From 954260ff5a4657eb97ad7e1618505074f1610acc Mon Sep 17 00:00:00 2001 From: Charlie Jenkins Date: Mon, 26 Aug 2024 09:36:45 -0700 Subject: [PATCH 1/3] Revert "RISC-V: mm: Document mmap changes" This mmap behavior caused unintended breakages so the behavior has been changed. Signed-off-by: Charlie Jenkins Link: https://lore.kernel.org/r/20240826-riscv_mmap-v1-1-cd8962afe47f@rivosinc.com Signed-off-by: Palmer Dabbelt --- Documentation/arch/riscv/vm-layout.rst | 16 ---------------- 1 file changed, 16 deletions(-) diff --git a/Documentation/arch/riscv/vm-layout.rst b/Documentation/arch/riscv/vm-layout.rst index 077b968dcc81..eabec99b5852 100644 --- a/Documentation/arch/riscv/vm-layout.rst +++ b/Documentation/arch/riscv/vm-layout.rst @@ -134,19 +134,3 @@ 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 48 bits the kernel will, by default, return virtual addresses to -userspace from a 48-bit range (sv48). This default behavior is achieved by -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. 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`. From 83dae72ac0382693540a055ec6210dd3691a8df6 Mon Sep 17 00:00:00 2001 From: Charlie Jenkins Date: Mon, 26 Aug 2024 09:36:46 -0700 Subject: [PATCH 2/3] riscv: selftests: Remove mmap hint address checks The mmap behavior that restricts the addresses returned by mmap caused unexpected behavior, so get rid of the test cases that check that behavior. Signed-off-by: Charlie Jenkins Fixes: 73d05262a2ca ("selftests: riscv: Generalize mm selftests") Link: https://lore.kernel.org/r/20240826-riscv_mmap-v1-2-cd8962afe47f@rivosinc.com Signed-off-by: Palmer Dabbelt --- .../selftests/riscv/mm/mmap_bottomup.c | 2 - .../testing/selftests/riscv/mm/mmap_default.c | 2 - tools/testing/selftests/riscv/mm/mmap_test.h | 67 ------------------- 3 files changed, 71 deletions(-) diff --git a/tools/testing/selftests/riscv/mm/mmap_bottomup.c b/tools/testing/selftests/riscv/mm/mmap_bottomup.c index 7f7d3eb8b9c9..f9ccae50349b 100644 --- a/tools/testing/selftests/riscv/mm/mmap_bottomup.c +++ b/tools/testing/selftests/riscv/mm/mmap_bottomup.c @@ -7,8 +7,6 @@ TEST(infinite_rlimit) { EXPECT_EQ(BOTTOM_UP, memory_layout()); - - 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 2ba3ec990006..3f53b6ecc326 100644 --- a/tools/testing/selftests/riscv/mm/mmap_default.c +++ b/tools/testing/selftests/riscv/mm/mmap_default.c @@ -7,8 +7,6 @@ TEST(default_rlimit) { EXPECT_EQ(TOP_DOWN, memory_layout()); - - 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 3b29ca3bb3d4..75918d15919f 100644 --- a/tools/testing/selftests/riscv/mm/mmap_test.h +++ b/tools/testing/selftests/riscv/mm/mmap_test.h @@ -10,76 +10,9 @@ #define TOP_DOWN 0 #define BOTTOM_UP 1 -#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 - -// Only works on 64 bit -#if __riscv_xlen == 64 #define PROT (PROT_READ | PROT_WRITE) #define 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)))); - - 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); \ - } \ - }) -#endif /* __riscv_xlen == 64 */ - static inline int memory_layout(void) { void *value1 = mmap(NULL, sizeof(int), PROT, FLAGS, 0, 0); From 2116988d5372aec51f8c4fb85bf8e305ecda47a0 Mon Sep 17 00:00:00 2001 From: Charlie Jenkins Date: Mon, 26 Aug 2024 09:36:47 -0700 Subject: [PATCH 3/3] riscv: mm: Do not restrict mmap address based on hint The hint address should not forcefully restrict the addresses returned by mmap as this causes mmap to report ENOMEM when there is memory still available. Signed-off-by: Charlie Jenkins Fixes: b5b4287accd7 ("riscv: mm: Use hint address in mmap if available") Fixes: add2cc6b6515 ("RISC-V: mm: Restrict address space for sv39,sv48,sv57") Closes: https://lore.kernel.org/linux-kernel/ZbxTNjQPFKBatMq+@ghost/T/#mccb1890466bf5a488c9ce7441e57e42271895765 Link: https://lore.kernel.org/r/20240826-riscv_mmap-v1-3-cd8962afe47f@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/processor.h | 26 ++------------------------ 1 file changed, 2 insertions(+), 24 deletions(-) diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index 8702b8721a27..efa1b3519b23 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -14,36 +14,14 @@ #include -/* - * addr is a hint to the maximum userspace address that mmap should provide, so - * this macro needs to return the largest address space available so that - * mmap_end < addr, being mmap_end the top of that address space. - * See Documentation/arch/riscv/vm-layout.rst for more details. - */ #define arch_get_mmap_end(addr, len, flags) \ ({ \ - unsigned long mmap_end; \ - typeof(addr) _addr = (addr); \ - if ((_addr) == 0 || is_compat_task() || \ - ((_addr + len) > BIT(VA_BITS - 1))) \ - mmap_end = STACK_TOP_MAX; \ - else \ - mmap_end = (_addr + len); \ - mmap_end; \ + STACK_TOP_MAX; \ }) #define arch_get_mmap_base(addr, base) \ ({ \ - unsigned long mmap_base; \ - typeof(addr) _addr = (addr); \ - typeof(base) _base = (base); \ - unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base); \ - if ((_addr) == 0 || is_compat_task() || \ - ((_addr + len) > BIT(VA_BITS - 1))) \ - mmap_base = (_base); \ - else \ - mmap_base = (_addr + len) - rnd_gap; \ - mmap_base; \ + base; \ }) #ifdef CONFIG_64BIT