commit e72b23dec1da5e62a0090c5da1d926778284e230 upstream. No need to use an ordered store in pa_tlb_lock() and update the comment regarng usage of the sid register to unlocak a spinlock in tlb_unlock0(). Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de> Cc: <stable@vger.kernel.org> # v5.0+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6e9f06ee6c9566f3606d93182ac8f803a148504b upstream. This reverts commit 9e5c602186a692a7e848c0da17aed40f49d30519. No need to use the ldcw instruction as SMP spinlock release barrier. Revert it to gain back speed again. Signed-off-by: Helge Deller <deller@gmx.de> Cc: <stable@vger.kernel.org> # v5.2+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current code in ftrace_regs_caller() doesn't assign %r3 to contain the address of the current frame. This is hidden if the kernel is compiled with FRAME_POINTER, but without it just crashes because it tries to dereference an arbitrary address. Fix this by always setting %r3 to the current stack frame. Signed-off-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de>
Allow KPROBES to use the ftrace infrastructure on PA-RISC. Signed-off-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de> Tested-by: Sven Schnelle <svens@stackframe.org> Acked-by: Christian Brauner <christian@brauner.io>
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 <do_sys_open>: 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 <address of ftrace> 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 <do_sys_open>: 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 <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de>
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 675 mass ave cambridge ma 02139 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 77 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.837555891@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PA-RISC uses a global spinlock to protect pagetable updates in the TLB fault handlers. When multiple cores are taking TLB faults simultaneously, the cache line containing the spinlock becomes a bottleneck. This patch embeds the spinlock in the top level page directory, so that every process has its own lock. It improves performance by 30% when doing parallel compilations. At least on the N class systems, only one PxTLB inter processor broadcast can be active at any one time on the Merced bus. If a Merced bus is found, this patch serializes the TLB flushes with the pa_tlb_flush_lock spinlock. v1: Initial patch by Mikulas v2: Added Merced detection by Helge v3: Revised TLB serialization by Dave & Helge Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
There are only a couple of instructions that can function as a memory barrier on parisc. Currently, we use the sync instruction as a memory barrier when releasing a spinlock. However, the ldcw instruction is a better barrier when we have a handy memory location since it operates in the cache on coherent machines. This patch updates the spinlock release code to use ldcw. I also changed the "stw,ma" instructions to "stw" instructions as it is not an adequate barrier. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
Use and mention the predefined LINUX_GATEWAY_SPACE constant in the various important code sections which deal with the gateway page. Signed-off-by: Helge Deller <deller@gmx.de>