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authorAnton Blanchard <anton@samba.org>2005-05-01 08:58:45 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-01 08:58:45 -0700
commita2f95a5ae99eb8209ad8d9faeaada00600bd8027 (patch)
treec135aff1ea47e57fcdfe22cca12e77738f433d27
parentd03853d566fb32c6bb8cab4bf2ecf53e692f001c (diff)
[PATCH] ppc64: noexec fixes
There were a few issues with the ppc64 noexec support: The 64bit ABI has a non executable stack by default. At the moment 64bit apps require a PT_GNU_STACK section in order to have a non executable stack. Disable the read implies exec workaround on the 64bit ABI. The 64bit toolchain has never had problems with incorrect mmap permissions (the 32bit has, thats why we need to retain the workaround). With these fixes as well as a gcc fix from Alan Modra (that was recently committed) 64bit apps work as expected. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/asm-ppc64/elf.h8
-rw-r--r--include/asm-ppc64/page.h15
2 files changed, 18 insertions, 5 deletions
diff --git a/include/asm-ppc64/elf.h b/include/asm-ppc64/elf.h
index 8457d90244f..6c42d61bedd 100644
--- a/include/asm-ppc64/elf.h
+++ b/include/asm-ppc64/elf.h
@@ -229,9 +229,13 @@ do { \
/*
* An executable for which elf_read_implies_exec() returns TRUE will
- * have the READ_IMPLIES_EXEC personality flag set automatically.
+ * have the READ_IMPLIES_EXEC personality flag set automatically. This
+ * is only required to work around bugs in old 32bit toolchains. Since
+ * the 64bit ABI has never had these issues dont enable the workaround
+ * even if we have an executable stack.
*/
-#define elf_read_implies_exec(ex, exec_stk) (exec_stk != EXSTACK_DISABLE_X)
+#define elf_read_implies_exec(ex, exec_stk) (test_thread_flag(TIF_32BIT) ? \
+ (exec_stk != EXSTACK_DISABLE_X) : 0)
#endif
diff --git a/include/asm-ppc64/page.h b/include/asm-ppc64/page.h
index 20e0f19324e..86219574c1a 100644
--- a/include/asm-ppc64/page.h
+++ b/include/asm-ppc64/page.h
@@ -252,10 +252,19 @@ extern u64 ppc64_pft_size; /* Log 2 of page table size */
/*
* This is the default if a program doesn't have a PT_GNU_STACK
- * program header entry.
+ * program header entry. The PPC64 ELF ABI has a non executable stack
+ * stack by default, so in the absense of a PT_GNU_STACK program header
+ * we turn execute permission off.
*/
-#define VM_STACK_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
- VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+#define VM_STACK_DEFAULT_FLAGS32 (VM_READ | VM_WRITE | VM_EXEC | \
+ VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#define VM_STACK_DEFAULT_FLAGS64 (VM_READ | VM_WRITE | \
+ VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#define VM_STACK_DEFAULT_FLAGS \
+ (test_thread_flag(TIF_32BIT) ? \
+ VM_STACK_DEFAULT_FLAGS32 : VM_STACK_DEFAULT_FLAGS64)
#endif /* __KERNEL__ */
#endif /* _PPC64_PAGE_H */