linux-kernel - [PATCH v9 14/18] arm64: kexec: offset for relocation function

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Message-Id: <20200326032420.27220-15-pasha.tatashin@soleen.com>
Date:   Wed, 25 Mar 2020 23:24:16 -0400
From:   Pavel Tatashin <pasha.tatashin@...een.com>
To:     pasha.tatashin@...een.com, jmorris@...ei.org, sashal@...nel.org,
        ebiederm@...ssion.com, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org, corbet@....net,
        catalin.marinas@....com, will@...nel.org,
        linux-arm-kernel@...ts.infradead.org, maz@...nel.org,
        james.morse@....com, vladimir.murzin@....com,
        matthias.bgg@...il.com, bhsharma@...hat.com, linux-mm@...ck.org,
        mark.rutland@....com, steve.capper@....com, rfontana@...hat.com,
        tglx@...utronix.de, selindag@...il.com
Subject: [PATCH v9 14/18] arm64: kexec: offset for relocation function

Soon, relocation function will share the same page with EL2 vectors.
Add offset within this page to arm64_relocate_new_kernel, and also
the total size of relocation code which will include both the function
and the EL2 vectors.

Signed-off-by: Pavel Tatashin <pasha.tatashin@...een.com>
---
 arch/arm64/include/asm/kexec.h      |  7 +++++++
 arch/arm64/kernel/machine_kexec.c   | 13 ++++---------
 arch/arm64/kernel/relocate_kernel.S | 16 +++++++++++-----
 3 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 990185744148..d944c2e289b2 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -90,6 +90,13 @@ static inline void crash_prepare_suspend(void) {}
 static inline void crash_post_resume(void) {}
 #endif
 
+#if defined(CONFIG_KEXEC_CORE)
+/* The beginning and size of relcation code to stage 2 kernel */
+extern const unsigned long kexec_relocate_code_size;
+extern const unsigned char kexec_relocate_code_start[];
+extern const unsigned long kexec_kern_reloc_offset;
+#endif
+
 /*
  * kern_reloc_arg is passed to kernel relocation function as an argument.
  * head		kimage->head, allows to traverse through relocation segments.
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index b1122eea627e..ab571fca9bd1 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -23,10 +23,6 @@
 
 #include "cpu-reset.h"
 
-/* Global variables for the arm64_relocate_new_kernel routine. */
-extern const unsigned char arm64_relocate_new_kernel[];
-extern const unsigned long arm64_relocate_new_kernel_size;
-
 /**
  * kexec_image_info - For debugging output.
  */
@@ -82,9 +78,8 @@ int machine_kexec_post_load(struct kimage *kimage)
 	if (!kern_reloc_arg)
 		return -ENOMEM;
 
-	memcpy(reloc_code, arm64_relocate_new_kernel,
-	       arm64_relocate_new_kernel_size);
-	kimage->arch.kern_reloc = __pa(reloc_code);
+	memcpy(reloc_code, kexec_relocate_code_start, kexec_relocate_code_size);
+	kimage->arch.kern_reloc = __pa(reloc_code) + kexec_kern_reloc_offset;
 	kimage->arch.kern_reloc_arg = __pa(kern_reloc_arg);
 	kern_reloc_arg->head = kimage->head;
 	kern_reloc_arg->entry_addr = kimage->start;
@@ -189,7 +184,7 @@ void machine_kexec(struct kimage *kimage)
 		"Some CPUs may be stale, kdump will be unreliable.\n");
 
 	/* Flush the reboot_code_buffer in preparation for its execution. */
-	__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
+	__flush_dcache_area(reboot_code_buffer, kexec_relocate_code_size);
 
 	/*
 	 * Although we've killed off the secondary CPUs, we don't update
@@ -198,7 +193,7 @@ void machine_kexec(struct kimage *kimage)
 	 * the offline CPUs. Therefore, we must use the __* variant here.
 	 */
 	__flush_icache_range((uintptr_t)reboot_code_buffer,
-			     arm64_relocate_new_kernel_size);
+			     kexec_relocate_code_size);
 
 	/* Flush the kimage list and its buffers. */
 	kexec_list_flush(kimage);
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 22ccdcb106d3..aa9f2b2cd77c 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -14,6 +14,9 @@
 #include <asm/page.h>
 #include <asm/sysreg.h>
 
+.globl kexec_relocate_code_start
+kexec_relocate_code_start:
+
 /*
  * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
  *
@@ -86,13 +89,16 @@ ENTRY(arm64_relocate_new_kernel)
 .ltorg
 END(arm64_relocate_new_kernel)
 
-.Lcopy_end:
+.Lkexec_relocate_code_end:
 .org	KEXEC_CONTROL_PAGE_SIZE
 .align 3	/* To keep the 64-bit values below naturally aligned. */
 /*
- * arm64_relocate_new_kernel_size - Number of bytes to copy to the
+ * kexec_relocate_code_size - Number of bytes to copy to the
  * control_code_page.
  */
-.globl arm64_relocate_new_kernel_size
-arm64_relocate_new_kernel_size:
-	.quad	.Lcopy_end - arm64_relocate_new_kernel
+.globl kexec_relocate_code_size
+kexec_relocate_code_size:
+	.quad	.Lkexec_relocate_code_end - kexec_relocate_code_start
+.globl kexec_kern_reloc_offset
+kexec_kern_reloc_offset:
+	.quad	arm64_relocate_new_kernel - kexec_relocate_code_start
-- 
2.17.1