From b5b4287accd702f562a49a60b10dbfaf7d40270f Mon Sep 17 00:00:00 2001 From: Charlie Jenkins Date: Tue, 30 Jan 2024 17:07:00 -0800 Subject: riscv: mm: Use hint address in mmap if available On riscv it is guaranteed that the address returned by mmap is less than the hint address. Allow mmap to return an address all the way up to addr, if provided, rather than just up to the lower address space. This provides a performance benefit as well, allowing mmap to exit after checking that the address is in range rather than searching for a valid address. It is possible to provide an address that uses at most the same number of bits, however it is significantly more computationally expensive to provide that number rather than setting the max to be the hint address. There is the instruction clz/clzw in Zbb that returns the highest set bit which could be used to performantly implement this, but it would still be slower than the current implementation. At worst case, half of the address would not be able to be allocated when a hint address is provided. Signed-off-by: Charlie Jenkins Link: https://lore.kernel.org/r/20240130-use_mmap_hint_address-v3-1-8a655cfa8bcb@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/processor.h | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-) diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index f19f861cda54..8ece7a8f0e18 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -14,22 +14,16 @@ #include -#ifdef CONFIG_64BIT -#define DEFAULT_MAP_WINDOW (UL(1) << (MMAP_VA_BITS - 1)) -#define STACK_TOP_MAX TASK_SIZE_64 - #define arch_get_mmap_end(addr, len, flags) \ ({ \ unsigned long mmap_end; \ typeof(addr) _addr = (addr); \ - if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())) \ + if ((_addr) == 0 || \ + (IS_ENABLED(CONFIG_COMPAT) && is_compat_task()) || \ + ((_addr + len) > BIT(VA_BITS - 1))) \ mmap_end = STACK_TOP_MAX; \ - else if ((_addr) >= VA_USER_SV57) \ - mmap_end = STACK_TOP_MAX; \ - else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48)) \ - mmap_end = VA_USER_SV48; \ else \ - mmap_end = VA_USER_SV39; \ + mmap_end = (_addr + len); \ mmap_end; \ }) @@ -39,17 +33,18 @@ typeof(addr) _addr = (addr); \ typeof(base) _base = (base); \ unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base); \ - if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())) \ + if ((_addr) == 0 || \ + (IS_ENABLED(CONFIG_COMPAT) && is_compat_task()) || \ + ((_addr + len) > BIT(VA_BITS - 1))) \ mmap_base = (_base); \ - else if (((_addr) >= VA_USER_SV57) && (VA_BITS >= VA_BITS_SV57)) \ - mmap_base = VA_USER_SV57 - rnd_gap; \ - else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48)) \ - mmap_base = VA_USER_SV48 - rnd_gap; \ else \ - mmap_base = VA_USER_SV39 - rnd_gap; \ + mmap_base = (_addr + len) - rnd_gap; \ mmap_base; \ }) +#ifdef CONFIG_64BIT +#define DEFAULT_MAP_WINDOW (UL(1) << (MMAP_VA_BITS - 1)) +#define STACK_TOP_MAX TASK_SIZE_64 #else #define DEFAULT_MAP_WINDOW TASK_SIZE #define STACK_TOP_MAX TASK_SIZE -- cgit From 73d05262a2ca28c72c5aec57d79b47c251fe77c5 Mon Sep 17 00:00:00 2001 From: Charlie Jenkins Date: Tue, 30 Jan 2024 17:07:01 -0800 Subject: selftests: riscv: Generalize mm selftests The behavior of mmap on riscv is defined to not provide an address that uses more bits than the hint address, if provided. Make the tests reflect that. Signed-off-by: Charlie Jenkins Link: https://lore.kernel.org/r/20240130-use_mmap_hint_address-v3-2-8a655cfa8bcb@rivosinc.com Signed-off-by: Palmer Dabbelt --- tools/testing/selftests/riscv/mm/mmap_bottomup.c | 23 +---- tools/testing/selftests/riscv/mm/mmap_default.c | 23 +---- tools/testing/selftests/riscv/mm/mmap_test.h | 107 ++++++++++++++--------- 3 files changed, 67 insertions(+), 86 deletions(-) diff --git a/tools/testing/selftests/riscv/mm/mmap_bottomup.c b/tools/testing/selftests/riscv/mm/mmap_bottomup.c index 1757d19ca89b..7f7d3eb8b9c9 100644 --- a/tools/testing/selftests/riscv/mm/mmap_bottomup.c +++ b/tools/testing/selftests/riscv/mm/mmap_bottomup.c @@ -6,30 +6,9 @@ TEST(infinite_rlimit) { -// Only works on 64 bit -#if __riscv_xlen == 64 - struct addresses