From 29d4591b07a4da53320e949557c6946c62c26bde Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Thu, 28 Sep 2023 00:07:18 +0200
Subject: [PATCH] hurd: Drop REG_GSFS and REG_ESDS from x86_64's ucontext

These are useless on x86_64, and __NGREG was actually wrong with them.
---
 sysdeps/mach/hurd/x86/trampoline.c         | 4 ++--
 sysdeps/mach/hurd/x86_64/bits/sigcontext.h | 8 +-------
 sysdeps/mach/x86/thread_state.h            | 6 ++++--
 sysdeps/x86_64/sys/ucontext.h              | 6 +-----
 4 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/sysdeps/mach/hurd/x86/trampoline.c b/sysdeps/mach/hurd/x86/trampoline.c
index 6318c95..bc3f15e 100644
--- a/sysdeps/mach/hurd/x86/trampoline.c
+++ b/sysdeps/mach/hurd/x86/trampoline.c
@@ -79,8 +79,8 @@ static void fill_ucontext (ucontext_t *uc, const struct sigcontext *sc)
 
   /* Registers.  */
 #ifdef __x86_64__
-  memcpy (&uc->uc_mcontext.gregs[REG_GSFS], &sc->sc_gs,
-          (REG_ERR - REG_GSFS) * sizeof (long));
+  memcpy (&uc->uc_mcontext.gregs[REG_R8], &sc->sc_r8,
+          (REG_ERR - REG_R8) * sizeof (long));
 #else
   memcpy (&uc->uc_mcontext.gregs[REG_GS], &sc->sc_gs,
           (REG_TRAPNO - REG_GS) * sizeof (int));
diff --git a/sysdeps/mach/hurd/x86_64/bits/sigcontext.h b/sysdeps/mach/hurd/x86_64/bits/sigcontext.h
index 6396054..7facc58 100644
--- a/sysdeps/mach/hurd/x86_64/bits/sigcontext.h
+++ b/sysdeps/mach/hurd/x86_64/bits/sigcontext.h
@@ -59,13 +59,7 @@ struct sigcontext
        }
        trampoline.c knows this, so it must be changed if this changes.  */
 
-#define sc_i386_thread_state sc_gs /* Beginning of correspondence.  */
-    /* Segment registers.  */
-    int sc_gs;
-    int sc_fs;
-    int sc_es;
-    int sc_ds;
-
+#define sc_i386_thread_state sc_r8 /* Beginning of correspondence.  */
     long sc_r8;
     long sc_r9;
     long sc_r10;
diff --git a/sysdeps/mach/x86/thread_state.h b/sysdeps/mach/x86/thread_state.h
index 8c41951..e237e46 100644
--- a/sysdeps/mach/x86/thread_state.h
+++ b/sysdeps/mach/x86/thread_state.h
@@ -34,12 +34,13 @@
 #define PC rip
 #define SP ursp
 #define SYSRETURN rax
+#define MACHINE_THREAD_STATE_FIX_NEW(ts) do { \
+	asm ("mov %%cs, %w0" : "=q" ((ts)->cs)); \
+} while(0)
 #else
 #define PC eip
 #define SP uesp
 #define SYSRETURN eax
-#endif
-
 #define MACHINE_THREAD_STATE_FIX_NEW(ts) do { \
 	asm ("mov %%cs, %w0" : "=q" ((ts)->cs)); \
 	asm ("mov %%ds, %w0" : "=q" ((ts)->ds)); \
@@ -47,6 +48,7 @@
 	asm ("mov %%fs, %w0" : "=q" ((ts)->fs)); \
 	asm ("mov %%gs, %w0" : "=q" ((ts)->gs)); \
 } while(0)
+#endif
 
 struct machine_thread_all_state
   {
diff --git a/sysdeps/x86_64/sys/ucontext.h b/sysdeps/x86_64/sys/ucontext.h
index d73a893..f1b6be7 100644
--- a/sysdeps/x86_64/sys/ucontext.h
+++ b/sysdeps/x86_64/sys/ucontext.h
@@ -47,11 +47,7 @@ typedef greg_t gregset_t[__NGREG];
 /* Number of each register in the `gregset_t' array.  */
 enum
 {
-  REG_GSFS = 0,		/* Actually int gs, fs.  */
-# define REG_GSFS	REG_GSFS
-  REG_ESDS,		/* Actually int es, ds.  */
-# define REG_ESDS	REG_ESDS
-  REG_R8,
+  REG_R8 = 0,
 # define REG_R8		REG_R8
   REG_R9,
 # define REG_R9		REG_R9
-- 
2.7.4