Re: [PATCH v2 6/8] arm64: Import latest memcpy()/memmove() implementation
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2021-06-08 12:41:04
Also in:
linux-amlogic
+ Kevin On 08.06.2021 13:37, Robin Murphy wrote:
Hi Marek, On 2021-06-08 12:15, Marek Szyprowski wrote:quoted
Hi Robin, On 27.05.2021 17:34, Robin Murphy wrote:quoted
Import the latest implementation of memcpy(), based on the upstream code of string/aarch64/memcpy.S at commit afd6244 from https://protect2.fireeye.com/v1/url?k=0e25d630-51beef28-0e245d7f-0cc47a314e9a-b41fdb2d4d06ff75&q=1&e=fcfaf71d-f01a-4bc4-8e16-8ae86e0c0116&u=https%3A%2F%2Fgithub.com%2FARM-software%2Foptimized-routines, and subsuming memmove() in the process. Note that for simplicity Arm have chosen to contribute this code to Linux under GPLv2 rather than the original MIT license. Note also that the needs of the usercopy routines vs. regular memcpy() have now diverged so far that we abandon the shared template idea and the damage which that incurred to the tuning of LDP/STP loops. We'll be back to tackle those routines separately in future. Signed-off-by: Robin Murphy <robin.murphy@arm.com>This patch landed recently in linux-next as commit 285133040e6c ("arm64: Import latest memcpy()/memmove() implementation"). Sadly it causes serious issues on Khadas VIM3 board. Reverting it on top of linux next-20210607 (together with 6b8f648959e5 and resolving the conflict in the Makefile) fixes the issue. Here is the kernel log: Unable to handle kernel paging request at virtual address ffff8000136bd204 Mem abort info: ESR = 0x96000061 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000061That's an alignment fault, which implies we're accessing something which isn't normal memory.quoted
CM = 0, WnR = 1 swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000009da6000 [ffff8000136bd204] pgd=10000000f4806003, p4d=10000000f4806003, pud=10000000f4805003, pmd=1000000000365003, pte=00680000ffe03713 Internal error: Oops: 96000061 [#1] PREEMPT SMP Modules linked in: brcmfmac brcmutil cfg80211 dw_hdmi_i2s_audio meson_gxl hci_uart btqca btbcm bluetooth panfrost ecdh_generic ecc snd_soc_meson_axg_sound_card crct10dif_ce snd_soc_meson_card_utils rfkill rtc_hym8563 gpu_sched dwmac_generic rc_khadas meson_gxbb_wdt meson_ir pwm_meson snd_soc_meson_axg_tdmin snd_soc_meson_g12a_tohdmitx rtc_meson_vrtc snd_soc_meson_axg_tdmout snd_soc_meson_axg_frddr reset_meson_audio_arb snd_soc_meson_codec_glue axg_audio meson_rng sclk_div dwmac_meson8b snd_soc_meson_axg_toddr mdio_mux_meson_g12a clk_phase stmmac_platform rng_core snd_soc_meson_axg_fifo meson_dw_hdmi stmmac meson_drm meson_canvas dw_hdmi pcs_xpcs display_connector snd_soc_meson_axg_tdm_interface nvmem_meson_efuse adc_keys snd_soc_meson_axg_tdm_formatter CPU: 4 PID: 135 Comm: kworker/4:3 Not tainted 5.13.0-rc5-next-20210607 #10441 Hardware name: Khadas VIM3 (DT) Workqueue: events request_firmware_work_func pstate: 20000005 (nzCv daif -PAN -UAO -TCO BTYPE=--) pc : __memcpy+0x2c/0x260 lr : sg_copy_buffer+0x90/0x118 ... Call trace: __memcpy+0x2c/0x260 sg_copy_to_buffer+0x14/0x20 meson_mmc_start_cmd+0xf4/0x2c8 meson_mmc_request+0x4c/0xb8 __mmc_start_request+0xa4/0x2a8 mmc_start_request+0x80/0xa8 mmc_wait_for_req+0x68/0xd8 mmc_io_rw_extended+0x1d4/0x2e0 sdio_io_rw_ext_helper+0xb0/0x1e8 sdio_memcpy_toio+0x20/0x28 