From 62c625fdd2ac776887c48af9cc758f6cc5e97699 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Mon, 30 Jan 2012 07:56:00 +0000
Subject: [PATCH] Finally, try to enable the nxstacks on amd64 and powerpc64
 for both 64bit and 32bit ABIs. Also try to enable nxstacks for PAE/i386 when
 supported, and some variants of powerpc32.

MFC after:	2 months (if ever)
---
 sys/i386/i386/initcpu.c     | 3 +++
 sys/kern/imgact_elf.c       | 7 ++++++-
 sys/powerpc/aim/mmu_oea64.c | 4 ++++
 sys/powerpc/booke/machdep.c | 5 +++++
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/sys/i386/i386/initcpu.c b/sys/i386/i386/initcpu.c
index c2daf54371f..ec77adbea91 100644
--- a/sys/i386/i386/initcpu.c
+++ b/sys/i386/i386/initcpu.c
@@ -650,6 +650,8 @@ enable_sse(void)
 #endif
 }
 
+extern int elf32_nxstack;
+
 void
 initializecpu(void)
 {
@@ -739,6 +741,7 @@ initializecpu(void)
 			msr = rdmsr(MSR_EFER) | EFER_NXE;
 			wrmsr(MSR_EFER, msr);
 			pg_nx = PG_NX;
+			elf32_nxstack = 1;
 		}
 #endif
 		break;
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 4da2ad785a4..bde590cda8a 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -118,7 +118,12 @@ static int elf_legacy_coredump = 0;
 SYSCTL_INT(_debug, OID_AUTO, __elfN(legacy_coredump), CTLFLAG_RW, 
     &elf_legacy_coredump, 0, "");
 
-static int __elfN(nxstack) = 0;
+int __elfN(nxstack) =
+#if defined(__amd64__) || defined(__powerpc64__) /* both 64 and 32 bit */
+	1;
+#else
+	0;
+#endif
 SYSCTL_INT(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO,
     nxstack, CTLFLAG_RW, &__elfN(nxstack), 0,
     __XSTRING(__CONCAT(ELF, __ELF_WORD_SIZE)) ": enable non-executable stack");
diff --git a/sys/powerpc/aim/mmu_oea64.c b/sys/powerpc/aim/mmu_oea64.c
index d58e8dee164..efe091f6ccc 100644
--- a/sys/powerpc/aim/mmu_oea64.c
+++ b/sys/powerpc/aim/mmu_oea64.c
@@ -1445,6 +1445,8 @@ moea64_uma_page_alloc(uma_zone_t zone, int bytes, u_int8_t *flags, int wait)
 	return (void *)va;
 }
 
+extern int elf32_nxstack;
+
 void
 moea64_init(mmu_t mmu)
 {
@@ -1464,6 +1466,8 @@ moea64_init(mmu_t mmu)
 		uma_zone_set_allocf(moea64_mpvo_zone,moea64_uma_page_alloc);
 	}
 
+	elf32_nxstack = 1;
+
 	moea64_initialized = TRUE;
 }
 
diff --git a/sys/powerpc/booke/machdep.c b/sys/powerpc/booke/machdep.c
index c2b5e6fa626..82a37e14100 100644
--- a/sys/powerpc/booke/machdep.c
+++ b/sys/powerpc/booke/machdep.c
@@ -192,6 +192,8 @@ void print_kernel_section_addr(void);
 void print_kenv(void);
 u_int booke_init(uint32_t, uint32_t);
 
+extern int elf32_nxstack;
+
 static void
 cpu_e500_startup(void *dummy)
 {
@@ -227,6 +229,9 @@ cpu_e500_startup(void *dummy)
 	/* Set up buffers, so they can be used to read disk labels. */
 	bufinit();
 	vm_pager_bufferinit();
+
+	/* Cpu supports execution permissions on the pages. */
+	elf32_nxstack = 1;
 }
 
 static char *