Subject: [PATCH 68/91] um: increase stack growth cushion in pagefault

Subject: [PATCH 68/91] um: increase stack growth cushion in pagefault

[Al Viro]

analog of [PATCH] i386: let usermode execute the "enter" instruction from
circa 2006.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/x86/um/asm/processor.h    |    3 +++
 arch/x86/um/asm/processor_32.h |    3 ---
 arch/x86/um/asm/processor_64.h |    3 ---
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/um/asm/processor.h b/arch/x86/um/asm/processor.h
index d3ac1ce..f34c4b2 100644
--- a/arch/x86/um/asm/processor.h
+++ b/arch/x86/um/asm/processor.h
@@ -10,6 +10,9 @@
 # include "processor_64.h"
 #endif
 
+#define ARCH_IS_STACKGROW(address) \
+       (address + 65536 + 32 * sizeof(unsigned long) >= UPT_SP(&current->thread.regs.regs))
+
 #include <asm/processor-generic.h>
 
 #endif
diff --git a/arch/x86/um/asm/processor_32.h b/arch/x86/um/asm/processor_32.h
index ae0d189..e5b72fa 100644
--- a/arch/x86/um/asm/processor_32.h
+++ b/arch/x86/um/asm/processor_32.h
@@ -63,9 +63,6 @@ static inline void rep_nop(void)
 #define current_text_addr() \
 	({ void *pc; __asm__("movl $1f,%0\n1:":"=g" (pc)); pc; })
 
-#define ARCH_IS_STACKGROW(address) \
-       (address + 32 >= UPT_SP(&current->thread.regs.regs))
-
 #define KSTK_EIP(tsk) KSTK_REG(tsk, EIP)
 #define KSTK_ESP(tsk) KSTK_REG(tsk, UESP)
 #define KSTK_EBP(tsk) KSTK_REG(tsk, EBP)
diff --git a/arch/x86/um/asm/processor_64.h b/arch/x86/um/asm/processor_64.h
index 6db812b..0186c61 100644
--- a/arch/x86/um/asm/processor_64.h
+++ b/arch/x86/um/asm/processor_64.h
@@ -42,9 +42,6 @@ static inline void arch_copy_thread(struct arch_thread *from,
 #define current_text_addr() \
 	({ void *pc; __asm__("movq $1f,%0\n1:":"=g" (pc)); pc; })
 
-#define ARCH_IS_STACKGROW(address) \
-        (address + 128 >= UPT_SP(&current->thread.regs.regs))
-
 #define KSTK_EIP(tsk) KSTK_REG(tsk, RIP)
 #define KSTK_ESP(tsk) KSTK_REG(tsk, RSP)
 
-- 
1.7.2.5