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s=mail; t=1687947536; bh=wjXfrVAEdgRtJih00XQKOmdI4zz3e9GGF55OJ8aSRzw=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=oHQVqn/3iKApHfD34tTWmZYFMMBrTnxwReaSl8LBOQ3XQjDw5efuXstg6bcE3wiZS VGvXS+qM4TGZ0/n3NV2wJPJVArHf3sUz4YwzciTX2WJxXS4F+E2xQoPsWhb4Opl0i3 e8dFSAngv0AoxnQwuTQtkdHEc0M8O1Wu7bJ6YLUS5irdjAfr9WxsA8qaHgdGeqLHh/ C4zN65aX7A467Ycz6z+LJg5xmcBwgJrtFnTPtOAtjGL39Zlem0rx0VOU8qKM0nKAJA BGAPxuwE9YbbReZV+VPGEi8oJ4aPpBSfx8jfQiv69DngzNLXK7YnVe36oIXkT1AZMR z3q/gYI8RWQEQ== Message-ID: <89dbc532-f8cc-5bfd-3dc0-d793fa1bde26@collabora.com> Date: Wed, 28 Jun 2023 15:18:49 +0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Cc: Muhammad Usama Anjum , atishp@rivosinc.com, conor@kernel.org, paul.walmsley@sifive.com, palmer@rivosinc.com, aou@eecs.berkeley.edu, bjorn@rivosinc.com, anup@brainfault.org, evan@rivosinc.com, linux-riscv@lists.infradead.org, konstantin@linuxfoundation.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 2/2] RISC-V: mm: Update documentation and include test Content-Language: en-US To: Charlie Jenkins , alexghiti@rivosinc.com References: <20230627222152.177716-1-charlie@rivosinc.com> <20230627222152.177716-3-charlie@rivosinc.com> From: Muhammad Usama Anjum In-Reply-To: <20230627222152.177716-3-charlie@rivosinc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 105B8160002 X-Rspam-User: X-Stat-Signature: pemt8nq1fxjfsdrfhedr9qq378iizoni X-Rspamd-Server: rspam03 X-HE-Tag: 1687947537-194160 X-HE-Meta: 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 ni9Gp01X Wxe+QWZvaZRFTuIGvvw4UdzzwklqIMSc2WLvz7tnV5ehi/mEcqnE0IVpuP0bIkn7gnW3iWR2fI+sPbGFtS3IVDlvvkBSx3BNrwylSOQ5rNFLqAkmilBIb49mNHtHjdoMP2e2xidgr8JzlEV/BoGLgTsV3lCvBjTP20vNYr45T41ObfTkms9WOUlZStWDPywAx5Blrh1alLShYgqzo8V+EYQ8Sv5ZsHvWo+qZL/0SDhq/oMVeAymwhj3wwdprVgEbrn/ZyazQt3R/fLpo= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000004, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 6/28/23 3:21 AM, Charlie Jenkins wrote: > Add documentation explaining the behavior of mmap. Include > a simple test that ensures that mmap returns an address less > than the hint address while there are still addresses available. > > Signed-off-by: Charlie Jenkins > --- > Documentation/riscv/vm-layout.rst | 20 ++++++++ > arch/riscv/include/asm/pgtable.h | 8 +-- > tools/testing/selftests/riscv/Makefile | 2 +- > tools/testing/selftests/riscv/mm/Makefile | 22 +++++++++ > .../selftests/riscv/mm/testcases/mmap.c | 49 +++++++++++++++++++ Please add a .gitignore file and specify the artifacts there i.e., mmap. > 5 files changed, 97 insertions(+), 4 deletions(-) > create mode 100644 tools/testing/selftests/riscv/mm/Makefile > create mode 100644 tools/testing/selftests/riscv/mm/testcases/mmap.c > > diff --git a/Documentation/riscv/vm-layout.rst b/Documentation/riscv/vm-layout.rst > index 5462c84f4723..365a481be90b 100644 > --- a/Documentation/riscv/vm-layout.rst > +++ b/Documentation/riscv/vm-layout.rst > @@ -133,3 +133,23 @@ RISC-V Linux Kernel SV57 > ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF > ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel > __________________|____________|__________________|_________|____________________________________________________________ > + > + > +Userspace VAs > +-------------------- > +To maintain compatibility with software that relies on the VA space > +with a maximum of 39-bits, the kernel will, by default, return virtual > +return virtual addresses to userspace from a 39-bit range. > + > +Software can "opt-in" to receiving VAs from other VA space by providing > +a hint address to mmap. A call to mmap is guaranteed to return an address > +that will not override the unset left-aligned bits in the hint address, > +unless there is no space left in the address space. If there is no space > +available in the requested address space, an address in the next smallest > +available address space will be returned. > + > +For example, in order to obtain 48-bit VA space, a hint address greater than > +:code:`1 << 38` must be provided. Note that this is 38 due to sv39 userspace > +ending at :code:`1 << 38` with the addresses beyond this and up to :code:`1 << 39` > +being reserved for the kernel. Similarly, to obtain 57-bit VA space addresses, a > +hint address greater than or equal to :code:`1 << 47` must be provided. > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index e83912e97870..93e7233d5d2a 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -841,14 +841,16 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte) > * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32. > * Note