I'm sorry, the v3 patch fixes this. I was incorrectly setting _DYNAMIC into the GOT during static builds.
On Fri, Sep 2, 2022 at 11:55 AM Lance Fredrickson lancethepants@gmail.com wrote:
I applied this patch but while compiling uclibc-ng I get
/opt/tomatoware/mipsel-soft-mmc/lib/gcc/mipsel-tomatoware-linux-uclibc/12.2.0/../../../../mipsel-tomatoware-linux-uclibc/bin/ld: ../lib/crt1.o: in function `__start': (.text+0x1c): undefined reference to `_DYNAMIC' collect2: error: ld returned 1 exit status
I also applied Max's patch from that other thread along with this patch, but with both applied I still get "undefined reference to `_DYNAMIC'"
On 9/1/2022 3:15 PM, linted wrote:
Ok! After a ton of research and tracking down a bug in the mips64 implementation, I was finally able to recreate and subsequently fix this bug. I'll submit the updated patch shortly!
On Wed, Aug 24, 2022 at 5:10 PM Lance Fredrickson lancethepants@gmail.com wrote:
Hmm, wonder if small endian mips*el* has anything to do with it.
I tried that patch on top of the other one and I get this error.
mipsel-linux-g++ -static-pie hello.cpp -o hello /opt/tomatoware/mipsel-soft-mmc/mipsel-tomatoware-linux-uclibc/sysroot/usr/lib/rcrt1.o: in function `__start': (.text+0x50): relocation truncated to fit: R_MIPS_PC16 against `reloc_static_pie' collect2: error: ld returned 1 exit status
On 8/24/2022 1:23 PM, linted wrote:
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 < lancethepants@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 linted@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 linted@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 $t9manually */
- 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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