[SRU][Xenial][PATCH 2/2] arm64: compat: Provide definition for COMPAT_SIGMINSTKSZ

[Juerg Haefliger]

From: Will Deacon <will.deacon at arm.com>

https://bugs.launchpad.net/bugs/1844155

arch/arm/ defines a SIGMINSTKSZ of 2k, so we should use the same value
for compat tasks.

Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Dominik Brodowski <linux at dominikbrodowski.net>
Cc: "Eric W. Biederman" <ebiederm at xmission.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Al Viro <viro at zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg at redhat.com>
Reviewed-by: Dave Martin <Dave.Martin at arm.com>
Reported-by: Steve McIntyre <steve.mcintyre at arm.com>
Tested-by: Steve McIntyre <93sam at debian.org>
Signed-off-by: Will Deacon <will.deacon at arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>

(cherry picked from commit 24951465cbd279f60b1fdc2421b3694405bcff42)
Signed-off-by: Juerg Haefliger <juergh at canonical.com>
---
 arch/arm64/include/asm/compat.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index eb8432bb82b8..b69e27152ea5 100644
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -234,6 +234,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
 }
 
 #define compat_user_stack_pointer() (user_stack_pointer(task_pt_regs(current)))
+#define COMPAT_MINSIGSTKSZ	2048
 
 static inline void __user *arch_compat_alloc_user_space(long len)
 {
-- 
2.20.1