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Tue, 27 Jun 2023 15:23:22 -0700 (PDT) Received: from ghost.hq.rivosinc.com ([50.221.140.188]) by smtp.gmail.com with ESMTPSA id 4-20020a170902c24400b001ac94b33ab1sm5108271plg.304.2023.06.27.15.23.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jun 2023 15:23:21 -0700 (PDT) From: Charlie Jenkins To: alexghiti@rivosinc.com Cc: charlie@rivosinc.com, 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: [PATCH 1/2] RISC-V: mm: Restrict address space for sv39,sv48,sv57 Date: Tue, 27 Jun 2023 15:21:51 -0700 Message-Id: <20230627222152.177716-2-charlie@rivosinc.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230627222152.177716-1-charlie@rivosinc.com> References: <20230627222152.177716-1-charlie@rivosinc.com> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 99D8F40014 X-Stat-Signature: j9ezqettr9ccyin93nhma38acdwy8oo8 X-HE-Tag: 1687904603-429365 X-HE-Meta: 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 HH/IotWH 8PdE10n4w6ZZ4V3CP0MxOgZRlZHhii/deJiGNW0MS+tGgm3QYj9CGIeSwCoFDWBIwVDKcPSJpBh1ZwcaOTlkbWDB2SMlUPuX79AjDRHQMFxBaRRLp17QLegt9dzeIxieBhFZKfz/v3RU1P70dr8nM5QzO9mXC34E+8Ftj6lgRKTvah+pM5FkmBkYFb4Ev3+orut+g7VNcDCVQXX/CSEux41eUJ95rgkGEMqARHw3HsLe6yrx6nwZ2pdmY86vWjAE7sgV7MN9YpJ4OuIgQf13jojTyXCXb/aF9rJbnz41kK9KwOryo7vOJM4LdfTlo+yOkYJTM2PoCUaMcoNLocljwKDrSBuobhcTU4zm2E9t2WXOkvkduGyxYgYECiGXq7di9Kli1W6WpJL9PHpT4qiG/6fKefjyE7oOWoRaZyXZYsvLP1jP1/zrF+P24M20ExyBHb7Tk X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Make sv39 the default address space for mmap as some applications currently depend on this assumption. The RISC-V specification enforces that bits outside of the virtual address range are not used, so restricting the size of the default address space as such should be temporary. A hint address passed to mmap will cause the largest address space that fits entirely into the hint to be used. If the hint is less than or equal to 1<<38, a 39-bit address will be used. After an address space is completely full, the next smallest address space will be used. Signed-off-by: Charlie Jenkins --- arch/riscv/include/asm/elf.h | 2 +- arch/riscv/include/asm/pgtable.h | 13 +++++++++- arch/riscv/include/asm/processor.h | 41 +++++++++++++++++++++++++----- 3 files changed, 47 insertions(+), 9 deletions(-) diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h index 30e7d2455960..1b57f13a1afd 100644 --- a/arch/riscv/include/asm/elf.h +++ b/arch/riscv/include/asm/elf.h @@ -49,7 +49,7 @@ extern bool compat_elf_check_arch(Elf32_Ehdr *hdr); * the loader. We need to make sure that it is out of the way of the program * that it will "exec", and that there is sufficient room for the brk. */ -#define ELF_ET_DYN_BASE ((TASK_SIZE / 3) * 2) +#define ELF_ET_DYN_BASE ((DEFAULT_MAP_WINDOW / 3) * 2) #ifdef CONFIG_64BIT #ifdef CONFIG_COMPAT diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 75970ee2bda2..e83912e97870 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -57,18 +57,29 @@ #define MODULES_END (PFN_ALIGN((unsigned long)&_start)) #endif + /* * Roughly size the vmemmap space to be large enough to fit enough * struct pages to map half the virtual address space. Then * position vmemmap directly below the VMALLOC region. */ #ifdef CONFIG_64BIT +#define VA_BITS_SV39 39 +#define VA_BITS_SV48 48 +#define VA_BITS_SV57 57 + +#define VA_USER_SV39 (UL(1) << (VA_BITS_SV39 - 1)) +#define VA_USER_SV48 (UL(1) << (VA_BITS_SV48 - 1)) +#define VA_USER_SV57 (UL(1) << (VA_BITS_SV57 - 1)) + #define VA_BITS (pgtable_l5_enabled ? \ - 57 : (pgtable_l4_enabled ? 48 : 39)) + VA_BITS_SV57 : (pgtable_l4_enabled ? VA_BITS_SV48 : VA_BITS_SV39)) #else #define VA_BITS 32 #endif +#define DEFAULT_VA_BITS ((VA_BITS >= VA_BITS_SV39) ? VA_BITS_SV39 : VA_BITS) + #define VMEMMAP_SHIFT \ (VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT) #define VMEMMAP_SIZE BIT(VMEMMAP_SHIFT) diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index 6fb8bbec8459..019dcd4ecae4 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -12,20 +12,47 @@ #include -/* - * This decides where the kernel will search for a free chunk of vm - * space during mmap's. - */ -#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3) - -#define STACK_TOP TASK_SIZE #ifdef CONFIG_64BIT +#define DEFAULT_MAP_WINDOW (UL(1) << (DEFAULT_VA_BITS - 1)) #define STACK_TOP_MAX TASK_SIZE_64 + +#define arch_get_mmap_end(addr, len, flags) \ + ((addr) == 0 || (addr) >= VA_USER_SV57 ? STACK_TOP_MAX : \ + (((addr) >= VA_USER_SV48) && (VA_BITS >= VA_BITS_SV48)) ? \ + VA_USER_SV48 : \ + VA_USER_SV39) + +#define arch_get_mmap_base(addr, base) \ + (((addr >= VA_USER_SV57) && (VA_BITS >= VA_BITS_SV57)) ? \ + base + STACK_TOP_MAX - DEFAULT_MAP_WINDOW : \ + (((addr) >= VA_USER_SV48) && (VA_BITS >= VA_BITS_SV48)) ? \ + base + VA_USER_SV48 - DEFAULT_MAP_WINDOW : \ + base) + #else +#define DEFAULT_MAP_WINDOW TASK_SIZE #define STACK_TOP_MAX TASK_SIZE + +#define arch_get_mmap_end(addr, len, flags) \ + ((addr) > DEFAULT_MAP_WINDOW ? STACK_TOP_MAX : DEFAULT_MAP_WINDOW) + +#define arch_get_mmap_base(addr, base) \ + ((addr > DEFAULT_MAP_WINDOW) ? \ + base + STACK_TOP_MAX - DEFAULT_MAP_WINDOW : \ + base) + #endif #define STACK_ALIGN 16 + +#define STACK_TOP DEFAULT_MAP_WINDOW + +/* + * This decides where the kernel will search for a free chunk of vm + * space during mmap's. + */ +#define TASK_UNMAPPED_BASE PAGE_ALIGN(DEFAULT_MAP_WINDOW / 3) + #ifndef __ASSEMBLY__ struct task_struct; From patchwork Tue Jun 27 22:21:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Charlie Jenkins X-Patchwork-Id: 13295061 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F6BEC001DE for ; Tue, 27 Jun 2023 22:23:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3C9818D0001; Tue, 27 Jun 2023 18:23:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 379D78E0001; 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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 +++++++++++++++++++ 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