| Message ID | 20230627222152.177716-3-charlie@rivosinc.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Make SV39 the default address space | expand |
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 <charlie@rivosinc.com> > --- > 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 <sys/mman.h> > +#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
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 <sys/mman.h> +#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
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 <charlie@rivosinc.com> --- 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