diff options
Diffstat (limited to 'payloads')
| -rw-r--r-- | payloads/libpayload/arch/arm64/memset.S | 106 |
1 files changed, 0 insertions, 106 deletions
diff --git a/payloads/libpayload/arch/arm64/memset.S b/payloads/libpayload/arch/arm64/memset.S index ee8f81859c..15ab5903f6 100644 --- a/payloads/libpayload/arch/arm64/memset.S +++ b/payloads/libpayload/arch/arm64/memset.S @@ -31,16 +31,6 @@ * */ -/* By default we assume that the DC instruction can be used to zero - data blocks more efficiently. In some circumstances this might be - unsafe, for example in an asymmetric multiprocessor environment with - different DC clear lengths (neither the upper nor lower lengths are - safe to use). The feature can be disabled by defining DONT_USE_DC. - - If code may be run in a virtualized environment, then define - MAYBE_VIRT. This will cause the code to cache the system register - values rather than re-reading them each call. */ - #define dstin x0 #define val w1 #define count x2 @@ -57,7 +47,6 @@ #define dst x8 #define tmp3w w9 - .macro def_fn f p2align=0 .text .p2align \p2align @@ -70,9 +59,6 @@ def_fn memset p2align=6 mov dst, dstin /* Preserve return value. */ ands A_lw, val, #255 -#ifndef DONT_USE_DC - b.eq .Lzero_mem -#endif orr A_lw, A_lw, A_lw, lsl #8 orr A_lw, A_lw, A_lw, lsl #16 orr A_l, A_l, A_l, lsl #32 @@ -148,95 +134,3 @@ def_fn memset p2align=6 add dst, dst, #16 b.ne .Ltail63 ret - -#ifndef DONT_USE_DC - /* For zeroing memory, check to see if we can use the ZVA feature to - * zero entire 'cache' lines. */ -.Lzero_mem: - mov A_l, #0 - cmp count, #63 - b.le .Ltail_maybe_tiny - neg tmp2, dst - ands tmp2, tmp2, #15 - b.eq 1f - sub count, count, tmp2 - stp A_l, A_l, [dst] - add dst, dst, tmp2 - cmp count, #63 - b.le .Ltail63 -1: - /* For zeroing small amounts of memory, it's not worth setting up - * the line-clear code. */ - cmp count, #128 - b.lt .Lnot_short -#ifdef MAYBE_VIRT - /* For efficiency when virtualized, we cache the ZVA capability. */ - adrp tmp2, .Lcache_clear - ldr zva_len, [tmp2, #:lo12:.Lcache_clear] - tbnz zva_len, #31, .Lnot_short - cbnz zva_len, .Lzero_by_line - mrs tmp1, dczid_el0 - tbz tmp1, #4, 1f - /* ZVA not available. Remember this for next time. */ - mov zva_len, #~0 - str zva_len, [tmp2, #:lo12:.Lcache_clear] - b .Lnot_short -1: - mov tmp3w, #4 - and zva_len, tmp1w, #15 /* Safety: other bits reserved. */ - lsl zva_len, tmp3w, zva_len - str zva_len, [tmp2, #:lo12:.Lcache_clear] -#else - mrs tmp1, dczid_el0 - tbnz tmp1, #4, .Lnot_short - mov tmp3w, #4 - and zva_len, tmp1w, #15 /* Safety: other bits reserved. */ - lsl zva_len, tmp3w, zva_len -#endif - -.Lzero_by_line: - /* Compute how far we need to go to become suitably aligned. We're - * already at quad-word alignment. */ - cmp count, zva_len_x - b.lt .Lnot_short /* Not enough to reach alignment. */ - sub zva_bits_x, zva_len_x, #1 - neg tmp2, dst - ands tmp2, tmp2, zva_bits_x - b.eq 1f /* Already aligned. */ - /* Not aligned, check that there's enough to copy after alignment. */ - sub tmp1, count, tmp2 - cmp tmp1, #64 - ccmp tmp1, zva_len_x, #8, ge /* NZCV=0b1000 */ - b.lt .Lnot_short - /* We know that there's at least 64 bytes to zero and that it's safe - * to overrun by 64 bytes. */ - mov count, tmp1 -2: - stp A_l, A_l, [dst] - stp A_l, A_l, [dst, #16] - stp A_l, A_l, [dst, #32] - subs tmp2, tmp2, #64 - stp A_l, A_l, [dst, #48] - add dst, dst, #64 - b.ge 2b - /* We've overrun a bit, so adjust dst downwards. */ - add dst, dst, tmp2 -1: - sub count, count, zva_len_x -3: - dc zva, dst - add dst, dst, zva_len_x - subs count, count, zva_len_x - b.ge 3b - ands count, count, zva_bits_x - b.ne .Ltail_maybe_long - ret - .size memset, .-memset -#ifdef MAYBE_VIRT - .bss - .p2align 2 - .Lcache_clear: - .space 4 -#endif -#endif /* DONT_USE_DC */ - |