From: Marc Zyngier <maz@kernel.org>
To: kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
James Morse <james.morse@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Hanjun Guo <guohanjun@huawei.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Eric Biederman <ebiederm@xmission.com>,
Bhupesh SHARMA <bhupesh.sharma@linaro.org>,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
Dave Young <dyoung@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Moritz Fischer <mdf@kernel.org>,
kernel-team@android.com
Subject: [PATCH v2 5/5] arm64: kexec_image: Restore full kexec functionnality
Date: Mon, 31 May 2021 10:57:20 +0100 [thread overview]
Message-ID: <20210531095720.77469-6-maz@kernel.org> (raw)
In-Reply-To: <20210531095720.77469-1-maz@kernel.org>
Provide an arm64-specific implementation for arch_kexec_locate_mem_hole(),
using the resource tree instead of memblock, and respecting
the reservations added by EFI.
This ensures that kexec_file is finally reliable.
Reported-by: Moritz Fischer <mdf@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kernel/kexec_image.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index acf9cd251307..2a51a2ebd2b7 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -156,12 +156,31 @@ const struct kexec_file_ops kexec_image_ops = {
*/
int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
{
+ int ret;
+
+ /* Arch knows where to place */
+ if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
+ return 0;
+
/*
- * For the time being, kexec_file_load isn't reliable except
- * for crash kernel. Say sorry to the user.
+ * Crash kernels land in a well known place that has been
+ * reserved upfront.
+ *
+ * Normal kexec kernels can however land anywhere in memory.
+ * We have to be extra careful not to step over critical
+ * memory ranges that have been marked as reserved in the
+ * iomem resource tree (LPI and ACPI tables, among others),
+ * hence the use of the child-excluding iterator. This
+ * matches what the userspace version of kexec does.
*/
- if (kbuf->image->type != KEXEC_TYPE_CRASH)
- return -EADDRNOTAVAIL;
-
- return kexec_locate_mem_hole(kbuf);
+ if (kbuf->image->type == KEXEC_TYPE_CRASH)
+ ret = walk_iomem_res_desc(crashk_res.desc,
+ IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
+ crashk_res.start, crashk_res.end,
+ kbuf, kexec_locate_mem_hole_callback);
+ else
+ ret = walk_system_ram_excluding_child_res(0, ULONG_MAX, kbuf,
+ kexec_locate_mem_hole_callback);
+
+ return ret == 1 ? 0 : -EADDRNOTAVAIL;
}
--
2.30.2
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next prev parent reply other threads:[~2021-05-31 10:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 9:57 [PATCH v2 0/5] arm64: Make kexec_file_load honor iomem reservations Marc Zyngier
2021-05-31 9:57 ` [PATCH v2 1/5] arm64: kexec_file: Forbid non-crash kernels Marc Zyngier
2021-05-31 19:37 ` Ard Biesheuvel
2021-06-01 8:36 ` Marc Zyngier
2021-06-04 16:20 ` James Morse
2021-05-31 9:57 ` [PATCH v2 2/5] kexec_file: Make locate_mem_hole_callback global Marc Zyngier
2021-05-31 9:57 ` [PATCH v2 3/5] kernel/resource: Allow find_next_iomem_res() to exclude overlapping child resources Marc Zyngier
2021-05-31 9:57 ` [PATCH v2 4/5] kernel/resource: Introduce walk_system_ram_excluding_child_res() Marc Zyngier
2021-05-31 9:57 ` Marc Zyngier [this message]
2021-05-31 19:36 ` [PATCH v2 0/5] arm64: Make kexec_file_load honor iomem reservations Ard Biesheuvel
2021-06-04 16:20 ` James Morse
2021-06-09 22:39 ` Moritz Fischer
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