LoongArch: Add support for TLS Descriptors

This is mostly based on AArch64 and RISC-V implementation.

Add R_LARCH_TLS_DESC32 and R_LARCH_TLS_DESC64 relocations.

For _dl_tlsdesc_dynamic function slow path, temporarily save and restore
all vector registers.

1 files changed, 436 insertions, 0 deletions

diff --git a/sysdeps/loongarch/dl-tlsdesc.S b/sysdeps/loongarch/dl-tlsdesc.S
new file mode 100644
index 0000000..15d5fa1
--- /dev/null
+++ b/sysdeps/loongarch/dl-tlsdesc.S
@@ -0,0 +1,436 @@
+/* Thread-local storage handling in the ELF dynamic linker.
+   LoongArch version.
+   Copyright (C) 2024 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <tls.h>
+#include "tlsdesc.h"
+
+	.text
+
+	/* Compute the thread pointer offset for symbols in the static
+	   TLS block. The offset is the same for all threads.
+	   Prototype:
+	   _dl_tlsdesc_return (tlsdesc *);  */
+	.hidden _dl_tlsdesc_return
+	.global	_dl_tlsdesc_return
+	.type	_dl_tlsdesc_return,%function
+	cfi_startproc
+	.align 2
+_dl_tlsdesc_return:
+	REG_L  a0, a0, 8
+	RET
+	cfi_endproc
+	.size	_dl_tlsdesc_return, .-_dl_tlsdesc_return
+
+	/* Handler for undefined weak TLS symbols.
+	   Prototype:
+	   _dl_tlsdesc_undefweak (tlsdesc *);
+
+	   The second word of the descriptor contains the addend.
+	   Return the addend minus the thread pointer. This ensures
+	   that when the caller adds on the thread pointer it gets back
+	   the addend.  */
+	.hidden _dl_tlsdesc_undefweak
+	.global	_dl_tlsdesc_undefweak
+	.type	_dl_tlsdesc_undefweak,%function
+	cfi_startproc
+	.align  2
+_dl_tlsdesc_undefweak:
+	REG_L	a0, a0, 8
+	sub.d	a0, a0, tp
+	RET
+	cfi_endproc
+	.size	_dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
+
+
+#ifdef SHARED
+
+#define FRAME_SIZE	  (-((-14 * SZREG) & ALMASK))
+#define FRAME_SIZE_LSX	  (-((-32 * SZVREG) & ALMASK))
+#define FRAME_SIZE_LASX	  (-((-32 * SZXREG) & ALMASK))
+#define FRAME_SIZE_FLOAT  (-((-24 * SZFREG) & ALMASK))
+
+	/* Handler for dynamic TLS symbols.
+	   Prototype:
+	   _dl_tlsdesc_dynamic (tlsdesc *) ;
+
+	   The second word of the descriptor points to a
+	   tlsdesc_dynamic_arg structure.
+
+	   Returns the offset between the thread pointer and the
+	   object referenced by the argument.
+
+	   ptrdiff_t
+	   _dl_tlsdesc_dynamic (struct tlsdesc *tdp)
+	   {
+	     struct tlsdesc_dynamic_arg *td = tdp->arg;
+	     dtv_t *dtv = *(dtv_t **)((char *)__thread_pointer - TCBHEAD_DTV);
+	     if (__glibc_likely (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
+		- __thread_pointer;
+
+	     return ___tls_get_addr (&td->tlsinfo) - __thread_pointer;
+	   }  */
+	.hidden _dl_tlsdesc_dynamic
+	.global	_dl_tlsdesc_dynamic
+	.type	_dl_tlsdesc_dynamic,%function
+	cfi_startproc
+	.align 2
+_dl_tlsdesc_dynamic:
+	/* Save just enough registers to support fast path, if we fall
+	   into slow path we will save additional registers.  */
+	ADDI	sp, sp, -24
+	REG_S	t0, sp, 0
+	REG_S	t1, sp, 8
+	REG_S	t2, sp, 16
+
+/* Runtime Storage Layout of Thread-Local Storage
+   TP point to the start of TLS block.
