linux-kernel - [PATCH 1/2] ARM: add TEXT_OFFSET to decompressor kexec image structure

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Date:   Thu, 06 Aug 2020 11:12:22 +0100
From:   Russell King <rmk+kernel@...linux.org.uk>
To:     Norbert Lange <nolange79@...il.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Petr Malat <oss@...at.biz>, Kees Cook <keescook@...omium.org>,
        Adam Borowski <kilobyte@...band.pl>,
        Sedat Dilek <sedat.dilek@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Nick Terrell <terrelln@...com>,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 1/2] ARM: add TEXT_OFFSET to decompressor kexec image
 structure

Add the TEXT_OFFSET to the decompressor's kexec image structure to
kexec knows what offset to use.

Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
---
 arch/arm/Makefile                      | 3 +++
 arch/arm/boot/compressed/Makefile      | 1 +
 arch/arm/boot/compressed/vmlinux.lds.S | 3 ++-
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 01ed27a538b4..ab2d66e40b7f 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -139,6 +139,9 @@ head-y		:= arch/arm/kernel/head$(MMUEXT).o
 
 # Text offset. This list is sorted numerically by address in order to
 # provide a means to avoid/resolve conflicts in multi-arch kernels.
+# Note: the 32kB below this value is reserved for use by the kernel
+# during boot, and this offset is critical to the functioning of
+# kexec-tools.
 textofs-y	:= 0x00008000
 # We don't want the htc bootloader to corrupt kernel during resume
 textofs-$(CONFIG_PM_H1940)      := 0x00108000
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 433fb7f04aa5..0890d82b8cf4 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -70,6 +70,7 @@ ZBSSADDR	:= ALIGN(8)
 endif
 
 CPPFLAGS_vmlinux.lds := -DTEXT_START="$(ZTEXTADDR)" -DBSS_START="$(ZBSSADDR)"
+CPPFLAGS_vmlinux.lds += -DTEXT_OFFSET="$(TEXT_OFFSET)"
 
 compress-$(CONFIG_KERNEL_GZIP) = gzip
 compress-$(CONFIG_KERNEL_LZO)  = lzo
diff --git a/arch/arm/boot/compressed/vmlinux.lds.S b/arch/arm/boot/compressed/vmlinux.lds.S
index 09ac33f52814..da1f6fa5345b 100644
--- a/arch/arm/boot/compressed/vmlinux.lds.S
+++ b/arch/arm/boot/compressed/vmlinux.lds.S
@@ -42,10 +42,11 @@ SECTIONS
   }
   .table : ALIGN(4) {
     _table_start = .;
-    LONG(ZIMAGE_MAGIC(4))
+    LONG(ZIMAGE_MAGIC(5))
     LONG(ZIMAGE_MAGIC(0x5a534c4b))
     LONG(ZIMAGE_MAGIC(__piggy_size_addr - _start))
     LONG(ZIMAGE_MAGIC(_kernel_bss_size))
+    LONG(ZIMAGE_MAGIC(TEXT_OFFSET))
     LONG(0)
     _table_end = .;
   }
-- 
2.20.1