Date: Tue, 18 Oct 2011 12:07:50 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Oliver Pinter <oliver.pntr@gmail.com> Cc: current@freebsd.org Subject: Re: [RFC] Enable nxstack by default Message-ID: <20111018090750.GG50300@deviant.kiev.zoral.com.ua> In-Reply-To: <CAPjTQNFCT5LBKwVQFf9FHk4aTzrJ243j2uN1nPmMeFp=cTdMUA@mail.gmail.com> References: <CAPjTQNFCT5LBKwVQFf9FHk4aTzrJ243j2uN1nPmMeFp=cTdMUA@mail.gmail.com>
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On Mon, Oct 17, 2011 at 09:30:56PM +0200, Oliver Pinter wrote:
> Hi all!
>=20
> I think, it's the time to enable the nxstack feature. Any comments,
> pros, cons?
I dragged the change long enough for it to miss the 9.0.
After the 9.0 is released, I will flip the switch with the following
change.
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 8455f48..926fe64 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -118,7 +118,12 @@ static int elf_legacy_coredump =3D 0;
SYSCTL_INT(_debug, OID_AUTO, __elfN(legacy_coredump), CTLFLAG_RW,=20
&elf_legacy_coredump, 0, "");
=20
-static int __elfN(nxstack) =3D 0;
+int __elfN(nxstack) =3D
+#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 sta=
ck");
diff --git a/sys/powerpc/aim/mmu_oea64.c b/sys/powerpc/aim/mmu_oea64.c
index 7500462..0e27351 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_i=
nt8_t *flags, int wait)
return (void *)va;
}
=20
+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);
}
=20
+ elf32_nxstack =3D 1;
+
moea64_initialized =3D TRUE;
}
=20
diff --git a/sys/powerpc/booke/machdep.c b/sys/powerpc/booke/machdep.c
index c2b5e6f..82a37e1 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);
=20
+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 =3D 1;
}
=20
static char *
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