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authorWill Newton <will.newton@linaro.org>2013-08-07 13:55:30 +0100
committerWill Newton <will.newton@linaro.org>2013-10-03 11:35:50 +0100
commitb7f2d27dbd85f6a0966dc389ad4f8205085b7ae8 (patch)
tree5d08889f9d642580e01d529303ed56409982a221 /ports/sysdeps/arm/jmpbuf-unwind.h
parent29c793b3c2947badd9d05e45736e406fb12021e8 (diff)
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ARM: Add pointer encryption support.
Add support for pointer encryption in glibc internal structures in C
and assembler code. Pointer encryption is a glibc security feature
described here:

https://sourceware.org/glibc/wiki/PointerEncryption

The ARM implementation uses global variables instead of thread pointer
relative accesses to get the value of the pointer encryption guard
because accessing the thread pointer can be very expensive on older
ARM cores.

ports/ChangeLog.arm:

2013-10-03  Will Newton  <will.newton@linaro.org>

	* sysdeps/arm/__longjmp.S (__longjmp): Demangle fp, sp
	and lr when restoring register values.
	* sysdeps/arm/include/bits/setjmp.h (JMP_BUF_REGLIST): Remove
	sp and lr from list and replace fp with a4.
	* sysdeps/arm/jmpbuf-unwind.h (_jmpbuf_sp): New function.
	(_JMPBUF_UNWINDS_ADJ): Call _jmpbuf_sp.
	* sysdeps/arm/setjmp.S (__sigsetjmp): Mangle fp, sp and lr
	before storing register values.
	* sysdeps/arm/sysdep.h (LDST_GLOBAL): New macro.
	* sysdeps/unix/sysv/linux/arm/sysdep.h (PTR_MANGLE): New macro.
	(PTR_DEMANGLE): Likewise. (PTR_MANGLE2): Likewise.
	(PTR_DEMANGLE2): Likewise.
Diffstat (limited to 'ports/sysdeps/arm/jmpbuf-unwind.h')
-rw-r--r--ports/sysdeps/arm/jmpbuf-unwind.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/ports/sysdeps/arm/jmpbuf-unwind.h b/ports/sysdeps/arm/jmpbuf-unwind.h
index 0863540ce0..1b0d0202e3 100644
--- a/ports/sysdeps/arm/jmpbuf-unwind.h
+++ b/ports/sysdeps/arm/jmpbuf-unwind.h
@@ -17,6 +17,7 @@
 
 #include <setjmp.h>
 #include <stdint.h>
+#include <sysdep.h>
 #include <unwind.h>
 
 /* Test if longjmp to JMPBUF would unwind the frame
@@ -27,8 +28,18 @@
 #define _JMPBUF_CFA_UNWINDS_ADJ(_jmpbuf, _context, _adj) \
   _JMPBUF_UNWINDS_ADJ (_jmpbuf, (void *) _Unwind_GetCFA (_context), _adj)
 
+static inline uintptr_t __attribute__ ((unused))
+_jmpbuf_sp (__jmp_buf regs)
+{
+  uintptr_t sp = regs[__JMP_BUF_SP];
+#ifdef PTR_DEMANGLE
+  PTR_DEMANGLE (sp);
+#endif
+  return sp;
+}
+
 #define _JMPBUF_UNWINDS_ADJ(_jmpbuf, _address, _adj) \
-  ((uintptr_t) (_address) - (_adj) < (uintptr_t) (_jmpbuf)[__JMP_BUF_SP] - (_adj))
+  ((uintptr_t) (_address) - (_adj) < _jmpbuf_sp (_jmpbuf) - (_adj))
 
 /* We use the normal longjmp for unwinding.  */
 #define __libc_unwind_longjmp(buf, val) __libc_longjmp (buf, val)