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| author | Mark Rutland <mark.rutland@arm.com> | 2017-07-14 12:23:09 +0100 |
|---|---|---|
| committer | Mark Rutland <mark.rutland@arm.com> | 2017-08-15 18:34:46 +0100 |
| commit | 48ac3c18cc62d4a23d5dc5c59f8720589d0de14b (patch) | |
| tree | cf21c9b379b4acf9a509d85f6b5edb02a2b86f80 /kernel/fork.c | |
| parent | c5bc503cbeee8586395aa541d2b53c69c3dd6930 (diff) | |
| download | lwn-48ac3c18cc62d4a23d5dc5c59f8720589d0de14b.tar.gz lwn-48ac3c18cc62d4a23d5dc5c59f8720589d0de14b.zip | |
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.c | 3 |
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, |