brcmf_sdiod_skbuff_write.isra.18+0x2c/0x68 [brcmfmac] brcmf_sdiod_ramrw+0xe0/0x230 [brcmfmac] brcmf_sdio_firmware_callback+0xa8/0x7c8 [brcmfmac] brcmf_fw_request_done+0x7c/0x100 [brcmfmac] request_firmware_work_func+0x4c/0xd8 process_one_work+0x2a8/0x718 worker_thread+0x48/0x460 kthread+0x12c/0x160 ret_from_fork+0x10/0x18 Code: 540000c3 a9401c26 a97f348c a9001c06 (a93f34ac) ---[ end trace be83fa283dc82415 ]--- I hope that the above log helps fixing the issue. IIRC the SDHCI driver on VIM3 board uses internal SRAM for transferring data (instead of DMA), so the issue is somehow related to that.Drivers shouldn't be using memcpy() on iomem mappings. Even if they happen to have got away with it sometimes ;) Taking a quick look at that driver, host->bounce_buf = host->regs + SD_EMMC_SRAM_DATA_BUF_OFF; is completely bogus, as Sparse will readily point out. Robin.quoted
quoted
--- arch/arm64/lib/Makefile | 2 +- arch/arm64/lib/memcpy.S | 272 ++++++++++++++++++++++++++++++++------- arch/arm64/lib/memmove.S | 189 --------------------------- 3 files changed, 230 insertions(+), 233 deletions(-) delete mode 100644 arch/arm64/lib/memmove.Sdiff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index d31e1169d9b8..01c596aa539c 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile@@ -1,7 +1,7 @@# SPDX-License-Identifier: GPL-2.0 lib-y := clear_user.o delay.o copy_from_user.o \ copy_to_user.o copy_in_user.o copy_page.o \ - clear_page.o csum.o memchr.o memcpy.o memmove.o \ + clear_page.o csum.o memchr.o memcpy.o \ memset.o memcmp.o strcmp.o strncmp.o strlen.o \ strnlen.o strchr.o strrchr.o tishift.o diff --git a/arch/arm64/lib/memcpy.S b/arch/arm64/lib/memcpy.S index dc8d2a216a6e..31073a8304fb 100644--- a/arch/arm64/lib/memcpy.S +++ b/arch/arm64/lib/memcpy.S@@ -1,66 +1,252 @@/* SPDX-License-Identifier: GPL-2.0-only */ /* - * Copyright (C) 2013 ARM Ltd. - * Copyright (C) 2013 Linaro. + * Copyright (c) 2012-2020, Arm Limited. * - * This code is based on glibc cortex strings work originally authored by Linaro - * be found @ - * - * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ - * files/head:/src/aarch64/ + * Adapted from the original at: + * https://protect2.fireeye.com/v1/url?k=30360c6b-6fad3573-30378724-0cc47a314e9a-eee98177cc643ca2&q=1&e=fcfaf71d-f01a-4bc4-8e16-8ae86e0c0116&u=https%3A%2F%2Fgithub.com%2FARM-software%2Foptimized-routines%2Fblob%2Fmaster%2Fstring%2Faarch64%2Fmemcpy.S */ #include <linux/linkage.h> #include <asm/assembler.h> -#include <asm/cache.h> -/* - * Copy a buffer from src to dest (alignment handled by the hardware) +/* Assumptions: + * + * ARMv8-a, AArch64, unaligned accesses. * - * Parameters: - * x0 - dest - * x1 - src - * x2 - n - * Returns: - * x0 - dest */ - .macro ldrb1 reg, ptr, val - ldrb \reg, [\ptr], \val - .endm - .macro strb1 reg, ptr, val - strb \reg, [\ptr], \val - .endm +#define L(label) .L ## label - .macro ldrh1 reg, ptr, val - ldrh \reg, [\ptr], \val - .endm +#define dstin x0 +#define src x1 +#define count x2 +#define dst x3 +#define srcend x4 +#define dstend x5 +#define A_l x6 +#define A_lw w6 +#define A_h x7 +#define B_l x8 +#define B_lw w8 +#define B_h x9 +#define C_l x10 +#define C_lw w10 +#define C_h x11 +#define D_l x12 +#define D_h x13 +#define E_l x14 +#define E_h x15 +#define F_l x16 +#define F_h x17 +#define G_l count +#define G_h dst +#define H_l src +#define H_h srcend +#define tmp1 x14 - .macro strh1 reg, ptr, val - strh \reg, [\ptr], \val - .endm +/* This implementation handles overlaps and supports both memcpy and memmove + from a single entry point. It uses unaligned accesses and branchless + sequences to keep the code small, simple and improve performance. - .macro ldr1 reg, ptr, val - ldr \reg, [\ptr], \val - .endm + Copies are split into 3 main cases: small copies of up to 32 bytes, medium + copies of up to 128 bytes, and large copies. The overhead of the overlap + check is negligible since it is only required for large copies. - .macro str1 reg, ptr, val - str \reg, [\ptr], \val - .endm - - .macro ldp1 reg1, reg2, ptr, val - ldp \reg1, \reg2, [\ptr], \val - .endm - - .macro stp1 reg1, reg2, ptr, val - stp \reg1, \reg2, [\ptr], \val - .endm + Large copies use a software pipelined loop processing 64 bytes per iteration. + The destination pointer is 16-byte aligned to minimize unaligned accesses. + The loop tail is handled by always copying 64 bytes from the end. +*/ +SYM_FUNC_START_ALIAS(__memmove) +SYM_FUNC_START_WEAK_ALIAS_PI(memmove) SYM_FUNC_START_ALIAS(__memcpy) SYM_FUNC_START_WEAK_PI(memcpy) -#include "copy_template.S" + add srcend, src, count + add dstend, dstin, count + cmp count, 128 + b.hi L(copy_long) + cmp count, 32 + b.hi L(copy32_128) + + /* Small copies: 0..32 bytes. */ + cmp count, 16 + b.lo L(copy16) + ldp A_l, A_h, [src] + ldp D_l, D_h, [srcend, -16] + stp A_l, A_h, [dstin] + stp D_l, D_h, [dstend, -16] ret + + /* Copy 8-15 bytes. */ +L(copy16): + tbz count, 3, L(copy8) + ldr A_l, [src] + ldr A_h, [srcend, -8] + str A_l, [dstin] + str A_h, [dstend, -8] + ret + + .p2align 3 + /* Copy 4-7 bytes. */ +L(copy8): + tbz count, 2, L(copy4) + ldr A_lw, [src] + ldr B_lw, [srcend, -4] + str A_lw, [dstin] + str B_lw, [dstend, -4] + ret + + /* Copy 0..3 bytes using a branchless sequence. */ +L(copy4): + cbz count, L(copy0) + lsr tmp1, count, 1 + ldrb A_lw, [src] + ldrb C_lw, [srcend, -1] + ldrb B_lw, [src, tmp1] + strb A_lw, [dstin] + strb B_lw, [dstin, tmp1] + strb C_lw, [dstend, -1] +L(copy0): + ret + + .p2align 4 + /* Medium copies: 33..128 bytes. */ +L(copy32_128): + ldp A_l, A_h, [src] + ldp B_l, B_h, [src, 16] + ldp C_l, C_h, [srcend, -32] + ldp D_l, D_h, [srcend, -16] + cmp count, 64 + b.hi L(copy128) + stp A_l, A_h, [dstin] + stp B_l, B_h, [dstin, 16] + stp C_l, C_h, [dstend, -32] + stp D_l, D_h, [dstend, -16] + ret + + .p2align 4 + /* Copy 65..128 bytes. */ +L(copy128): + ldp E_l, E_h, [src, 32] + ldp F_l, F_h, [src, 48] + cmp count, 96 + b.ls L(copy96) + ldp G_l, G_h, [srcend, -64] + ldp H_l, H_h, [srcend, -48] + stp G_l, G_h, [dstend, -64] + stp H_l, H_h, [dstend, -48] +L(copy96): + stp A_l, A_h, [dstin] + stp B_l, B_h, [dstin, 16] + stp E_l, E_h, [dstin, 32] + stp F_l, F_h, [dstin, 48] + stp C_l, C_h, [dstend, -32] + stp D_l, D_h, [dstend, -16] + ret + + .p2align 4 + /* Copy more than 128 bytes. */ +L(copy_long): + /* Use backwards copy if there is an overlap. */ + sub tmp1, dstin, src + cbz tmp1, L(copy0) + cmp tmp1, count + b.lo L(copy_long_backwards) + + /* Copy 16 bytes and then align dst to 16-byte alignment. */ + + ldp D_l, D_h, [src] + and tmp1, dstin, 15 + bic dst, dstin, 15 + sub src, src, tmp1 + add count, count, tmp1 /* Count is now 16 too large. */ + ldp A_l, A_h, [src, 