| Message ID | 1438612891-3718-11-git-send-email-drjones@redhat.com |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Mon, Aug 03, 2015 at 04:41:27PM +0200, Andrew Jones wrote: > QEMU loads the unit test, but due to the way it translates the > unit test's linker VMA to the LMA, we can't just link such that > VMA == LMA. Thus, we link with VMA == 0x0, and then deal with > relocation. > > Signed-off-by: Andrew Jones <drjones@redhat.com> > --- > configure | 2 ++ > powerpc/Makefile.common | 13 +++++++++--- > powerpc/Makefile.ppc64 | 1 + > powerpc/cstart64.S | 40 +++++++++++++++++++++++++++++++---- > powerpc/flat.lds | 13 +++++++++++- > powerpc/reloc64.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ > 6 files changed, 116 insertions(+), 8 deletions(-) > create mode 100644 powerpc/reloc64.c > > diff --git a/configure b/configure > index b367224093369..b2ad199da7873 100755 > --- a/configure > +++ b/configure > @@ -5,6 +5,7 @@ kerneldir=/lib/modules/$(uname -r)/build > cc=gcc > ld=ld > objcopy=objcopy > +objdump=objdump > ar=ar > arch=`uname -m | sed -e s/i.86/i386/ | sed -e 's/arm.*/arm/'` > host=$arch > @@ -132,6 +133,7 @@ PROCESSOR=$processor > CC=$cross_prefix$cc > LD=$cross_prefix$ld > OBJCOPY=$cross_prefix$objcopy > +OBJDUMP=$cross_prefix$objdump > AR=$cross_prefix$ar > API=$api > TEST_DIR=$testdir > diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common > index d6356540918a5..b130342dee60e 100644 > --- a/powerpc/Makefile.common > +++ b/powerpc/Makefile.common > @@ -27,6 +27,7 @@ CFLAGS += -Wextra > CFLAGS += -O2 > CFLAGS += -I lib -I lib/libfdt > CFLAGS += -Wa,-mregnames > +CFLAGS += -fpie > > asm-offsets = lib/$(ARCH)/asm-offsets.h > include scripts/asm-offsets.mak > @@ -43,11 +44,17 @@ libgcc := $(shell $(CC) $(machine) --print-libgcc-file-name) > start_addr := $(shell printf "%x\n" $$(( $(phys_base) + $(kernel_offset) ))) > > FLATLIBS = $(libcflat) $(LIBFDT_archive) $(libgcc) > -%.elf: LDFLAGS = $(CFLAGS) -nostdlib > +%.elf: LDFLAGS = $(CFLAGS) -nostdlib -pie > %.elf: %.o $(FLATLIBS) powerpc/flat.lds > $(CC) $(LDFLAGS) -o $@ \ > -Wl,-T,powerpc/flat.lds,--build-id=none,-Ttext=$(start_addr) \ > $(filter %.o, $^) $(FLATLIBS) > + @echo -n Checking $@ for unsupported reloc types... > + @if $(OBJDUMP) -R $@ | grep R_ | grep -v R_PPC64_RELATIVE; then \ > + false; \ > + else \ > + echo " looks good."; \ > + fi > > powerpc_clean: libfdt_clean asm_offsets_clean > $(RM) $(TEST_DIR)/*.{o,elf} \ > @@ -59,5 +66,5 @@ generated_files = $(asm-offsets) > > test_cases: $(generated_files) $(tests-common) $(tests) > > -$(TEST_DIR)/$(TEST).elf: $(cstart.o) $(TEST_DIR)/$(TEST).o > -$(TEST_DIR)/selftest.elf: $(cstart.o) $(TEST_DIR)/selftest.o > +$(TEST_DIR)/$(TEST).elf: $(cstart.o) $(reloc.o) $(TEST_DIR)/$(TEST).o > +$(TEST_DIR)/selftest.elf: $(cstart.o) $(reloc.o) $(TEST_DIR)/selftest.o > diff --git a/powerpc/Makefile.ppc64 b/powerpc/Makefile.ppc64 > index 7c61933dfa8ba..7274e0d98b5a5 100644 > --- a/powerpc/Makefile.ppc64 > +++ b/powerpc/Makefile.ppc64 > @@ -8,6 +8,7 @@ ldarch = elf64-powerpc #elf64-powerpcle (eventually) > kernel_offset = 0x0 > > cstart.o = $(TEST_DIR)/cstart64.o > +reloc.o = $(TEST_DIR)/reloc64.o > cflatobjs += lib/ppc64/processor.o > cflatobjs += lib/ppc64/spinlock.o > > diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S > index 141d4563563d5..8edaaa6e251fc 100644 > --- a/powerpc/cstart64.S > +++ b/powerpc/cstart64.S > @@ -26,18 +26,50 @@ > */ > .globl start > start: > - LOAD_REG_IMMEDIATE(r1, stackptr) > - LOAD_REG_IMMEDIATE(r2, tocptr) > + /* > + * We were loaded at QEMU's kernel load address, but we're not > + * allowed to link there due to how QEMU deals with linker VMAs, > + * so we just linked at zero. This means the first thing to do is > + * to find our stack and toc, and then do a relocate. > + */ > + bl . + 4 "bl 0f" might make the connection to the following instructions clearer. > +0: mflr r31 > + subi r31, r31, 0b - start /* QEMU's kernel load address */ > + ld r1, (p_stack - start)(r31) > + ld r2, (p_toc - start)(r31) > + add r1, r1, r31 > + add r2, r2, r31 > + > + /* save DTB pointer */ > + std r3, 56(r1) > + > + /* > + * Call relocate. relocate is C code, but careful to not use > + * any global references, as they may use absolute addresses, > + * which are, obviously, not yet relocated. > + */ > + mr r3, r31 > + ld r4, (p_dyn - start)(r31) > + add r4, r4, r31 > + bl .relocate > + > + /* complete setup */ > + ld r3, 56(r1) > bl .setup > > /* run the test */ > - LOAD_REG_IMMEDIATE(r5, __argc) > - LOAD_REG_IMMEDIATE(r4, __argv) > + LOAD_REG_ADDR(r5, __argc) > + LOAD_REG_ADDR(r4, __argv) > lwz r3, 0(r5) > bl .main > bl .exit > b halt > > +.align 3 > +p_stack: .llong stackptr > +p_toc: .llong tocptr > +p_dyn: .llong dynamic_start > + > .text > .align 3 > > diff --git a/powerpc/flat.lds b/powerpc/flat.lds > index bd075efb2c51b..8a573d27346de 100644 > --- a/powerpc/flat.lds > +++ b/powerpc/flat.lds > @@ -6,11 +6,22 @@ SECTIONS > etext = .; > .opd : { *(.opd) } > . = ALIGN(16); > + .dynamic : { > + dynamic_start = .; > + *(.dynamic) > + } > + .dynsym : { > + dynsym_start = .; > + *(.dynsym) > + } > + .rela.dyn : { *(.rela*) } > + . = ALIGN(16); > .data : { > *(.data) > + *(.data.rel*) > } > . = ALIGN(16); > - .rodata : { *(.rodata) } > + .rodata : { *(.rodata) *(.rodata.*) } > . = ALIGN(16); > .bss : { *(.bss) } > . = ALIGN(16); > diff --git a/powerpc/reloc64.c b/powerpc/reloc64.c > new file mode 100644 > index 0000000000000..2804823bdfee3 > --- /dev/null > +++ b/powerpc/reloc64.c > @@ -0,0 +1,55 @@ > +/* > + * relocate R_PPC_RELATIVE RELA entries. Normally this is done in > + * assembly code to avoid the risk of using absolute addresses before > + * they're relocated. We use C, but cautiously (no global references). > + * > + * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@redhat.com> > + * > + * This work is licensed under the terms of the GNU LGPL, version 2. > + */ > +#define DT_NULL 0 > +#define DT_RELA 7 > +#define DT_RELACOUNT 0x6ffffff9 > +#define R_PPC_RELATIVE 22 > + > +struct elf64_dyn { > + signed long long tag; > + unsigned long long val; > +}; > + > +#define RELA_GET_TYPE(rela_ptr) ((rela_ptr)->info & 0xffffffff) > +struct elf64_rela { > + unsigned long long offset; > + unsigned long long info; > + signed long long addend; > +}; > + > +void relocate(unsigned long load_addr, struct elf64_dyn *dyn_table) > +{ > + unsigned long long rela_addr = 0, rela_count = 0, *addr; > + struct elf64_dyn *d = dyn_table; > + struct elf64_rela *r; > + > + while (d && d->tag != DT_NULL) { > + if (d->tag == DT_RELA) > + rela_addr = d->val; > + else if (d->tag == DT_RELACOUNT) > + rela_count = d->val; > + if (rela_addr && rela_count) > + break; > + ++d; > + } > + > + if (!rela_addr || !rela_count) > + return; > + > + r = (void *)(rela_addr + load_addr); > + > + while (rela_count--) { > + if (RELA_GET_TYPE(r) == R_PPC_RELATIVE) { > + addr = (void *)(r->offset + load_addr); > + *addr = r->addend + load_addr; > + } > + ++r; > + } > +}
On Tue, Aug 04, 2015 at 01:53:24PM +1000, David Gibson wrote: > On Mon, Aug 03, 2015 at 04:41:27PM +0200, Andrew Jones wrote: > > QEMU loads the unit test, but due to the way it translates the > > unit test's linker VMA to the LMA, we can't just link such that > > VMA == LMA. Thus, we link with VMA == 0x0, and then deal with > > relocation. > > > > Signed-off-by: Andrew Jones <drjones@redhat.com> > > --- > > configure | 2 ++ > > powerpc/Makefile.common | 13 +++++++++--- > > powerpc/Makefile.ppc64 | 1 + > > powerpc/cstart64.S | 40 +++++++++++++++++++++++++++++++---- > > powerpc/flat.lds | 13 +++++++++++- > > powerpc/reloc64.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ > > 6 files changed, 116 insertions(+), 8 deletions(-) > > create mode 100644 powerpc/reloc64.c > > > > diff --git a/configure b/configure > > index b367224093369..b2ad199da7873 100755 > > --- a/configure > > +++ b/configure > > @@ -5,6 +5,7 @@ kerneldir=/lib/modules/$(uname -r)/build > > cc=gcc > > ld=ld > > objcopy=objcopy > > +objdump=objdump > > ar=ar > > arch=`uname -m | sed -e s/i.86/i386/ | sed -e 's/arm.*/arm/'` > > host=$arch > > @@ -132,6 +133,7 @@ PROCESSOR=$processor > > CC=$cross_prefix$cc > > LD=$cross_prefix$ld > > OBJCOPY=$cross_prefix$objcopy > > +OBJDUMP=$cross_prefix$objdump > > AR=$cross_prefix$ar > > API=$api > > TEST_DIR=$testdir > > diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common > > index d6356540918a5..b130342dee60e 100644 > > --- a/powerpc/Makefile.common > > +++ b/powerpc/Makefile.common > > @@ -27,6 +27,7 @@ CFLAGS += -Wextra > > CFLAGS += -O2 > > CFLAGS += -I lib -I lib/libfdt > > CFLAGS += -Wa,-mregnames > > +CFLAGS += -fpie > > > > asm-offsets = lib/$(ARCH)/asm-offsets.h > > include scripts/asm-offsets.mak > > @@ -43,11 +44,17 @@ libgcc := $(shell $(CC) $(machine) --print-libgcc-file-name) > > start_addr := $(shell printf "%x\n" $$(( $(phys_base) + $(kernel_offset) ))) > > > > FLATLIBS = $(libcflat) $(LIBFDT_archive) $(libgcc) > > -%.elf: LDFLAGS = $(CFLAGS) -nostdlib > > +%.elf: LDFLAGS = $(CFLAGS) -nostdlib -pie > > %.elf: %.o $(FLATLIBS) powerpc/flat.lds > > $(CC) $(LDFLAGS) -o $@ \ > > -Wl,-T,powerpc/flat.lds,--build-id=none,-Ttext=$(start_addr) \ > > $(filter %.o, $^) $(FLATLIBS) > > + @echo -n Checking $@ for unsupported reloc types... > > + @if $(OBJDUMP) -R $@ | grep R_ | grep -v R_PPC64_RELATIVE; then \ > > + false; \ > > + else \ > > + echo " looks good."; \ > > + fi > > > > powerpc_clean: libfdt_clean asm_offsets_clean > > $(RM) $(TEST_DIR)/*.{o,elf} \ > > @@ -59,5 +66,5 @@ generated_files = $(asm-offsets) > > > > test_cases: $(generated_files) $(tests-common) $(tests) > > > > -$(TEST_DIR)/$(TEST).elf: $(cstart.o) $(TEST_DIR)/$(TEST).o > > -$(TEST_DIR)/selftest.elf: $(cstart.o) $(TEST_DIR)/selftest.o > > +$(TEST_DIR)/$(TEST).elf: $(cstart.o) $(reloc.o) $(TEST_DIR)/$(TEST).o > > +$(TEST_DIR)/selftest.elf: $(cstart.o) $(reloc.o) $(TEST_DIR)/selftest.o > > diff --git a/powerpc/Makefile.ppc64 b/powerpc/Makefile.ppc64 > > index 7c61933dfa8ba..7274e0d98b5a5 100644 > > --- a/powerpc/Makefile.ppc64 > > +++ b/powerpc/Makefile.ppc64 > > @@ -8,6 +8,7 @@ ldarch = elf64-powerpc #elf64-powerpcle (eventually) > > kernel_offset = 0x0 > > > > cstart.o = $(TEST_DIR)/cstart64.o > > +reloc.o = $(TEST_DIR)/reloc64.o > > cflatobjs += lib/ppc64/processor.o > > cflatobjs += lib/ppc64/spinlock.o > > > > diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S > > index 141d4563563d5..8edaaa6e251fc 100644 > > --- a/powerpc/cstart64.S > > +++ b/powerpc/cstart64.S > > @@ -26,18 +26,50 @@ > > */ > > .globl start > > start: > > - LOAD_REG_IMMEDIATE(r1, stackptr) > > - LOAD_REG_IMMEDIATE(r2, tocptr) > > + /* > > + * We were loaded at QEMU's kernel load address, but we're not > > + * allowed to link there due to how QEMU deals with linker VMAs, > > + * so we just linked at zero. This means the first thing to do is > > + * to find our stack and toc, and then do a relocate. > > + */ > > + bl . + 4 > > "bl 0f" might make the connection to the following instructions > clearer. Thanks, I'll change it. drew > > > +0: mflr r31 > > + subi r31, r31, 0b - start /* QEMU's kernel load address */ > > + ld r1, (p_stack - start)(r31) > > + ld r2, (p_toc - start)(r31) > > + add r1, r1, r31 > > + add r2, r2, r31 > > + > > + /* save DTB pointer */ > > + std r3, 56(r1) > > + > > + /* > > + * Call relocate. relocate is C code, but careful to not use > > + * any global references, as they may use absolute addresses, > > + * which are, obviously, not yet relocated. > > + */ > > + mr r3, r31 > > + ld r4, (p_dyn - start)(r31) > > + add r4, r4, r31 > > + bl .relocate > > + > > + /* complete setup */ > > + ld r3, 56(r1) > > bl .setup > > > > /* run the test */ > > - LOAD_REG_IMMEDIATE(r5, __argc) > > - LOAD_REG_IMMEDIATE(r4, __argv) > > + LOAD_REG_ADDR(r5, __argc) > > + LOAD_REG_ADDR(r4, __argv) > > lwz r3, 0(r5) > > bl .main > > bl .exit > > b halt > > > > +.align 3 > > +p_stack: .llong stackptr > > +p_toc: .llong tocptr > > +p_dyn: .llong dynamic_start > > + > > .text > > .align 3 > > > > diff --git a/powerpc/flat.lds b/powerpc/flat.lds > > index bd075efb2c51b..8a573d27346de 100644 > > --- a/powerpc/flat.lds > > +++ b/powerpc/flat.lds > > @@ -6,11 +6,22 @@ SECTIONS > > etext = .; > > .opd : { *(.opd) } > > . = ALIGN(16); > > + .dynamic : { > > + dynamic_start = .; > > + *(.dynamic) > > + } > > + .dynsym : { > > + dynsym_start = .; > > + *(.dynsym) > > + } > > + .rela.dyn : { *(.rela*) } > > + . = ALIGN(16); > > .data : { > > *(.data) > > + *(.data.rel*) > > } > > . = ALIGN(16); > > - .rodata : { *(.rodata) } > > + .rodata : { *(.rodata) *(.rodata.*) } > > . = ALIGN(16); > > .bss : { *(.bss) } > > . = ALIGN(16); > > diff --git a/powerpc/reloc64.c b/powerpc/reloc64.c > > new file mode 100644 > > index 0000000000000..2804823bdfee3 > > --- /dev/null > > +++ b/powerpc/reloc64.c > > @@ -0,0 +1,55 @@ > > +/* > > + * relocate R_PPC_RELATIVE RELA entries. Normally this is done in > > + * assembly code to avoid the risk of using absolute addresses before > > + * they're relocated. We use C, but cautiously (no global references). > > + * > > + * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@redhat.com> > > + * > > + * This work is licensed under the terms of the GNU LGPL, version 2. > > + */ > > +#define DT_NULL 0 > > +#define DT_RELA 7 > > +#define DT_RELACOUNT 0x6ffffff9 > > +#define R_PPC_RELATIVE 22 > > + > > +struct elf64_dyn { > > + signed long long tag; > > + unsigned long long val; > > +}; > > + > > +#define RELA_GET_TYPE(rela_ptr) ((rela_ptr)->info & 0xffffffff) > > +struct elf64_rela { > > + unsigned long long offset; > > + unsigned long long info; > > + signed long long addend; > > +}; > > + > > +void relocate(unsigned long load_addr, struct elf64_dyn *dyn_table) > > +{ > > + unsigned long long rela_addr = 0, rela_count = 0, *addr; > > + struct elf64_dyn *d = dyn_table; > > + struct elf64_rela *r; > > + > > + while (d && d->tag != DT_NULL) { > > + if (d->tag == DT_RELA) > > + rela_addr = d->val; > > + else if (d->tag == DT_RELACOUNT) > > + rela_count = d->val; > > + if (rela_addr && rela_count) > > + break; > > + ++d; > > + } > > + > > + if (!rela_addr || !rela_count) > > + return; > > + > > + r = (void *)(rela_addr + load_addr); > > + > > + while (rela_count--) { > > + if (RELA_GET_TYPE(r) == R_PPC_RELATIVE) { > > + addr = (void *)(r->offset + load_addr); > > + *addr = r->addend + load_addr; > > + } > > + ++r; > > + } > > +} > > -- > David Gibson | I'll have my music baroque, and my code > david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ > | _way_ _around_! > http://www.ozlabs.org/~dgibson -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/configure b/configure index b367224093369..b2ad199da7873 100755 --- a/configure +++ b/configure @@ -5,6 +5,7 @@ kerneldir=/lib/modules/$(uname -r)/build cc=gcc ld=ld objcopy=objcopy +objdump=objdump ar=ar arch=`uname -m | sed -e s/i.86/i386/ | sed -e 's/arm.*/arm/'` host=$arch @@ -132,6 +133,7 @@ PROCESSOR=$processor CC=$cross_prefix$cc LD=$cross_prefix$ld OBJCOPY=$cross_prefix$objcopy +OBJDUMP=$cross_prefix$objdump AR=$cross_prefix$ar API=$api TEST_DIR=$testdir diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common index d6356540918a5..b130342dee60e 100644 --- a/powerpc/Makefile.common +++ b/powerpc/Makefile.common @@ -27,6 +27,7 @@ CFLAGS += -Wextra CFLAGS += -O2 CFLAGS += -I lib -I lib/libfdt CFLAGS += -Wa,-mregnames +CFLAGS += -fpie asm-offsets = lib/$(ARCH)/asm-offsets.h include scripts/asm-offsets.mak @@ -43,11 +44,17 @@ libgcc := $(shell $(CC) $(machine) --print-libgcc-file-name) start_addr := $(shell printf "%x\n" $$(( $(phys_base) + $(kernel_offset) ))) FLATLIBS = $(libcflat) $(LIBFDT_archive) $(libgcc) -%.elf: LDFLAGS = $(CFLAGS) -nostdlib +%.elf: LDFLAGS = $(CFLAGS) -nostdlib -pie %.elf: %.o $(FLATLIBS) powerpc/flat.lds $(CC) $(LDFLAGS) -o $@ \ -Wl,-T,powerpc/flat.lds,--build-id=none,-Ttext=$(start_addr) \ $(filter %.o, $^) $(FLATLIBS) + @echo -n Checking $@ for unsupported reloc types... + @if $(OBJDUMP) -R $@ | grep R_ | grep -v R_PPC64_RELATIVE; then \ + false; \ + else \ + echo " looks good."; \ + fi powerpc_clean: libfdt_clean asm_offsets_clean $(RM) $(TEST_DIR)/*.{o,elf} \ @@ -59,5 +66,5 @@ generated_files = $(asm-offsets) test_cases: $(generated_files) $(tests-common) $(tests) -$(TEST_DIR)/$(TEST).elf: $(cstart.o) $(TEST_DIR)/$(TEST).o -$(TEST_DIR)/selftest.elf: $(cstart.o) $(TEST_DIR)/selftest.o +$(TEST_DIR)/$(TEST).elf: $(cstart.o) $(reloc.o) $(TEST_DIR)/$(TEST).o +$(TEST_DIR)/selftest.elf: $(cstart.o) $(reloc.o) $(TEST_DIR)/selftest.o diff --git a/powerpc/Makefile.ppc64 b/powerpc/Makefile.ppc64 index 7c61933dfa8ba..7274e0d98b5a5 100644 --- a/powerpc/Makefile.ppc64 +++ b/powerpc/Makefile.ppc64 @@ -8,6 +8,7 @@ ldarch = elf64-powerpc #elf64-powerpcle (eventually) kernel_offset = 0x0 cstart.o = $(TEST_DIR)/cstart64.o +reloc.o = $(TEST_DIR)/reloc64.o cflatobjs += lib/ppc64/processor.o cflatobjs += lib/ppc64/spinlock.o diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S index 141d4563563d5..8edaaa6e251fc 100644 --- a/powerpc/cstart64.S +++ b/powerpc/cstart64.S @@ -26,18 +26,50 @@ */ .globl start start: - LOAD_REG_IMMEDIATE(r1, stackptr) - LOAD_REG_IMMEDIATE(r2, tocptr) + /* + * We were loaded at QEMU's kernel load address, but we're not + * allowed to link there due to how QEMU deals with linker VMAs, + * so we just linked at zero. This means the first thing to do is + * to find our stack and toc, and then do a relocate. + */ + bl . + 4 +0: mflr r31 + subi r31, r31, 0b - start /* QEMU's kernel load address */ + ld r1, (p_stack - start)(r31) + ld r2, (p_toc - start)(r31) + add r1, r1, r31 + add r2, r2, r31 + + /* save DTB pointer */ + std r3, 56(r1) + + /* + * Call relocate. relocate is C code, but careful to not use + * any global references, as they may use absolute addresses, + * which are, obviously, not yet relocated. + */ + mr r3, r31 + ld r4, (p_dyn - start)(r31) + add r4, r4, r31 + bl .relocate + + /* complete setup */ + ld r3, 56(r1) bl .setup /* run the test */ - LOAD_REG_IMMEDIATE(r5, __argc) - LOAD_REG_IMMEDIATE(r4, __argv) + LOAD_REG_ADDR(r5, __argc) + LOAD_REG_ADDR(r4, __argv) lwz r3, 0(r5) bl .main bl .exit b halt +.align 3 +p_stack: .llong stackptr +p_toc: .llong tocptr +p_dyn: .llong dynamic_start + .text .align 3 diff --git a/powerpc/flat.lds b/powerpc/flat.lds index bd075efb2c51b..8a573d27346de 100644 --- a/powerpc/flat.lds +++ b/powerpc/flat.lds @@ -6,11 +6,22 @@ SECTIONS etext = .; .opd : { *(.opd) } . = ALIGN(16); + .dynamic : { + dynamic_start = .; + *(.dynamic) + } + .dynsym : { + dynsym_start = .; + *(.dynsym) + } + .rela.dyn : { *(.rela*) } + . = ALIGN(16); .data : { *(.data) + *(.data.rel*) } . = ALIGN(16); - .rodata : { *(.rodata) } + .rodata : { *(.rodata) *(.rodata.*) } . = ALIGN(16); .bss : { *(.bss) } . = ALIGN(16); diff --git a/powerpc/reloc64.c b/powerpc/reloc64.c new file mode 100644 index 0000000000000..2804823bdfee3 --- /dev/null +++ b/powerpc/reloc64.c @@ -0,0 +1,55 @@ +/* + * relocate R_PPC_RELATIVE RELA entries. Normally this is done in + * assembly code to avoid the risk of using absolute addresses before + * they're relocated. We use C, but cautiously (no global references). + * + * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@redhat.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2. + */ +#define DT_NULL 0 +#define DT_RELA 7 +#define DT_RELACOUNT 0x6ffffff9 +#define R_PPC_RELATIVE 22 + +struct elf64_dyn { + signed long long tag; + unsigned long long val; +}; + +#define RELA_GET_TYPE(rela_ptr) ((rela_ptr)->info & 0xffffffff) +struct elf64_rela { + unsigned long long offset; + unsigned long long info; + signed long long addend; +}; + +void relocate(unsigned long load_addr, struct elf64_dyn *dyn_table) +{ + unsigned long long rela_addr = 0, rela_count = 0, *addr; + struct elf64_dyn *d = dyn_table; + struct elf64_rela *r; + + while (d && d->tag != DT_NULL) { + if (d->tag == DT_RELA) + rela_addr = d->val; + else if (d->tag == DT_RELACOUNT) + rela_count = d->val; + if (rela_addr && rela_count) + break; + ++d; + } + + if (!rela_addr || !rela_count) + return; + + r = (void *)(rela_addr + load_addr); + + while (rela_count--) { + if (RELA_GET_TYPE(r) == R_PPC_RELATIVE) { + addr = (void *)(r->offset + load_addr); + *addr = r->addend + load_addr; + } + ++r; + } +}
QEMU loads the unit test, but due to the way it translates the unit test's linker VMA to the LMA, we can't just link such that VMA == LMA. Thus, we link with VMA == 0x0, and then deal with relocation. Signed-off-by: Andrew Jones <drjones@redhat.com> --- configure | 2 ++ powerpc/Makefile.common | 13 +++++++++--- powerpc/Makefile.ppc64 | 1 + powerpc/cstart64.S | 40 +++++++++++++++++++++++++++++++---- powerpc/flat.lds | 13 +++++++++++- powerpc/reloc64.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 116 insertions(+), 8 deletions(-) create mode 100644 powerpc/reloc64.c