On Thu, 5 Oct 2017, Chris Brandt wrote: > On Wednesday, October 04, 2017, Nicolas Pitre wrote: > > Anyway, here's a replacement for patch 4/5 below: > > > > ----- >8 > > Subject: cramfs: add mmap support > > > > When cramfs_physmem is used then we have the opportunity to map files > > directly from ROM, directly into user space, saving on RAM usage. > > This gives us Execute-In-Place (XIP) support. > > > Tested on my setup: > * Cortex A9 (with MMU) > * CONFIG_XIP_KERNEL=y > * booted with XIP CRAMFS as my rootfs > * all apps and libraries marked as XIP in my cramfs image > > > > So far, functionally it seems to work the same as [PATCH v4 4/5]. > > As Nicolas said, before you could easily see that all my apps and > libraries were XIP from Flash: > > $ cat /proc/self/maps > 00008000-000a1000 r-xp 1b005000 00:0c 18192 /bin/busybox > 000a9000-000aa000 rw-p 00099000 00:0c 18192 /bin/busybox > 000aa000-000ac000 rw-p 00000000 00:00 0 [heap] > b6e69000-b6f42000 r-xp 1b0bc000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f42000-b6f4a000 ---p 1b195000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f4a000-b6f4c000 r--p 000d9000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f4c000-b6f4d000 rw-p 000db000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f4d000-b6f50000 rw-p 00000000 00:00 0 > b6f50000-b6f67000 r-xp 1b0a4000 00:0c 670372 /lib/ld-2.18-2013.10.so > b6f6a000-b6f6b000 rw-p 00000000 00:00 0 > b6f6c000-b6f6e000 rw-p 00000000 00:00 0 > b6f6e000-b6f6f000 r--p 00016000 00:0c 670372 /lib/ld-2.18-2013.10.so > b6f6f000-b6f70000 rw-p 00017000 00:0c 670372 /lib/ld-2.18-2013.10.so > beac0000-beae1000 rw-p 00000000 00:00 0 [stack] > bebc9000-bebca000 r-xp 00000000 00:00 0 [sigpage] > ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors] > > > > But now just busybox looks like it's XIP: > > $ cat /proc/self/maps > 00008000-000a1000 r-xp 1b005000 00:0c 18192 /bin/busybox > 000a9000-000aa000 rw-p 00099000 00:0c 18192 /bin/busybox > 000aa000-000ac000 rw-p 00000000 00:00 0 [heap] > b6e4d000-b6f26000 r-xp 00000000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f26000-b6f2e000 ---p 000d9000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f2e000-b6f30000 r--p 000d9000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f30000-b6f31000 rw-p 000db000 00:0c 766540 /lib/libc-2.18-2013.10.so > b6f31000-b6f34000 rw-p 00000000 00:00 0 > b6f34000-b6f4b000 r-xp 00000000 00:0c 670372 /lib/ld-2.18-2013.10.so > b6f4e000-b6f4f000 rw-p 00000000 00:00 0 > b6f50000-b6f52000 rw-p 00000000 00:00 0 > b6f52000-b6f53000 r--p 00016000 00:0c 670372 /lib/ld-2.18-2013.10.so > b6f53000-b6f54000 rw-p 00017000 00:0c 670372 /lib/ld-2.18-2013.10.so > bec93000-becb4000 rw-p 00000000 00:00 0 [stack] > befad000-befae000 r-xp 00000000 00:00 0 [sigpage] > ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors] Do you have the same amount of free memory once booted in both cases? > Regardless, from a functional standpoint: > > Tested-by: Chris Brandt <chris.brandt@xxxxxxxxxxx> Thanks. > Just FYI, the previous [PATCH v4 4/5] also included this (which was the > only real difference between v3 and v4): > > > diff --git a/fs/cramfs/Kconfig b/fs/cramfs/Kconfig > index 5b4e0b7e13..306549be25 100644 > --- a/fs/cramfs/Kconfig > +++ b/fs/cramfs/Kconfig > @@ -30,7 +30,7 @@ config CRAMFS_BLOCKDEV > > config CRAMFS_PHYSMEM > bool "Support CramFs image directly mapped in physical memory" > - depends on CRAMFS > + depends on CRAMFS = y Yeah, that was necessary because split_vma() wasn't exported to modules. Now split_vma() is no longer used so the no-module restriction has also been removed. Nicolas -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
