From patchwork Tue Aug 27 08:07:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yangyu Chen X-Patchwork-Id: 13779079 Received: from out203-205-221-153.mail.qq.com (out203-205-221-153.mail.qq.com [203.205.221.153]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4798B13A25B; Tue, 27 Aug 2024 08:13:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.205.221.153 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724746414; cv=none; b=gOTb1QO446PIJrWHE/2pGonjmTlgbjCnQP35eVZnkue/FLd1Bll5pDSIcEvrXD83XFB5ju50+f71dKOaCiTPG6p9j5huPds+3139Wh6N+d8K/koq+YxjgalpF8FYGQdDDiCR9HL32MnsO8VaIqDj+/aEBJjucvVK8dx7eZZKVsE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724746414; c=relaxed/simple; bh=brxIHIhoJFw108t/+E6yNWww1AL7fWvuY4Jx+V5yz6k=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=hv5hN3aOT7KaeYjPIlJkoQO8A9Lz3QZbvyBXfjQmWDM9SXU4og1F926AUsB1vKDnqD3Sk2vt8VUnNf62pJDKIhOnmEtOIH42x94d91GKWzpY9FTzHPwLQRbv67+2u34JnZtb9dbyYBhuwlJMKaN98OXErtCcBMgMRKX/imPyhUk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=cyyself.name; spf=none smtp.mailfrom=cyyself.name; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b=DS1XSX/B; arc=none smtp.client-ip=203.205.221.153 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=cyyself.name Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=cyyself.name Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b="DS1XSX/B" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1724746406; bh=CgMtB9NDiiOVMtrdwmpIxkXfBYM+Acie7PSpkw7YuOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DS1XSX/BVNbCRcpOQFqXOlg2JPLDOhgFHSwb6xzAvIdczwnV5pAJRlczOoMOxRVa9 u/imr10u+X99JZFJ34zp8fU3I0oYz5e7XDgrlP7GRRPUVDiYXkjrnGqNOalvcoJ7O+ NGdTBTJ0hLiV14wxq0/NJTKDWBKOExS3x8Bji9yU= Received: from cyy-pc.lan ([240e:379:224b:5f00:16b6:fb41:2849:da9d]) by newxmesmtplogicsvrszc13-0.qq.com (NewEsmtp) with SMTP id 1CBA7234; Tue, 27 Aug 2024 16:07:11 +0800 X-QQ-mid: xmsmtpt1724746031tezlmmzao Message-ID: X-QQ-XMAILINFO: OaubouGXmhNzKe8gtNppzHDxLG7c3mFvh6NtIPeJyusxWfaLbmxKeF7Vq1moLz Yzqmo2u4gO9I8sHODtIT1ur8ndKDpu5N+8CNRUG5Y1gKKXu6xdTBIJwS0DKgbl1uzntqrdlTzPEu vKmz6N5cbn9ql5cbuk/srU7/19hiZpVtwVng5ThGr6krXsN0tr8MCAXhFkEL2W8B8RI39TMFuCKA M/ZA+Vj96OdLAvi6+YbDpM5XkWhIt15q+B2F+R3j4Vv5PB0WJdk734Wkyn/xUdCyWHhWirS6I+Pc UZgDVN4MyherF+Q1bvByOC+tZr8Pisfe2UI8NtdlfP4U/Md1+pl9MddrZ0mbX5Th6SmxzwZo9hfq VAKCr9OdCpQg8RyjuBDpIAgz4hM0z52aEEsgtIJeDOND7jaZokLljeu8i2zpC/eWnIxakbGwN/08 TakhPOAYZKQ3EKqH+EpyZFegUFyt9KgoF8/AdpqDchrNEBtGs0HNHpTMyFoNCwpHj5wrGNNim+9G GDH6mdzM7RXFX7riLYSdq2sp5Qmcgb2MdsdStHqwGjgwMMHysDtZ7NOmR2XFv/Zk+ue4IcpafiER rQFSlyL9lEm1og3ui0JMhUhDa4gcJWhqAnew2VVipfcf/YKa0ZuLZf1ABPq9w1bpu81LZm3rR4xv 2Izlo79ZTWPwYyLBXTQy8MeSfgK4k0mhEQsvutcLVEdveucF4tX+vne8X9umbpSP+0kQ7WEyX0+l YQrhcGEUCizd49cpdrPZYHyJtHUc4oZpVG//bxqq0SAs9EHe6I1rHQJx/emQjMwSy0tERi6P2txl yibVxH7WohvEXPc6g04rIteIrrkeaey+2NedUFVkNYPnuRP0MPXPxlip/4YXtn4FNum6E6QJvdr7 rbOC8HF6WxDG9+WPPziNNTaV8t7NxKhpokzooMrjbd3hWvNmFwfhdxAGZqVZhoUGXgM40dHd9j8p uTv1oKBqoFiiJbbsVjbILgh7kFfLXOS10ssdMaKZYQ2Ixk2OGfKWl2C6UdCkV0IwIMRHX5m7mMoP f2e1YisQ== X-QQ-XMRINFO: OWPUhxQsoeAVDbp3OJHYyFg= From: Yangyu Chen To: linux-riscv@lists.infradead.org Cc: Charlie Jenkins , Jonathan Corbet , Paul Walmsley , Palmer Dabbelt , Albert Ou , Shuah Khan , Levi Zim , Alexandre Ghiti , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Palmer Dabbelt , linux-kselftest@vger.kernel.org, Yangyu Chen Subject: [PATCH v3 1/3] riscv: selftests: Remove mmap hint address checks Date: Tue, 27 Aug 2024 16:07:05 +0800 X-OQ-MSGID: <20240827080707.3788836-1-cyy@cyyself.name> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Charlie Jenkins 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") Signed-off-by: Yangyu Chen --- .../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 patchwork Tue Aug 27 08:07:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yangyu Chen X-Patchwork-Id: 13779067 Received: from out162-62-57-49.mail.qq.com (out162-62-57-49.mail.qq.com [162.62.57.