xavi/android_kernel_m2note/Documentation, branch ng-7.1.2

BACKPORT: tcp: add tcp_min_snd_mss sysctl

2019-07-18T18:56:22+00:00

commit 5f3e2bf008c2221478101ee72f5cb4654b9fc363 upstream. Some TCP peers announce a very small MSS option in their SYN and/or SYN/ACK messages. This forces the stack to send packets with a very high network/cpu overhead. Linux has enforced a minimal value of 48. Since this value includes the size of TCP options, and that the options can consume up to 40 bytes, this means that each segment can include only 8 bytes of payload. In some cases, it can be useful to increase the minimal value to a saner value. We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility reasons. Note that TCP_MAXSEG socket option enforces a minimal value of (TCP_MIN_MSS). David Miller increased this minimal value in commit c39508d6f118 ("tcp: Make TCP_MAXSEG minimum more correct.") from 64 to 88. We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS. CVE-2019-11479 -- tcp mss hardcoded to 48 Signed-off-by: Eric Dumazet Suggested-by: Jonathan Looney Acked-by: Neal Cardwell Cc: Yuchung Cheng Cc: Tyler Hicks Cc: Bruce Curtis Cc: Jonathan Lemon Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman [BACKPORT to 3.10: use previous sysctrl method] Signed-off-by: syphyr@gmail.com Change-Id: Ib5e91a60fe4f4c00afc27ed92b1bd8dfe39fb7c9

ANDROID: lib: vsprintf: additional kernel pointer filtering options

2019-05-03T16:09:53+00:00

Add the kptr_restrict setting of 3 which results in both %p and %pK values being replaced by zeros. Add an additional %pP value inspired by the Grsecurity option which explicitly whitelists pointers for output. This patch is based on work by William Roberts [CV: fixed GCC warning on 32 bit targets] BUG: 30368199 Change-Id: Ic5cef86617f7758514271edd67199683d2c4e2bb Signed-off-by: Dave Weinstein

gcov: compile specific gcov implementation based on gcc version

2019-05-02T12:28:26+00:00

Compile the correct gcov implementation file for the specific gcc version. Signed-off-by: Frantisek Hrbata Cc: Jan Stancek Cc: Kees Cook Acked-by: Peter Oberparleiter Cc: Rusty Russell Cc: Arnd Bergmann Cc: Andy Gospodarek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kbuild: Allow arch Makefiles to override {cpp,ld,c}flags

2018-11-29T15:57:57+00:00

Since commit a1c48bb1 (Makefile: Fix unrecognized cross-compiler command line options), the arch Makefile is included earlier by the main Makefile, preventing the arc architecture to set its -O3 compiler option. Since there might be more use cases for an arch Makefile to fine-tune the options, add support for ARCH_CPPFLAGS, ARCH_AFLAGS and ARCH_CFLAGS variables that are appended to the respective kbuild variables. The user still has the final say via the KCPPFLAGS, KAFLAGS and KCFLAGS variables. Reported-by: Vineet Gupta Cc: stable@vger.kernel.org # 3.16+ Signed-off-by: Michal Marek

kconfig: make allnoconfig disable options behind EMBEDDED and EXPERT

2018-11-29T14:53:12+00:00

"make allnoconfig" exists to ease testing of minimal configurations. Documentation/SubmitChecklist includes a note to test with allnoconfig. This helps catch missing dependencies on common-but-not-required functionality, which might otherwise go unnoticed. However, allnoconfig still leaves many symbols enabled, because they're hidden behind CONFIG_EMBEDDED or CONFIG_EXPERT. For instance, allnoconfig still has CONFIG_PRINTK and CONFIG_BLOCK enabled, so drivers don't typically get build-tested with those disabled. To address this, introduce a new Kconfig option "allnoconfig_y", used on symbols which only exist to hide other symbols. Set it on CONFIG_EMBEDDED (which then selects CONFIG_EXPERT). allnoconfig will then disable all the symbols hidden behind those. Signed-off-by: Josh Triplett Tested-by: Paul E. McKenney Cc: Michal Marek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kconfig: do not allow more than one symbol to have 'option modules'

