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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>
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Recently arm64 linux kernel added support for Armv8.3-A Pointer
Authentication feature. If this feature is enabled in the kernel and the
hardware supports address authentication then the return addresses are
signed and stored in the stack to prevent ROP kind of attack. Kdump tool
will now dump the kernel with signed lr values in the stack.
Any user analysis tool for this kernel dump may need the kernel pac mask
information in vmcoreinfo to generate the correct return address for
stacktrace purpose as well as to resolve the symbol name.
This patch is similar to commit ec6e822d1a22d0eef ("arm64: expose user PAC
bit positions via ptrace") which exposes pac mask information via ptrace
interfaces.
The config gaurd ARM64_PTR_AUTH is removed form asm/compiler.h so macros
like ptrauth_kernel_pac_mask can be used ungaurded. This config protection
is confusing as the pointer authentication feature may be missing at
runtime even though this config is present.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/1589202116-18265-1-git-send-email-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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Since commit 23c85094fe18 ("proc/kcore: add vmcoreinfo note to /proc/kcore")
the kernel has exported the vmcoreinfo PT_NOTE on /proc/kcore as well
as /proc/vmcore.
arm64 only exposes it's additional arch information via
arch_crash_save_vmcoreinfo() if built with CONFIG_KEXEC, as kdump was
previously the only user of vmcoreinfo.
Move this weak function to a separate file that is built at the same
time as its caller in kernel/crash_core.c. This ensures values like
'kimage_voffset' are always present in the vmcoreinfo PT_NOTE.
CC: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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