linux-stable.git/arch/powerpc/kernel/setup_64.c, branch v5.12.2

powerpc/setup_64: Make some routines static

2021-01-30T00:39:28+00:00

The following routines are only called by local services and do not
need to be external symbols.

It fixes these W=1 errors :

../arch/powerpc/kernel/setup_64.c:261:13: error: no previous prototype for ‘record_spr_defaults’ [-Werror=missing-prototypes]
  261 | void __init record_spr_defaults(void)
      |             ^~~~~~~~~~~~~~~~~~~
../arch/powerpc/kernel/setup_64.c:1011:6: error: no previous prototype for ‘entry_flush_enable’ [-Werror=missing-prototypes]
 1011 | void entry_flush_enable(bool enable)
      |      ^~~~~~~~~~~~~~~~~~
../arch/powerpc/kernel/setup_64.c:1023:6: error: no previous prototype for ‘uaccess_flush_enable’ [-Werror=missing-prototypes]
 1023 | void uaccess_flush_enable(bool enable)
      |      ^~~~~~~~~~~~~~~~~~~~

Signed-off-by: Cédric Le Goater 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210104143206.695198-7-clg@kaod.org

Merge branch 'fixes' into next

2020-11-25T12:17:31+00:00

Merge our fixes branch, in particular to bring in the changes for the
entry/uaccess flush.

powerpc/64s: flush L1D after user accesses

2020-11-19T12:47:18+00:00

IBM Power9 processors can speculatively operate on data in the L1 cache
before it has been completely validated, via a way-prediction mechanism. It
is not possible for an attacker to determine the contents of impermissible
memory using this method, since these systems implement a combination of
hardware and software security measures to prevent scenarios where
protected data could be leaked.

However these measures don't address the scenario where an attacker induces
the operating system to speculatively execute instructions using data that
the attacker controls. This can be used for example to speculatively bypass
"kernel user access prevention" techniques, as discovered by Anthony
Steinhauser of Google's Safeside Project. This is not an attack by itself,
but there is a possibility it could be used in conjunction with
side-channels or other weaknesses in the privileged code to construct an
attack.

This issue can be mitigated by flushing the L1 cache between privilege
boundaries of concern. This patch flushes the L1 cache after user accesses.

This is part of the fix for CVE-2020-4788.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Daniel Axtens 
Signed-off-by: Michael Ellerman

powerpc/64s: flush L1D on kernel entry

2020-11-19T12:47:15+00:00

IBM Power9 processors can speculatively operate on data in the L1 cache
before it has been completely validated, via a way-prediction mechanism. It
is not possible for an attacker to determine the contents of impermissible
memory using this method, since these systems implement a combination of
hardware and software security measures to prevent scenarios where
protected data could be leaked.

However these measures don't address the scenario where an attacker induces
the operating system to speculatively execute instructions using data that
the attacker controls. This can be used for example to speculatively bypass
"kernel user access prevention" techniques, as discovered by Anthony
Steinhauser of Google's Safeside Project. This is not an attack by itself,
but there is a possibility it could be used in conjunction with
side-channels or other weaknesses in the privileged code to construct an
attack.

This issue can be mitigated by flushing the L1 cache between privilege
boundaries of concern. This patch flushes the L1 cache on kernel entry.

This is part of the fix for CVE-2020-4788.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Daniel Axtens 
Signed-off-by: Michael Ellerman

powerpc: Avoid broken GCC attribute((optimize))

2020-11-19T03:50:14+00:00

Commit 7053f80d9696 ("powerpc/64: Prevent stack protection in early
boot") introduced a couple of uses of __attribute__((optimize)) with
function scope, to disable the stack protector in some early boot
code.

Unfortunately, and this is documented in the GCC man pages [0],
overriding function attributes for optimization is broken, and is only
supported for debug scenarios, not for production: the problem appears
to be that setting GCC -f flags using this method will cause it to
forget about some or all other optimization settings that have been
applied.

So the only safe way to disable the stack protector is to disable it
for the entire source file.

[0] https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html

Fixes: 7053f80d9696 ("powerpc/64: Prevent stack protection in early boot")
Signed-off-by: Ard Biesheuvel 
[mpe: Drop one remaining use of __nostackprotector, reported by snowpatch]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201028080433.26799-1-ardb@kernel.org

powerpc/64/mm: implement page mapping percpu first chunk allocator

2020-09-15T12:13:22+00:00

Implement page mapping percpu first chunk allocator as a fallback to
the embedding allocator. With 4K hash translation we limit our page
table range to 64TB and commit: 0034d395f89d ("powerpc/mm/hash64: Map all the
kernel regions in the same 0xc range") moved all kernel mapping to
that 64TB range. In-order to support sparse memory layout we need
to increase our linear mapping space and reduce other mappings.

With such a layout percpu embedded first chunk allocator will fail
because of small vmalloc range. Add a fallback to page mapping
percpu first chunk allocator for such failures.

The below dmesg output can be observed in such case.

 percpu: max_distance=0x1ffffef00000 too large for vmalloc space 0x10000000000
 PERCPU: auto allocator failed (-22), falling back to page size
 percpu: 40 4K pages/cpu s148816 r0 d15024

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200608070904.387440-2-aneesh.kumar@linux.ibm.com

powerpc/percpu: Update percpu bootmem allocator

2020-09-15T12:13:21+00:00

This update the ppc64 version to be closer to x86/sparc.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200608070904.387440-1-aneesh.kumar@linux.ibm.com

powerpc/64s: system call support for scv/rfscv instructions

2020-07-22T13:00:27+00:00

Add support for the scv instruction on POWER9 and later CPUs.

For now this implements the zeroth scv vector 'scv 0', as identical to
'sc' system calls, with the exception that LR is not preserved, nor
are volatile CR registers, and error is not indicated with CR0[SO],
but by returning a negative errno.

rfscv is implemented to return from scv type system calls. It can not
be used to return from sc system calls because those are defined to
preserve LR.

getpid syscall throughput on POWER9 is improved by 26% (428 to 318
cycles), largely due to reducing mtmsr and mtspr.

Signed-off-by: Nicholas Piggin 
[mpe: Fix ppc64e build]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200611081203.995112-3-npiggin@gmail.com

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