linux-kernel - [PATCH v6 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230714165508.94561-2-charlie@rivosinc.com>
Date:   Fri, 14 Jul 2023 09:54:49 -0700
From:   Charlie Jenkins <charlie@...osinc.com>
To:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     charlie@...osinc.com, conor@...nel.org, paul.walmsley@...ive.com,
        palmer@...osinc.com, aou@...s.berkeley.edu, anup@...infault.org,
        konstantin@...uxfoundation.org, linux-doc@...r.kernel.org,
        linux-kselftest@...r.kernel.org, linux-mm@...ck.org,
        mick@....forth.gr, jrtc27@...c27.com, rdunlap@...radead.org,
        alexghiti@...osinc.com
Subject: [PATCH v6 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57

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@...osinc.com>
---
 arch/riscv/include/asm/elf.h       |  2 +-
 arch/riscv/include/asm/pgtable.h   | 12 +++++++-
 arch/riscv/include/asm/processor.h | 46 +++++++++++++++++++++++++-----
 3 files changed, 51 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..e13f5872bfe9 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -63,12 +63,22 @@
  * position vmemmap directly below the VMALLOC region.
  */
 #ifdef CONFIG_64BIT
+#define VA_BITS_SV39 39
+#define VA_BITS_SV48 48
+#define VA_BITS_SV57 57
+
+#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))
+
 #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
 #endif
 
+#define MMAP_VA_BITS ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS)
+
 #define VMEMMAP_SHIFT \
 	(VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)
 #define VMEMMAP_SIZE	BIT(VMEMMAP_SHIFT)
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index c950a8d9edef..14a5396eed3d 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -13,20 +13,52 @@
 
 #include <asm/ptrace.h>
 
-/*
- * 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 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;	\
+	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 if ((addr) == 0)	\
+		mmap_end = DEFAULT_MAP_WINDOW;	\
+	else	\
+		mmap_end = VA_USER_SV39;	\
+	mmap_end;	\
+})
+
+#define arch_get_mmap_base(addr, base)	\
+({	\
+	unsigned long mmap_base;	\
+	if (((addr) >= VA_USER_SV57) && (VA_BITS >= VA_BITS_SV57))	\
+		mmap_base = (base) + (VA_USER_SV57 - DEFAULT_MAP_WINDOW);	\
+	else if ((((addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48))	\
+		mmap_base = (base) + (VA_USER_SV48 - DEFAULT_MAP_WINDOW);	\
+	else if ((addr) == 0)	\
+		mmap_base = (base);	\
+	else	\
+		mmap_base = (base) + (VA_USER_SV39 - DEFAULT_MAP_WINDOW);	\
+	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(DEFAULT_MAP_WINDOW / 3)
+
 #ifndef __ASSEMBLY__
 
 struct task_struct;
-- 
2.41.0