mmap_addresses; - EXPECT_EQ(BOTTOM_UP, memory_layout()); - do_mmaps(&mmap_addresses); - - EXPECT_NE(MAP_FAILED, mmap_addresses.no_hint); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_37_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_38_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_46_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_47_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_55_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_56_addr); - - EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.no_hint); - EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_37_addr); - EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_38_addr); - EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_46_addr); - EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_47_addr); - EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_55_addr); - EXPECT_GT(1UL << 56, (unsigned long)mmap_addresses.on_56_addr); -#endif + TEST_MMAPS; } TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/riscv/mm/mmap_default.c b/tools/testing/selftests/riscv/mm/mmap_default.c index c63c60b9397e..2ba3ec990006 100644 --- a/tools/testing/selftests/riscv/mm/mmap_default.c +++ b/tools/testing/selftests/riscv/mm/mmap_default.c @@ -6,30 +6,9 @@ TEST(default_rlimit) { -// Only works on 64 bit -#if __riscv_xlen == 64 - struct addresses mmap_addresses; - EXPECT_EQ(TOP_DOWN, memory_layout()); - do_mmaps(&mmap_addresses); - - EXPECT_NE(MAP_FAILED, mmap_addresses.no_hint); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_37_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_38_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_46_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_47_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_55_addr); - EXPECT_NE(MAP_FAILED, mmap_addresses.on_56_addr); - - EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.no_hint); - EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_37_addr); - EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_38_addr); - EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_46_addr); - EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_47_addr); - EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_55_addr); - EXPECT_GT(1UL << 56, (unsigned long)mmap_addresses.on_56_addr); -#endif + TEST_MMAPS; } TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/riscv/mm/mmap_test.h b/tools/testing/selftests/riscv/mm/mmap_test.h index 9b8434f62f57..36e78d991d5e 100644 --- a/tools/testing/selftests/riscv/mm/mmap_test.h +++ b/tools/testing/selftests/riscv/mm/mmap_test.h @@ -4,60 +4,83 @@ #include #include #include +#include +#include "../../kselftest_harness.h" #define TOP_DOWN 0 #define BOTTOM_UP 1 -struct addresses { - int *no_hint; - int *on_37_addr; - int *on_38_addr; - int *on_46_addr; - int *on_47_addr; - int *on_55_addr; - int *on_56_addr; +#if __riscv_xlen == 64 +uint64_t random_addresses[] = { + 0x19764f0d73b3a9f0, 0x016049584cecef59, 0x3580bdd3562f4acd, + 0x1164219f20b17da0, 0x07d97fcb40ff2373, 0x76ec528921272ee7, + 0x4dd48c38a3de3f70, 0x2e11415055f6997d, 0x14b43334ac476c02, + 0x375a60795aff19f6, 0x47f3051725b8ee1a, 0x4e697cf240494a9f, + 0x456b59b5c2f9e9d1, 0x101724379d63cb96, 0x7fe9ad31619528c1, + 0x2f417247c495c2ea, 0x329a5a5b82943a5e, 0x06d7a9d6adcd3827, + 0x327b0b9ee37f62d5, 0x17c7b1851dfd9b76, 0x006ebb6456ec2cd9, + 0x00836cd14146a134, 0x00e5c4dcde7126db, 0x004c29feadf75753, + 0x00d8b20149ed930c, 0x00d71574c269387a, 0x0006ebe4a82acb7a, + 0x0016135df51f471b, 0x00758bdb55455160, 0x00d0bdd949b13b32, + 0x00ecea01e7c5f54b, 0x00e37b071b9948b1, 0x0011fdd00ff57ab3, + 0x00e407294b52f5ea, 0x00567748c200ed20, 0x000d073084651046, + 0x00ac896f4365463c, 0x00eb0d49a0b26216, 0x0066a2564a982a31, + 0x002e0d20237784ae, 0x0000554ff8a77a76, 0x00006ce07a54c012, + 0x000009570516d799, 0x00000954ca15b84d, 0x0000684f0d453379, + 0x00002ae5816302b5, 0x0000042403fb54bf, 0x00004bad7392bf30, + 0x00003e73bfa4b5e3, 0x00005442c29978e0, 0x00002803f11286b6, + 0x000073875d745fc6, 0x00007cede9cb8240, 0x000027df84cc6a4f, + 0x00006d7e0e74242a, 0x00004afd0b836e02, 0x000047d0e837cd82, + 0x00003b42405efeda, 0x00001531bafa4c95, 0x00007172cae34ac4, }; +#else +uint32_t random_addresses[] = { + 0x8dc302e0, 0x929ab1e0, 0xb47683ba, 0xea519c73, 0xa19f1c90, 0xc49ba213, + 0x8f57c625, 0xadfe5137, 0x874d4d95, 0xaa20f09d, 0xcf21ebfc, 0xda7737f1, + 0xcedf392a, 0x83026c14, 0xccedca52, 0xc6ccf826, 0xe0cd9415, 0x997472ca, + 0xa21a44c1, 0xe82196f5, 0xa23fd66b, 0xc28d5590, 0xd009cdce, 0xcf0be646, + 0x8fc8c7ff, 0xe2a85984, 0xa3d3236b, 0x89a0619d, 