Hey Lance,
I'm having a bit of trouble recreating this bug. I do however have a couple
of possible solutions. Do you mind trying the following patch on top of my
previous one and letting me know if it solves the problem?
---
diff --git a/libc/sysdeps/linux/mips/crt1.S b/libc/sysdeps/linux/mips/crt1.S
index a7f72a90f..811b15387 100644
--- a/libc/sysdeps/linux/mips/crt1.S
+++ b/libc/sysdeps/linux/mips/crt1.S
@@ -81,6 +81,7 @@
#ifdef L_rcrt1
.type reloc_static_pie,@function
.weak reloc_static_pie
+ .hidden .L0
#endif
.type main,@function
.type __uClibc_main,@function
@@ -97,8 +98,8 @@ __start:
#ifdef L_rcrt1
PTR_LA $4, _DYNAMIC /* Place _DYNAMIC into the GOT */
REG_S $4, -0x7ff0($28)
- jal L0 /* Get the current $pc address */
-L0:
+ jal .L0 /* Get the current $pc address */
+.L0:
INT_SUB $25, $31, $25 /* Calculate load addr */
move $4, $25 /* store load addr in param 1 */
and $29, -2 * SZREG /* Ensure stack is aligned */
On Mon, Aug 22, 2022 at 1:37 PM Lance Fredrickson <lancethepa...@gmail.com>
wrote:
> Gave this patch a go with patched gcc for -static-pie for mips.
>
> It works when compiling hello.c, but when I tried c++ hello.cpp program
> I get the following build error.
>
> mipsel-linux-g++ -s -static-pie hello.cpp -o hello
> /opt/tomatoware/mipsel-soft-mmc/mipsel-tomatoware-linux-uclibc/sysroot/usr/lib/rcrt1.o:
>
> in function `L0':
> (.text+0x50): relocation truncated to fit: R_MIPS_PC16 against
> `reloc_static_pie'
> collect2: error: ld returned 1 exit status
>
> Also tested arm with the new reworked patch and it seems to work for c
> and c++ hello world.
>
> Lance
>
> On 8/20/2022 10:32 PM, linted wrote:
> > Hello,
> > I have completed a patch to get static pie support working for the
> > mips architecture.
> >
> > Unfortunately a lot of the optimizations I made for previous
> > architectures needed to be rewritten in order to support the way that
> > mips works. There is a substantial rewrite of reloc_static_pie,
> > however the code is nearly a copy paste from dl-startup.c and has been
> > tested with all the currently supported architectures to ensure that
> > it still works.
> >
> > In order to compile with gcc, a patch for mips static pie is required.
> > I'm actively working on submitting said patch, but I do not have a
> > link for it yet. In the meantime, compilation using the following
> > flags passed to gcc should suffice.
> >
> > mips-linux-gcc -static-pie -Bstatic -pie --no-dynamic-linker -z text
> > input.c -o output
> >
> > ----
> > From a6fa331c7ea16b5146c0d3ba3b2d6d723f09a9b4 Mon Sep 17 00:00:00 2001
> > From: linted <lin...@users.noreply.github.com>
> > Date: Sat, 20 Aug 2022 16:41:38 -0400
> > Subject: [PATCH] Added support for creation of Static
> Position-Independent
> > Executables (PIE) on mips
> >
> > Updated config to allow compilation of rcrt1.o for mips and modified
> > it's crt1.S to perform relocates in __start.
> >
> > The mips architecture performs relocations differently then most other
> > architectures. reloc_static_pie was rewritten, taking code from
> > dl-startup.c, in order to perform the additional relocations.
> > Modifications were made to mips' dl-startup.h to allow for the use of
> > contained macros without including _start definition.
