4.17-stable review patch. If anyone has any objections, please let me know.
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From: Dave Hansen dave.hansen@linux.intel.com
commit 9f515cdb411ef34f1aaf4c40bb0c932cf6db5de1 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/mm/init_64.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
--- 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();