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[PATCH v7 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57

Charlie Jenkins posted 4 patches 2 years, 1 month ago
There is a newer version of this series
[PATCH v7 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57
Posted by Charlie Jenkins 2 years, 1 month ago 
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   | 13 ++++++++-
 arch/riscv/include/asm/processor.h | 47 +++++++++++++++++++++++++-----
 3 files changed, 53 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..530f6a171a2b 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -63,12 +63,23 @@
  * 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 MMAP_MIN_VA_BITS ((VA_BITS >= VA_BITS_SV39) ? VA_BITS_SV39 : 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..050e27577419 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -13,20 +13,53 @@
 
 #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) == 0)	\
+		mmap_end = DEFAULT_MAP_WINDOW;	\
+	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; \
+	unsigned long rnd_gap = (base) - DEFAULT_MAP_WINDOW; \
+	if ((addr) == 0) \
+		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(MMAP_MIN_VA_BITS / 3)
+
 #ifndef __ASSEMBLY__
 
 struct task_struct;
-- 
2.41.0
Re: [PATCH v7 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57
Posted by Conor Dooley 2 years, 1 month ago 
Hey Charlie,

On Wed, Jul 26, 2023 at 09:45:55AM -0700, Charlie Jenkins wrote:
> 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   | 13 ++++++++-
>  arch/riscv/include/asm/processor.h | 47 +++++++++++++++++++++++++-----
>  3 files changed, 53 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..530f6a171a2b 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -63,12 +63,23 @@
>   * 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

Please, at the very least, build test things for rv32 if you are going
to change things in mm:
io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'

Thanks,
Conor.
Re: [PATCH v7 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57
Posted by Charlie Jenkins 2 years, 1 month ago 
On Thu, Jul 27, 2023 at 01:33:41PM +0100, Conor Dooley wrote:
> Hey Charlie,
> 
> On Wed, Jul 26, 2023 at 09:45:55AM -0700, Charlie Jenkins wrote:
> > 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   | 13 ++++++++-
> >  arch/riscv/include/asm/processor.h | 47 +++++++++++++++++++++++++-----
> >  3 files changed, 53 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..530f6a171a2b 100644
> > --- a/arch/riscv/include/asm/pgtable.h
> > +++ b/arch/riscv/include/asm/pgtable.h
> > @@ -63,12 +63,23 @@
> >   * 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
> 
> Please, at the very least, build test things for rv32 if you are going
> to change things in mm:
> io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
> io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
> io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
> io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
> io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
> io_uring/io_uring.c:3457:20: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/util.c:441:19: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
> mm/mmap.c:1770:20: error: use of undeclared identifier 'VA_BITS_SV39'
> 
> Thanks,
> Conor.
Thanks for that catch, I sent out a new patch to fix that up. There were
also some problems with 32-bit compat support that I resolved.

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