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Subject[tip:x86/pti] x86/mm/init: Pass unconverted symbol addresses to free_init_pages()
Commit-ID:  9f515cdb411ef34f1aaf4c40bb0c932cf6db5de1
Gitweb: https://git.kernel.org/tip/9f515cdb411ef34f1aaf4c40bb0c932cf6db5de1
Author: Dave Hansen <dave.hansen@linux.intel.com>
AuthorDate: Thu, 2 Aug 2018 15:58:28 -0700
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 5 Aug 2018 22:21:02 +0200

x86/mm/init: Pass unconverted symbol addresses to free_init_pages()

The x86 code has several places where it frees parts of kernel image:

1. Unused SMP alternative
2. __init code
3. The hole between text and rodata
4. The hole between rodata and data

We call free_init_pages() to do this. Strangely, we convert the symbol
addresses to kernel direct map addresses in some cases (#3, #4) but not
others (#1, #2).

The virt_to_page() and the other code in free_reserved_area() now works
fine for for symbol addresses on x86, so don't bother converting the
addresses to direct map addresses before freeing them.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@google.com
Cc: aarcange@redhat.com
Cc: jgross@suse.com
Cc: jpoimboe@redhat.com
Cc: gregkh@linuxfoundation.org
Cc: peterz@infradead.org
Cc: hughd@google.com
Cc: torvalds@linux-foundation.org
Cc: bp@alien8.de
Cc: luto@kernel.org
Cc: ak@linux.intel.com
Cc: Kees Cook <keescook@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20180802225828.89B2D0E2@viggo.jf.intel.com

---
arch/x86/mm/init_64.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a688617c727e..73158655c4a7 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1283,12 +1283,8 @@ void mark_rodata_ro(void)
set_memory_ro(start, (end-start) >> PAGE_SHIFT);
#endif

- free_init_pages("unused kernel",
- (unsigned long) __va(__pa_symbol(text_end)),
- (unsigned long) __va(__pa_symbol(rodata_start)));
- free_init_pages("unused kernel",
- (unsigned long) __va(__pa_symbol(rodata_end)),
- (unsigned long) __va(__pa_symbol(_sdata)));
+ free_init_pages("unused kernel", text_end, rodata_start);
+ free_init_pages("unused kernel", rodata_end, _sdata);

debug_checkwx();

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