2018-11-29T14:49:58+00:00

Previously, it was possible to have more than one symbol with the 'option modules' attached to them, although only the last one would in fact control tristates. Since this does not make much sense, only allow at most one symbol to control tristates. Note: it is still possible to have more than one symbol that control tristates, but indirectly: config MOD1 bool "mod1" select MODULES config MOD2 bool "mod2" select MODULES config MODULES bool option modules Signed-off-by: "Yann E. MORIN" Cc: Sam Ravnborg Signed-off-by: Michal Marek

ether_addr_equal: Optimize implementation, remove unused compare_ether_addr

2018-05-16T11:18:51+00:00

Add a new check for CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to reduce the number of or's used in the ether_addr_equal comparison to very slightly improve function performance. Simplify the ether_addr_equal_64bits implementation. Integrate and remove the zap_last_2bytes helper as it's now used only once. Remove the now unused compare_ether_addr function. Update the unaligned-memory-access documentation to remove the compare_ether_addr description and show how unaligned accesses could occur with ether_addr_equal. Signed-off-by: Joe Perches Signed-off-by: David S. Miller

dm cache: add block sizes and total cache blocks to status output

2018-01-02T12:52:11+00:00

Improve cache_status to emit: <#used metadata blocks>/<#total metadata blocks> <#used cache blocks>/<#total cache blocks> ... Adding the block sizes allows for easier calculation of the overall size of both the metadata and cache devices. Adding <#total cache blocks> provides useful context for how much of the cache is used. Unfortunately these additions to the status will require updates to users' scripts that monitor the cache status. But these changes help provide more comprehensive information about the cache device and will simplify tools that are being developed to manage dm-cache devices -- because they won't need to issue 3 operations to cobble together the information that we can easily provide via a single status ioctl. While updating the status documentation in cache.txt spaces were tabify'd. Requested-by: Jonathan Brassow Signed-off-by: Mike Snitzer Acked-by: Joe Thornber Signed-off-by: Joe Maples

CHROMIUM: dm: boot time specification of dm=

2017-12-27T17:51:14+00:00

This is a wrap-up of three patches pending upstream approval. I'm bundling them because they are interdependent, and it'll be easier to drop it on rebase later. 1. dm: allow a dm-fs-style device to be shared via dm-ioctl Integrates feedback from Alisdair, Mike, and Kiyoshi. Two main changes occur here: - One function is added which allows for a programmatically created mapped device to be inserted into the dm-ioctl hash table. This binds the device to a name and, optional, uuid which is needed by udev and allows for userspace management of the mapped device. - dm_table_complete() was extended to handle all of the final functional changes required for the table to be operational once called. 2. init: boot to device-mapper targets without an initr* Add a dm= kernel parameter modeled after the md= parameter from do_mounts_md. It allows for device-mapper targets to be configured at boot time for use early in the boot process (as the root device or otherwise). It also replaces /dev/XXX calls with major:minor opportunistically. The format is dm="name uuid ro,table line 1,table line 2,...". The parser expects the comma to be safe to use as a newline substitute but, otherwise, uses the normal separator of space. Some attempt has been made to make it forgiving of additional spaces (using skip_spaces()). A mapped device created during boot will be assigned a minor of 0 and may be access via /dev/dm-0. An example dm-linear root with no uuid may look like: root=/dev/dm-0 dm="lroot none ro, 0 4096 linear /dev/ubdb 0, 4096 4096 linear /dv/ubdc 0" Once udev is started, /dev/dm-0 will become /dev/mapper/lroot. Older upstream threads: http://marc.info/?l=dm-devel&m=127429492521964&w=2 http://marc.info/?l=dm-devel&m=127429499422096&w=2 http://marc.info/?l=dm-devel&m=127429493922000&w=2 Latest upstream threads: https://patchwork.kernel.org/patch/104859/ https://patchwork.kernel.org/patch/104860/ https://patchwork.kernel.org/patch/104861/ BUG: 27175947 Signed-off-by: Will Drewry Review URL: http://codereview.chromium.org/2020011 Change-Id: I92bd53432a11241228d2e5ac89a3b20d19b05a31

dm verity: add ignore_zero_blocks feature

2017-12-27T17:50:01+00:00

If ignore_zero_blocks is enabled dm-verity will return zeroes for blocks matching a zero hash without validating the content. Bug: 21893453 Change-Id: Ib9552f872bd82b1ba6a090686d2934a9551a3b48 Signed-off-by: Sami Tolvanen Signed-off-by: Mike Snitzer (cherry picked from commit 0b7462a60aad0c0819a138608c43998f3c46d6a8)