[glibc] Remove the jmp_buf stack pointer demangle on ABIs that do not mangle it

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c626d764d7ea2ffe3e5dd60452435eeaebdf68f6

commit c626d764d7ea2ffe3e5dd60452435eeaebdf68f6
Author: Adhemerval Zanella <[email protected]>
Date:   Fri Jun 12 13:10:13 2026 -0300

    Remove the jmp_buf stack pointer demangle on ABIs that do not mangle it
    
    arc, m68k, microblaze, mips, and riscv store the raw stack pointer in
    setjmp, while their jmpbuf-unwind.h applies PTR_DEMANGLE to it in
    _jmpbuf_sp.  This is currently harmless because these ABIs use the
    generic pointer_guard.h, where the C PTR_DEMANGLE is a no-op.
    
    No functional change.
    
    Reviewed-by: DJ Delorie <[email protected]>

Diff:
---
 sysdeps/arc/jmpbuf-unwind.h        | 7 +++----
 sysdeps/m68k/jmpbuf-unwind.h       | 7 +++----
 sysdeps/microblaze/jmpbuf-unwind.h | 7 +++----
 sysdeps/mips/jmpbuf-unwind.h       | 7 +++----
 sysdeps/riscv/jmpbuf-unwind.h      | 7 +++----
 5 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/sysdeps/arc/jmpbuf-unwind.h b/sysdeps/arc/jmpbuf-unwind.h
index d007c78564..48a9f9a7c5 100644
--- a/sysdeps/arc/jmpbuf-unwind.h
+++ b/sysdeps/arc/jmpbuf-unwind.h
@@ -20,7 +20,6 @@
 #include <jmpbuf-offsets.h>
 #include <stdint.h>
 #include <unwind.h>
-#include <pointer_guard.h>
 
 /* Test if longjmp to JMPBUF would unwind the frame
    containing a local variable at ADDRESS.  */
@@ -31,12 +30,12 @@
 #define _JMPBUF_CFA_UNWINDS_ADJ(_jmpbuf, _context, _adj) \
   _JMPBUF_UNWINDS_ADJ (_jmpbuf, (void *) _Unwind_GetCFA (_context), _adj)
 
+/* setjmp does not mangle the stack pointer on this ABI, so the saved
+   value is used as-is.  */
 static inline uintptr_t __attribute__ ((unused))
 _jmpbuf_sp (__jmp_buf jmpbuf)
 {
-  uintptr_t sp = jmpbuf[JB_SP];
-  PTR_DEMANGLE (sp);
-  return sp;
+  return jmpbuf[JB_SP];
 }
 
 #define _JMPBUF_UNWINDS_ADJ(_jmpbuf, _address, _adj) \
diff --git a/sysdeps/m68k/jmpbuf-unwind.h b/sysdeps/m68k/jmpbuf-unwind.h
index 9c5206fb69..2f4bc71d5b 100644
--- a/sysdeps/m68k/jmpbuf-unwind.h
+++ b/sysdeps/m68k/jmpbuf-unwind.h
@@ -19,7 +19,6 @@
 #include <setjmp.h>
 #include <stdint.h>
 #include <unwind.h>
-#include <pointer_guard.h>
 
 /* Test if longjmp to JMPBUF would unwind the frame
    containing a local variable at ADDRESS.  */
@@ -29,12 +28,12 @@
 #define _JMPBUF_CFA_UNWINDS_ADJ(_jmpbuf, _context, _adj) \
   _JMPBUF_UNWINDS_ADJ (_jmpbuf, (void *) _Unwind_GetCFA (_context), _adj)
 
+/* setjmp does not mangle the stack pointer on this ABI, so the saved
+   value is used as-is.  */
 static inline uintptr_t __attribute__ ((unused))
 _jmpbuf_sp (__jmp_buf regs)
 {
-  uintptr_t sp = (uintptr_t) regs[0].__sp;
-  PTR_DEMANGLE (sp);
-  return sp;
+  return (uintptr_t) regs[0].__sp;
 }
 
 #define _JMPBUF_UNWINDS_ADJ(_jmpbuf, _address, _adj) \
diff --git a/sysdeps/microblaze/jmpbuf-unwind.h b/sysdeps/microblaze/jmpbuf-unwind.h
index cb28dd83ec..9584203257 100644
--- a/sysdeps/microblaze/jmpbuf-unwind.h
+++ b/sysdeps/microblaze/jmpbuf-unwind.h
@@ -20,7 +20,6 @@
 #include <stdint.h>
 #include <unwind.h>
 #include <sysdep.h>
-#include <pointer_guard.h>
 
 /* Test if longjmp to JMPBUF would unwind the frame
    containing a local variable at ADDRESS.  */
@@ -30,12 +29,12 @@
 #define _JMPBUF_CFA_UNWINDS_ADJ(_jmpbuf, _context, _adj) \
   _JMPBUF_UNWINDS_ADJ (_jmpbuf, (void *) _Unwind_GetCFA (_context), _adj)
 
+/* setjmp does not mangle the stack pointer on this ABI, so the saved
+   value is used as-is.  */
 static inline uintptr_t __attribute__ ((unused))
 _jmpbuf_sp (__jmp_buf regs)
 {
-  void *sp = (void *) regs[0].__sp;
-  PTR_DEMANGLE (sp);
-  return (uintptr_t) sp;
+  return (uintptr_t) regs[0].__sp;
 }
 
 #define _JMPBUF_UNWINDS_ADJ(_jmpbuf, _address, _adj) \
diff --git a/sysdeps/mips/jmpbuf-unwind.h b/sysdeps/mips/jmpbuf-unwind.h
index c213c0a97f..039cad5de8 100644
--- a/sysdeps/mips/jmpbuf-unwind.h
+++ b/sysdeps/mips/jmpbuf-unwind.h
@@ -19,7 +19,6 @@
 #include <stdint.h>
 #include <unwind.h>
 #include <sysdep.h>
-#include <pointer_guard.h>
 
 /* Test if longjmp to JMPBUF would unwind the frame
    containing a local variable at ADDRESS.  */
@@ -31,12 +30,12 @@
 		       (void *) (_Unwind_Ptr) _Unwind_GetCFA (_context), \
 		       _adj)
 
+/* setjmp does not mangle the stack pointer on this ABI, so the saved
+   value is used as-is.  */
 static inline uintptr_t __attribute__ ((unused))
 _jmpbuf_sp (__jmp_buf regs)
 {
-  uintptr_t sp = (uintptr_t) regs[0].__sp;
-  PTR_DEMANGLE (sp);
-  return sp;
+  return (uintptr_t) regs[0].__sp;
 }
 
 #define _JMPBUF_UNWINDS_ADJ(_jmpbuf, _address, _adj) \
diff --git a/sysdeps/riscv/jmpbuf-unwind.h b/sysdeps/riscv/jmpbuf-unwind.h
index 1a4de568d2..9676723b57 100644
--- a/sysdeps/riscv/jmpbuf-unwind.h
+++ b/sysdeps/riscv/jmpbuf-unwind.h
@@ -20,7 +20,6 @@
 #include <stdint.h>
 #include <unwind.h>
 #include <sysdep.h>
-#include <pointer_guard.h>
 
 /* Test if longjmp to JMPBUF would unwind the frame
    containing a local variable at ADDRESS.  */
@@ -30,12 +29,12 @@
 #define _JMPBUF_CFA_UNWINDS_ADJ(_jmpbuf, _context, _adj) \
   _JMPBUF_UNWINDS_ADJ (_jmpbuf, (void *) _Unwind_GetCFA (_context), _adj)
 
+/* setjmp does not mangle the stack pointer on this ABI, so the saved
+   value is used as-is.  */
 static inline uintptr_t __attribute__ ((unused))
 _jmpbuf_sp (__jmp_buf regs)
 {
-  uintptr_t sp = regs[0].__sp;
-  PTR_DEMANGLE (sp);
-  return sp;
+  return regs[0].__sp;
 }
 
 #define _JMPBUF_UNWINDS_ADJ(_jmpbuf, _address, _adj) \