diff options
Diffstat (limited to 'libc/ports/sysdeps/arm/dl-tlsdesc.S')
| -rw-r--r-- | libc/ports/sysdeps/arm/dl-tlsdesc.S | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/libc/ports/sysdeps/arm/dl-tlsdesc.S b/libc/ports/sysdeps/arm/dl-tlsdesc.S new file mode 100644 index 000000000..f21555281 --- /dev/null +++ b/libc/ports/sysdeps/arm/dl-tlsdesc.S @@ -0,0 +1,218 @@ +/* Thread-local storage handling in the ELF dynamic linker. ARM version. + Copyright (C) 2006, 2010, 2011 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> +#include <tls.h> +#include "tlsdesc.h" + +#ifdef __USE_BX__ + #define BX(x) bx x +#else + #define BX(x) mov pc, x +#endif + + .text + @ emit debug information with cfi + @ use arm-specific pseudos for unwinding itself + .cfi_sections .debug_frame + .hidden _dl_tlsdesc_return + .global _dl_tlsdesc_return + .type _dl_tlsdesc_return,#function + cfi_startproc + .fnstart + .align 2 +_dl_tlsdesc_return: + ldr r0, [r0] + BX (lr) + .fnend + cfi_endproc + .size _dl_tlsdesc_return, .-_dl_tlsdesc_return + + .hidden _dl_tlsdesc_undefweak + .global _dl_tlsdesc_undefweak + .type _dl_tlsdesc_undefweak,#function + cfi_startproc + .fnstart + .align 2 +_dl_tlsdesc_undefweak: + @ Are we allowed a misaligned stack pointer calling read_tp? + .save {lr} + stmdb sp!, {lr} + cfi_adjust_cfa_offset (4) + cfi_rel_offset (lr,0) + bl __aeabi_read_tp + rsb r0, r0, #0 + ldmia sp!, {lr} + cfi_adjust_cfa_offset (-4) + cfi_restore (lr) + BX (lr) + + cfi_endproc + .fnend + .size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak + +#ifdef SHARED + .hidden _dl_tlsdesc_dynamic + .global _dl_tlsdesc_dynamic + .type _dl_tlsdesc_dynamic,#function + + +/* + The assembly code that follows is a rendition of the following + C code, hand-optimized a little bit. + +ptrdiff_t +_dl_tlsdesc_dynamic(struct tlsdesc *tdp) +{ + struct tlsdesc_dynamic_arg *td = tdp->argument.pointer; + dtv_t *dtv = (dtv_t *)THREAD_DTV(); + if (__builtin_expect (td->gen_count <= dtv[0].counter + && dtv[td->tlsinfo.ti_module].pointer.val + != TLS_DTV_UNALLOCATED, + 1)) + return dtv[td->tlsinfo.ti_module].pointer.val + + td->tlsinfo.ti_offset - __builtin_thread_pointer(); + + return __tls_get_addr (&td->tlsinfo) - __builtin_thread_pointer(); +} + +*/ + cfi_startproc + .fnstart + .align 2 +_dl_tlsdesc_dynamic: + /* Our calling convention is to clobber r0, r1 and the processor + flags. All others that are modified must be saved */ + .save {r2,r3,r4,lr} + stmdb sp!, {r2,r3,r4,lr} + cfi_adjust_cfa_offset (16) + cfi_rel_offset (r2,0) + cfi_rel_offset (r3,4) + cfi_rel_offset (r4,8) + cfi_rel_offset (lr,12) + ldr r1, [r0] /* td */ + bl __aeabi_read_tp + mov r4, r0 /* r4 = tp */ + ldr r0, [r0] + ldr r2, [r1, #8] /* gen_count */ + ldr r3, [r0] + cmp r2, r3 + bhi 1f + ldr r3, [r1] + ldr r2, [r0, r3, lsl #3] + cmn r2, #1 + ldrne r3, [r1, #4] + addne r3, r2, r3 + rsbne r0, r4, r3 + bne 2f +1: mov r0, r1 + bl __tls_get_addr + rsb r0, r4, r0 +2: ldmia sp!, {r2,r3,r4, lr} + cfi_adjust_cfa_offset (-16) + cfi_restore (lr) + cfi_restore (r4) + cfi_restore (r3) + cfi_restore (r2) + BX (lr) + .fnend + cfi_endproc + .size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic +#endif /* SHARED */ + +/* lazy resolved for tls descriptors. */ + .hidden _dl_tlsdesc_lazy_resolver + .global _dl_tlsdesc_lazy_resolver + .type _dl_tlsdesc_lazy_resolver,#function + cfi_startproc + .fnstart + .align 2 +_dl_tlsdesc_lazy_resolver: + /* r0 points at the tlsdesc, + r1 points at the GOT + r2 was pushed by the trampoline and used as a temp, + we need to pop it here. + We push the remaining call-clobbered registers here, and also + R1 -- to keep the stack correctly aligned. */ + /* Tell the unwinder that r2 has already been pushed. */ + .save {r2} + cfi_adjust_cfa_offset (4) + cfi_rel_offset (r2, 0) + .save {r0,r1,r3,ip,lr} + stmdb sp!, {r0, r1, r3, ip, lr} + cfi_adjust_cfa_offset (20) + cfi_rel_offset (r0, 0) + cfi_rel_offset (r1, 4) + cfi_rel_offset (r3, 8) + cfi_rel_offset (ip, 12) + cfi_rel_offset (lr, 16) + bl _dl_tlsdesc_lazy_resolver_fixup + ldmia sp!, {r0, r1, r3, ip, lr} + cfi_adjust_cfa_offset (-20) + cfi_restore (lr) + cfi_restore (ip) + cfi_restore (r3) + cfi_restore (r1) + cfi_restore (r0) + ldmia sp!, {r2} + cfi_adjust_cfa_offset (-4) + cfi_restore (r2) + ldr r1, [r0, #4] + BX (r1) + .fnend + cfi_endproc + .size _dl_tlsdesc_lazy_resolver, .-_dl_tlsdesc_lazy_resolver + +/* Holder for lazy tls descriptors being resolve in another thread. + Same ABI as the lazy resolver itself. */ + .hidden _dl_tlsdesc_resolve_hold + .global _dl_tlsdesc_resolve_hold + .type _dl_tlsdesc_resolve_hold,#function + cfi_startproc + .fnstart + .align 2 +_dl_tlsdesc_resolve_hold: + /* Tell the unwinder that r2 has already been pushed. */ + .save {r2} + cfi_adjust_cfa_offset (4) + cfi_rel_offset (r2, 0) + .save {r0,r1,r3,ip,lr} + stmdb sp!, {r0, r1, r3, ip, lr} + cfi_adjust_cfa_offset (20) + cfi_rel_offset (r0, 0) + cfi_rel_offset (r1, 4) + cfi_rel_offset (r3, 8) + cfi_rel_offset (ip, 12) + cfi_rel_offset (lr, 16) + adr r2, _dl_tlsdesc_resolve_hold + bl _dl_tlsdesc_resolve_hold_fixup + ldmia sp!, {r0, r1, r3, ip, lr} + cfi_adjust_cfa_offset (-20) + cfi_restore (lr) + cfi_restore (ip) + cfi_restore (r3) + cfi_restore (r1) + cfi_restore (r0) + ldmia sp!, {r2} + cfi_adjust_cfa_offset (-4) + cfi_restore (r2) + ldr r1, [r0, #4] + BX (r1) + .fnend + cfi_endproc + .size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold |