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| author | Reiji Watanabe <reijiw@google.com> | 2021-12-06 03:47:35 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-12-06 20:02:10 +0300 |
| commit | f0616abd4e67143b45b04b565839148458857347 (patch) | |
| tree | d7a91f6f0b594dfe6aa6133300cd5fff29197688 /arch/arm64/lib | |
| parent | d58071a8a76d779eedab38033ae4c821c30295a5 (diff) | |
| download | linux-f0616abd4e67143b45b04b565839148458857347.tar.xz | |
arm64: clear_page() shouldn't use DC ZVA when DCZID_EL0.DZP == 1
Currently, clear_page() uses DC ZVA instruction unconditionally. But it
should make sure that DCZID_EL0.DZP, which indicates whether or not use
of DC ZVA instruction is prohibited, is zero when using the instruction.
Use STNP instead when DCZID_EL0.DZP == 1.
Fixes: f27bb139c387 ("arm64: Miscellaneous library functions")
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20211206004736.1520989-2-reijiw@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/lib')
| -rw-r--r-- | arch/arm64/lib/clear_page.S | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm64/lib/clear_page.S b/arch/arm64/lib/clear_page.S index b84b179edba3..1fd5d790ab80 100644 --- a/arch/arm64/lib/clear_page.S +++ b/arch/arm64/lib/clear_page.S @@ -16,6 +16,7 @@ */ SYM_FUNC_START_PI(clear_page) mrs x1, dczid_el0 + tbnz x1, #4, 2f /* Branch if DC ZVA is prohibited */ and w1, w1, #0xf mov x2, #4 lsl x1, x2, x1 @@ -25,5 +26,14 @@ SYM_FUNC_START_PI(clear_page) tst x0, #(PAGE_SIZE - 1) b.ne 1b ret + +2: stnp xzr, xzr, [x0] + stnp xzr, xzr, [x0, #16] + stnp xzr, xzr, [x0, #32] + stnp xzr, xzr, [x0, #48] + add x0, x0, #64 + tst x0, #(PAGE_SIZE - 1) + b.ne 2b + ret SYM_FUNC_END_PI(clear_page) EXPORT_SYMBOL(clear_page) |