acpi: Prevent GPL-only code from seeping into non-GPL binaries

Some code (specifically, introduced by commit 801d469ad ("[HVM] ACPI
support patch 3 of 4: ACPI _PRT table.")) has only been licensed under
GPLv2. We want to prevent this code from showing up in non-GPL
binaries which might become possible after we make ACPI builder code
available to users other than hvmloader.

There are two pieces that we need to be careful about:
(1) A small chunk of code in dsdt.asl that implements _PIC method
(2) A chunk of ASL generator in mk_dsdt.c that describes with PCI
    interrupt routing.

This code will now be generated by a GPL-only script which will be
invoked only when ACPI builder's Makefile is called with GPL variable
set.

We also strip license header from generated ASL files to prevent
inadverent use of those files with incorrect license.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

tools/firmware/hvmloader/Makefile

@@ -65,6 +65,9 @@ ROMBIOS_ROM := $(ROMBIOS_DIR)/BIOS-bochs-latest
 ROMS += $(ROMBIOS_ROM) $(STDVGA_ROM) $(CIRRUSVGA_ROM) $(ETHERBOOT_ROMS)
 endif
 
+# Certain parts of ACPI builder are GPL-only
+export GPL := y
+
 .PHONY: all
 all: subdirs-all
 	$(MAKE) hvmloader

tools/firmware/hvmloader/acpi/Makefile

@@ -17,7 +17,8 @@
 XEN_ROOT = $(CURDIR)/../../../..
 include $(XEN_ROOT)/tools/firmware/Rules.mk
 
-C_SRC = build.c dsdt_anycpu.c dsdt_15cpu.c static_tables.c dsdt_anycpu_qemu_xen.c
+C_SRC-$(GPL) = build.c dsdt_anycpu.c dsdt_15cpu.c dsdt_anycpu_qemu_xen.c
+C_SRC = build.c static_tables.c $(C_SRC-y)
 OBJS  = $(patsubst %.c,%.o,$(C_SRC))
 
 CFLAGS += $(CFLAGS_xeninclude)
@@ -36,18 +37,25 @@ ssdt_s3.h ssdt_s4.h ssdt_pm.h ssdt_tpm.h: %.h: %.asl iasl
 mk_dsdt: mk_dsdt.c
 	$(HOSTCC) $(HOSTCFLAGS) $(CFLAGS_xeninclude) -o $@ mk_dsdt.c
 
-dsdt_anycpu_qemu_xen.asl: dsdt.asl dsdt_acpi_info.asl mk_dsdt
+ifeq ($(GPL),y)
+dsdt_anycpu_qemu_xen.asl: dsdt.asl dsdt_acpi_info.asl gpl/mk_dsdt_gpl.sh mk_dsdt
 	awk 'NR > 1 {print s} {s=$$0}' $< > $@.$(TMP_SUFFIX)
+	# Strip license comment
+	sed -i '1,/\*\//{/\/\*/,/\*\//d}' $@.$(TMP_SUFFIX)
+	$(SHELL) gpl/mk_dsdt_gpl.sh >> $@.$(TMP_SUFFIX)
 	cat dsdt_acpi_info.asl >> $@.$(TMP_SUFFIX)
 	./mk_dsdt --debug=$(debug) --dm-version qemu-xen >> $@.$(TMP_SUFFIX)
 	mv -f $@.$(TMP_SUFFIX) $@
 
 # NB. awk invocation is a portable alternative to 'head -n -1'
-dsdt_%cpu.asl: dsdt.asl dsdt_acpi_info.asl mk_dsdt
+dsdt_%cpu.asl: dsdt.asl dsdt_acpi_info.asl gpl/mk_dsdt_gpl.sh mk_dsdt
 	awk 'NR > 1 {print s} {s=$$0}' $< > $@.$(TMP_SUFFIX)
+	sed -i '1,/\*\//{/\/\*/,/\*\//d}' $@.$(TMP_SUFFIX)
+	$(SHELL) gpl/mk_dsdt_gpl.sh >> $@.$(TMP_SUFFIX)
 	cat dsdt_acpi_info.asl >> $@.$(TMP_SUFFIX)
 	./mk_dsdt --debug=$(debug) --maxcpu $*  >> $@.$(TMP_SUFFIX)
 	mv -f $@.$(TMP_SUFFIX) $@
+endif
 
