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authorBhupesh Sharma2020-05-14 00:22:37 +0530
committerCatalin Marinas2020-07-02 17:56:49 +0100
commitbbdbc11804ff0b4130e7550113b452e96a74d16e (patch)
treed2541374bf8be92d105309b05ba8fc90f6b6ff05 /Documentation/admin-guide/kdump
parent1d50e5d0c5052446cb85a3bf11fe8ba4e8d770ca (diff)
arm64/crash_core: Export TCR_EL1.T1SZ in vmcoreinfo
TCR_EL1.TxSZ, which controls the VA space size, is configured by a single kernel image to support either 48-bit or 52-bit VA space. If the ARMv8.2-LVA optional feature is present and we are running with a 64KB page size, then it is possible to use 52-bits of address space for both userspace and kernel addresses. However, any kernel binary that supports 52-bit must also be able to fall back to 48-bit at early boot time if the hardware feature is not present. Since TCR_EL1.T1SZ indicates the size of the memory region addressed by TTBR1_EL1, export the same in vmcoreinfo. User-space utilities like makedumpfile and crash-utility need to read this value from vmcoreinfo for determining if a virtual address lies in the linear map range. While at it also add documentation for TCR_EL1.T1SZ variable being added to vmcoreinfo. It indicates the size offset of the memory region addressed by TTBR1_EL1. Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com> Tested-by: John Donnelly <john.p.donnelly@oracle.com> Tested-by: Kamlakant Patel <kamlakantp@marvell.com> Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Reviewed-by: James Morse <james.morse@arm.com> Reviewed-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Steve Capper <steve.capper@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Dave Anderson <anderson@redhat.com> Cc: Kazuhito Hagio <k-hagio@ab.jp.nec.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org Link: https://lore.kernel.org/r/1589395957-24628-3-git-send-email-bhsharma@redhat.com [catalin.marinas@arm.com: removed vabits_actual from the commit log] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'Documentation/admin-guide/kdump')
-rw-r--r--Documentation/admin-guide/kdump/vmcoreinfo.rst11
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index 2a632020f809..2baad0bfb09d 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -404,6 +404,17 @@ KERNELPACMASK
The mask to extract the Pointer Authentication Code from a kernel virtual
address.
+TCR_EL1.T1SZ
+------------
+
+Indicates the size offset of the memory region addressed by TTBR1_EL1.
+The region size is 2^(64-T1SZ) bytes.
+
+TTBR1_EL1 is the table base address register specified by ARMv8-A
+architecture which is used to lookup the page-tables for the Virtual
+addresses in the higher VA range (refer to ARMv8 ARM document for
+more details).
+
arm
===