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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>
This commit is contained in:
Bhupesh Sharma 2020-05-14 00:22:37 +05:30 committed by Catalin Marinas
parent 1d50e5d0c5
commit bbdbc11804
3 changed files with 22 additions and 0 deletions
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11
Documentation/admin-guide/kdump/vmcoreinfo.rst
View File

@ -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
===

1
arch/arm64/include/asm/pgtable-hwdef.h
View File

@ -216,6 +216,7 @@
#define TCR_TxSZ(x) (TCR_T0SZ(x) | TCR_T1SZ(x))
#define TCR_TxSZ_WIDTH 6
#define TCR_T0SZ_MASK (((UL(1) << TCR_TxSZ_WIDTH) - 1) << TCR_T0SZ_OFFSET)
#define TCR_T1SZ_MASK (((UL(1) << TCR_TxSZ_WIDTH) - 1) << TCR_T1SZ_OFFSET)
#define TCR_EPD0_SHIFT 7
#define TCR_EPD0_MASK (UL(1) << TCR_EPD0_SHIFT)

10
arch/arm64/kernel/crash_core.c
View File

@ -7,6 +7,14 @@
#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)
{
@ -16,6 +24,8 @@ void arch_crash_save_vmcoreinfo(void)
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() ?