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authorSteven Rostedt <srostedt@redhat.com>2009-10-27 20:15:11 +0300
committerSteven Rostedt <rostedt@goodmis.org>2009-10-27 20:15:11 +0300
commit883242dd0e5faaba041528a9a99f483f2a656c83 (patch)
tree58002261f3b7335b9dc9f17bdf095997c91da10e /arch/x86/mm/pageattr.c
parent4868402d9582bfb00a5f0157ae5d7ffd2d539fb0 (diff)
downloadlinux-883242dd0e5faaba041528a9a99f483f2a656c83.tar.xz
tracing: allow to change permissions for text with dynamic ftrace enabled
The commit 74e081797bd9d2a7d8005fe519e719df343a2ba8 x86-64: align RODATA kernel section to 2MB with CONFIG_DEBUG_RODATA prevents text sections from becoming read/write using set_memory_rw. The dynamic ftrace changes all text pages to read/write just before converting the calls to tracing to nops, and vice versa. I orginally just added a flag to allow this transaction when ftrace did the change, but I also found that when the CPA testing was running it would remove the read/write as well, and ftrace does not do the text conversion on boot up, and the CPA changes caused the dynamic tracer to fail on self tests. The current solution I have is to simply not to prevent change_page_attr from setting the RW bit for kernel text pages. Reported-by: Ingo Molnar <mingo@elte.hu> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
-rw-r--r--arch/x86/mm/pageattr.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index b494fc4a986e..78d3168b3c64 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -279,7 +279,8 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
__pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
pgprot_val(forbidden) |= _PAGE_RW;
-#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
+#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) && \
+ !defined(CONFIG_DYNAMIC_FTRACE)
/*
* Kernel text mappings for the large page aligned .rodata section
* will be read-only. For the kernel identity mappings covering