RepoMirrors
/
musl
mirror of git://git.musl-libc.org/musl
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
musl/arch/sh/crt_arch.h

24 lines
477 B
C
Raw Normal View History

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.
2015-04-13 06:56:26 +00:00
__asm__(
add .text section directive to all crt_arch.h files missing it i386 and x86_64 versions already had the .text directive; other archs did not. normally, top-level (file scope) __asm__ starts in the .text section anyway, but problems were reported with some versions of clang, and it seems preferable to set it explicitly anyway, at least for the sake of consistency between archs.
2015-05-22 05:50:05 +00:00
".text \n"
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.
2015-04-13 06:56:26 +00:00
".global " START " \n"
START ": \n"
" mova 1f, r0 \n"
" mov.l 1f, r5 \n"
" add r0, r5 \n"
" mov r15, r4 \n"
" mov #-16, r0 \n"
" and r0, r15 \n"
" bsr " START "_c \n"
" nop \n"
".align 2 \n"
".weak _DYNAMIC \n"
".hidden _DYNAMIC \n"
"1: .long _DYNAMIC-. \n"
);
superh: fix dynamic linking of __fpscr_values Applications ended up with copy relocations for this array, which resulted in libc's references to this array pointing to the application's copy. The dynamic linker, however, can require this array before the application is relocated, and therefore before the application's copy of this array is initialized. This resulted in garbage being loaded into FPSCR before executing main, which violated the ABI. We fix this by putting the array in crt1 and making the libc copy private. This prevents libc's reference to the array from pointing to an uninitialized copy in the application.
2014-03-16 21:17:28 +00:00
/* used by gcc for switching the FPU between single and double precision */
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.
2015-04-13 06:56:26 +00:00
#ifdef SHARED
__attribute__((__visibility__("hidden")))
#endif
superh: fix dynamic linking of __fpscr_values Applications ended up with copy relocations for this array, which resulted in libc's references to this array pointing to the application's copy. The dynamic linker, however, can require this array before the application is relocated, and therefore before the application's copy of this array is initialized. This resulted in garbage being loaded into FPSCR before executing main, which violated the ABI. We fix this by putting the array in crt1 and making the libc copy private. This prevents libc's reference to the array from pointing to an uninitialized copy in the application.
2014-03-16 21:17:28 +00:00
const unsigned long __fpscr_values[2] = { 0, 0x80000 };