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linux-next/arch/arm64/kernel/crash_core.c
Bhupesh Sharma bbdbc11804 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>
2020-07-02 17:56:49 +01:00

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952 B
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) Linaro.
* Copyright (C) Huawei Futurewei Technologies.
*/
#include <linux/crash_core.h>
#include <asm/cpufeature.h>
#include <asm/memory.h>
#include <asm/pgtable-hwdef.h>
static inline u64 get_tcr_el1_t1sz(void);
static inline u64 get_tcr_el1_t1sz(void)
{
return (read_sysreg(tcr_el1) & TCR_T1SZ_MASK) >> TCR_T1SZ_OFFSET;
}
void arch_crash_save_vmcoreinfo(void)
{
VMCOREINFO_NUMBER(VA_BITS);
/* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */
vmcoreinfo_append_str("NUMBER(kimage_voffset)=0x%llx\n",
kimage_voffset);
vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%llx\n",
PHYS_OFFSET);
vmcoreinfo_append_str("NUMBER(TCR_EL1_T1SZ)=0x%llx\n",
get_tcr_el1_t1sz());
vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
vmcoreinfo_append_str("NUMBER(KERNELPACMASK)=0x%llx\n",
system_supports_address_auth() ?
ptrauth_kernel_pac_mask() : 0);
}