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| author |   Shanker Donthineni <shankerd@codeaurora.org> | 2017-02-22 21:10:48 -0600 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2017-02-24 10:55:31 +0000 |
| commit | ea6eac904f0a5a0c223bcfb133ec880ba9c70ae3 (patch) | |
| tree | 378e05fa48ffe527b80b8f12bec6808ef3a5e46c /arch/arm64 | |
| parent | arm64/kprobes: consistently handle MRS/MSR with XZR (diff) | |
| download | linux-dev-ea6eac904f0a5a0c223bcfb133ec880ba9c70ae3.tar.xz linux-dev-ea6eac904f0a5a0c223bcfb133ec880ba9c70ae3.zip | |
arm64: Avoid clobbering mm in erratum workaround on QDF2400
Commit 38fd94b0275c ("arm64: Work around Falkor erratum 1003") tried to
work around a hardware erratum, but actually caused a system crash of
its own during switch_mm:
cpu_do_switch_mm+0x20/0x40
efi_virtmap_load+0x34/0x40
virt_efi_get_next_variable+0x64/0xc8
efivar_init+0x8c/0x348
efisubsys_init+0xd4/0x270
do_one_initcall+0x80/0x110
kernel_init_freeable+0x19c/0x240
kernel_init+0x10/0x100
ret_from_fork+0x10/0x50
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
In cpu_do_switch_mm, x1 contains the mm_struct pointer, which needs to
be preserved by the pre_ttbr0_update_workaround macro rather than passed
as a temporary.
This patch clobbers x2 and x3 instead, keeping the mm_struct intact
after the workaround has run.
Fixes: 38fd94b0275c ("arm64: Work around Falkor erratum 1003")
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/mm/proc.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index cd4d53d7e458..877d42fb0df6 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -138,7 +138,7 @@ ENDPROC(cpu_do_resume) * - pgd_phys - physical address of new TTB */ ENTRY(cpu_do_switch_mm) - pre_ttbr0_update_workaround x0, x1, x2 + pre_ttbr0_update_workaround x0, x2, x3 mmid x1, x1 // get mm->context.id bfi x0, x1, #48, #16 // set the ASID msr ttbr0_el1, x0 // set TTBR0 |