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author | Rich Felker <dalias@aerifal.cx> | 2015-04-13 02:56:26 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2015-04-13 03:04:42 -0400 |
commit | f3ddd173806fd5c60b3f034528ca24542aecc5b9 (patch) | |
tree | 63cc7432a3c40f011c4818de32ef6257acbf0e73 /arch/microblaze | |
parent | 385c01112c083eb383d972da45836d497cc0556d (diff) | |
download | musl-f3ddd173806fd5c60b3f034528ca24542aecc5b9.tar.gz musl-f3ddd173806fd5c60b3f034528ca24542aecc5b9.tar.bz2 musl-f3ddd173806fd5c60b3f034528ca24542aecc5b9.tar.xz musl-f3ddd173806fd5c60b3f034528ca24542aecc5b9.zip |
dynamic linker bootstrap overhaul
this overhaul further reduces the amount of arch-specific code needed
by the dynamic linker and removes a number of assumptions, including:
- that symbolic function references inside libc are bound at link time
via the linker option -Bsymbolic-functions.
- that libc functions used by the dynamic linker do not require
access to data symbols.
- that static/internal function calls and data accesses can be made
without performing any relocations, or that arch-specific startup
code handled any such relocations needed.
removing these assumptions paves the way for allowing libc.so itself
to be built with stack protector (among other things), and is achieved
by a three-stage bootstrap process:
1. relative relocations are processed with a flat function.
2. symbolic relocations are processed with no external calls/data.
3. main program and dependency libs are processed with a
fully-functional libc/ldso.
reduction in arch-specific code is achived through the following:
- crt_arch.h, used for generating crt1.o, now provides the entry point
for the dynamic linker too.
- asm is no longer responsible for skipping the beginning of argv[]
when ldso is invoked as a command.
- the functionality previously provided by __reloc_self for heavily
GOT-dependent RISC archs is now the arch-agnostic stage-1.
- arch-specific relocation type codes are mapped directly as macros
rather than via an inline translation function/switch statement.
Diffstat (limited to 'arch/microblaze')
-rw-r--r-- | arch/microblaze/crt_arch.h | 27 | ||||
-rw-r--r-- | arch/microblaze/reloc.h | 47 |
2 files changed, 25 insertions, 49 deletions
diff --git a/arch/microblaze/crt_arch.h b/arch/microblaze/crt_arch.h index 8917c695..ada98c86 100644 --- a/arch/microblaze/crt_arch.h +++ b/arch/microblaze/crt_arch.h @@ -1,11 +1,16 @@ -__asm__("\ -.global _start \n\ -.align 2 \n\ -_start: \n\ - add r19, r0, r0 \n\ - ori r5, r1, 0 \n\ - andi r1, r1, -8 \n\ - addik r1, r1, -8 \n\ - bri __cstart \n\ - nop \n\ -"); +__asm__( +".global " START " \n" +".align 2 \n" +START ": \n" +" add r19, r0, r0 \n" +" ori r5, r1, 0 \n" +"1: mfs r6, rpc \n" +".weak _DYNAMIC \n" +".hidden _DYNAMIC \n" +" addik r6, r6, _GLOBAL_OFFSET_TABLE_+8 \n" +" addik r6, r6, _DYNAMIC@GOTOFF \n" +" andi r1, r1, -8 \n" +" addik r1, r1, -8 \n" +" bri " START "_c \n" +" nop \n" +); diff --git a/arch/microblaze/reloc.h b/arch/microblaze/reloc.h index 71a6219c..611db465 100644 --- a/arch/microblaze/reloc.h +++ b/arch/microblaze/reloc.h @@ -1,5 +1,3 @@ -#include <string.h> -#include <elf.h> #include <endian.h> #if __BYTE_ORDER == __LITTLE_ENDIAN @@ -12,40 +10,13 @@ #define TPOFF_K 0 -static int remap_rel(int type) -{ - switch(type) { - case R_MICROBLAZE_32: - return REL_SYMBOLIC; - case R_MICROBLAZE_GLOB_DAT: - return REL_GOT; - case R_MICROBLAZE_JUMP_SLOT: - return REL_PLT; - case R_MICROBLAZE_REL: - return REL_RELATIVE; - case R_MICROBLAZE_COPY: - return REL_COPY; - case R_MICROBLAZE_TLSDTPMOD32: - return REL_DTPMOD; - case R_MICROBLAZE_TLSDTPREL32: - return REL_DTPOFF; - } - return 0; -} +#define REL_SYMBOLIC R_MICROBLAZE_32 +#define REL_GOT R_MICROBLAZE_GLOB_DAT +#define REL_PLT R_MICROBLAZE_JUMP_SLOT +#define REL_RELATIVE R_MICROBLAZE_REL +#define REL_COPY R_MICROBLAZE_COPY +#define REL_DTPMOD R_MICROBLAZE_TLSDTPMOD32 +#define REL_DTPOFF R_MICROBLAZE_TLSDTPREL32 -#include "syscall.h" -void __reloc_self(int c, size_t *a, size_t *dynv) -{ - char dot = '.', ex = 'x'; - char *base; - size_t t[20], n; - for (a+=c+1; *a; a++); - for (a++; *a; a+=2) if (*a<20) t[*a] = a[1]; - base = (char *)t[AT_BASE]; - if (!base) base = (char *)(t[AT_PHDR] & -t[AT_PAGESZ]); - for (a=dynv; *a; a+=2) if (*a<20) t[*a] = a[1]; - n = t[DT_RELASZ]; - for (a=(void *)(base+t[DT_RELA]); n; a+=3, n-=12) - if (a[1]%256 == R_MICROBLAZE_REL) - *(size_t *)(base+a[0]) = (size_t)base + a[2]; -} +#define CRTJMP(pc,sp) __asm__ __volatile__( \ + "addik r1,%1,0 ; bra %0" : : "r"(pc), "r"(sp) : "memory" ) |