[Qemu-devel] Re: Problems encountered while building qemu-0.6.1

["Peter S. Mazinger" <ps.m@gmx.net>]

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On Tue, 22 Feb 2005, Peter S. Mazinger wrote:

> On Tue, 22 Feb 2005, Peter S. Mazinger wrote:
> 
> > On Sun, 20 Feb 2005, Peter S. Mazinger wrote:
> > 
> > I have attached 2 patches showing what is needed (and commented the 
> > errors) building w/ gcc-3.3.5 and gcc-3.4.3 (the only diff is building 
> > op_helper.o fails w/ gcc-3.3.5)
> > 
> > I can help w/ the ssp (stack-protector) tests, if noone has such gcc, the 
> > -fno-pic failure can be easily "simulated" replacing -fno-pic with -fPIC.
> > 
> > The tests were done w/ latest cvs (20050221)
> > The attached patches allow building qemu, but do not remove the text 
> > relocations (probably produced by using -fno-pic)
> 
> the relocation types not recognized by dyngen are
> R_386_GOT32/R_386_GOTOFF/R_386_GOTPC/R_386_PLT32

after adding these to dyngen.c (I think also the equivalent x86_64 types 
should be added too) all the arch-user/qemu-* files are w/o text 
relocations
Remaining issue w/ PIC code are op.o and helper.o for all softmmu targets 
(ifdef CONFIG_SOFTMMU)

if these files are built
for i386-softmmu/op.c:
target-i386/ops_mem.h: In function `op_ldub_kernel_T0_A0':
softmmu_header.h:96: error: can't find a register in class `GENERAL_REGS' 
while reloading `asm'

for i386-softmmu/helper.o:
softmmu_template.h: In function slow_ldq_mmu
159: error: unable to find a register to spill in class `GENERAL_REGS' ... 
insn ...

if I add -fno-pic to op.o (i386-softmmu) and helper.o (all softmmu 
targets) the above errors are gone, but all the qemu-system-* files have 
text relocations.

Attached my latest working release, the rest of the problems related to 
ssp/propolice remain.

Peter

> > 
> > > On Sun, 20 Feb 2005, Peter S. Mazinger wrote:
> > > 
> > > for current cvs almost everything applies, some changes though.
> > > 
> > > > Hello!
> > > > 
> > > > 1. CFLAGS/LDFLAGS from config-host.mak are overwritten/ignored
> > > > 2. VL_LDFLAGS/OP_CFLAGS should also "inherit" from config-host.mak
> > > > 3. Trying to build qemu in an environment, where gcc defaults to -fPIC
> > > > fails building op.o/osdep.o/helper.o.
> > > 
> > > only op.o/helper.o fail.
> > > 
> > > > If I disable -fPIC on the complete build, the resulting qemu-* files 
> > > > contain text relocations (readelf -d <file>). Due to the fact that they 
> > > > are like shared libs, the text relocs should not be present.
> > > > 4. The files qemu-* (user and sofmmu) are created w/ LDFLAGS=-Wl,-shared
> > > > creting ET_DYN/PIE executables. gcc-3.4 and binutils-2.15 support gcc 
> > > > -pie/ld -pie, this can be checked by gcc -fpie and ld --help | grep pie
> > > > 5. building qemu w/ a propolice/ssp patched gcc, op.o creation fails if 
> > > > -fstack-protector-all is enabled.
> > > 
> > > if op.o is built w/ -fstack-protector, it fails creating op.h
> > > 
> > > > 
> > > > Please CC to me, I am not subscribed, thanks.
> > > > 
> > > > Peter
> > > > 
> > > > 
> > > 
> > > 
> > 
> > 
> 
> 

-- 
Peter S. Mazinger <ps dot m at gmx dot net>           ID: 0xA5F059F2
Key fingerprint = 92A4 31E1 56BC 3D5A 2D08  BB6E C389 975E A5F0 59F2

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--- qemu/dyngen.c.mps	2005-02-22 13:41:53 +0100
+++ qemu/dyngen.c	2005-02-22 15:57:53 +0100
@@ -1661,6 +1661,10 @@
                     type = ELF32_R_TYPE(rel->r_info);
                     switch(type) {
                     case R_386_32:
+		    case R_386_GOTPC:
+		    case R_386_GOT32:
+		    case R_386_PLT32:
+		    case R_386_GOTOFF:
                         fprintf(outfile, "    *(uint32_t *)(gen_code_ptr + %d) = %s + %d;\n", 
                                 rel->r_offset - start_offset, name, addend);
                         break;
--- qemu/Makefile.target.mps	2005-02-22 11:06:38 +0100
+++ qemu/Makefile.target	2005-02-22 16:25:13 +0100
@@ -399,11 +399,24 @@
 gen-op.h: op.o $(DYNGEN)
 	$(DYNGEN) -g -o $@ $<
 
+# -fno-pic: out of registers
 op.o: op.c
-	$(CC) $(OP_CFLAGS) $(DEFINES) -c -o $@ $<
+ifeq ($(TARGET_BASE_ARCH), i386)
+ifdef CONFIG_SOFTMMU
+	$(CC) $(OP_CFLAGS) $(DEFINES) -fno-stack-protector -fno-pic -c -o $@ $<
+else
+	$(CC) $(OP_CFLAGS) $(DEFINES) -fno-stack-protector -c -o $@ $<
+endif
+else
+	$(CC) $(OP_CFLAGS) $(DEFINES) -fno-stack-protector-all -c -o $@ $<
+endif
 
 helper.o: helper.c
+ifdef CONFIG_SOFTMMU
+	$(CC) $(HELPER_CFLAGS) $(DEFINES) -fno-pic -c -o $@ $<
+else
 	$(CC) $(HELPER_CFLAGS) $(DEFINES) -c -o $@ $<
+endif
 
 ifeq ($(TARGET_BASE_ARCH), i386)
 op.o: op.c opreg_template.h ops_template.h ops_template_mem.h ops_mem.h ops_sse.h