Re: [PATCH v5 14/14] riscv: Make mmap allocation top-down by default

2019-07-31 Thread Paul Walmsley 
On Tue, 30 Jul 2019, Alexandre Ghiti wrote:

> In order to avoid wasting user address space by using bottom-up mmap
> allocation scheme, prefer top-down scheme when possible.
> 
> Before:
> root@qemuriscv64:~# cat /proc/self/maps
> 0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
> 00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
> 00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
> 00018000-00039000 rw-p  00:00 0  [heap]
> 156000-16d000 r-xp  fe:00 7193   /lib/ld-2.28.so
> 16d000-16e000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
> 16e000-16f000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
> 16f000-17 rw-p  00:00 0
> 17-172000 r-xp  00:00 0  [vdso]
> 174000-176000 rw-p  00:00 0
> 176000-1555674000 r-xp  fe:00 7187   /lib/libc-2.28.so
> 1555674000-1555678000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
> 1555678000-155567a000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
> 155567a000-15556a rw-p  00:00 0
> 3fffb9-3fffbb1000 rw-p  00:00 0  [stack]
> 
> After:
> root@qemuriscv64:~# cat /proc/self/maps
> 0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
> 00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
> 00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
> 2de81000-2dea2000 rw-p  00:00 0  [heap]
> 3ff7eb6000-3ff7ed8000 rw-p  00:00 0
> 3ff7ed8000-3ff7fd6000 r-xp  fe:00 7187   /lib/libc-2.28.so
> 3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
> 3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
> 3ff7fdc000-3ff7fe2000 rw-p  00:00 0
> 3ff7fe4000-3ff7fe6000 r-xp  00:00 0  [vdso]
> 3ff7fe6000-3ff7ffd000 r-xp  fe:00 7193   /lib/ld-2.28.so
> 3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
> 3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
> 3ff7fff000-3ff800 rw-p  00:00 0
> 3fff888000-3fff8a9000 rw-p  00:00 0  [stack]
> 
> Signed-off-by: Alexandre Ghiti 
> Reviewed-by: Christoph Hellwig 
> Reviewed-by: Kees Cook 
> Reviewed-by: Luis Chamberlain 

Acked-by: Paul Walmsley  # for arch/riscv

As Alex notes, this patch depends on "[PATCH] riscv: kbuild: add virtual 
memory system selection":

https://lore.kernel.org/linux-riscv/alpine.deb.2.21..1907301218560.3...@viisi.sifive.com/T/#t

which will likely go up during v5.3-rc.


- Paul

Re: [PATCH v5 14/14] riscv: Make mmap allocation top-down by default

2019-07-31 Thread Guenter Roeck 
On Wed, Jul 31, 2019 at 02:05:23AM -0400, Alex Ghiti wrote:
> On 7/30/19 1:51 AM, Alexandre Ghiti wrote:
> >In order to avoid wasting user address space by using bottom-up mmap
> >allocation scheme, prefer top-down scheme when possible.
> >
> >Before:
> >root@qemuriscv64:~# cat /proc/self/maps
> >0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
> >00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
> >00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
> >00018000-00039000 rw-p  00:00 0  [heap]
> >156000-16d000 r-xp  fe:00 7193   /lib/ld-2.28.so
> >16d000-16e000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
> >16e000-16f000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
> >16f000-17 rw-p  00:00 0
> >17-172000 r-xp  00:00 0  [vdso]
> >174000-176000 rw-p  00:00 0
> >176000-1555674000 r-xp  fe:00 7187   /lib/libc-2.28.so
> >1555674000-1555678000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
> >1555678000-155567a000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
> >155567a000-15556a rw-p  00:00 0
> >3fffb9-3fffbb1000 rw-p  00:00 0  [stack]
> >
> >After:
> >root@qemuriscv64:~# cat /proc/self/maps
> >0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
> >00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
> >00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
> >2de81000-2dea2000 rw-p  00:00 0  [heap]
> >3ff7eb6000-3ff7ed8000 rw-p  00:00 0
> >3ff7ed8000-3ff7fd6000 r-xp  fe:00 7187   /lib/libc-2.28.so
> >3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
> >3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
> >3ff7fdc000-3ff7fe2000 rw-p  00:00 0
> >3ff7fe4000-3ff7fe6000 r-xp  00:00 0  [vdso]
> >3ff7fe6000-3ff7ffd000 r-xp  fe:00 7193   /lib/ld-2.28.so
> >3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
> >3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
> >3ff7fff000-3ff800 rw-p  00:00 0
> >3fff888000-3fff8a9000 rw-p  00:00 0  [stack]
> >
> >Signed-off-by: Alexandre Ghiti 
> >Reviewed-by: Christoph Hellwig 
> >Reviewed-by: Kees Cook 
> >Reviewed-by: Luis Chamberlain 
> >---
> >  arch/riscv/Kconfig | 13 +
> >  1 file changed, 13 insertions(+)
> >
> >diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> >index 8ef64fe2c2b3..8d0d8af1a744 100644
> >--- a/arch/riscv/Kconfig
> >+++ b/arch/riscv/Kconfig
> >@@ -54,6 +54,19 @@ config RISCV
> > select EDAC_SUPPORT
> > select ARCH_HAS_GIGANTIC_PAGE
> > select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
> >+select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
> >+select HAVE_ARCH_MMAP_RND_BITS
> >+
> >+config ARCH_MMAP_RND_BITS_MIN
> >+default 18 if 64BIT
> >+default 8
> >+
> >+# max bits determined by the following formula:
> >+#  VA_BITS - PAGE_SHIFT - 3
> >+config ARCH_MMAP_RND_BITS_MAX
> >+default 33 if RISCV_VM_SV48
> >+default 24 if RISCV_VM_SV39
> >+default 17 if RISCV_VM_SV32
> >  config MMU
> > def_bool y
> 
> 
> Hi Andrew,
> 
> I have just seen you took this series into mmotm but without Paul's patch
> ("riscv: kbuild: add virtual memory system selection") on which this commit
> relies, I'm not sure it could
> compile without it as there is no default for ARCH_MMAP_RND_BITS_MAX.
> 
Yes, this patch results in a bad configuration file.

CONFIG_ARCH_MMAP_RND_BITS_MIN=18
CONFIG_HAVE_ARCH_MMAP_RND_BITS=y
CONFIG_ARCH_MMAP_RND_BITS=0

CONFIG_ARCH_MMAP_RND_BITS=0 is outside the valid range, causing make to ask
for a valid number. Since none exists, one is stuck with something like:

Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 1
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 2
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 3
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 4
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 5
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 6
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 7
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 8
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 19
Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [0] 
(NEW) 18

when trying to compile riscv images. Plus, of course, all automatic builders
bail out as result. 

Guenter

Re: [PATCH v5 14/14] riscv: Make mmap allocation top-down by default

2019-07-31 Thread Alex Ghiti 

On 7/30/19 1:51 AM, Alexandre Ghiti wrote:

In order to avoid wasting user address space by using bottom-up mmap
allocation scheme, prefer top-down scheme when possible.

Before:
root@qemuriscv64:~# cat /proc/self/maps
0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
00018000-00039000 rw-p  00:00 0  [heap]
156000-16d000 r-xp  fe:00 7193   /lib/ld-2.28.so
16d000-16e000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
16e000-16f000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
16f000-17 rw-p  00:00 0
17-172000 r-xp  00:00 0  [vdso]
174000-176000 rw-p  00:00 0
176000-1555674000 r-xp  fe:00 7187   /lib/libc-2.28.so
1555674000-1555678000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
1555678000-155567a000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
155567a000-15556a rw-p  00:00 0
3fffb9-3fffbb1000 rw-p  00:00 0  [stack]

After:
root@qemuriscv64:~# cat /proc/self/maps
0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
2de81000-2dea2000 rw-p  00:00 0  [heap]
3ff7eb6000-3ff7ed8000 rw-p  00:00 0
3ff7ed8000-3ff7fd6000 r-xp  fe:00 7187   /lib/libc-2.28.so
3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
3ff7fdc000-3ff7fe2000 rw-p  00:00 0
3ff7fe4000-3ff7fe6000 r-xp  00:00 0  [vdso]
3ff7fe6000-3ff7ffd000 r-xp  fe:00 7193   /lib/ld-2.28.so
3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
3ff7fff000-3ff800 rw-p  00:00 0
3fff888000-3fff8a9000 rw-p  00:00 0  [stack]

Signed-off-by: Alexandre Ghiti 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Kees Cook 
Reviewed-by: Luis Chamberlain 
---
  arch/riscv/Kconfig | 13 +
  1 file changed, 13 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 8ef64fe2c2b3..8d0d8af1a744 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -54,6 +54,19 @@ config RISCV
select EDAC_SUPPORT
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
+   select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
+   select HAVE_ARCH_MMAP_RND_BITS
+
+config ARCH_MMAP_RND_BITS_MIN
+   default 18 if 64BIT
+   default 8
+
+# max bits determined by the following formula:
+#  VA_BITS - PAGE_SHIFT - 3
+config ARCH_MMAP_RND_BITS_MAX
+   default 33 if RISCV_VM_SV48
+   default 24 if RISCV_VM_SV39
+   default 17 if RISCV_VM_SV32
  
  config MMU

def_bool y



Hi Andrew,

I have just seen you took this series into mmotm but without Paul's 
patch ("riscv: kbuild: add virtual memory system selection") on which 
this commit relies, I'm not sure it could

compile without it as there is no default for ARCH_MMAP_RND_BITS_MAX.

Thanks,

Alex

[PATCH v5 14/14] riscv: Make mmap allocation top-down by default

2019-07-30 Thread Alexandre Ghiti 
In order to avoid wasting user address space by using bottom-up mmap
allocation scheme, prefer top-down scheme when possible.

Before:
root@qemuriscv64:~# cat /proc/self/maps
0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
00018000-00039000 rw-p  00:00 0  [heap]
156000-16d000 r-xp  fe:00 7193   /lib/ld-2.28.so
16d000-16e000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
16e000-16f000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
16f000-17 rw-p  00:00 0
17-172000 r-xp  00:00 0  [vdso]
174000-176000 rw-p  00:00 0
176000-1555674000 r-xp  fe:00 7187   /lib/libc-2.28.so
1555674000-1555678000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
1555678000-155567a000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
155567a000-15556a rw-p  00:00 0
3fffb9-3fffbb1000 rw-p  00:00 0  [stack]

After:
root@qemuriscv64:~# cat /proc/self/maps
0001-00016000 r-xp  fe:00 6389   /bin/cat.coreutils
00016000-00017000 r--p 5000 fe:00 6389   /bin/cat.coreutils
00017000-00018000 rw-p 6000 fe:00 6389   /bin/cat.coreutils
2de81000-2dea2000 rw-p  00:00 0  [heap]
3ff7eb6000-3ff7ed8000 rw-p  00:00 0
3ff7ed8000-3ff7fd6000 r-xp  fe:00 7187   /lib/libc-2.28.so
3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187   /lib/libc-2.28.so
3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187   /lib/libc-2.28.so
3ff7fdc000-3ff7fe2000 rw-p  00:00 0
3ff7fe4000-3ff7fe6000 r-xp  00:00 0  [vdso]
3ff7fe6000-3ff7ffd000 r-xp  fe:00 7193   /lib/ld-2.28.so
3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193   /lib/ld-2.28.so
3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193   /lib/ld-2.28.so
3ff7fff000-3ff800 rw-p  00:00 0
3fff888000-3fff8a9000 rw-p  00:00 0  [stack]

Signed-off-by: Alexandre Ghiti 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Kees Cook 
Reviewed-by: Luis Chamberlain 
---
 arch/riscv/Kconfig | 13 +
 1 file changed, 13 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 8ef64fe2c2b3..8d0d8af1a744 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -54,6 +54,19 @@ config RISCV
select EDAC_SUPPORT
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
+   select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
+   select HAVE_ARCH_MMAP_RND_BITS
+
+config ARCH_MMAP_RND_BITS_MIN
+   default 18 if 64BIT
+   default 8
+
+# max bits determined by the following formula:
+#  VA_BITS - PAGE_SHIFT - 3
+config ARCH_MMAP_RND_BITS_MAX
+   default 33 if RISCV_VM_SV48
+   default 24 if RISCV_VM_SV39
+   default 17 if RISCV_VM_SV32
 
 config MMU
def_bool y
-- 
2.20.1