+
+				      dtv
+Low address	TCB ----------------> dtv0(counter)
+	 TP -->	static_block0  <----- dtv1
+		static_block1  <----- dtv2
+		static_block2  <----- dtv3
+		dynamic_block0 <----- dtv4
+Hign address	dynamic_block1 <----- dtv5  */
+
+	REG_L	t0, tp, -SIZE_OF_TCB	  /* t0 = dtv */
+	REG_L	a0, a0, TLSDESC_ARG	  /* a0(td) = tdp->arg */
+	REG_L	t1, a0, TLSDESC_GEN_COUNT /* t1 = td->gen_count */
+	REG_L	t2, t0, DTV_COUNTER	  /* t2 = dtv[0].counter */
+	/* If dtv[0].counter < td->gen_count, goto slow path.  */
+	bltu	t2, t1, .Lslow
+
+	REG_L	t1, a0, TLSDESC_MODID /* t1 = td->tlsinfo.ti_module */
+	/* t1 = t1 * sizeof(dtv_t) = t1 * (2 * sizeof(void*)) */
+	slli.d	t1, t1, 4
+	add.d	t1, t1, t0  /* t1 = dtv[td->tlsinfo.ti_module] */
+	REG_L	t1, t1, 0   /* t1 = dtv[td->tlsinfo.ti_module].pointer.val */
+	li.d	t2, TLS_DTV_UNALLOCATED
+	/* If dtv[td->tlsinfo.ti_module].pointer.val is TLS_DTV_UNALLOCATED,
+	   goto slow path.  */
+	beq	t1, t2, .Lslow
+
+	REG_L	t2, a0, TLSDESC_MODOFF	/* t2 = td->tlsinfo.ti_offset */
+	/* dtv[td->tlsinfo.ti_module].pointer.val + td->tlsinfo.ti_offset */
+	add.d	a0, t1, t2
+.Lret:
+	sub.d	a0, a0, tp
+	REG_L	t0, sp, 0
+	REG_L	t1, sp, 8
+	REG_L	t2, sp, 16
+	ADDI	sp, sp, 24
+	RET
+
+.Lslow:
+	/* This is the slow path. We need to call __tls_get_addr() which
+	   means we need to save and restore all the register that the
+	   callee will trash.  */
+
+	/* Save the remaining registers that we must treat as caller save.  */
+	ADDI	sp, sp, -FRAME_SIZE
+	REG_S	ra, sp, 0 * SZREG
+	REG_S	a1, sp, 1 * SZREG
+	REG_S	a2, sp, 2 * SZREG
+	REG_S	a3, sp, 3 * SZREG
+	REG_S	a4, sp, 4 * SZREG
+	REG_S	a5, sp, 5 * SZREG
+	REG_S	a6, sp, 6 * SZREG
+	REG_S	a7, sp, 7 * SZREG
+	REG_S	t3, sp, 8 * SZREG
+	REG_S	t4, sp, 9 * SZREG
+	REG_S	t5, sp, 10 * SZREG
+	REG_S	t6, sp, 11 * SZREG
+	REG_S	t7, sp, 12 * SZREG
+	REG_S	t8, sp, 13 * SZREG
+
+#ifndef __loongarch_soft_float
+
+	/* Save fcsr0 register.
+	   Only one physical fcsr0 register, fcsr1-fcsr3 are aliases
+	   of some fields in fcsr0.  */
+	ADDI	sp, sp, -SZFCSREG
+	movfcsr2gr  t0, fcsr0
+	st.w	t0, sp, 0
+
+	/* Whether support LASX.  */
+	la.global   t0, _rtld_global_ro
+	REG_L	t0, t0, GLRO_DL_HWCAP_OFFSET
+	andi	t0, t0, HWCAP_LOONGARCH_LASX
+	beqz	t0, .Llsx
+
+	/* Save 256-bit vector registers.
