powerpc: Add Strong Access Ordering
Things I don't like about this patch:
1. All the includes I added to asm-powerpc/mman.h
2. It doesn't look like mmap() used to validate prot. Now instead of
ignoring invalid values, it will return -EINVAL. Could this be a problem?
3. Are these new functions in any hot paths that the extra instructions will
add any significant overhead?
Signed-off-by: Dave Kleikamp <[EMAIL PROTECTED]>
---
arch/powerpc/kernel/syscalls.c | 3 +++
include/asm-powerpc/mman.h | 26 ++++++++++++++++++++++++++
2 files changed, 29 insertions(+)
diff -Nurp linux004/arch/powerpc/kernel/syscalls.c
linux005/arch/powerpc/kernel/syscalls.c
--- linux004/arch/powerpc/kernel/syscalls.c 2008-06-05 10:07:32.000000000
-0500
+++ linux005/arch/powerpc/kernel/syscalls.c 2008-06-10 16:48:59.000000000
-0500
@@ -143,6 +143,9 @@ static inline unsigned long do_mmap2(uns
struct file * file = NULL;
unsigned long ret = -EINVAL;
+ if (!arch_validate_prot(prot))
+ goto out;
+
if (shift) {
if (off & ((1 << shift) - 1))
goto out;
diff -Nurp linux004/include/asm-powerpc/mman.h
linux005/include/asm-powerpc/mman.h
--- linux004/include/asm-powerpc/mman.h 2008-06-10 16:48:59.000000000 -0500
+++ linux005/include/asm-powerpc/mman.h 2008-06-10 16:48:59.000000000 -0500
@@ -1,7 +1,9 @@
#ifndef _ASM_POWERPC_MMAN_H
#define _ASM_POWERPC_MMAN_H
+#include <asm/cputable.h>
#include <asm-generic/mman.h>
+#include <linux/mm.h>
/*
* This program is free software; you can redistribute it and/or
@@ -26,4 +28,28 @@
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
+#define HAVE_ARCH_PROT_BITS
+
+/*
+ * This file is included by linux/mman.h, so we can't use cacl_vm_prot_bits()
+ * here. How important is the optimization?
+ */
+static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot)
+{
+ return (prot & PROT_SAO) ? VM_SAO : 0;
+}
+
+static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
+{
+ return (vm_flags & VM_SAO) ? __pgprot(_PAGE_SAO) : 0;
+}
+
+static inline int arch_validate_prot(unsigned long prot)
+{
+ if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM | PROT_SAO))
+ return 1;
+ if ((prot & PROT_SAO) && !cpu_has_feature(CPU_FTR_SAO))
+ return 1;
+ return 0;
+}
#endif /* _ASM_POWERPC_MMAN_H */
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