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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 /src/ldso/or1k/start.s | |
parent | 385c01112c083eb383d972da45836d497cc0556d (diff) | |
download | musl-f3ddd173806fd5c60b3f034528ca24542aecc5b9.tar.gz |
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 'src/ldso/or1k/start.s')
-rw-r--r-- | src/ldso/or1k/start.s | 34 |
1 files changed, 0 insertions, 34 deletions
diff --git a/src/ldso/or1k/start.s b/src/ldso/or1k/start.s deleted file mode 100644 index 83b7c2c6..00000000 --- a/src/ldso/or1k/start.s +++ /dev/null @@ -1,34 +0,0 @@ -.global _dlstart -_dlstart: - l.jal 1f - l.nop -1: l.movhi r5, gotpchi(_GLOBAL_OFFSET_TABLE_+0) - l.ori r5, r5, gotpclo(_GLOBAL_OFFSET_TABLE_+4) - l.add r5, r5, r9 - l.movhi r3, gotoffhi(_DYNAMIC) - l.ori r3, r3, gotofflo(_DYNAMIC) - l.add r5, r5, r3 - - l.lwz r3, 0(r1) - l.addi r4, r1, 4 - l.jal plt(__reloc_self) - l.addi r1, r1, -16 - - l.lwz r3, 16(r1) - l.jal plt(__dynlink) - l.addi r4, r1, 20 - l.addi r1, r1, 16 - - l.lwz r4, 0(r1) -1: l.addi r4, r4, -1 - l.lwz r5, 4(r1) - l.sfeqi r5, -1 - l.bf 1b - l.addi r1, r1, 4 - - l.addi r4, r4, 1 - l.addi r1, r1, -4 - l.sw 0(r1), r4 - - l.jr r11 - l.ori r3, r0, 0 |