 $(filter dsdt_%.c,$(C_SRC)): %.c: iasl %.asl
 	iasl -vs -p $* -tc $*.asl

tools/firmware/hvmloader/acpi/dsdt.asl

@@ -26,20 +26,6 @@ DefinitionBlock ("DSDT.aml", "DSDT", 2, "Xen", "HVM", 0)
     Name (\APCL, 0x00010000)
     Name (\PUID, 0x00)
 
-    /* _S3 and _S4 are in separate SSDTs */
-    Name (\_S5, Package (0x04)
-    {
-        0x00,  /* PM1a_CNT.SLP_TYP */
-        0x00,  /* PM1b_CNT.SLP_TYP */
-        0x00,  /* reserved */
-        0x00   /* reserved */
-    })
-
-    Name(PICD, 0)
-    Method(_PIC, 1)
-    {
-        Store(Arg0, PICD) 
-    }
 
     Scope (\_SB)
     {

tools/firmware/hvmloader/acpi/gpl/mk_dsdt_gpl.sh

@@ -0,0 +1,117 @@
+#!/bin/sh
+
+# This program is free software; you can redistribute it and/or modify it
+# under the terms and conditions of the GNU General Public License,
+# version 2, as published by the Free Software Foundation.
+#
+# This program is distributed in the hope it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; If not, see <http://www.gnu.org/licenses/>.
+#
+
+cat <<'EndOfASL'
+    /* Beginning of GPL-only code */
+
+    /* _S3 and _S4 are in separate SSDTs */
+    Name (\_S5, Package (0x04) {
+        0x00,  /* PM1a_CNT.SLP_TYP */
+        0x00,  /* PM1b_CNT.SLP_TYP */
+        0x00,  /* reserved */
+        0x00   /* reserved */
+    })
+    Name(PICD, 0)
+    Method(_PIC, 1) {
+        Store(Arg0, PICD)
+    }
+EndOfASL
+
+# PCI-ISA link definitions
+# BUFA: List of ISA IRQs available for linking to PCI INTx.
+# BUFB: IRQ descriptor for returning from link-device _CRS methods.
+cat <<'EndOfASL'
+    Scope ( \_SB.PCI0 )  {
+        Name ( BUFA, ResourceTemplate() { IRQ(Level, ActiveLow, Shared) { 5, 10, 11 } } )
+        Name ( BUFB, Buffer() { 0x23, 0x00, 0x00, 0x18, 0x79, 0 } )
+        CreateWordField ( BUFB, 0x01, IRQV )
+EndOfASL
+
+for i in $(seq 1 4)
+do
+    link=`echo "A B C D" | cut -d" " -f $i`
+    cat <<EndOfASL
+        Device ( LNK$link ) {
+            Name ( _HID,  EISAID("PNP0C0F") )
+            Name ( _UID, $i)
+            Method ( _STA, 0) {
+                If ( And(PIR$link, 0x80) ) {
+                    Return ( 0x09 )
+                } Else {
+                    Return ( 0x0B )
+                }
+            }
+            Method ( _PRS ) {
+                Return ( BUFA )
+            }
+            Method ( _DIS ) {
+                Or ( PIR$link, 0x80, PIR$link )
+            }
+            Method ( _CRS ) {
+                And ( PIR$link, 0x0f, Local0 )
+                ShiftLeft ( 0x1, Local0, IRQV )
+                Return ( BUFB )
+            }
+            Method ( _SRS, 1 ) {
+                CreateWordField ( ARG0, 0x01, IRQ1 )
+                FindSetRightBit ( IRQ1, Local0 )
+                Decrement ( Local0 )
+                Store ( Local0, PIR$link )
+            }
+        }
+EndOfASL
+done
+
+# PCI interrupt routing definitions
+# _PRT: Method to return routing table.
+cat <<'EndOfASL'
+        Method ( _PRT, 0 ) {
+            If ( PICD ) {
+                Return ( PRTA )
+            }
+            Return ( PRTP )
+        }
+EndOfASL
+
+# PRTP: PIC routing table (via ISA links).
+echo "        Name(PRTP, Package() {"
+for dev in $(seq 1 31)
+do
+    for intx in $(seq 0 3)  # INTA-D
+    do
+	link_idx=$(( ((dev + intx) & 3) + 1 ))
+	link=`echo "A B C D" | cut -d" " -f $link_idx`
+	printf "            Package(){0x%04xffff, %u, \\\\_SB.PCI0.LNK%c, 0},\n" \
+	    $dev $intx $link
+    done
+done
+echo "        })"
+
+# PRTA: APIC routing table (via non-legacy IOAPIC GSIs).
+echo "        Name(PRTA, Package() {"
+for dev in $(seq 1 31)
+do
+    for intx in $(seq 0 3)  # INTA-D
+    do
+	idx=$(( ((dev * 4 + dev/8 + intx) & 31) + 16 ))
+	printf "            Package(){0x%04xffff, %u, 0, %u},\n" \
+	    $dev $intx $idx
+    done
+done
+echo "        })"
+
+echo "    }"
+
+echo "    /* End of GPL-only code */"

