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| author | Steven Rostedt <srostedt@redhat.com> | 2009-10-27 20:15:11 +0300 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2009-10-27 20:15:11 +0300 |
| commit | 883242dd0e5faaba041528a9a99f483f2a656c83 (patch) | |
| tree | 58002261f3b7335b9dc9f17bdf095997c91da10e /arch/x86/mm/pageattr.c | |
| parent | 4868402d9582bfb00a5f0157ae5d7ffd2d539fb0 (diff) | |
| download | linux-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.c | 3 |
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 |