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From: Pasha 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 v17 09/15] arm64: kexec: relocate in EL1 mode
Date: Thu, 16 Sep 2021 19:13:19 -0400	[thread overview]
Message-ID: <20210916231325.125533-10-pasha.tatashin@soleen.com> (raw)
In-Reply-To: <20210916231325.125533-1-pasha.tatashin@soleen.com>

Since we are going to keep MMU enabled during relocation, we need to
keep EL1 mode throughout the relocation.

Keep EL1 enabled, and switch EL2 only before entering the new world.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/cpu-reset.h       |  3 +--
 arch/arm64/kernel/machine_kexec.c   |  4 ++--
 arch/arm64/kernel/relocate_kernel.S | 13 +++++++++++--
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
index 81b3d0fe7a63..296abbac7192 100644
--- a/arch/arm64/kernel/cpu-reset.h
+++ b/arch/arm64/kernel/cpu-reset.h
@@ -20,11 +20,10 @@ static inline void __noreturn __nocfi cpu_soft_restart(unsigned long entry,
 {
 	typeof(__cpu_soft_restart) *restart;
 
-	unsigned long el2_switch = is_hyp_nvhe();
 	restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart));
 
 	cpu_install_idmap();
-	restart(el2_switch, entry, arg0, arg1, arg2);
+	restart(0, entry, arg0, arg1, arg2);
 	unreachable();
 }
 
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 59a4b4172b68..cf5d6f22a041 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -240,8 +240,8 @@ void machine_kexec(struct kimage *kimage)
 	} else {
 		if (is_hyp_nvhe())
 			__hyp_set_vectors(kimage->arch.el2_vectors);
-		cpu_soft_restart(kimage->arch.kern_reloc, virt_to_phys(kimage),
-				 0, 0);
+		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 63ea19868f63..b4fb97312a80 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -13,6 +13,7 @@
 #include <asm/kexec.h>
 #include <asm/page.h>
 #include <asm/sysreg.h>
+#include <asm/virt.h>
 
 /*
  * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
@@ -61,12 +62,20 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	isb
 
 	/* Start new image. */
+	ldr	x1, [x0, #KIMAGE_ARCH_EL2_VECTORS]	/* relocation start */
+	cbz	x1, .Lel1
+	ldr	x1, [x0, #KIMAGE_START]		/* relocation start */
+	ldr	x2, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */
+	mov	x3, xzr
+	mov	x4, xzr
+	mov     x0, #HVC_SOFT_RESTART
+	hvc	#0				/* Jumps from el2 */
+.Lel1:
 	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	x4
+	br	x4				/* Jumps from el1 */
 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:[~2021-09-16 23:13 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-16 23:13 [PATCH v17 00/15] arm64: MMU enabled kexec relocation Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 01/15] arm64: kernel: add helper for booted at EL2 and not VHE Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 02/15] arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 03/15] arm64: hibernate: abstract ttrb0 setup function Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 04/15] arm64: kexec: flush image and lists during kexec load time Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 05/15] arm64: kexec: skip relocation code for inplace kexec Pasha Tatashin
2021-09-29 12:13   ` Will Deacon
2021-09-30  2:44     ` Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 06/15] arm64: kexec: Use dcache ops macros instead of open-coding Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 07/15] arm64: kexec: pass kimage as the only argument to relocation function Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 08/15] arm64: kexec: configure EL2 vectors for kexec Pasha Tatashin
2021-09-29 12:35   ` Will Deacon
2021-09-30  3:54     ` Pasha Tatashin
2021-09-30  8:16       ` Will Deacon
2021-09-30 11:59         ` Pasha Tatashin
2021-09-16 23:13 ` Pasha Tatashin [this message]
2021-09-16 23:13 ` [PATCH v17 10/15] arm64: kexec: use ld script for relocation function Pasha Tatashin
2021-09-29 12:45   ` Will Deacon
2021-09-30  3:57     ` Pasha Tatashin
2021-09-30  4:08     ` Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 11/15] arm64: kexec: install a copy of the linear-map Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 12/15] arm64: kexec: keep MMU enabled during kexec relocation Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 13/15] arm64: kexec: remove the pre-kexec PoC maintenance Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 14/15] arm64: kexec: remove cpu-reset.h Pasha Tatashin
2021-09-16 23:13 ` [PATCH v17 15/15] arm64: trans_pgd: remove trans_pgd_map_page() Pasha Tatashin
2021-09-29 16:43   ` Catalin Marinas
2021-09-30  4:12     ` Pasha Tatashin
2021-09-29 12:49 ` [PATCH v17 00/15] arm64: MMU enabled kexec relocation Will Deacon
2021-09-30  4:13   ` Pasha Tatashin
2021-09-29 17:21 ` Catalin Marinas
2021-09-30  4:13   ` Pasha Tatashin

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