From c667987391a179b4c5468fec37d42866569a062b Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Tue, 17 Jan 2023 18:56:51 -0800
Subject: [PATCH] ircd: Update x86_64 jump_fcontext stack offset. (boost-1.81)

---
 ircd/Makefile.am  |  2 +-
 ircd/ctx_x86_64.S | 25 +++++++++++++++++++------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/ircd/Makefile.am b/ircd/Makefile.am
index 868e7c16d..66cd54a7c 100644
--- a/ircd/Makefile.am
+++ b/ircd/Makefile.am
@@ -278,7 +278,7 @@ if OPENCL
 cl.lo:                AM_CPPFLAGS := @OPENCL_CPPFLAGS@ ${AM_CPPFLAGS}
 endif
 client.lo:            AM_CPPFLAGS := ${AM_CPPFLAGS} ${ASIO_UNIT_CPPFLAGS}
-ctx_x86_64.lo:        AM_CPPFLAGS := -I$(top_srcdir)/include
+ctx_x86_64.lo:        AM_CPPFLAGS := -I$(top_srcdir)/include ${BOOST_CPPFLAGS}
 ctx.lo:               AM_CPPFLAGS := ${AM_CPPFLAGS} ${ASIO_UNIT_CPPFLAGS}
 ctx_ole.lo:           AM_CPPFLAGS := ${AM_CPPFLAGS} ${ASIO_UNIT_CPPFLAGS}
 ctx_eh.lo:            AM_CPPFLAGS := ${AM_CPPFLAGS} ${ASIO_UNIT_CPPFLAGS}
diff --git a/ircd/ctx_x86_64.S b/ircd/ctx_x86_64.S
index 248853fb4..54aab8b90 100644
--- a/ircd/ctx_x86_64.S
+++ b/ircd/ctx_x86_64.S
@@ -13,11 +13,24 @@
 //
 
 #include <ircd/config.h>
+#include <boost/version.hpp>
 #if defined(__x86_64__) && defined(__ELF__)
 
 .file "ctx_x86_64.S"
 .globl jump_fcontext
 
+// Sizes of additional items saved on context switch
+.equiv x87_ctrl_sz, 0x04
+.equiv mmx_ctrl_sz, 0x04
+.equiv stack_prot_sz, 0x08
+
+// Total size of all additional items
+.if BOOST_VERSION >= 108100
+.equiv alloc_sz, x87_ctrl_sz + mmx_ctrl_sz + stack_prot_sz
+.else
+.equiv alloc_sz, x87_ctrl_sz + mmx_ctrl_sz
+.endif
+
 .text
 .type jump_fcontext, @function
 
@@ -32,15 +45,15 @@ jump_fcontext:
 	push      %r14                     // store r14 0x18
 	push      %r13                     // store r13 0x10
 	push      %r12                     // store r12 0x08
-	subq      $0x08, %rsp              // alloc fc_mxcsr | fc_x87_cw
-//	fnstcw    0x04(%rsp)               // store x87 control-word
-//	stmxcsr   0x00(%rsp)               // store MMX control- and status-word
+	subq      $alloc_sz, %rsp          // additional allocation
+	fnstcw    0x04(%rsp)               // store x87 control-word
+	stmxcsr   0x00(%rsp)               // store MMX control- and status-word
 	xchgq     %rsp, %rdi               // swap stack
 	movq      %rsi, %rdx               // store transfer_t.data (retval)
 	movq      %rdi, %rax               // store transfer_t.fctx (retval)
-//	ldmxcsr   0x00(%rsp)               // load MMX control- and status-word
-//	fldcw     0x04(%rsp)               // load x87 control-word
-	addq      $0x08, %rsp              // free fc_mxcsr | fc_x87_cw
+	ldmxcsr   0x00(%rsp)               // load MMX control- and status-word
+	fldcw     0x04(%rsp)               // load x87 control-word
+	addq      $alloc_sz, %rsp          // free allocation
 	pop       %r12                     // load r12                    <-- LLd miss
 	pop       %r13                     // load r13
 	pop       %r14                     // load r14