linux.git/arch/parisc/kernel/entry.S, branch v5.15

parisc: Optimize per-pagetable spinlocks

2021-02-12T15:39:42+00:00

On parisc a spinlock is stored in the next page behind the pgd which
protects against parallel accesses to the pgd. That's why one additional
page (PGD_ALLOC_ORDER) is allocated for the pgd.

Matthew Wilcox suggested that we instead should use a pointer in the
struct page table for this spinlock and noted, that the comments for the
PGD_ORDER and PMD_ORDER defines were wrong.

Both suggestions are addressed with this patch. Instead of having an own
spinlock to protect the pgd, we now switch to use the existing
page_table_lock.  Additionally, beside loading the pgd into cr25 in
switch_mm_irqs_off(), the physical address of this lock is loaded into
cr28 (tr4), so that we can avoid implementing a complicated lookup in
assembly for this lock in the TLB fault handlers.

The existing Hybrid L2/L3 page table scheme (where the pmd is adjacent
to the pgd) has been dropped with this patch.

Remove the locking in set_pte() and the huge-page pte functions too.
They trigger a spinlock recursion on 32bit machines and seem unnecessary.

Suggested-by: Matthew Wilcox 
Fixes: b37d1c1898b2 ("parisc: Use per-pagetable spinlock")
Signed-off-by: John David Anglin 
Signed-off-by: Helge Deller

parisc: Enable -mlong-calls gcc option by default when !CONFIG_MODULES

2021-01-26T19:16:21+00:00

When building a kernel without module support, the CONFIG_MLONGCALL option
needs to be enabled in order to reach symbols which are outside of a 22-bit
branch.

This patch changes the autodetection in the Kconfig script to always enable
CONFIG_MLONGCALL when modules are disabled and uses a far call to
preempt_schedule_irq() in intr_do_preempt() to reach the symbol in all cases.

Signed-off-by: Helge Deller 
Reported-by: kernel test robot 
Cc: stable@vger.kernel.org # v5.6+

parisc: Use _TIF_USER_WORK_MASK in entry.S

2020-11-11T13:58:54+00:00

The constant _TIF_USER_WORK_MASK will get extended by additional flags
in the future, so check against the bits set in this mask - with the
exception of _TIF_NEED_RESCHED which was tested a few lines above.

Signed-off-by: Helge Deller

parisc: Fix comments and enable interrupts later

2020-10-15T06:10:38+00:00

Correct the comments: The jump is forwards, not backwards.
Enable the interrupts after %r29 (reference param area) was loaded.

Signed-off-by: John David Anglin 
Signed-off-by: Helge Deller

parisc: Do not use an ordered store in pa_tlb_lock()

2020-07-28T17:29:38+00:00

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 
Signed-off-by: Helge Deller 
Cc:  # v5.0+

Revert "parisc: Use ldcw instruction for SMP spinlock release barrier"

2020-07-28T16:54:40+00:00

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 
Cc:  # v5.2+

mm: reorder includes after introduction of linux/pgtable.h

2020-06-09T16:39:13+00:00

The replacement of  with  made the include
of the latter in the middle of asm includes.  Fix this up with the aid of
the below script and manual adjustments here and there.

	import sys
	import re

	if len(sys.argv) is not 3:
	    print "USAGE: %s  " % (sys.argv[0])
	    sys.exit(1)

	hdr_to_move="#include " % sys.argv[2]
	moved = False
	in_hdrs = False

	with open(sys.argv[1], "r") as f:
	    lines = f.readlines()
	    for _line in lines:
		line = _line.rstrip('
')
		if line == hdr_to_move:
		    continue
		if line.startswith("#include 
Signed-off-by: Andrew Morton 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: Brian Cain 
Cc: Catalin Marinas 
Cc: Chris Zankel 
Cc: "David S. Miller" 
Cc: Geert Uytterhoeven 
Cc: Greentime Hu 
Cc: Greg Ungerer 
Cc: Guan Xuetao 
Cc: Guo Ren 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: Ingo Molnar 
Cc: Ley Foon Tan 
Cc: Mark Salter 
Cc: Matthew Wilcox 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Nick Hu 
Cc: Paul Walmsley 
Cc: Richard Weinberger 
Cc: Rich Felker 
Cc: Russell King 
Cc: Stafford Horne 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: Vincent Chen 
Cc: Vineet Gupta 
Cc: Will Deacon 
Cc: Yoshinori Sato 
Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org
Signed-off-by: Linus Torvalds

mm: introduce include/linux/pgtable.h

2020-06-09T16:39:13+00:00

The include/linux/pgtable.h is going to be the home of generic page table
manipulation functions.

Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and
make the latter include asm/pgtable.h.

Signed-off-by: Mike Rapoport 
Signed-off-by: Andrew Morton 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: Brian Cain 
Cc: Catalin Marinas 
Cc: Chris Zankel 
Cc: "David S. Miller" 
Cc: Geert Uytterhoeven 
Cc: Greentime Hu 
Cc: Greg Ungerer 
Cc: Guan Xuetao 
Cc: Guo Ren 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: Ingo Molnar 
Cc: Ley Foon Tan 
Cc: Mark Salter 
Cc: Matthew Wilcox 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Nick Hu 
Cc: Paul Walmsley 
Cc: Richard Weinberger 
Cc: Rich Felker 
Cc: Russell King 
Cc: Stafford Horne 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: Vincent Chen 
Cc: Vineet Gupta 
Cc: Will Deacon 
Cc: Yoshinori Sato 
Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org
Signed-off-by: Linus Torvalds

sched/rt, parisc: Use CONFIG_PREEMPTION

2019-12-08T13:37:34+00:00

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the entry code over to use CONFIG_PREEMPTION.

[bigeasy: +Kconfig]

Signed-off-by: Thomas Gleixner 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Cc: Helge Deller 
Cc: James E.J. Bottomley 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: linux-parisc@vger.kernel.org
Link: https://lore.kernel.org/r/20191015191821.11479-16-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar

parisc: fix frame pointer in ftrace_regs_caller()

2019-10-30T20:24:40+00:00

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 
Signed-off-by: Helge Deller