[v7,1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57
Commit Message
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(-)
Comments
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.
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.
@@ -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
@@ -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)
@@ -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;