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Diffstat (limited to 'ports/sysdeps/arm/dl-trampoline.S')
| -rw-r--r-- | ports/sysdeps/arm/dl-trampoline.S | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/ports/sysdeps/arm/dl-trampoline.S b/ports/sysdeps/arm/dl-trampoline.S new file mode 100644 index 0000000000..370bda3467 --- /dev/null +++ b/ports/sysdeps/arm/dl-trampoline.S @@ -0,0 +1,217 @@ +/* PLT trampolines. ARM version. + Copyright (C) 2005, 2010 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 <libc-symbols.h> + +#if defined(__USE_BX__) +#define BX(x) bx x +#else +#define BX(x) mov pc, x +#endif + + .text + .globl _dl_runtime_resolve + .type _dl_runtime_resolve, #function + .cfi_sections .debug_frame + cfi_startproc + .align 2 +_dl_runtime_resolve: + cfi_adjust_cfa_offset (4) + cfi_rel_offset (lr, 0) + + @ we get called with + @ stack[0] contains the return address from this call + @ ip contains &GOT[n+3] (pointer to function) + @ lr points to &GOT[2] + + @ Save arguments. We save r4 to realign the stack. + stmdb sp!,{r0-r4} + cfi_adjust_cfa_offset (20) + cfi_rel_offset (r0, 0) + cfi_rel_offset (r1, 4) + cfi_rel_offset (r2, 8) + cfi_rel_offset (r3, 12) + + @ get pointer to linker struct + ldr r0, [lr, #-4] + + @ prepare to call _dl_fixup() + @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each + sub r1, ip, lr + sub r1, r1, #4 + add r1, r1, r1 + + @ call fixup routine + bl _dl_fixup + + @ save the return + mov ip, r0 + + @ get arguments and return address back. We restore r4 + @ only to realign the stack. + ldmia sp!, {r0-r4,lr} + cfi_adjust_cfa_offset (-24) + + @ jump to the newly found address + BX(ip) + + cfi_endproc + .size _dl_runtime_resolve, .-_dl_runtime_resolve + +#ifndef PROF + .globl _dl_runtime_profile + .type _dl_runtime_profile, #function + .cfi_sections .debug_frame + cfi_startproc + .align 2 +_dl_runtime_profile: + cfi_adjust_cfa_offset (4) + cfi_rel_offset (lr, 0) + + @ we get called with + @ stack[0] contains the return address from this call + @ ip contains &GOT[n+3] (pointer to function) + @ lr points to &GOT[2] + + @ Stack layout: + @ 212 - saved lr + @ 208 - framesize returned from pltenter + @ 16 - La_arm_regs + @ 8 - Saved two arguments to _dl_profile_fixup + @ 4 - Saved result of _dl_profile_fixup + @ 0 - outgoing argument to _dl_profile_fixup + @ For now, we only save the general purpose registers. + + sub sp, sp, #196 + cfi_adjust_cfa_offset (196) + stmia sp, {r0-r3} + cfi_rel_offset (r0, 0) + cfi_rel_offset (r1, 4) + cfi_rel_offset (r2, 8) + cfi_rel_offset (r3, 12) + + sub sp, sp, #16 + cfi_adjust_cfa_offset (16) + + @ Save sp and lr. + add r0, sp, #216 + str r0, [sp, #32] + ldr r2, [sp, #212] + str r2, [sp, #36] + + @ get pointer to linker struct + ldr r0, [lr, #-4] + + @ prepare to call _dl_profile_fixup() + @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each + sub r1, ip, lr + sub r1, r1, #4 + add r1, r1, r1 + + @ Save these two arguments for pltexit. + add r3, sp, #8 + stmia r3!, {r0,r1} + + @ Set up extra args for _dl_profile_fixup. + @ r2 and r3 are already loaded. + add ip, sp, #208 + str ip, [sp, #0] + + @ call profiling fixup routine + bl _dl_profile_fixup + + @ The address to call is now in r0. + + @ Check whether we're wrapping this function. + ldr ip, [sp, #208] + cmp ip, #0 + bge 1f + cfi_remember_state + + @ save the return + mov ip, r0 + + @ get arguments and return address back + add sp, sp, #16 + cfi_adjust_cfa_offset (-16) + ldmia sp, {r0-r3,sp,lr} + cfi_adjust_cfa_offset (-200) + + @ jump to the newly found address + BX(ip) + + cfi_restore_state +1: + @ The new frame size is in ip. + + @ New stack layout: + @ 268 - saved r7 + @ 264 - saved result of _dl_profile_fixup + @ 72 - La_arm_regs + @ 64 - Saved two arguments to _dl_profile_fixup + @ 0 - La_arm_retval + @ For now, we only save the general purpose registers. + + @ Build the new frame. + str r7, [sp, #212] + cfi_rel_offset (r7, 212) + sub r7, sp, #56 + cfi_def_cfa_register (r7) + cfi_adjust_cfa_offset (56) + sub sp, sp, ip + bic sp, sp, #7 + + @ Save the _dl_profile_fixup result around the call to memcpy. + str r0, [r7, #264] + + @ Copy the stack arguments. + mov r0, sp + add r1, r7, #272 + mov r2, ip + bl memcpy + + @ Call the function. + add ip, r7, #72 + ldmia ip, {r0-r3} + ldr ip, [r7, #264] + mov lr, pc + BX(ip) + stmia r7, {r0-r3} + + @ Call pltexit. + add ip, r7, #64 + ldmia ip, {r0,r1} + add r2, r7, #72 + add r3, r7, #0 + bl _dl_call_pltexit + + @ Return to caller. + ldmia r7, {r0-r3} + mov sp, r7 + cfi_def_cfa_register (sp) + ldr r7, [sp, #268] + ldr lr, [sp, #92] + add sp, sp, #272 + cfi_adjust_cfa_offset (-272) + BX(lr) + + cfi_endproc + .size _dl_runtime_profile, .-_dl_runtime_profile +#endif + .previous |