tools/firmware/hvmloader/acpi/mk_dsdt.c

@@ -91,7 +91,7 @@ static struct option options[] = {
 
 int main(int argc, char **argv)
 {
-    unsigned int slot, dev, intx, link, cpu, max_cpus = HVM_MAX_VCPUS;
+    unsigned int slot, cpu, max_cpus = HVM_MAX_VCPUS;
     dm_version dm_version = QEMU_XEN_TRADITIONAL;
 
     for ( ; ; )
@@ -273,72 +273,6 @@ int main(int argc, char **argv)
         }
     } pop_block();
 
-    /*** PCI-ISA link definitions ***/
-    /* BUFA: List of ISA IRQs available for linking to PCI INTx. */
-    stmt("Name", "BUFA, ResourceTemplate() { "
-         "IRQ(Level, ActiveLow, Shared) { 5, 10, 11 } }");
-    /* BUFB: IRQ descriptor for returning from link-device _CRS methods. */
-    stmt("Name", "BUFB, Buffer() { "
-         "0x23, 0x00, 0x00, 0x18, " /* IRQ descriptor */
-         "0x79, 0 }");              /* End tag, null checksum */
-    stmt("CreateWordField", "BUFB, 0x01, IRQV");
-    /* Create four PCI-ISA link devices: LNKA, LNKB, LNKC, LNKD. */
-    for ( link = 0; link < 4; link++ )
-    {
-        push_block("Device", "LNK%c", 'A'+link);
-        stmt("Name", "_HID,  EISAID(\"PNP0C0F\")");  /* PCI interrupt link */
-        stmt("Name", "_UID, %u", link+1);
-        push_block("Method", "_STA, 0");
-        push_block("If", "And(PIR%c, 0x80)", 'A'+link);
-        stmt("Return", "0x09");
-        pop_block();
-        push_block("Else", NULL);
-        stmt("Return", "0x0B");
-        pop_block();
-        pop_block();
-        push_block("Method", "_PRS");
-        stmt("Return", "BUFA");
-        pop_block();
-        push_block("Method", "_DIS");
-        stmt("Or", "PIR%c, 0x80, PIR%c", 'A'+link, 'A'+link);
-        pop_block();
-        push_block("Method", "_CRS");
-        stmt("And", "PIR%c, 0x0f, Local0", 'A'+link);
-        stmt("ShiftLeft", "0x1, Local0, IRQV");
-        stmt("Return", "BUFB");
-        pop_block();
-        push_block("Method", "_SRS, 1");
-        stmt("CreateWordField", "ARG0, 0x01, IRQ1");
-        stmt("FindSetRightBit", "IRQ1, Local0");
-        stmt("Decrement", "Local0");
-        stmt("Store", "Local0, PIR%c", 'A'+link);
-        pop_block();
-        pop_block();
-    }
-
-    /*** PCI interrupt routing definitions***/
-    /* _PRT: Method to return routing table. */
-    push_block("Method", "_PRT, 0");
-    push_block("If", "PICD");
-    stmt("Return", "PRTA");
-    pop_block();
-    stmt("Return", "PRTP");
-    pop_block();
-    /* PRTP: PIC routing table (via ISA links). */
-    printf("Name(PRTP, Package() {\n");
-    for ( dev = 1; dev < 32; dev++ )
-        for ( intx = 0; intx < 4; intx++ ) /* INTA-D */
-            printf("Package(){0x%04xffff, %u, \\_SB.PCI0.LNK%c, 0},\n",
-                   dev, intx, 'A'+((dev+intx)&3));
-    printf("})\n");
-    /* PRTA: APIC routing table (via non-legacy IOAPIC GSIs). */
-    printf("Name(PRTA, Package() {\n");
-    for ( dev = 1; dev < 32; dev++ )
-        for ( intx = 0; intx < 4; intx++ ) /* INTA-D */
-            printf("Package(){0x%04xffff, %u, 0, %u},\n",
-                   dev, intx, ((dev*4+dev/8+intx)&31)+16);
-    printf("})\n");
-
     /*
      * Each PCI hotplug slot needs at least two methods to handle
      * the ACPI event: