linux-kernel - [tip:x86/pti] x86/mm/init: Add helper for freeing kernel image pages

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Message-ID: <tip-6ea2738e0ca0e626c75202fb051c1e88d7a950fa@git.kernel.org>
Date:   Sun, 5 Aug 2018 13:32:25 -0700
From:   tip-bot for Dave Hansen <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     ak@...ux.intel.com, hpa@...or.com, aarcange@...hat.com,
        gregkh@...uxfoundation.org, jgross@...e.com,
        torvalds@...ux-foundation.org, peterz@...radead.org,
        hughd@...gle.com, linux-kernel@...r.kernel.org, tglx@...utronix.de,
        bp@...en8.de, keescook@...gle.com, dave.hansen@...ux.intel.com,
        mingo@...nel.org, jpoimboe@...hat.com, luto@...nel.org
Subject: [tip:x86/pti] x86/mm/init: Add helper for freeing kernel image
 pages

Commit-ID:  6ea2738e0ca0e626c75202fb051c1e88d7a950fa
Gitweb:     https://git.kernel.org/tip/6ea2738e0ca0e626c75202fb051c1e88d7a950fa
Author:     Dave Hansen <dave.hansen@...ux.intel.com>
AuthorDate: Thu, 2 Aug 2018 15:58:29 -0700
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Sun, 5 Aug 2018 22:21:03 +0200

x86/mm/init: Add helper for freeing kernel image pages

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

---
 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(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index cfd29ee8c3da..59663c08c949 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -966,6 +966,7 @@ static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
 
 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
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index cee58a972cb2..bc11dedffc45 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -773,13 +773,22 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 	}
 }
 
+/*
+ * 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
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 73158655c4a7..68c292cb1ebf 100644
--- 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();