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The LoongArch Architecture Manual defines a hardware capability bit
CPUCFG2_DIV32 (bit 26 of CPUCFG 0x2). When this bit is set to 1, it
indicates that on 64-bit machines, the division and mod instructions
(DIV.W[U] and MOD.W[U]) will ignore the upper 32 bits of the input
registers and only compute based on the lower 32 bits.
On certain CPU cores without this feature, these 32-bit instructions
require both input operands to be properly sign-extended. Otherwise,
the hardware execution results can be randomly meaningless values.
Add the CPU_FEATURE_DIV32 definition, detect and export this hardware
capability via elf_hwcap and cpu_has_div32 (in cpuinfo). This provides
the infrastructure for subsystems like BPF JIT to safely choose either
native 32-bit instructions or fallback instruction sequences based on
the actual CPU hardware capabilities.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Currently, neither /proc/cpuinfo nor hwcap exposes the existence of the
LAMCAS extension, which is part of LA64v1.1. For example, on a Loongson
3B6000, /proc/cpuinfo is as follows:
processor : 23
package : 0
core : 11
global_id : 31
CPU Family : Loongson-64bit
Model Name : Loongson-3B6000
PRID : LA664 (0014d011)
CPU Revision : 0x11
FPU Revision : 0x01
CPU MHz : 2200.00
BogoMIPS : 4400.00
TLB Entries : 2112
Address Sizes : 48 bits physical, 48 bits virtual
ISA : loongarch32r loongarch32s loongarch64
Features : cpucfg lam lam_bh scq ual fpu lsx lasx
crc32 complex crypto lspw lvz lbt_x86 lbt_arm lbt_mips
Hardware Watchpoint : yes, iwatch count: 8, dwatch count: 4
... while the CPUCFG 2 instruction reads "0x7e7ccfcf", whose bit28 is 1,
indicating the actual presence of LAMCAS.
This hinders user-space inspection and detection of LAMCAS. For example,
in SpiderMonkey, we need to switch to larchintrin.h and then use the raw
__cpucfg() to manually perform the bit extraction. Also, a curious user
reading /proc/cpuinfo might be puzzled by the lack of display of LAMCAS.
Expose the existence of LAMCAS via cpuinfo and hwcap. The definition
point of the new LOONGARCH_CPU_LAMCAS flag is chosen so as to match the
practices in commit 1dd3e8a8eeb4059fb34b ("LoongArch: Define instruction
formats for AM{SWAP/ADD}.{B/H} and DBAR").
After this patch, /proc/cpuinfo looks like the following:
processor : 23
package : 0
core : 11
global_id : 31
CPU Family : Loongson-64bit
Model Name : Loongson-3B6000
PRID : LA664 (0014d011)
CPU Revision : 0x11
FPU Revision : 0x01
CPU MHz : 2200.00
BogoMIPS : 4400.00
TLB Entries : 2112
Address Sizes : 48 bits physical, 48 bits virtual
ISA : loongarch32r loongarch32s loongarch64
Features : cpucfg lam lam_bh lamcas scq ual fpu lsx
lasx crc32 complex crypto lspw lvz lbt_x86 lbt_arm lbt_mips
Hardware Watchpoint : yes, iwatch count: 8, dwatch count: 4
Note the addition of "lamcas" to the "Features" row.
Signed-off-by: Rong Bao <rong.bao@csmantle.top>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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The 8 and 16 bit read-modify-write atomic instructions amadd.{b/h} and
amswap.{b/h} were newly added in the latest LoongArch Reference Manual,
define the instruction format and check whether support via CPUCFG.
Furthermore, define the instruction format for DBAR which will be used
to support BPF load-acquire and store-release instructions.
This is preparation for later patches.
Acked-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Fix warnings like: "Prefer seq_puts to seq_printf" by checkpatch.pl.
Replace seq_printf() calls with seq_puts() in show_cpuinfo() when
outputting simple constant strings without format specifiers.
This improves performance slightly as seq_puts() avoids parsing the
format string.
Signed-off-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Check the CPUCFG2_SCQ bit to determine if the current CPU supports the
SC.Q instruction.
Reviewed-by: Hengqi Chen <hengqi.chen@gmail.com>
Tested-by: Hengqi Chen <hengqi.chen@gmail.com>
Co-developed-by: Yangyang Lian <lianyangyang@kylinos.cn>
Signed-off-by: Yangyang Lian <lianyangyang@kylinos.cn>
Signed-off-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Adjust time routines for both 32BIT and 64BIT, including: rdtime_h() /
rdtime_l() definitions for 32BIT and rdtime_d() definition for 64BIT,
get_cycles() and get_cycles64() definitions for 32BIT/64BIT, show time
frequency info ("CPU MHz" and "BogoMIPS") in /proc/cpuinfo, etc.
Use do_div() for division which works on both 32BIT and 64BIT platforms.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Some processors have no IOCSR.VENDOR and IOCSR.CPUNAME, some processors
have these registers but there is no valid information.
Consolidate CPU names in /proc/cpuinfo:
1. Add "PRID" to display the PRID & Core-Name;
2. Let "Model Name" display "Unknown" if no valid name.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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The notifier hook mechanism in proc and cpuinfo is actually unnecessary
for LoongArch because it's not used anywhere.
It was originally added to the MIPS code in commit d6d3c9afaab4 ("MIPS:
MT: proc: Add support for printing VPE and TC ids"), and LoongArch then
inherited it.
But as the kernel code stands now, this notifier hook mechanism doesn't
really make sense for either LoongArch or MIPS.