+	   FIXME: Without vector ABI, save all vector registers.  */
+	ADDI	sp, sp, -FRAME_SIZE_LASX
+	xvst	xr0, sp, 0*SZXREG
+	xvst	xr1, sp, 1*SZXREG
+	xvst	xr2, sp, 2*SZXREG
+	xvst	xr3, sp, 3*SZXREG
+	xvst	xr4, sp, 4*SZXREG
+	xvst	xr5, sp, 5*SZXREG
+	xvst	xr6, sp, 6*SZXREG
+	xvst	xr7, sp, 7*SZXREG
+	xvst	xr8, sp, 8*SZXREG
+	xvst	xr9, sp, 9*SZXREG
+	xvst	xr10, sp, 10*SZXREG
+	xvst	xr11, sp, 11*SZXREG
+	xvst	xr12, sp, 12*SZXREG
+	xvst	xr13, sp, 13*SZXREG
+	xvst	xr14, sp, 14*SZXREG
+	xvst	xr15, sp, 15*SZXREG
+	xvst	xr16, sp, 16*SZXREG
+	xvst	xr17, sp, 17*SZXREG
+	xvst	xr18, sp, 18*SZXREG
+	xvst	xr19, sp, 19*SZXREG
+	xvst	xr20, sp, 20*SZXREG
+	xvst	xr21, sp, 21*SZXREG
+	xvst	xr22, sp, 22*SZXREG
+	xvst	xr23, sp, 23*SZXREG
+	xvst	xr24, sp, 24*SZXREG
+	xvst	xr25, sp, 25*SZXREG
+	xvst	xr26, sp, 26*SZXREG
+	xvst	xr27, sp, 27*SZXREG
+	xvst	xr28, sp, 28*SZXREG
+	xvst	xr29, sp, 29*SZXREG
+	xvst	xr30, sp, 30*SZXREG
+	xvst	xr31, sp, 31*SZXREG
+	b	    .Ltga
+
+.Llsx:
+	/* Whether support LSX.  */
+	andi	t0, t0, HWCAP_LOONGARCH_LSX
+	beqz	t0, .Lfloat
+
+	/* Save 128-bit vector registers.  */
+	ADDI	sp, sp, -FRAME_SIZE_LSX
+	vst	vr0, sp, 0*SZVREG
+	vst	vr1, sp, 1*SZVREG
+	vst	vr2, sp, 2*SZVREG
+	vst	vr3, sp, 3*SZVREG
+	vst	vr4, sp, 4*SZVREG
+	vst	vr5, sp, 5*SZVREG
+	vst	vr6, sp, 6*SZVREG
+	vst	vr7, sp, 7*SZVREG
+	vst	vr8, sp, 8*SZVREG
+	vst	vr9, sp, 9*SZVREG
+	vst	vr10, sp, 10*SZVREG
+	vst	vr11, sp, 11*SZVREG
+	vst	vr12, sp, 12*SZVREG
+	vst	vr13, sp, 13*SZVREG
+	vst	vr14, sp, 14*SZVREG
+	vst	vr15, sp, 15*SZVREG
+	vst	vr16, sp, 16*SZVREG
+	vst	vr17, sp, 17*SZVREG
+	vst	vr18, sp, 18*SZVREG
+	vst	vr19, sp, 19*SZVREG
+	vst	vr20, sp, 20*SZVREG
+	vst	vr21, sp, 21*SZVREG
+	vst	vr22, sp, 22*SZVREG
+	vst	vr23, sp, 23*SZVREG
+	vst	vr24, sp, 24*SZVREG
+	vst	vr25, sp, 25*SZVREG
+	vst	vr26, sp, 26*SZVREG
+	vst	vr27, sp, 27*SZVREG
+	vst	vr28, sp, 28*SZVREG
+	vst	vr29, sp, 29*SZVREG
+	vst	vr30, sp, 30*SZVREG
+	vst	vr31, sp, 31*SZVREG
+	b	    .Ltga
+
+.Lfloat:
+	/* Save float registers.  */
+	ADDI	sp, sp, -FRAME_SIZE_FLOAT
+	FREG_S	fa0, sp, 0*SZFREG
+	FREG_S	fa1, sp, 1*SZFREG
+	FREG_S	fa2, sp, 2*SZFREG