16] + stp D_l, D_h, [dstin] + ldp B_l, B_h, [src, 32] + ldp C_l, C_h, [src, 48] + ldp D_l, D_h, [src, 64]! + subs count, count, 128 + 16 /* Test and readjust count. */ + b.ls L(copy64_from_end) + +L(loop64): + stp A_l, A_h, [dst, 16] + ldp A_l, A_h, [src, 16] + stp B_l, B_h, [dst, 32] + ldp B_l, B_h, [src, 32] + stp C_l, C_h, [dst, 48] + ldp C_l, C_h, [src, 48] + stp D_l, D_h, [dst, 64]! + ldp D_l, D_h, [src, 64]! + subs count, count, 64 + b.hi L(loop64) + + /* Write the last iteration and copy 64 bytes from the end. */ +L(copy64_from_end): + ldp E_l, E_h, [srcend, -64] + stp A_l, A_h, [dst, 16] + ldp A_l, A_h, [srcend, -48] + stp B_l, B_h, [dst, 32] + ldp B_l, B_h, [srcend, -32] + stp C_l, C_h, [dst, 48] + ldp C_l, C_h, [srcend, -16] + stp D_l, D_h, [dst, 64] + stp E_l, E_h, [dstend, -64] + stp A_l, A_h, [dstend, -48] + stp B_l, B_h, [dstend, -32] + stp C_l, C_h, [dstend, -16] + ret + + .p2align 4 + + /* Large backwards copy for overlapping copies. + Copy 16 bytes and then align dst to 16-byte alignment. */ +L(copy_long_backwards): + ldp D_l, D_h, [srcend, -16] + and tmp1, dstend, 15 + sub srcend, srcend, tmp1 + sub count, count, tmp1 + ldp A_l, A_h, [srcend, -16] + stp D_l, D_h, [dstend, -16] + ldp B_l, B_h, [srcend, -32] + ldp C_l, C_h, [srcend, -48] + ldp D_l, D_h, [srcend, -64]! + sub dstend, dstend, tmp1 + subs count, count, 128 + b.ls L(copy64_from_start) + +L(loop64_backwards): + stp A_l, A_h, [dstend, -16] + ldp A_l, A_h, [srcend, -16] + stp B_l, B_h, [dstend, -32] + ldp B_l, B_h, [srcend, -32] + stp C_l, C_h, [dstend, -48] + ldp C_l, C_h, [srcend, -48] + stp D_l, D_h, [dstend, -64]! + ldp D_l, D_h, [srcend, -64]! + subs count, count, 64 + b.hi L(loop64_backwards) + + /* Write the last iteration and copy 64 bytes from the start. */ +L(copy64_from_start): + ldp G_l, G_h, [src, 48] + stp A_l, A_h, [dstend, -16] + ldp A_l, A_h, [src, 32] + stp B_l, B_h, [dstend, -32] + ldp B_l, B_h, [src, 16] + stp C_l, C_h, [dstend, -48] + ldp C_l, C_h, [src] + stp D_l, D_h, [dstend, -64] + stp G_l, G_h, [dstin, 48] + stp A_l, A_h, [dstin, 32] + stp B_l, B_h, [dstin, 16] + stp C_l, C_h, [dstin] + ret + SYM_FUNC_END_PI(memcpy) EXPORT_SYMBOL(memcpy) SYM_FUNC_END_ALIAS(__memcpy) EXPORT_SYMBOL(__memcpy) +SYM_FUNC_END_ALIAS_PI(memmove) +EXPORT_SYMBOL(memmove) +SYM_FUNC_END_ALIAS(__memmove) +EXPORT_SYMBOL(__memmove) \ No newline at end of filediff --git a/arch/arm64/lib/memmove.S b/arch/arm64/lib/memmove.S deleted file mode 100644 index 1035dce4bdaf..000000000000 --- a/arch/arm64/lib/memmove.S +++ /dev/null@@ -1,189 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* - * Copyright (C) 2013 ARM Ltd. - * Copyright (C) 2013 Linaro. - * - * This code is based on glibc cortex strings work originallyauthored by Linaro - * be found @ - * - * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ - * files/head:/src/aarch64/ - */ - -#include <linux/linkage.h> -#include <asm/assembler.h> -#include <asm/cache.h> - -/* - * Move a buffer from src to test (alignment handled by the hardware). - * If dest <= src, call memcpy, otherwise copy in reverse order. - * - * Parameters: - * x0 - dest - * x1 - src - * x2 - n - * Returns: - * x0 - dest - */ -dstin .req x0 -src .req x1 -count .req x2 -tmp1 .req x3 -tmp1w .req w3 -tmp2 .req x4 -tmp2w .req w4 -tmp3 .req x5 -tmp3w .req w5 -dst .req x6 - -A_l .req x7 -A_h .req x8 -B_l .req x9 -B_h .req x10 -C_l .req x11 -C_h .req x12 -D_l .req x13 -D_h .req x14 - -SYM_FUNC_START_ALIAS(__memmove) -SYM_FUNC_START_WEAK_PI(memmove) - cmp dstin, src - b.lo __memcpy - add tmp1, src, count - cmp dstin, tmp1 - b.hs __memcpy /* No overlap. */ - - add dst, dstin, count - add src, src, count - cmp count, #16 - b.lo .Ltail15 /*probably non-alignment accesses.*/ - - ands tmp2, src, #15 /* Bytes to reach alignment. */ - b.eq .LSrcAligned - sub count, count, tmp2 - /* - * process the aligned offset length to make the src aligned firstly. - * those extra instructions' cost is acceptable. It also make the - * coming accesses are based on aligned address. - */ - tbz tmp2, #0, 1f - ldrb tmp1w, [src, #-1]! - strb tmp1w, [dst, #-1]! -1: - tbz tmp2, #1, 2f - ldrh tmp1w, [src, #-2]! - strh tmp1w, [dst, #-2]! -2: - tbz tmp2, #2, 3f - ldr tmp1w, [src, #-4]! - str tmp1w, [dst, #-4]! -3: - tbz tmp2, #3, .LSrcAligned - ldr tmp1, [src, #-8]! - str tmp1, [dst, #-8]! - -.LSrcAligned: - cmp count, #64 - b.ge .Lcpy_over64 - - /* - * Deal with small copies quickly by dropping straight into the - * exit block. - */ -.Ltail63: - /* - * Copy up to 48 bytes of data. At this point we only need the - * bottom 6 bits of count to be accurate. - */ - ands tmp1, count, #0x30 - b.eq .Ltail15 - cmp tmp1w, #0x20 - b.eq 1f - b.lt 2f - ldp A_l, A_h, [src, #-16]! - stp A_l, A_h, [dst, #-16]! -1: - ldp A_l, A_h, [src, #-16]! - stp A_l, A_h, [dst, #-16]! -2: - ldp A_l, A_h, [src, #-16]! - stp A_l, A_h, [dst, #-16]! - -.Ltail15: - tbz count, #3, 1f - ldr tmp1, [src, #-8]! - str tmp1, [dst, #-8]! -1: - tbz count, #2, 2f - ldr tmp1w, [src, #-4]! - str tmp1w, [dst, #-4]! -2: - tbz count, #1, 3f - ldrh tmp1w, [src, #-2]! - strh tmp1w, [dst, #-2]! -3: - tbz count, #0, .Lexitfunc - ldrb tmp1w, [src, #-1] - strb tmp1w, [dst, #-1] - -.Lexitfunc: - ret - -.Lcpy_over64: - subs count, count, #128 - b.ge .Lcpy_body_large - /* - * Less than 128 bytes to copy, so handle 64 bytes here and then jump - * to the tail. - */ - ldp A_l, A_h, [src, #-16] - stp A_l, A_h, [dst, #-16] - ldp B_l, B_h, [src, #-32] - ldp C_l, C_h, [src, #-48] - stp B_l, B_h, [dst, #-32] - stp C_l, C_h, [dst, #-48] - ldp D_l, D_h, [src, #-64]! - stp D_l, D_h, [dst, #-64]! - - tst count, #0x3f - b.ne .Ltail63 - ret - - /* - * Critical loop. Start at a new cache line boundary. Assuming - * 64 bytes per line this ensures the entire loop is in one line. - */ - .p2align L1_CACHE_SHIFT -.Lcpy_body_large: - /* pre-load 64 bytes data. */ - ldp A_l, A_h, [src, #-16] - ldp B_l, B_h, [src, #-32] - ldp C_l, C_h, [src, #-48] - ldp D_l, D_h, [src, #-64]! -1: - /* - * interlace the load of next 64 bytes data block with store of the last - * loaded 64 bytes data. - */ - stp A_l, A_h, [dst, #-16] - ldp A_l, A_h, [src, #-16] - stp B_l, B_h, [dst, #-32] - ldp B_l, B_h, [src, #-32] - stp C_l, C_h, [dst, #-48] - ldp C_l, C_h, [src, #-48] - stp D_l, D_h, [dst, #-64]! - ldp D_l, D_h, [src, #-64]! - subs count, count, #64 - b.ge 1b - stp A_l, A_h, [dst, #-16] - stp B_l, B_h, [dst, #-32] - stp C_l, C_h, [dst, #-48] - stp D_l, D_h, [dst, #-64]! - - tst count, #0x3f - b.ne .Ltail63 - ret -SYM_FUNC_END_PI(memmove) -EXPORT_SYMBOL(memmove) -SYM_FUNC_END_ALIAS(__memmove) -EXPORT_SYMBOL(__memmove)Best regards
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel