linux-kernel - [tip:x86/pti] x86/mm/init: Pass unconverted symbol addresses to free_init

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Date:   Sun, 5 Aug 2018 13:31:55 -0700
From:   tip-bot for Dave Hansen <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, aarcange@...hat.com, keescook@...gle.com,
        linux-kernel@...r.kernel.org, mingo@...nel.org,
        gregkh@...uxfoundation.org, luto@...nel.org, hughd@...gle.com,
        torvalds@...ux-foundation.org, dave.hansen@...ux.intel.com,
        peterz@...radead.org, jgross@...e.com, jpoimboe@...hat.com,
        tglx@...utronix.de, ak@...ux.intel.com, bp@...en8.de
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@...ux.intel.com>
AuthorDate: Thu, 2 Aug 2018 15:58:28 -0700
Committer:  Thomas Gleixner <tglx@...utronix.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@...ux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: keescook@...gle.com
Cc: aarcange@...hat.com
Cc: jgross@...e.com
Cc: jpoimboe@...hat.com
Cc: gregkh@...uxfoundation.org
Cc: peterz@...radead.org
Cc: hughd@...gle.com
Cc: torvalds@...ux-foundation.org
Cc: bp@...en8.de
Cc: luto@...nel.org
Cc: ak@...ux.intel.com
Cc: Kees Cook <keescook@...gle.com>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Andi Kleen <ak@...ux.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();