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2b1d7148e3
since https://sourceware.org/ml/libc-alpha/2014-04/msg00006.html setcontext etc is no longer tied to the kernel use of ucontext. in that patch the ucontext reserved space is not used consistently with the kernel abi: the d8,d9 pair is saved in the slot of q8. this is ok (*context functions work together), but probably not desirable (ucontexts created by the kernel and getcontext are subtly different). the fix just replaces dN with qN in the save/restore code, which does a bit more than needed (saves/restores the top half of qN that is not callee saved), but this should not be an issue (and avoids having to deal with endianness). (kernel fpsimd context layout: the first 64bit contains 0x210 the fpsimd context size and 0x46508001 the FPSIMD_MAGIC, the second 64bit is for fpsr and fpcr, and the rest is the 128bit q0..q31 registers). given d8=8.1, d9=9.1,... d15=15.1, the context created by getcontext is current: (gdb) x/40xg ctx.uc_mcontext.__reserved 0x410df0 <ctx+464>: 0x0000021046508001 0x0000000000000000 0x410e00 <ctx+480>: 0x0000000000000000 0x0000000000000000 0x410e10 <ctx+496>: 0x0000000000000000 0x0000000000000000 0x410e20 <ctx+512>: 0x0000000000000000 0x0000000000000000 0x410e30 <ctx+528>: 0x0000000000000000 0x0000000000000000 0x410e40 <ctx+544>: 0x0000000000000000 0x0000000000000000 0x410e50 <ctx+560>: 0x0000000000000000 0x0000000000000000 0x410e60 <ctx+576>: 0x0000000000000000 0x0000000000000000 0x410e70 <ctx+592>: 0x0000000000000000 0x0000000000000000 0x410e80 <ctx+608>: 0x4020333333333333 0x4022333333333333 0x410e90 <ctx+624>: 0x0000000000000000 0x0000000000000000 0x410ea0 <ctx+640>: 0x4024333333333333 0x4026333333333333 0x410eb0 <ctx+656>: 0x0000000000000000 0x0000000000000000 0x410ec0 <ctx+672>: 0x4028333333333333 0x402a333333333333 0x410ed0 <ctx+688>: 0x0000000000000000 0x0000000000000000 0x410ee0 <ctx+704>: 0x402c333333333333 0x402e333333333333 0x410ef0 <ctx+720>: 0x0000000000000000 0x0000000000000000 0x410f00 <ctx+736>: 0x0000000000000000 0x0000000000000000 0x410f10 <ctx+752>: 0x0000000000000000 0x0000000000000000 0x410f20 <ctx+768>: 0x0000000000000000 0x0000000000000000 fixed: (gdb) x/40xg ctx.uc_mcontext.__reserved 0x410d70 <ctx+464>: 0x0000021046508001 0x0000000000000000 0x410d80 <ctx+480>: 0x0000000000000000 0x0000000000000000 0x410d90 <ctx+496>: 0x0000000000000000 0x0000000000000000 0x410da0 <ctx+512>: 0x0000000000000000 0x0000000000000000 0x410db0 <ctx+528>: 0x0000000000000000 0x0000000000000000 0x410dc0 <ctx+544>: 0x0000000000000000 0x0000000000000000 0x410dd0 <ctx+560>: 0x0000000000000000 0x0000000000000000 0x410de0 <ctx+576>: 0x0000000000000000 0x0000000000000000 0x410df0 <ctx+592>: 0x0000000000000000 0x0000000000000000 0x410e00 <ctx+608>: 0x4020333333333333 0x0000000000000000 0x410e10 <ctx+624>: 0x4022333333333333 0x0000000000000000 0x410e20 <ctx+640>: 0x4024333333333333 0x0000000000000000 0x410e30 <ctx+656>: 0x4026333333333333 0x0000000000000000 0x410e40 <ctx+672>: 0x4028333333333333 0x0000000000000000 0x410e50 <ctx+688>: 0x402a333333333333 0x0000000000000000 0x410e60 <ctx+704>: 0x402c333333333333 0x0000000000000000 0x410e70 <ctx+720>: 0x402e333333333333 0x0000000000000000 0x410e80 <ctx+736>: 0x0000000000000000 0x0000000000000000 0x410e90 <ctx+752>: 0x0000000000000000 0x0000000000000000 0x410ea0 <ctx+768>: 0x0000000000000000 0x0000000000000000 2015-07-06 Szabolcs Nagy <szabolcs.nagy@arm.com> * sysdeps/unix/sysv/linux/aarch64/getcontext.S (__getcontext): Use q registers instead of d ones so the layout is kernel abi compatible. * sysdeps/unix/sysv/linux/aarch64/setcontext.S (__setcontext): Likewise. * sysdeps/unix/sysv/linux/aarch64/swapcontext.S (__swapcontext): Likewise.# Please enter the commit message for your changes. Lines starting
109 lines
2.9 KiB
ArmAsm
109 lines
2.9 KiB
ArmAsm
/* Save current context.
