
+
+    len = pkg - alloc.buf;
+    len = alloc.used - len;
+
+    return len;
+}
+
+/*
+ * On success, an object in the following form is stored at @buf.
+ *   @byte
+ *   the original content in @buf
+ */
+static int build_prepend_byte(uint8_t *buf, uint8_t byte)
+{
+    uint32_t len;
+
+    len = buf - alloc.buf;
+    len = alloc.used - len;
+
+    if ( !aml_buf_alloc(sizeof(uint8_t)) )
+        return -1;
+
+    if ( len )
+        memmove(buf + 1, buf, len);
+    buf[0] = byte;
+
+    return 0;
+}
+
+/*
+ * On success, an object in the following form is stored at @buf.
+ *   AML encoding of four-character @name
+ *   the original content in @buf
+ *
+ * Refer to  ACPI spec 6.1, Sec 20.2.2 "Name Objects Encoding".
+ *
+ * XXX: names of multiple segments (e.g. X.Y.Z) are not supported
+ */
+static int build_prepend_name(uint8_t *buf, const char *name)
+{
+    uint8_t *p = buf;
+    const char *s = name;
+    uint32_t len, name_len;
+
+    while ( *s == '\\' || *s == '^' )
+    {
+        if ( build_prepend_byte(p, (uint8_t) *s) )
+            return -1;
+        ++p;
+        ++s;
+    }
+
+    if ( !*s )
+        return build_prepend_byte(p, 0x00);
+
+    len = p - alloc.buf;
+    len = alloc.used - len;
+    name_len = strlen(s);
+    ASSERT(name_len <= ACPI_NAMESEG_LEN);
+
+    if ( !aml_buf_alloc(ACPI_NAMESEG_LEN) )
+        return -1;
+    if ( len )
+        memmove(p + ACPI_NAMESEG_LEN, p, len);
+    memcpy(p, s, name_len);
+    memcpy(p + name_len, "____", ACPI_NAMESEG_LEN - name_len);
+
+    return 0;
+}
+
+enum {
+    PACKAGE_LENGTH_1BYTE_SHIFT = 6, /* Up to 63 - use extra 2 bits. */
+    PACKAGE_LENGTH_2BYTE_SHIFT = 4,
+    PACKAGE_LENGTH_3BYTE_SHIFT = 12,
+    PACKAGE_LENGTH_4BYTE_SHIFT = 20,
+};
+
+/*
+ * On success, an object in the following form is stored at @pkg.
+ *   AML encoding of package length @length
+ *   the original content in @pkg
+ *
+ * Refer to ACPI spec 6.1, Sec 20.2.4 "Package Length Encoding".
+ */
+static int build_prepend_package_length(uint8_t *pkg, uint32_t length)
+{
+    int rc = 0;
+    uint8_t byte;
+    unsigned length_bytes;
+
+    if ( length + 1 < (1 << PACKAGE_LENGTH_1BYTE_SHIFT) )
+        length_bytes = 1;
+    else if ( length + 2 < (1 << PACKAGE_LENGTH_3BYTE_SHIFT) )
+        length_bytes = 2;
+    else if ( length + 3 < (1 << PACKAGE_LENGTH_4BYTE_SHIFT) )
+        length_bytes = 3;
+    else
+        length_bytes = 4;
+
+    length += length_bytes;
+
+    switch ( length_bytes )
+    {
+    case 1:
+        byte = length;
+        return build_prepend_byte(pkg, byte);
+
+    case 4:
+        byte = length >> PACKAGE_LENGTH_4BYTE_SHIFT;
+        if ( build_prepend_byte(pkg, byte) )
+            break;
+        length &= (1 << PACKAGE_LENGTH_4BYTE_SHIFT) - 1;
+        /* fall through */
+    case 3:
+        byte = length >> PACKAGE_LENGTH_3BYTE_SHIFT;
+        if ( build_prepend_byte(pkg, byte) )
+            break;
+        length &= (1 << PACKAGE_LENGTH_3BYTE_SHIFT) - 1;
+        /* fall through */
+    case 2:
+        byte = length >> PACKAGE_LENGTH_2BYTE_SHIFT;
+        if ( build_prepend_byte(pkg, byte) )
+            break;
+        length &= (1 << PACKAGE_LENGTH_2BYTE_SHIFT) - 1;
+        /* fall through */
+    }
+
+    if ( !rc )
+    {
+        /*
+         * Most significant two bits of byte zero indicate how many
+         * following bytes are in PkgLength encoding.
+         */
+        byte = ((length_bytes - 1) << PACKAGE_LENGTH_1BYTE_SHIFT) | length;
+        rc = build_prepend_byte(pkg, byte);
+    }
+
+    return rc;
+}
+
+/*
+ * On success, an object in the following form is stored at @buf.
+ *   @op
+ *   AML encoding of package length of @buf
+ *   original content in @buf
+ *
+ * Refer to comments of callers for ACPI spec sections.
+ */
+static int build_prepend_package(uint8_t *buf, uint8_t op)
+{
+    uint32_t length = get_package_length(buf);
+
+    if ( !build_prepend_package_length(buf, length) )
+        return build_prepend_byte(buf, op);
+    else
+        return -1;
+}
+
+/*
+ * On success, an object in the following form is stored at @buf.
+ *   AML_OP_EXT
+ *   @op
+ *   AML encoding of package length of @buf
+ *   original content in @buf
+ *
+ * Refer to comments of callers for ACPI spec sections.
+ */
+static int build_prepend_ext_package(uint8_t *buf, uint8_t op)
+{
+    if ( !build_prepend_package(buf, op) )
+        return build_prepend_byte(buf, AML_OP_EXT);
+    else
+        return -1;
+}
+
+void *aml_build_begin(struct acpi_ctxt *ctxt)
+{
+    uint32_t align = ctxt->min_alloc_byte_align;
+
+    alloc.ctxt = ctxt;
+    alloc.buf = ctxt->mem_ops.alloc(ctxt, align, align);
+    alloc.capacity = align;
+    alloc.used = 0;
+
+    return alloc.buf;
+}
+
+uint32_t aml_build_end(void)
+{
+    return alloc.used;
+}
+
+/*
+ * On success, an object in the following form is stored at @buf.
+ *   the first @length bytes in @blob
+ *   the original content in @buf
+ */
+int aml_prepend_blob(uint8_t *buf, const void *blob, uint32_t blob_length)
+{
+    uint32_t len;
+
+    ASSERT(buf >= alloc.buf);
+    len = buf - alloc.buf;
+    ASSERT(alloc.used >= len);
+    len = alloc.used - len;
+
+    if ( !aml_buf_alloc(blob_length) )
+        return -1;
+    if ( len )
+        memmove(buf + blob_length, buf, len);
+
+    memcpy(buf, blob, blob_length);
+
+    return 0;
+}
+
+/*
+ * On success, an object decoded as below is stored at @buf.
+ *   Device (@name)
+ *   {
+ *     the original content in @buf
+ *   }
+ *
+ * Refer to ACPI spec 6.1, Sec 20.2.5.2 "Named Objects Encoding" -
+ * "DefDevice".
+ */
+int aml_prepend_device(uint8_t *buf, const char *name)
+{
+    if ( !build_prepend_name(buf, name) )
+        return build_prepend_ext_package(buf, AML_OP_DEVICE);
+    else
+        return -1;
+}
+
+/*
+ * On success, an object decoded as below is stored at @buf.
+ *   Scope (@name)
+ *   {
+ *     the original content in @buf
+ *   }
+ *
+ * Refer to ACPI spec 6.1, Sec 20.2.5.1 "Namespace Modifier Objects
+ * Encoding" - "DefScope".
+ */
+int aml_prepend_scope(uint8_t *buf, const char *name)
+{
+    if ( !build_prepend_name(buf, name) )
+        return build_prepend_package(buf, AML_OP_SCOPE);
+    else
+        return -1;
+}
diff --git a/tools/libacpi/aml_build.h b/tools/libacpi/aml_build.h
new file mode 100644
index 0000000000..30acc0f7a1
--- /dev/null
+++ b/tools/libacpi/aml_build.h
@@ -0,0 +1,116 @@
+/*
+ * tools/libacpi/aml_build.h
+ *
+ * Copyright (C) 2017, Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License, version 2.1, as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _AML_BUILD_H_
+#define _AML_BUILD_H_
+
+#include <stdint.h>
+#include "libacpi.h"
+
+/*
+ * NB: All aml_prepend_* calls, which build AML code in one ACPI
+ *     table, should be placed between a pair of calls to
+ *     aml_build_begin() and aml_build_end(). Nested aml_build_begin()
+ *     and aml_build_end() are not supported.