that PGDIR_SIZE must evenly divide TASK_SIZE. > * Task size is: > - * - 0x9fc00000 (~2.5GB) for RV32. > - * - 0x4000000000 ( 256GB) for RV64 using SV39 mmu > - * - 0x800000000000 ( 128TB) for RV64 using SV48 mmu > + * - 0x9fc00000 (~2.5GB) for RV32. > + * - 0x4000000000 ( 256GB) for RV64 using SV39 mmu > + * - 0x800000000000 ( 128TB) for RV64 using SV48 mmu > + * - 0x100000000000000 ( 64PB) for RV64 using SV57 mmu > * > * Note that PGDIR_SIZE must evenly divide TASK_SIZE since "RISC-V > * Instruction Set Manual Volume II: Privileged Architecture" states that > * "load and store effective addresses, which are 64bits, must have bits > * 63–48 all equal to bit 47, or else a page-fault exception will occur." > + * Similarly for SV57, bits 63–57 must be equal to bit 56. > */ > #ifdef CONFIG_64BIT > #define TASK_SIZE_64 (PGDIR_SIZE * PTRS_PER_PGD / 2) > diff --git a/tools/testing/selftests/riscv/Makefile b/tools/testing/selftests/riscv/Makefile > index 32a72902d045..0fee58f990ae 100644 > --- a/tools/testing/selftests/riscv/Makefile > +++ b/tools/testing/selftests/riscv/Makefile > @@ -5,7 +5,7 @@ > ARCH ?= $(shell uname -m 2>/dev/null || echo not) > > ifneq (,$(filter $(ARCH),riscv)) > -RISCV_SUBTARGETS ?= hwprobe > +RISCV_SUBTARGETS ?= hwprobe mm > else > RISCV_SUBTARGETS := > endif > diff --git a/tools/testing/selftests/riscv/mm/Makefile b/tools/testing/selftests/riscv/mm/Makefile > new file mode 100644 > index 000000000000..4aadf04401db > --- /dev/null > +++ b/tools/testing/selftests/riscv/mm/Makefile > @@ -0,0 +1,22 @@ > +# SPDX-License-Identifier: GPL-2.0 > +# Copyright (C) 2019 ARM Limited > +# Originally tools/testing/selftests/arm64/signal > + > +# Additional include paths needed by kselftest.h and local headers > +CFLAGS += -D_GNU_SOURCE -std=gnu99 -I. > + > +SRCS := $(filter-out testcases/testcases.c,$(wildcard testcases/*.c)) > +PROGS := $(patsubst %.c,%,$(SRCS)) > + > +# Generated binaries to be installed by top KSFT script > +TEST_GEN_PROGS := $(notdir $(PROGS)) > + > +# Get Kernel headers installed and use them. > + > +# Including KSFT lib.mk here will also mangle the TEST_GEN_PROGS list > +# to account for any OUTPUT target-dirs optionally provided by > +# the toplevel makefile > +include ../../lib.mk > + > +$(TEST_GEN_PROGS): $(PROGS) > + cp $(PROGS) $(OUTPUT)/ > \ No newline at end of file > diff --git a/tools/testing/selftests/riscv/mm/testcases/mmap.c b/tools/testing/selftests/riscv/mm/testcases/mmap.c > new file mode 100644 > index 000000000000..aa37a623b93f > --- /dev/null > +++ b/tools/testing/selftests/riscv/mm/testcases/mmap.c > @@ -0,0 +1,49 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +#include > +#include "../../kselftest_harness.h" > + > +TEST(sv57_test) > +{ > + // Only works on 64 bit > + #if __riscv_xlen == 64 > + // Place all of the hint addresses on the boundaries of mmap > + // sv39, sv48, sv57 > + // User addresses end at 1<<38, 1<<47, 1<<56 respectively > + void *on_37_bits = (void *) (1UL << 37); > + void *on_38_bits = (void *) (1UL << 38); > + void *on_46_bits = (void *) (1UL << 46); > + void *on_47_bits = (void *) (1UL << 47); > + void *on_55_bits = (void *) (1UL << 55); > + void *on_56_bits = (void *) (1UL << 56); > + > + int prot = PROT_READ | PROT_WRITE; > + int flags = MAP_PRIVATE | MAP_ANONYMOUS; > + > + int *no_hint = mmap(NULL, 5*sizeof(int), prot, flags, 0, 0); > + int *on_37_addr = mmap(on_37_bits, 5*sizeof(int), prot, flags, 0, 0); > + int *on_38_addr = mmap(on_38_bits, 5*sizeof(int), prot, flags, 0, 0); > + int *on_46_addr = mmap(on_46_bits, 5*sizeof(int), prot, flags, 0, 0); > + int *on_47_addr = mmap(on_47_bits, 5*sizeof(int), prot, flags, 0, 0); > + int *on_55_addr = mmap(on_55_bits, 5*sizeof(int), prot, flags, 0, 0); > + int *on_56_addr = mmap(on_56_bits, 5*sizeof(int), prot, flags, 0, 0); > + > + EXPECT_NE(no_hint, MAP_FAILED); > + EXPECT_NE(on_37_addr, MAP_FAILED); > + EXPECT_NE(on_38_addr, MAP_FAILED); > + EXPECT_NE(on_46_addr, MAP_FAILED); > + EXPECT_NE(on_47_addr, MAP_FAILED); > + EXPECT_NE(on_55_addr, MAP_FAILED); > + EXPECT_NE(on_56_addr, MAP_FAILED); > + > + EXPECT_LT((unsigned long) no_hint, 1UL << 38); > + EXPECT_LT((unsigned long) on_37_addr, 1UL << 38); > + EXPECT_LT((unsigned long) on_38_addr, 1UL << 38); > + EXPECT_LT((unsigned long) on_46_addr, 1UL << 38); > + EXPECT_LT((unsigned long) on_47_addr, 1UL << 47); > + EXPECT_LT((unsigned long) on_55_addr, 1UL << 47); > + EXPECT_LT((unsigned long) on_56_addr, 1UL << 57); > + #else > + #endif > +} > + > +TEST_HARNESS_MAIN -- BR, Muhammad Usama Anjum