> >
> > Signed-off-by: linted <lin...@users.noreply.github.com>
> > ---
> > extra/Configs/Config.in | 2 +-
> > ldso/ldso/mips/dl-startup.h | 3 +-
> > libc/misc/internals/Makefile.in | 2 +-
> > libc/misc/internals/reloc_static_pie.c | 91 ++++++++++++++++++++++----
> > libc/sysdeps/linux/mips/crt1.S | 22 +++++++
> > 5 files changed, 103 insertions(+), 17 deletions(-)
> >
> > diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in
> > index e0905e956..43c04fd0a 100644
> > --- a/extra/Configs/Config.in
> > +++ b/extra/Configs/Config.in
> > @@ -324,7 +324,7 @@ config DOPIC
> > config STATIC_PIE
> > bool "Add support for Static Position Independent Executables (PIE)"
> > default n
> > - depends on DOPIC && !UCLIBC_FORMAT_FDPIC_ELF && (TARGET_arm ||
> > TARGET_i386 || TARGET_x86_64 || TARGET_aarch64)
> > + depends on DOPIC && !UCLIBC_FORMAT_FDPIC_ELF && (TARGET_arm ||
> > TARGET_i386 || TARGET_x86_64 || TARGET_aarch64 || TARGET_mips)
> >
> > config ARCH_HAS_NO_SHARED
> > bool
> > diff --git a/ldso/ldso/mips/dl-startup.h b/ldso/ldso/mips/dl-startup.h
> > index 8026f1702..c2168d774 100644
> > --- a/ldso/ldso/mips/dl-startup.h
> > +++ b/ldso/ldso/mips/dl-startup.h
> > @@ -7,6 +7,7 @@
> >
> >
> > #include <sgidefs.h>
> > +#ifndef L_rcrt1
> > __asm__(""
> > " .text\n"
> > " .globl _start\n"
> > @@ -114,6 +115,7 @@ __asm__(""
> > "\n\n"
> > ".previous\n"
> > );
> > +#endif
> >
> > /*
> > * Get a pointer to the argv array. On many platforms this can be just
> > @@ -191,6 +193,5 @@ do { \
> > case R_MIPS_NONE: \
> > break; \
> > default: \
> > - SEND_STDERR("Aiieeee!"); \
> > _dl_exit(1); \
> > }
> > diff --git a/libc/misc/internals/Makefile.in
> > b/libc/misc/internals/Makefile.in
> > index 69af8b76e..908b18321 100644
> > --- a/libc/misc/internals/Makefile.in
> > +++ b/libc/misc/internals/Makefile.in
> > @@ -17,7 +17,7 @@ MISC_INTERNALS_SRC := $(patsubst
> > %.c,$(MISC_INTERNALS_DIR)/%.c,$(CSRC-y))
> > MISC_INTERNALS_OBJ := $(patsubst
> %.c,$(MISC_INTERNALS_OUT)/%.o,$(CSRC-y))
> >
> > CFLAGS-__uClibc_main.c := $(SSP_DISABLE_FLAGS)
> > -CFLAGS-reloc_static_pie.c := $(SSP_DISABLE_FLAGS)
> > +CFLAGS-reloc_static_pie.c := $(SSP_DISABLE_FLAGS) -DL_rcrt1
> >
> > libc-y += $(MISC_INTERNALS_OBJ)
> > ifneq ($(UCLIBC_FORMAT_SHARED_FLAT),y)
> > diff --git a/libc/misc/internals/reloc_static_pie.c
> > b/libc/misc/internals/reloc_static_pie.c
> > index 578202d23..cd9190d60 100644
> > --- a/libc/misc/internals/reloc_static_pie.c
> > +++ b/libc/misc/internals/reloc_static_pie.c
> > @@ -20,28 +20,91 @@
> > #include <elf.h>
> > #include <dl-elf.h>
> >
> > +#include <ldso.h>
> > +#ifdef __mips__
> > +#include <dl-startup.h>
> > +#endif
> > +
> > ElfW(Addr) _dl_load_base = NULL;
> >
> > void
> > reloc_static_pie (ElfW(Addr) load_addr);
> >
> > void
> > -reloc_static_pie (ElfW(Addr) load_addr)
> > +reloc_static_pie(ElfW(Addr) load_addr)
> > {
> > - ElfW(Word) relative_count = 0;
> > - ElfW(Addr) rel_addr = 0;
> > - ElfW(Dyn) * dyn_addr = NULL;
> > - unsigned long dynamic_info[DYNAMIC_SIZE] = {0};
> > + int indx;
> > + ElfW(Addr) got;
> > + ElfW(Dyn) *dpnt;
> > + struct elf_resolve tpnt_tmp;
> > + struct elf_resolve *tpnt = &tpnt_tmp;
> > +
> > + DL_BOOT_COMPUTE_GOT(got);
> > + DL_BOOT_COMPUTE_DYN(dpnt, got, (DL_LOADADDR_TYPE)load_addr);
> > +
> > + _dl_memset(tpnt, 0, sizeof(struct elf_resolve));
> > + tpnt->loadaddr = load_addr;
> > + tpnt->dynamic_addr = dpnt;
> > +
> > + __dl_parse_dynamic_info(dpnt, tpnt->dynamic_info, NULL, load_addr);
> > +
> > +#if defined(PERFORM_BOOTSTRAP_GOT)
> > + /* some arches (like MIPS) we have to tweak the GOT before
> > relocations */
> > + PERFORM_BOOTSTRAP_GOT(tpnt);
> > +#endif
> > +
> > +
> > +#if defined(ELF_MACHINE_PLTREL_OVERLAP)
> > +# define INDX_MAX 1
> > +#else
> > +# define INDX_MAX 2
> > +#endif
> > +
> > + for (indx = 0; indx < INDX_MAX; indx++) {
