linux-kernel - [PATCH 4.18 05/22] x86/mm/init: Add helper for freeing kernel image pages

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Message-Id: <20180823074759.514011135@linuxfoundation.org>
Date:   Thu, 23 Aug 2018 09:56:31 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dave Hansen <dave.hansen@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>, keescook@...gle.com,
        aarcange@...hat.com, jgross@...e.com, jpoimboe@...hat.com,
        peterz@...radead.org, hughd@...gle.com,
        torvalds@...ux-foundation.org, bp@...en8.de, luto@...nel.org,
        ak@...ux.intel.com
Subject: [PATCH 4.18 05/22] x86/mm/init: Add helper for freeing kernel image pages

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Hansen <dave.hansen@...ux.intel.com>

commit 6ea2738e0ca0e626c75202fb051c1e88d7a950fa upstream.

When chunks of the kernel image are freed, free_init_pages() is used
directly.  Consolidate the three sites that do this.  Also update the
string to give an incrementally better description of that memory versus
what was there before.

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/20180802225829.FE0E32EA@viggo.jf.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/include/asm/processor.h |    1 +
 arch/x86/mm/init.c               |   15 ++++++++++++---
 arch/x86/mm/init_64.c            |    4 ++--
 3 files changed, 15 insertions(+), 5 deletions(-)

--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -971,6 +971,7 @@ static inline uint32_t hypervisor_cpuid_
 
 extern unsigned long arch_align_stack(unsigned long sp);
 extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
+extern void free_kernel_image_pages(void *begin, void *end);
 
 void default_idle(void);
 #ifdef	CONFIG_XEN
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -775,13 +775,22 @@ void free_init_pages(char *what, unsigne
 	}
 }
 
+/*
+ * begin/end can be in the direct map or the "high kernel mapping"
+ * used for the kernel image only.  free_init_pages() will do the
+ * right thing for either kind of address.
+ */
+void free_kernel_image_pages(void *begin, void *end)
+{
+	free_init_pages("unused kernel image",
+			(unsigned long)begin, (unsigned long)end);
+}
+
 void __ref free_initmem(void)
 {
 	e820__reallocate_tables();
 
-	free_init_pages("unused kernel",
-			(unsigned long)(&__init_begin),
-			(unsigned long)(&__init_end));
+	free_kernel_image_pages(&__init_begin, &__init_end);
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1283,8 +1283,8 @@ void mark_rodata_ro(void)
 	set_memory_ro(start, (end-start) >> PAGE_SHIFT);
 #endif
 
-	free_init_pages("unused kernel", text_end, rodata_start);
-	free_init_pages("unused kernel", rodata_end, _sdata);
+	free_kernel_image_pages((void *)text_end, (void *)rodata_start);
+	free_kernel_image_pages((void *)rodata_end, (void *)_sdata);
 
 	debug_checkwx();