linux-dev/arch/parisc/kernel/Makefile, branch master

kbuild: use obj-y instead extra-y for objects placed at the head

2022-10-02T09:04:05Z

The objects placed at the head of vmlinux need special treatments: - arch/$(SRCARCH)/Makefile adds them to head-y in order to place them before other archives in the linker command line. - arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of obj-y to avoid them going into built-in.a. This commit gets rid of the latter. Create vmlinux.a to collect all the objects that are unconditionally linked to vmlinux. The objects listed in head-y are moved to the head of vmlinux.a by using 'ar m'. With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y for builtin objects. There is no *.o that is directly linked to vmlinux. Drop unneeded code in scripts/clang-tools/gen_compile_commands.py. $(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested by Nathan Chancellor [1]. [1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/ Signed-off-by: Masahiro Yamada Tested-by: Nick Desaulniers Reviewed-by: Nicolas Schier

parisc: Switch from GENERIC_CPU_DEVICES to GENERIC_ARCH_TOPOLOGY

2022-03-29T19:37:12Z

Switch away from the own cpu topology code to common code which is used by ARM64 and RISCV. That will allow us to enable CPU hotplug later on. Signed-off-by: Helge Deller

parisc: Add vDSO support

2022-03-11T18:49:30Z

Add minimal vDSO support, which provides the signal trampoline helpers, but none of the userspace syscall helpers like time wrappers. The big benefit of this vDSO implementation is, that we now don't need an executeable stack any longer. PA-RISC is one of the last architectures where an executeable stack was needed in oder to implement the signal trampolines by putting assembly instructions on the stack which then gets executed. Instead the kernel will provide the relevant code in the vDSO page and only put the pointers to the signal information on the stack. By dropping the need for executable stacks we avoid running into issues with applications which want non executable stacks for security reasons. Additionally, alternative stacks on memory areas without exec permissions are supported too. This code is based on an initial implementation by Randolph Chung from 2006: https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/ I did the porting and lifted the code to current code base. Dave fixed the unwind code so that gdb and glibc are able to backtrace through the code. An additional patch to gdb will be pushed upstream by Dave. Signed-off-by: Helge Deller Signed-off-by: Dave Anglin Cc: Randolph Chung Signed-off-by: Helge Deller

parisc: Enable TOC (transfer of contents) feature unconditionally

2022-01-11T10:57:37Z

Before this patch, the TOC code used a pre-allocated stack of 16kb for each possible CPU. That space overhead was the reason why the TOC feature wasn't enabled by default for 32-bit kernels. This patch rewrites the TOC code to use a per-cpu stack. That way we use much less memory now and as such we enable the TOC feature by default on all kernels. Additionally the dump of the registers and the stacktrace wasn't serialized, which led to multiple CPUs printing the stack backtrace at once which rendered the output unreadable. Now the backtraces are nicely serialized by a lock. Signed-off-by: Helge Deller

parisc: add support for TOC (transfer of control)

2021-11-01T06:35:59Z

Almost all PA-RISC machines have either a button that is labeled with 'TOC' or a BMC function to trigger a TOC. TOC is a non-maskable interrupt that is sent to the processor. This can be used for diagnostic purposes like obtaining a stack trace/register dump or to enter KDB/KGDB. As an example, on my c8000, TOC can be used with: CONFIG_KGDB=y CONFIG_KGDB_KDB=y and the 'kgdboc=ttyS0,115200' appended to the command line. Press ^[( on serial console, which will enter the BMC command line, and enter 'TOC s': root@(none):/# ( cli>TOC s Sending TOC/INIT. 2800035d03e00000 0000000040c21ac8 CC_ERR_CHECK_TOC 2800035d00e00000 0000000040c21ad0 CC_ERR_CHECK_TOC 2800035d02e00000 0000000040c21ac8 CC_ERR_CHECK_TOC 2800035d01e00000 0000000040c21ad0 CC_ERR_CHECK_TOC 37000f7303e00000 2000000000000000 CC_ERR_CPU_CHECK_SUMMARY 37000f7300e00000 2000000000000000 CC_ERR_CPU_CHECK_SUMMARY 37000f7302e00000 2000000000000000 CC_ERR_CPU_CHECK_SUMMARY 37000f7301e00000 2000000000000000 CC_ERR_CPU_CHECK_SUMMARY 4300100803e00000 c0000000001d26cc CC_MC_BR_TO_OS_TOC 4300100800e00000 c0000000001d26cc CC_MC_BR_TO_OS_TOC 4300100802e00000 c0000000001d26cc CC_MC_BR_TO_OS_TOC 4300100801e00000 c0000000001d26cc CC_MC_BR_TO_OS_TOC Entering kdb (current=0x00000000411cef80, pid 0) on processor 0 due to NonMaskable Interrupt @ 0x40c21ad0 [0]kdb> Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller

parisc: fix compilation when KEXEC=n and KEXEC_FILE=y

2019-12-15T20:05:38Z

Fix compilation when the CONFIG_KEXEC_FILE=y and CONFIG_KEXEC=n. Reported-by: kbuild test robot Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller

parisc: add support for kexec_file_load() syscall

2019-09-08T13:41:46Z

Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller

parisc: add kexec syscall support

2019-09-08T13:37:04Z

Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller

parisc: add dynamic ftrace

2019-06-08T10:56:29Z

This patch implements dynamic ftrace for PA-RISC. The required mcount call sequences can get pretty long, so instead of patching the whole call sequence out of the functions, we are using -fpatchable-function-entry from gcc. This puts a configurable amount of NOPS before/at the start of the function. Taking do_sys_open() as example, which would look like this when the call is patched out: 1036b248: 08 00 02 40 nop 1036b24c: 08 00 02 40 nop 1036b250: 08 00 02 40 nop 1036b254: 08 00 02 40 nop 1036b258 : 1036b258: 08 00 02 40 nop 1036b25c: 08 03 02 41 copy r3,r1 1036b260: 6b c2 3f d9 stw rp,-14(sp) 1036b264: 08 1e 02 43 copy sp,r3 1036b268: 6f c1 01 00 stw,ma r1,80(sp) When ftrace gets enabled for this function the kernel will patch these NOPs to: 1036b248: 10 19 57 20

1036b24c: 6f c1 00 80 stw,ma r1,40(sp) 1036b250: 48 21 3f d1 ldw -18(r1),r1 1036b254: e8 20 c0 02 bv,n r0(r1) 1036b258 : 1036b258: e8 3f 1f df b,l,n .-c,r1 1036b25c: 08 03 02 41 copy r3,r1 1036b260: 6b c2 3f d9 stw rp,-14(sp) 1036b264: 08 1e 02 43 copy sp,r3 1036b268: 6f c1 01 00 stw,ma r1,80(sp) So the first NOP in do_sys_open() will be patched to jump backwards into some minimal trampoline code which pushes a stackframe, saves r1 which holds the return address, loads the address of the real ftrace function, and branches to that location. For 64 Bit things are getting a bit more complicated (and longer) because we must make sure that the address of ftrace location is 8 byte aligned, and the offset passed to ldd for fetching the address is 8 byte aligned as well. Note that gcc has a bug which misplaces the function label, and needs a patch to make dynamic ftrace work. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90751 for details. Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller

parisc: Add static branch and JUMP_LABEL feature

2019-05-05T22:10:03Z

Signed-off-by: Helge Deller