ia64: longjmp_chk: support signal stacks [BZ #16372]

The sp check has to be moved up to the start of the func since it now
makes a system call and that'll clobber a lot of registers.

URL: https://sourceware.org/bugzilla/show_bug.cgi?id=16372
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

NEWS

@@ -23,7 +23,7 @@ Version 2.19
   16038, 16041, 16055, 16071, 16072, 16074, 16077, 16078, 16103, 16112,
   16143, 16144, 16146, 16150, 16151, 16153, 16167, 16172, 16195, 16214,
   16245, 16271, 16274, 16283, 16289, 16293, 16314, 16316, 16330, 16337,
-  16338, 16356, 16369, 16375.
+  16338, 16356, 16369, 16372, 16375.
 
 * Slovenian translations for glibc messages have been contributed by the
   Translation Project's Slovenian team of translators.

ports/ChangeLog.ia64

@@ -1,3 +1,14 @@
+2013-12-30  Mike Frysinger  <vapier@gentoo.org>
+
+	* sysdeps/unix/sysv/linux/ia64/Makefile (gen-as-const-headers): Add
+	sigaltstack-offsets.sym.
+	* sysdeps/unix/sysv/linux/ia64/____longjmp_chk.S: Include new
+	sigaltstack-offsets.h header.
+	(STACK_SPACE): Define.
+	(CHECK_RSP): Rewrite to support sigaltstack.
+	* sysdeps/unix/sysv/linux/ia64/__longjmp.S: Move CHECK_RSP to top.
+	* sysdeps/unix/sysv/linux/ia64/sigaltstack-offsets.sym: New file.
+
 2013-12-30  Mike Frysinger  <vapier@gentoo.org>
 
 	[BZ #16379]

ports/sysdeps/unix/sysv/linux/ia64/Makefile

@@ -10,6 +10,7 @@ endif
 ifeq ($(subdir),misc)
 sysdep_headers += sys/io.h
 sysdep_routines += ioperm clone2
+gen-as-const-headers += sigaltstack-offsets.sym
 endif
 
 ifeq ($(subdir),elf)

ports/sysdeps/unix/sysv/linux/ia64/____longjmp_chk.S

@@ -15,6 +15,8 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <sigaltstack-offsets.h>
+
 	.section .rodata.str1.8,"aMS",@progbits,1
 	.align 8
 .LC0:
@@ -29,13 +31,58 @@ longjmp_msg:
 
 #define __longjmp ____longjmp_chk
 
-#define CHECK_RSP(reg) \
-	cmp.ltu p0, p8 = reg, r12;				\
-(p8)	br.cond.dpnt .Lok;;					\
-	addl r28 = @ltoffx(longjmp_msg#), r1;;			\
-	ld8.mov r28 = [r28], longjmp_msg#;;			\
-	ld8 out0 = [r28];					\
+/* We use 32 bytes (rather than sizeof(stack_t)) so that we keep the stack
+   properly aligned.  But we still want a sanity check to make sure 32 is
+   actually enough.  */
+#define STACK_SPACE ((sizeSS + 31) & -32)
+
+/* Check the stack pointer held in the jumpbuf.  Make sure it's in either the
+   current stack (r12) or in the signal stack.  */
+#define CHECK_RSP						\
+	ld8 loc0 = [in0];					\
+	;;							\
+	/* First see if target stack is within current one.  */	\
+	cmp.ltu p0, p8 = loc0, r12;				\
+(p8)	br.cond.dptk.many .Lok;					\
+								\
+	/* Check if it's an alternative signal stack.  */	\
+	mov out0 = r0;						\
+	add out1 = -STACK_SPACE, r12;				\
+	;;							\
+	mov r12 = out1;						\
+	DO_CALL_VIA_BREAK (SYS_ify (sigaltstack));		\
+	;;							\
+	/* If the syscall failed, then assume it's OK.  */	\
+	cmp.eq p8, p0 = -1, r10;				\
+(p8)	br.cond.spnt .Lok;					\
+	/* Move stack_t into regs.  */				\
+	add r14 = oSS_FLAGS, r12;	/* ss_flags */		\
+	add r15 = oSS_SIZE, r12;	/* ss_size */		\
+	ld8 r16 = [r12];		/* ss_sp */		\
+	;;							\
+	ld4 r17 = [r14];		/* ss_flags */		\
+	ld8 r18 = [r15];		/* ss_size */		\
+	;;							\
+	sub r19 = r16, r18;		/* sp - size */		\
+	/* See if we're currently on the altstack.  */		\
+	tbit.nz p0, p8 = r17, 0;	/* SS_ONSTACK */	\
+(p8)	br.cond.spnt .Lfail;					\
+	/* Verify target is within alternative stack.  */	\
+	cmp.gtu p7, p0 = loc0, r16;				\
+(p7)	br.cond.spnt .Lfail;					\
+	;;							\
+	cmp.ltu p0, p8 = loc0, r19;				\
+(p8)	br.cond.sptk.many .Lok;					\
+	;;							\
+								\
+	/* Still here?  Abort!  */				\
+.Lfail:								\
+	add r12 = STACK_SPACE, r12;				\
+	addl loc0 = @ltoffx(longjmp_msg#), r1;;			\
+	ld8.mov loc0 = [loc0], longjmp_msg#;;			\
+	ld8 out0 = [loc0];					\
 	br.call.sptk.many b0 = HIDDEN_JUMPTARGET(__fortify_fail)#;; \
-.Lok:
+.Lok:								\
+	add r12 = STACK_SPACE, r12;
 
 #include "__longjmp.S"

ports/sysdeps/unix/sysv/linux/ia64/__longjmp.S

@@ -42,9 +42,10 @@
 
 LEAF(__longjmp)
 #ifdef CHECK_RSP
-	alloc r8=ar.pfs,2,1,1,0
+	alloc r8=ar.pfs,2,1,3,0
+	CHECK_RSP
 #else
-	alloc r8=ar.pfs,2,1,0,0
+	alloc r8=ar.pfs,2,0,0,0
 #endif
 	mov r27=ar.rsc
 	add r2=0x98,in0		// r2 <- &jmpbuf.orig_jmp_buf_addr
@@ -79,9 +80,6 @@ LEAF(__longjmp)
 	mov r26=ar.rnat
 	mov ar.unat=r25		// setup ar.unat (NaT bits for r1, r4-r7, and r12)
 	;;
-#ifdef CHECK_RSP
-	CHECK_RSP (r28)
-#endif
 	ld8.fill.nta gp=[r3],32		// r1 (gp)
 	dep r11=-1,r23,3,6	// r11 <- ia64_rse_rnat_addr(jmpbuf.ar_bsp)
 	mov sp=r28		// r12 (sp)

ports/sysdeps/unix/sysv/linux/ia64/sigaltstack-offsets.sym

@@ -0,0 +1,13 @@
+#include <stddef.h>
+#include <signal.h>
+
+--
+
+#define sigaltstack(member)	offsetof (stack_t, member)
+
+sizeSS				sizeof (stack_t)
+oSS_SP				sigaltstack (ss_sp)
+oSS_FLAGS			sigaltstack (ss_flags)
+oSS_SIZE			sigaltstack (ss_size)
+
+SS_ONSTACK