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authorMark Rutland <mark.rutland@arm.com>2017-07-14 12:23:09 +0100
committerMark Rutland <mark.rutland@arm.com>2017-08-15 18:34:46 +0100
commit48ac3c18cc62d4a23d5dc5c59f8720589d0de14b (patch)
treecf21c9b379b4acf9a509d85f6b5edb02a2b86f80 /kernel/fork.c
parentc5bc503cbeee8586395aa541d2b53c69c3dd6930 (diff)
downloadlinux-48ac3c18cc62d4a23d5dc5c59f8720589d0de14b.tar.bz2
fork: allow arch-override of VMAP stack alignment
In some cases, an architecture might wish its stacks to be aligned to a boundary larger than THREAD_SIZE. For example, using an alignment of double THREAD_SIZE can allow for stack overflows smaller than THREAD_SIZE to be detected by checking a single bit of the stack pointer. This patch allows architectures to override the alignment of VMAP'd stacks, by defining THREAD_ALIGN. Where not defined, this defaults to THREAD_SIZE, as is the case today. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Tested-by: Laura Abbott <labbott@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 17921b0390b4..f12882a2323b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -88,6 +88,7 @@
#include <linux/sysctl.h>
#include <linux/kcov.h>
#include <linux/livepatch.h>
+#include <linux/thread_info.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -217,7 +218,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
return s->addr;
}
- stack = __vmalloc_node_range(THREAD_SIZE, THREAD_SIZE,
+ stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN,
VMALLOC_START, VMALLOC_END,
THREADINFO_GFP,
PAGE_KERNEL,