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 474D34C92; 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Result in ENOMEM error caused when hint address + size is not big enough. Thus, this patch makes the behavior of mmap syscall to align with x86, arm64, powerpc by only limiting the address space to DEFAULT_MAP_WINDOW which is defined as not larger than 47-bit. If a user program wants to use sv57 address space, it can use mmap with a hint address larger than BIT(47) as it is already documented in x86 and arm64. [1] https://lore.kernel.org/linux-riscv/20240130-use_mmap_hint_address-v3-0-8a655cfa8bcb@rivosinc.com/ Signed-off-by: Yangyu Chen --- arch/riscv/include/asm/processor.h | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index 8702b8721a27..faf3e230ab24 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -13,22 +13,17 @@ #include #include +#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))) \ + if (((_addr + len) > DEFAULT_MAP_WINDOW) || \ + ((flags) & MAP_FIXED)) \ mmap_end = STACK_TOP_MAX; \ else \ - mmap_end = (_addr + len); \ + mmap_end = DEFAULT_MAP_WINDOW; \ mmap_end; \ }) @@ -38,11 +33,10 @@ 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); \ + if ((_addr + len) > DEFAULT_MAP_WINDOW) \ + mmap_base = (STACK_TOP_MAX - rnd_gap); \ else \ - mmap_base = (_addr + len) - rnd_gap; \ + mmap_base = (_base); \ mmap_base; \ }) From patchwork Tue Aug 27 08:07:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yangyu Chen X-Patchwork-Id: 13779080 Received: from xmbghk7.mail.qq.com (xmbghk7.mail.qq.com [43.163.128.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE66F13D53F; Tue, 27 Aug 2024 08:13:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Most of the content is copied from the corresponding feature in x86_64 with some modifications to align with the current kernel's behavior on RISC-V. Signed-off-by: Yangyu Chen --- Documentation/arch/riscv/vm-layout.rst | 43 +++++++++++++++++--------- 1 file changed, 29 insertions(+), 14 deletions(-) diff --git a/Documentation/arch/riscv/vm-layout.rst b/Documentation/arch/riscv/vm-layout.rst index 077b968dcc81..826d0a3f4cbf 100644 --- a/Documentation/arch/riscv/vm-layout.rst +++ b/Documentation/arch/riscv/vm-layout.rst @@ -136,17 +136,32 @@ RISC-V Linux Kernel SV57 __________________|____________|__________________|_________|____________________________________________________________ -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`. +User-space and large virtual address space +========================================== +On RISC-V, Sv57 paging enables 56-bit userspace virtual address space. Not all +user space is ready to handle wide addresses. It's known that at least some JIT +compilers use higher bits in pointers to encode their information. It collides +with valid pointers with Sv57 paging and leads to crashes. + +To mitigate this, we are not going to allocate virtual address space above +47-bit by default. + +But userspace can ask for allocation from full address space by specifying hint +address (with or without MAP_FIXED) above 47-bits, or hint address + size above +47-bits with MAP_FIXED. + +If hint address set above 47-bit, but MAP_FIXED is not specified, we try to look +for unmapped area by specified address. If it's already occupied, we look for +unmapped area in *full* address space, rather than from 47-bit window. + +A high hint address would only affect the allocation in question, but not any +future mmap()s. + +Specifying high hint address without MAP_FIXED on older kernel or on machine +without Sv57 paging support is safe. The hint will be treated as the upper bound +of the address space to search, but this was removed in the future version of +kernels. On machine without Sv57 paging support, the kernel will fall back to +allocation from the supported address space. + +This approach helps to easily make application's memory allocator aware about +large address space without manually tracking allocated virtual address space.