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Copyright (C) 2009-2015 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include "ucontext_i.h"
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#include "ucontext-internal.h"
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/* int getcontext (ucontext_t *ucp)
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Returns 0 on success -1 and errno on failure.
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*/
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.text
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ENTRY(__getcontext)
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/* The saved context will return to the getcontext() call point
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with a return value of 0 */
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str xzr, [x0, oX0 + 0 * SZREG]
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stp x18, x19, [x0, oX0 + 18 * SZREG]
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stp x20, x21, [x0, oX0 + 20 * SZREG]
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stp x22, x23, [x0, oX0 + 22 * SZREG]
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stp x24, x25, [x0, oX0 + 24 * SZREG]
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stp x26, x27, [x0, oX0 + 26 * SZREG]
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stp x28, x29, [x0, oX0 + 28 * SZREG]
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str x30, [x0, oX0 + 30 * SZREG]
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/* Place LR into the saved PC, this will ensure that when
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switching to this saved context with setcontext() control
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will pass back to the caller of getcontext(), we have
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already arrange to return the appropriate return value in x0
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above. */
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str x30, [x0, oPC]
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/* Save the current SP */
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mov x2, sp
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str x2, [x0, oSP]
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/* Initialize the pstate. */
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str xzr, [x0, oPSTATE]
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/* Figure out where to place the first context extension
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block. */
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add x2, x0, #oEXTENSION
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/* Write the context extension fpsimd header. */
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mov w3, #(FPSIMD_MAGIC & 0xffff)
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movk w3, #(FPSIMD_MAGIC >> 16), lsl #16
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str w3, [x2, #oHEAD + oMAGIC]
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mov w3, #FPSIMD_CONTEXT_SIZE
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str w3, [x2, #oHEAD + oSIZE]
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/* Fill in the FP SIMD context. */
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add x3, x2, #oV0 + 8 * SZVREG
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stp q8, q9, [x3], # 2 * SZVREG
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stp q10, q11, [x3], # 2 * SZVREG
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stp q12, q13, [x3], # 2 * SZVREG
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stp q14, q15, [x3], # 2 * SZVREG
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add x3, x2, oFPSR
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mrs x4, fpsr
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str w4, [x3]
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mrs x4, fpcr
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str w4, [x3, oFPCR - oFPSR]
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/* Write the termination context extension header. */
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add x2, x2, #FPSIMD_CONTEXT_SIZE
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str xzr, [x2, #oHEAD + oMAGIC]
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str xzr, [x2, #oHEAD + oSIZE]
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/* Grab the signal mask */
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/* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
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add x2, x0, #UCONTEXT_SIGMASK
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mov x0, SIG_BLOCK
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mov x1, 0
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mov x3, _NSIG8
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mov x8, SYS_ify (rt_sigprocmask)
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svc 0
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cbnz x0, 1f
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/* Return 0 for success */
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mov x0, 0
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RET
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1:
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b C_SYMBOL_NAME(__syscall_error)
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PSEUDO_END (__getcontext)
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weak_alias (__getcontext, getcontext)
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