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From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: pasha.tatashin@soleen.com, jmorris@namei.org, sashal@kernel.org,
	ebiederm@xmission.com, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org, corbet@lwn.net,
	catalin.marinas@arm.com, will@kernel.org,
	linux-arm-kernel@lists.infradead.org, maz@kernel.org,
	james.morse@arm.com, vladimir.murzin@arm.com,
	matthias.bgg@gmail.com, linux-mm@kvack.org, mark.rutland@arm.com,
	steve.capper@arm.com, rfontana@redhat.com, tglx@linutronix.de,
	selindag@gmail.com, tyhicks@linux.microsoft.com,
	kernelfans@gmail.com, akpm@linux-foundation.org,
	madvenka@linux.microsoft.com
Subject: [PATCH v16 07/15] arm64: kexec: pass kimage as the only argument to relocation function
Date: Mon,  2 Aug 2021 17:54:00 -0400	[thread overview]
Message-ID: <20210802215408.804942-8-pasha.tatashin@soleen.com> (raw)
In-Reply-To: <20210802215408.804942-1-pasha.tatashin@soleen.com>

Currently, kexec relocation function (arm64_relocate_new_kernel) accepts
the following arguments:

head:		start of array that contains relocation information.
entry:		entry point for new kernel or purgatory.
dtb_mem:	first and only argument to entry.

The number of arguments cannot be easily expended, because this
function is also called from HVC_SOFT_RESTART, which preserves only
three arguments. And, also arm64_relocate_new_kernel is written in
assembly but called without stack, thus no place to move extra arguments
to free registers.

Soon, we will need to pass more arguments: once we enable MMU we
will need to pass information about page tables.

Pass kimage to arm64_relocate_new_kernel, and teach it to get the
required fields from kimage.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/asm-offsets.c     |  7 +++++++
 arch/arm64/kernel/machine_kexec.c   |  7 +++++--
 arch/arm64/kernel/relocate_kernel.S | 10 ++++------
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index c85670692afa..b41409b09d04 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -9,6 +9,7 @@
 
 #include <linux/arm_sdei.h>
 #include <linux/sched.h>
+#include <linux/kexec.h>
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
 #include <linux/kvm_host.h>
@@ -170,6 +171,12 @@ int main(void)
   DEFINE(PTRAUTH_KERNEL_KEY_APIA,	offsetof(struct ptrauth_keys_kernel, apia));
 #endif
   BLANK();
+#endif
+#ifdef CONFIG_KEXEC_CORE
+  DEFINE(KIMAGE_ARCH_DTB_MEM,		offsetof(struct kimage, arch.dtb_mem));
+  DEFINE(KIMAGE_HEAD,			offsetof(struct kimage, head));
+  DEFINE(KIMAGE_START,			offsetof(struct kimage, start));
+  BLANK();
 #endif
   return 0;
 }
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 7f1cb5a2a463..e210b19592c6 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -84,6 +84,9 @@ static void kexec_list_flush(struct kimage *kimage)
 {
 	kimage_entry_t *entry;
 
+	dcache_clean_inval_poc((unsigned long)kimage,
+			       (unsigned long)kimage + sizeof(*kimage));
+
 	for (entry = &kimage->head; ; entry++) {
 		unsigned int flag;
 		unsigned long addr;
@@ -206,8 +209,8 @@ void machine_kexec(struct kimage *kimage)
 		restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem,
 			0, 0);
 	} else {
-		cpu_soft_restart(kimage->arch.kern_reloc, kimage->head,
-				 kimage->start, kimage->arch.dtb_mem);
+		cpu_soft_restart(kimage->arch.kern_reloc, virt_to_phys(kimage),
+				 0, 0);
 	}
 
 	BUG(); /* Should never get here. */
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 8c43779e8cc6..63ea19868f63 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -27,9 +27,7 @@
  */
 SYM_CODE_START(arm64_relocate_new_kernel)
 	/* Setup the list loop variables. */
-	mov	x18, x2				/* x18 = dtb address */
-	mov	x17, x1				/* x17 = kimage_start */
-	mov	x16, x0				/* x16 = kimage_head */
+	ldr	x16, [x0, #KIMAGE_HEAD]		/* x16 = kimage_head */
 	mov	x14, xzr			/* x14 = entry ptr */
 	mov	x13, xzr			/* x13 = copy dest */
 	raw_dcache_line_size x15, x1		/* x15 = dcache line size */
@@ -63,12 +61,12 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	isb
 
 	/* Start new image. */
-	mov	x0, x18
+	ldr	x4, [x0, #KIMAGE_START]		/* relocation start */
+	ldr	x0, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */
 	mov	x1, xzr
 	mov	x2, xzr
 	mov	x3, xzr
-	br	x17
-
+	br	x4
 SYM_CODE_END(arm64_relocate_new_kernel)
 
 .align 3	/* To keep the 64-bit values below naturally aligned. */
-- 
2.25.1


  parent reply	other threads:[~2021-08-02 21:54 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 21:53 [PATCH v16 00/15] arm64: MMU enabled kexec relocation Pavel Tatashin
2021-08-02 21:53 ` [PATCH v16 01/15] arm64: kernel: add helper for booted at EL2 and not VHE Pavel Tatashin
2021-08-02 21:53 ` [PATCH v16 02/15] arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors Pavel Tatashin
2021-08-02 21:53 ` [PATCH v16 03/15] arm64: hibernate: abstract ttrb0 setup function Pavel Tatashin
2021-08-02 21:53 ` [PATCH v16 04/15] arm64: kexec: flush image and lists during kexec load time Pavel Tatashin
2021-08-02 21:53 ` [PATCH v16 05/15] arm64: kexec: skip relocation code for inplace kexec Pavel Tatashin
2021-08-02 21:53 ` [PATCH v16 06/15] arm64: kexec: Use dcache ops macros instead of open-coding Pavel Tatashin
2021-08-02 21:54 ` Pavel Tatashin [this message]
2021-08-02 21:54 ` [PATCH v16 08/15] arm64: kexec: configure EL2 vectors for kexec Pavel Tatashin
2021-08-02 21:54 ` [PATCH v16 09/15] arm64: kexec: relocate in EL1 mode Pavel Tatashin
2021-08-02 21:54 ` [PATCH v16 10/15] arm64: kexec: use ld script for relocation function Pavel Tatashin
2021-08-02 21:54 ` [PATCH v16 11/15] arm64: kexec: install a copy of the linear-map Pavel Tatashin
2021-08-02 21:54 ` [PATCH v16 12/15] arm64: kexec: keep MMU enabled during kexec relocation Pavel Tatashin
2021-08-02 21:54 ` [PATCH v16 13/15] arm64: kexec: remove the pre-kexec PoC maintenance Pavel Tatashin
2021-08-02 21:54 ` [PATCH v16 14/15] arm64: kexec: remove cpu-reset.h Pavel Tatashin
2021-08-02 21:54 ` [PATCH v16 15/15] arm64: trans_pgd: remove trans_pgd_map_page() Pavel Tatashin
2021-08-24 18:05 ` [PATCH v16 00/15] arm64: MMU enabled kexec relocation Catalin Marinas
2021-08-26 15:03   ` Pavel Tatashin
2021-09-16  9:37     ` Catalin Marinas
2021-09-16 22:32       ` Pasha Tatashin
2021-09-08  8:59 ` Pingfan Liu

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