+ *
+ * NB: If a call to aml_prepend_*() fails, the AML builder buffer
+ *     will be in an inconsistent state, and any following calls to
+ *     aml_prepend_*() will result in undefined behavior.
+ */
+
+/**
+ * Reset the AML builder and begin a new round of building.
+ *
+ * Parameters:
+ *   ctxt: ACPI context used by the AML builder
+ *
+ * Returns:
+ *   a pointer to the builder buffer where the AML code will be stored
+ */
+void *aml_build_begin(struct acpi_ctxt *ctxt);
+
+/**
+ * Mark the end of a round of AML building.
+ *
+ * Returns:
+ *  the number of bytes in the builder buffer built in this round
+ */
+uint32_t aml_build_end(void);
+
+/**
+ * Prepend a blob, which can contain arbitrary content, to the builder buffer.
+ *
+ * On success, an object in the following form is stored at @buf.
+ *   the first @length bytes in @blob
+ *   the original content in @buf
+ *
+ * Parameters:
+ *   buf:    pointer to the builder buffer
+ *   blob:   pointer to the blob
+ *   length: the number of bytes in the blob
+ *
+ * Return:
+ *   0 on success, -1 on failure.
+ */
+int aml_prepend_blob(uint8_t *buf, const void *blob, uint32_t length);
+
+/**
+ * Prepend an AML device structure to the builder buffer. The existing
+ * data in the builder buffer is included in the AML device.
+ *
+ * On success, an object decoded as below is stored at @buf.
+ *   Device (@name)
+ *   {
+ *     the original content in @buf
+ *   }
+ *
+ * Refer to ACPI spec 6.1, Sec 20.2.5.2 "Named Objects Encoding" -
+ * "DefDevice".
+ *
+ * Parameters:
+ *   buf:  pointer to the builder buffer
+ *   name: the name of the device
+ *
+ * Return:
+ *   0 on success, -1 on failure.
+ */
+int aml_prepend_device(uint8_t *buf, const char *name);
+
+/**
+ * Prepend an AML scope structure to the builder buffer. The existing
+ * data in the builder buffer is included in the AML scope.
+ *
+ * On success, an object decoded as below is stored at @buf.
+ *   Scope (@name)
+ *   {
+ *     the original content in @buf
+ *   }
+ *
+ * Refer to ACPI spec 6.1, Sec 20.2.5.1 "Namespace Modifier Objects
+ * Encoding" - "DefScope".
+ *
+ * Parameters:
+ *   buf:  pointer to the builder buffer
+ *   name: the name of the scope
+ *
+ * Return:
+ *   0 on success, -1 on failure.
+ */
+int aml_prepend_scope(uint8_t *buf, const char *name);
+
+#endif /* _AML_BUILD_H_ */
diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index f00d9ef355..a3e5e9909f 100644
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -77,11 +77,12 @@ endif
 
 ACPI_PATH  = $(XEN_ROOT)/tools/libacpi
 DSDT_FILES-$(CONFIG_X86) = dsdt_pvh.c
-ACPI_OBJS  = $(patsubst %.c,%.o,$(DSDT_FILES-y)) build.o static_tables.o
+ACPI_OBJS  = $(patsubst %.c,%.o,$(DSDT_FILES-y)) build.o static_tables.o 
aml_build.o
 $(DSDT_FILES-y): acpi
 $(ACPI_OBJS): CFLAGS += -I. -DLIBACPI_STDUTILS=\"$(CURDIR)/libxl_x86_acpi.h\"
 vpath build.c $(ACPI_PATH)/
 vpath static_tables.c $(ACPI_PATH)/
+vpath aml_build.c $(ACPI_PATH)/
 LIBXL_OBJS-$(CONFIG_X86) += $(ACPI_OBJS)
 
 .PHONY: acpi
-- 
2.12.0


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