0xc03db924, 0xb5d4cc1b, + 0xb96ee04c, 0xd191da48, 0xb432a000, 0xaa2bebbc, 0xa2fcb289, 0xb0cca89b, + 0xb0c18d6a, 0x88f58deb, 0xa4d42d1c, 0xe4d74e86, 0x99902b09, 0x8f786d31, + 0xbec5e381, 0x9a727e65, 0xa9a65040, 0xa880d789, 0x8f1b335e, 0xfc821c1e, + 0x97e34be4, 0xbbef84ed, 0xf447d197, 0xfd7ceee2, 0xe632348d, 0xee4590f4, + 0x958992a5, 0xd57e05d6, 0xfd240970, 0xc5b0dcff, 0xd96da2c2, 0xa7ae041d, +}; +#endif -static inline void do_mmaps(struct addresses *mmap_addresses) -{ - /* - * 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); +#define PROT (PROT_READ | PROT_WRITE) +#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS) - int prot = PROT_READ | PROT_WRITE; - int flags = MAP_PRIVATE | MAP_ANONYMOUS; +/* mmap must return a value that doesn't use more bits than the hint address. */ +static inline unsigned long get_max_value(unsigned long input) +{ + unsigned long max_bit = (1UL << (((sizeof(unsigned long) * 8) - 1 - + __builtin_clzl(input)))); - mmap_addresses->no_hint = - mmap(NULL, 5 * sizeof(int), prot, flags, 0, 0); - mmap_addresses->on_37_addr = - mmap(on_37_bits, 5 * sizeof(int), prot, flags, 0, 0); - mmap_addresses->on_38_addr = - mmap(on_38_bits, 5 * sizeof(int), prot, flags, 0, 0); - mmap_addresses->on_46_addr = - mmap(on_46_bits, 5 * sizeof(int), prot, flags, 0, 0); - mmap_addresses->on_47_addr = - mmap(on_47_bits, 5 * sizeof(int), prot, flags, 0, 0); - mmap_addresses->on_55_addr = - mmap(on_55_bits, 5 * sizeof(int), prot, flags, 0, 0); - mmap_addresses->on_56_addr = - mmap(on_56_bits, 5 * sizeof(int), prot, flags, 0, 0); + return max_bit + (max_bit - 1); } +#define TEST_MMAPS \ + ({ \ + void *mmap_addr; \ + for (int i = 0; i < ARRAY_SIZE(random_addresses); i++) { \ + mmap_addr = mmap((void *)random_addresses[i], \ + 5 * sizeof(int), PROT, FLAGS, 0, 0); \ + EXPECT_NE(MAP_FAILED, mmap_addr); \ + EXPECT_GE((void *)get_max_value(random_addresses[i]), \ + mmap_addr); \ + mmap_addr = mmap((void *)random_addresses[i], \ + 5 * sizeof(int), PROT, FLAGS, 0, 0); \ + EXPECT_NE(MAP_FAILED, mmap_addr); \ + EXPECT_GE((void *)get_max_value(random_addresses[i]), \ + mmap_addr); \ + } \ + }) + static inline int memory_layout(void) { - int prot = PROT_READ | PROT_WRITE; - int flags = MAP_PRIVATE | MAP_ANONYMOUS; - - void *value1 = mmap(NULL, sizeof(int), prot, flags, 0, 0); - void *value2 = mmap(NULL, sizeof(int), prot, flags, 0, 0); + void *value1 = mmap(NULL, sizeof(int), PROT, FLAGS, 0, 0); + void *value2 = mmap(NULL, sizeof(int), PROT, FLAGS, 0, 0); return value2 > value1; } -- cgit From 371a3c2055dbb8a88754902fe19aa4fcc4318c29 Mon Sep 17 00:00:00 2001 From: Charlie Jenkins Date: Tue, 30 Jan 2024 17:07:02 -0800 Subject: docs: riscv: Define behavior of mmap Define mmap on riscv to not provide an address that uses more bits than the hint address, if provided. Signed-off-by: Charlie Jenkins Link: https://lore.kernel.org/r/20240130-use_mmap_hint_address-v3-3-8a655cfa8bcb@rivosinc.com Signed-off-by: Palmer Dabbelt --- Documentation/arch/riscv/vm-layout.rst | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/Documentation/arch/riscv/vm-layout.rst b/Documentation/arch/riscv/vm-layout.rst index 69ff6da1dbf8..e476b4386bd9 100644 --- a/Documentation/arch/riscv/vm-layout.rst +++ b/Documentation/arch/riscv/vm-layout.rst @@ -144,14 +144,8 @@ passing 0 into the hint address parameter of mmap. On CPUs with an address space smaller than sv48, the CPU maximum supported address space will be the default. Software can "opt-in" to receiving VAs from another VA space by providing -a hint address to mmap. A hint address passed to mmap will cause the largest -address space that fits entirely into the hint to be used, 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 << 47` must be provided. Note that this is 47 due to sv48 userspace -ending at :code:`1 << 47` and the addresses beyond this are reserved for the -kernel. Similarly, to obtain 57-bit VA space addresses, a hint address greater -than or equal to :code:`1 << 56` must be provided. +a hint address to mmap. When a hint address is passed to mmap, the returned +address will never use more bits than the hint address. For example, if a hint +address of `1 << 40` is passed to mmap, a valid returned address will never use +bits 41 through 63. If no mappable addresses are available in that range, mmap +will return `MAP_FAILED`. -- cgit