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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 /include/linux/thread_info.h
parentc5bc503cbeee8586395aa541d2b53c69c3dd6930 (diff)
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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 'include/linux/thread_info.h')
-rw-r--r--include/linux/thread_info.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 250a27614328..905d769d8ddc 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -38,6 +38,10 @@ enum {
#ifdef __KERNEL__
+#ifndef THREAD_ALIGN
+#define THREAD_ALIGN THREAD_SIZE
+#endif
+
#ifdef CONFIG_DEBUG_STACK_USAGE
# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \
__GFP_ZERO)