From: Charlie Jenkins <charlie@rivosinc.com>
To: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: charlie@rivosinc.com, conor@kernel.org, paul.walmsley@sifive.com,
palmer@rivosinc.com, aou@eecs.berkeley.edu, anup@brainfault.org,
konstantin@linuxfoundation.org, linux-doc@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-mm@kvack.org,
mick@ics.forth.gr, jrtc27@jrtc27.com, rdunlap@infradead.org,
alexghiti@rivosinc.com
Subject: [PATCH v10 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57
Date: Wed, 9 Aug 2023 16:22:01 -0700 [thread overview]
Message-ID: <20230809232218.849726-2-charlie@rivosinc.com> (raw)
In-Reply-To: <20230809232218.849726-1-charlie@rivosinc.com>
Make sv48 the default address space for mmap as some applications
currently depend on this assumption. 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, an sv39 address will
be used. An exception is that if the hint address is 0, then a sv48
address will be used. After an address space is completely full, the next
smallest address space will be used.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
arch/riscv/include/asm/elf.h | 2 +-
arch/riscv/include/asm/pgtable.h | 25 ++++++++++++--
arch/riscv/include/asm/processor.h | 52 ++++++++++++++++++++++++++----
3 files changed, 70 insertions(+), 9 deletions(-)
diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
index c24280774caf..5d3368d5585c 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..bb0b9ac7b581 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -62,11 +62,16 @@
* struct pages to map half the virtual address space. Then
* position vmemmap directly below the VMALLOC region.
*/
+#define VA_BITS_SV32 32
#ifdef CONFIG_64BIT
+#define VA_BITS_SV39 39
+#define VA_BITS_SV48 48
+#define VA_BITS_SV57 57
+
#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
+#define VA_BITS VA_BITS_SV32
#endif
#define VMEMMAP_SHIFT \
@@ -111,11 +116,27 @@
#include <asm/page.h>
#include <asm/tlbflush.h>
#include <linux/mm_types.h>
+#include <asm/compat.h>
#define __page_val_to_pfn(_val) (((_val) & _PAGE_PFN_MASK) >> _PAGE_PFN_SHIFT)
#ifdef CONFIG_64BIT
#include <asm/pgtable-64.h>
+
+#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))
+
+#ifdef CONFIG_COMPAT
+#define MMAP_VA_BITS_64 ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS)
+#define MMAP_MIN_VA_BITS_64 (VA_BITS_SV39)
+#define MMAP_VA_BITS (is_compat_task() ? VA_BITS_SV32 : MMAP_VA_BITS_64)
+#define MMAP_MIN_VA_BITS (is_compat_task() ? VA_BITS_SV32 : MMAP_MIN_VA_BITS_64)
+#else
+#define MMAP_VA_BITS ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS)
+#define MMAP_MIN_VA_BITS (VA_BITS_SV39)
+#endif /* CONFIG_COMPAT */
+
#else
#include <asm/pgtable-32.h>
#endif /* CONFIG_64BIT */
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index c950a8d9edef..3e23e1786d05 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -13,19 +13,59 @@
#include <asm/ptrace.h>
+#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())) \
+ 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; \
+})
+
+#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_ENABLED(CONFIG_COMPAT) && is_compat_task())) \
+ 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; \
+})
+
+#else
+#define DEFAULT_MAP_WINDOW TASK_SIZE
+#define STACK_TOP_MAX TASK_SIZE
+#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(TASK_SIZE / 3)
-
-#define STACK_TOP TASK_SIZE
#ifdef CONFIG_64BIT
-#define STACK_TOP_MAX TASK_SIZE_64
+#define TASK_UNMAPPED_BASE PAGE_ALIGN((UL(1) << MMAP_MIN_VA_BITS) / 3)
#else
-#define STACK_TOP_MAX TASK_SIZE
+#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3)
#endif
-#define STACK_ALIGN 16
#ifndef __ASSEMBLY__
--
2.34.1
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next prev parent reply other threads:[~2023-08-09 23:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-09 23:22 [PATCH v10 0/4] RISC-V: mm: Make SV48 the default address space Charlie Jenkins
2023-08-09 23:22 ` Charlie Jenkins [this message]
2023-08-09 23:22 ` [PATCH v10 2/4] RISC-V: mm: Add tests for RISC-V mm Charlie Jenkins
2023-08-09 23:22 ` [PATCH v10 3/4] RISC-V: mm: Update pgtable comment documentation Charlie Jenkins
2023-08-09 23:22 ` [PATCH v10 4/4] RISC-V: mm: Document mmap changes Charlie Jenkins
2023-08-30 13:20 ` [PATCH v10 0/4] RISC-V: mm: Make SV48 the default address space patchwork-bot+linux-riscv
2024-01-13 17:26 ` Yangyu Chen
2024-01-20 1:34 ` Charlie Jenkins
2024-01-20 6:13 ` Yangyu Chen
2024-01-20 6:49 ` Charlie Jenkins
2024-01-20 7:09 ` Yangyu Chen
2024-01-22 19:56 ` Charlie Jenkins
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