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authorShanker Donthineni <shankerd@codeaurora.org>2017-02-23 06:10:48 +0300
committerWill Deacon <will.deacon@arm.com>2017-02-24 13:55:31 +0300
commitea6eac904f0a5a0c223bcfb133ec880ba9c70ae3 (patch)
tree378e05fa48ffe527b80b8f12bec6808ef3a5e46c /arch/arm64/mm
parentffe7afd1713558d73483834c2e2d03a1e39a4062 (diff)
downloadlinux-ea6eac904f0a5a0c223bcfb133ec880ba9c70ae3.tar.xz
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/mm')
-rw-r--r--arch/arm64/mm/proc.S2
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