+	FREG_S	fa3, sp, 3*SZFREG
+	FREG_S	fa4, sp, 4*SZFREG
+	FREG_S	fa5, sp, 5*SZFREG
+	FREG_S	fa6, sp, 6*SZFREG
+	FREG_S	fa7, sp, 7*SZFREG
+	FREG_S	ft0, sp, 8*SZFREG
+	FREG_S	ft1, sp, 9*SZFREG
+	FREG_S	ft2, sp, 10*SZFREG
+	FREG_S	ft3, sp, 11*SZFREG
+	FREG_S	ft4, sp, 12*SZFREG
+	FREG_S	ft5, sp, 13*SZFREG
+	FREG_S	ft6, sp, 14*SZFREG
+	FREG_S	ft7, sp, 15*SZFREG
+	FREG_S	ft8, sp, 16*SZFREG
+	FREG_S	ft9, sp, 17*SZFREG
+	FREG_S	ft10, sp, 18*SZFREG
+	FREG_S	ft11, sp, 19*SZFREG
+	FREG_S	ft12, sp, 20*SZFREG
+	FREG_S	ft13, sp, 21*SZFREG
+	FREG_S	ft14, sp, 22*SZFREG
+	FREG_S	ft15, sp, 23*SZFREG
+
+#endif /* #ifndef __loongarch_soft_float */
+
+.Ltga:
+	bl	HIDDEN_JUMPTARGET(__tls_get_addr)
+	ADDI	a0, a0, -TLS_DTV_OFFSET
+
+#ifndef __loongarch_soft_float
+
+	la.global   t0, _rtld_global_ro
+	REG_L	t0, t0, GLRO_DL_HWCAP_OFFSET
+	andi	t0, t0, HWCAP_LOONGARCH_LASX
+	beqz	t0, .Llsx1
+
+	/* Restore 256-bit vector registers.  */
+	xvld	xr0, sp, 0*SZXREG
+	xvld	xr1, sp, 1*SZXREG
+	xvld	xr2, sp, 2*SZXREG
+	xvld	xr3, sp, 3*SZXREG
+	xvld	xr4, sp, 4*SZXREG
+	xvld	xr5, sp, 5*SZXREG
+	xvld	xr6, sp, 6*SZXREG
+	xvld	xr7, sp, 7*SZXREG
+	xvld	xr8, sp, 8*SZXREG
+	xvld	xr9, sp, 9*SZXREG
+	xvld	xr10, sp, 10*SZXREG
+	xvld	xr11, sp, 11*SZXREG
+	xvld	xr12, sp, 12*SZXREG
+	xvld	xr13, sp, 13*SZXREG
+	xvld	xr14, sp, 14*SZXREG
+	xvld	xr15, sp, 15*SZXREG
+	xvld	xr16, sp, 16*SZXREG
+	xvld	xr17, sp, 17*SZXREG
+	xvld	xr18, sp, 18*SZXREG
+	xvld	xr19, sp, 19*SZXREG
+	xvld	xr20, sp, 20*SZXREG
+	xvld	xr21, sp, 21*SZXREG
+	xvld	xr22, sp, 22*SZXREG
+	xvld	xr23, sp, 23*SZXREG
+	xvld	xr24, sp, 24*SZXREG
+	xvld	xr25, sp, 25*SZXREG
+	xvld	xr26, sp, 26*SZXREG
+	xvld	xr27, sp, 27*SZXREG
+	xvld	xr28, sp, 28*SZXREG
+	xvld	xr29, sp, 29*SZXREG
+	xvld	xr30, sp, 30*SZXREG
+	xvld	xr31, sp, 31*SZXREG
+	ADDI	sp, sp, FRAME_SIZE_LASX
+	b .Lfcsr
+
+.Llsx1:
+	andi	t0, s0, HWCAP_LOONGARCH_LSX
+	beqz	t0, .Lfloat1
+
+	/* Restore 128-bit vector registers.  */
+	vld	vr0, sp, 0*SZVREG
+	vld	vr1, sp, 1*SZVREG
+	vld	vr2, sp, 2*SZVREG
+	vld	vr3, sp, 3*SZVREG
+	vld	vr4, sp, 4*SZVREG
+	vld	vr5, sp, 5*SZVREG
+	vld	vr6, sp, 6*SZVREG
+	vld	vr7, sp, 7*SZVREG
+	vld	vr8, sp, 8*SZVREG