In addition, the seq_file forward declaration needs to be moved to its
proper place, as only the show_ipi_list() function in smp.c requires it.
Co-developed-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: Yuli Wang <wangyuli@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Remove hard-coded strings by using the str_yes_no() helper function.
Similar to commit c4a0a4a45a45 ("MIPS: kernel: proc: Use str_yes_no()
helper function").
Co-developed-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: Yuli Wang <wangyuli@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Probe ISA level, TLB, IOCSR information from CPUCFG to improve kernel
resilience to different core implementations.
BTW, IOCSR register definition appears to be a platform-specific spec
instead of an architecture spec, even for the Loongson CPUs there is no
guarantee that IOCSR will always present.
Thus it's dangerous to perform IOCSR probing without checking CPU type
and instruction availability.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Loongson-3A6000 and newer processors have hardware page table walker
(PTW) support. PTW can handle all fastpaths of TLBI/TLBL/TLBS/TLBM
exceptions by hardware, software only need to handle slowpaths (page
faults).
BTW, PTW doesn't append _PAGE_MODIFIED for page table entries, so we
change pmd_dirty() and pte_dirty() to also check _PAGE_DIRTY for the
"dirty" attribute.
Signed-off-by: Liang Gao <gaoliang@loongson.cn>
Signed-off-by: Jun Yi <yijun@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Loongson-3A6000 has SMT (Simultaneous Multi-Threading) support, each
physical core has two logical cores (threads). This patch add SMT probe
and scheduler support via ACPI PPTT.
If SCHED_SMT enabled, Loongson-3A6000 is treated as 4 cores, 8 threads;
If SCHED_SMT disabled, Loongson-3A6000 is treated as 8 cores, 8 threads.
Remove smp_num_siblings to support HMP (Heterogeneous Multi-Processing).
Signed-off-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Not all LoongArch processors support CRC32 instructions. This feature
is indicated by CPUCFG1.CRC32 (Bit25) but it is wrongly defined in the
previous versions of the ISA manual (and so does in loongarch.h). The
CRC32 feature is set unconditionally now, so fix it.
BTW, expose the CRC32 feature in /proc/cpuinfo.
Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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When CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS is selected,
cpu_max_bits_warn() generates a runtime warning similar as below while
we show /proc/cpuinfo. Fix this by using nr_cpu_ids (the runtime limit)
instead of NR_CPUS to iterate CPUs.
[ 3.052463] ------------[ cut here ]------------
[ 3.059679] WARNING: CPU: 3 PID: 1 at include/linux/cpumask.h:108 show_cpuinfo+0x5e8/0x5f0
[ 3.070072] Modules linked in: efivarfs autofs4
[ 3.076257] CPU: 0 PID: 1 Comm: systemd Not tainted 5.19-rc5+ #1052
[ 3.084034] Hardware name: Loongson Loongson-3A5000-7A1000-1w-V0.1-CRB/Loongson-LS3A5000-7A1000-1w-EVB-V1.21, BIOS Loongson-UDK2018-V2.0.04082-beta7 04/27
[ 3.099465] Stack : 9000000100157b08 9000000000f18530 9000000000cf846c 9000000100154000
[ 3.109127] 9000000100157a50 0000000000000000 9000000100157a58 9000000000ef7430
[ 3.118774] 90000001001578e8 0000000000000040 0000000000000020 ffffffffffffffff
[ 3.128412] 0000000000aaaaaa 1ab25f00eec96a37 900000010021de80 900000000101c890
[ 3.138056] 0000000000000000 0000000000000000 0000000000000000 0000000000aaaaaa
[ 3.147711] ffff8000339dc220 0000000000000001 0000000006ab4000 0000000000000000
[ 3.157364] 900000000101c998 0000000000000004 9000000000ef7430 0000000000000000
[ 3.167012] 0000000000000009 000000000000006c 0000000000000000 0000000000000000
[ 3.176641] 9000000000d3de08 9000000001639390 90000000002086d8 00007ffff0080286
[ 3.186260] 00000000000000b0 0000000000000004 0000000000000000 0000000000071c1c
[ 3.195868] ...
[ 3.199917] Call Trace:
[ 3.203941] [<90000000002086d8>] show_stack+0x38/0x14c
[ 3.210666] [<9000000000cf846c>] dump_stack_lvl+0x60/0x88
[ 3.217625] [<900000000023d268>] __warn+0xd0/0x100
[ 3.223958] [<9000000000cf3c90>] warn_slowpath_fmt+0x7c/0xcc
[ 3.231150] [<9000000000210220>] show_cpuinfo+0x5e8/0x5f0
[ 3.238080] [<90000000004f578c>] seq_read_iter+0x354/0x4b4
[ 3.245098] [<90000000004c2e90>] new_sync_read+0x17c/0x1c4
[ 3.252114] [<90000000004c5174>] vfs_read+0x138/0x1d0
[ 3.258694] [<90000000004c55f8>] ksys_read+0x70/0x100
[ 3.265265] [<9000000000cfde9c>] do_syscall+0x7c/0x94
[ 3.271820] [<9000000000202fe4>] handle_syscall+0xc4/0x160
[ 3.281824] ---[ end trace 8b484262b4b8c24c ]---
Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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LoongArch-based procesors have 4, 8 or 16 cores per package. This patch
adds multi-processor (SMP) support for LoongArch.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Add some misc common routines for LoongArch, including: asm-offsets
routines, futex functions, i/o memory access functions, frame-buffer
functions, procfs information display, etc.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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