> > + unsigned long rel_addr, rel_size;
> > + ElfW(Word) relative_count = tpnt->dynamic_info[DT_RELCONT_IDX];
> > +
> > + rel_addr = (indx ? tpnt->dynamic_info[DT_JMPREL] :
> > + tpnt->dynamic_info[DT_RELOC_TABLE_ADDR]);
> > + rel_size = (indx ? tpnt->dynamic_info[DT_PLTRELSZ] :
> > + tpnt->dynamic_info[DT_RELOC_TABLE_SIZE]);
> > +
> > + if (!rel_addr)
> > + continue;
> >
> > - /* Read our own dynamic section and fill in the info array. */
> > - dyn_addr = ((void *) load_addr + elf_machine_dynamic ());
> > + if((0 == indx) && relative_count) {
> > + rel_size -= relative_count * sizeof(ELF_RELOC);
> > + elf_machine_relative(load_addr, rel_addr, relative_count);
> > + rel_addr += relative_count * sizeof(ELF_RELOC);
> > + }
> >
> > - /* Use the underlying function to avoid TLS access before
> > initialization */
> > - __dl_parse_dynamic_info(dyn_addr, dynamic_info, NULL, load_addr);
> > +#ifdef ARCH_NEEDS_BOOTSTRAP_RELOCS
> > + {
> > + ELF_RELOC *rpnt;
> > + unsigned int i;
> > + ElfW(Sym) *sym;
> > + unsigned long symbol_addr;
> > + int symtab_index;
> > + unsigned long *reloc_addr;
> >
> > - /* Perform relocations */
> > - relative_count = dynamic_info[DT_RELCONT_IDX];
> > - rel_addr = dynamic_info[DT_RELOC_TABLE_ADDR];
> > - elf_machine_relative(load_addr, rel_addr, relative_count);
> > + /* Now parse the relocation information */
> > + rpnt = (ELF_RELOC *) rel_addr;
> > + for (i = 0; i < rel_size; i += sizeof(ELF_RELOC), rpnt++) {
> > + reloc_addr = (unsigned long *) DL_RELOC_ADDR(load_addr, (unsigned
> > long)rpnt->r_offset);
> > + symtab_index = ELF_R_SYM(rpnt->r_info);
> > + symbol_addr = 0;
> > + sym = NULL;
> > + if (symtab_index) {
> > + ElfW(Sym) *symtab;
> > + symtab = (ElfW(Sym) *) tpnt->dynamic_info[DT_SYMTAB];
> > + sym = &symtab[symtab_index];
> > + symbol_addr = (unsigned long) DL_RELOC_ADDR(load_addr, sym->st_value);
> > + }
> > + /* Use this machine-specific macro to perform the actual relocation.
> */
> > + PERFORM_BOOTSTRAP_RELOC(rpnt, reloc_addr, symbol_addr, load_addr, sym);
> > + }
> > + }
> > +#endif
> > + }
> > _dl_load_base = load_addr;
> > -}
> > +}
> > \ No newline at end of file
> > diff --git a/libc/sysdeps/linux/mips/crt1.S
> > b/libc/sysdeps/linux/mips/crt1.S
> > index 083615515..a7f72a90f 100644
> > --- a/libc/sysdeps/linux/mips/crt1.S
> > +++ b/libc/sysdeps/linux/mips/crt1.S
> > @@ -77,6 +77,10 @@
> > #ifndef __UCLIBC_CTOR_DTOR__
> > .weak _init
> > .weak _fini
> > +#endif
> > +#ifdef L_rcrt1
> > + .type reloc_static_pie,@function
> > + .weak reloc_static_pie
> > #endif
> > .type main,@function
> > .type __uClibc_main,@function
> > @@ -90,6 +94,24 @@ __start:
> > PTR_LA $28, _gp /* Setup GP correctly if we're non-PIC. */
> > move $31, $0
> > #endif
> > +#ifdef L_rcrt1
> > + PTR_LA $4, _DYNAMIC /* Place _DYNAMIC into the GOT */
> > + REG_S $4, -0x7ff0($28)
> > + jal L0 /* Get the current $pc address */
> > +L0:
> > + INT_SUB $25, $31, $25 /* Calculate load addr */
> > + move $4, $25 /* store load addr in param 1 */
> > + and $29, -2 * SZREG /* Ensure stack is aligned */
> > + addi $29, $29, (-2 * SZREG) /* Allocate 2 register spaces on stack */
> > + REG_S $2, SZREG($29) /* Store atexit in case it exists */
> > + PTR_LA $5, reloc_static_pie /* function calls before relocation
> > + don't work unless we set $t9 manually
> */
> > + INT_ADDU $25, $25, $5 /* store reloc_static_pie in $t9 */
> > + bal reloc_static_pie /* call, and pray the compiler adds a nop
> > + in delay slot */
> > + REG_L $2, SZREG($29) /* cleanup stack */
> > + addi $29, $29, (2 * SZREG)
> > +#endif
> >
> > PTR_LA $4, main /* main */
> > PTR_L $5, 0($29) /* argc */
> > --
> > 2.34.1
> >
> >
> > _______________________________________________
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>
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