+	vld	vr9, sp, 9*SZVREG
+	vld	vr10, sp, 10*SZVREG
+	vld	vr11, sp, 11*SZVREG
+	vld	vr12, sp, 12*SZVREG
+	vld	vr13, sp, 13*SZVREG
+	vld	vr14, sp, 14*SZVREG
+	vld	vr15, sp, 15*SZVREG
+	vld	vr16, sp, 16*SZVREG
+	vld	vr17, sp, 17*SZVREG
+	vld	vr18, sp, 18*SZVREG
+	vld	vr19, sp, 19*SZVREG
+	vld	vr20, sp, 20*SZVREG
+	vld	vr21, sp, 21*SZVREG
+	vld	vr22, sp, 22*SZVREG
+	vld	vr23, sp, 23*SZVREG
+	vld	vr24, sp, 24*SZVREG
+	vld	vr25, sp, 25*SZVREG
+	vld	vr26, sp, 26*SZVREG
+	vld	vr27, sp, 27*SZVREG
+	vld	vr28, sp, 28*SZVREG
+	vld	vr29, sp, 29*SZVREG
+	vld	vr30, sp, 30*SZVREG
+	vld	vr31, sp, 31*SZVREG
+	ADDI	sp, sp, FRAME_SIZE_LSX
+	b	    .Lfcsr
+
+.Lfloat1:
+	/* Restore float registers.  */
+	FREG_L	fa0, sp, 0*SZFREG
+	FREG_L	fa1, sp, 1*SZFREG
+	FREG_L	fa2, sp, 2*SZFREG
+	FREG_L	fa3, sp, 3*SZFREG
+	FREG_L	fa4, sp, 4*SZFREG
+	FREG_L	fa5, sp, 5*SZFREG
+	FREG_L	fa6, sp, 6*SZFREG
+	FREG_L	fa7, sp, 7*SZFREG
+	FREG_L	ft0, sp, 8*SZFREG
+	FREG_L	ft1, sp, 9*SZFREG
+	FREG_L	ft2, sp, 10*SZFREG
+	FREG_L	ft3, sp, 11*SZFREG
+	FREG_L	ft4, sp, 12*SZFREG
+	FREG_L	ft5, sp, 13*SZFREG
+	FREG_L	ft6, sp, 14*SZFREG
+	FREG_L	ft7, sp, 15*SZFREG
+	FREG_L	ft8, sp, 16*SZFREG
+	FREG_L	ft9, sp, 17*SZFREG
+	FREG_L	ft10, sp, 18*SZFREG
+	FREG_L	ft11, sp, 19*SZFREG
+	FREG_L	ft12, sp, 20*SZFREG
+	FREG_L	ft13, sp, 21*SZFREG
+	FREG_L	ft14, sp, 22*SZFREG
+	FREG_L	ft15, sp, 23*SZFREG
+	ADDI	sp, sp, FRAME_SIZE_FLOAT
+
+.Lfcsr:
+	/* Restore fcsr0 register.  */
+	ld.w	t0, sp, 0
+	movgr2fcsr  fcsr0, t0
+	ADDI	sp, sp, SZFCSREG
+
+#endif /* #ifndef __loongarch_soft_float */
+
+	REG_L	ra, sp, 0 * SZREG
+	REG_L	a1, sp, 1 * SZREG
+	REG_L	a2, sp, 2 * SZREG
+	REG_L	a3, sp, 3 * SZREG
+	REG_L	a4, sp, 4 * SZREG
+	REG_L	a5, sp, 5 * SZREG
+	REG_L	a6, sp, 6 * SZREG
+	REG_L	a7, sp, 7 * SZREG
+	REG_L	t3, sp, 8 * SZREG
+	REG_L	t4, sp, 9 * SZREG
+	REG_L	t5, sp, 10 * SZREG
+	REG_L	t6, sp, 11 * SZREG
+	REG_L	t7, sp, 12 * SZREG
+	REG_L	t8, sp, 13 * SZREG
+	ADDI	sp, sp, FRAME_SIZE
+
+	b	.Lret
+	cfi_endproc
+	.size	_dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
+	.hidden HIDDEN_JUMPTARGET(__tls_get_addr)
+
+#endif /* #ifdef SHARED */