linux-stable.git/arch/powerpc/kernel, branch v4.14.331

powerpc/iommu: Fix notifiers being shared by PCI and VIO buses

2023-09-23T08:46:57+00:00

[ Upstream commit c37b6908f7b2bd24dcaaf14a180e28c9132b9c58 ]

fail_iommu_setup() registers the fail_iommu_bus_notifier struct to both
PCI and VIO buses.  struct notifier_block is a linked list node, so this
causes any notifiers later registered to either bus type to also be
registered to the other since they share the same node.

This causes issues in (at least) the vgaarb code, which registers a
notifier for PCI buses.  pci_notify() ends up being called on a vio
device, converted with to_pci_dev() even though it's not a PCI device,
and finally makes a bad access in vga_arbiter_add_pci_device() as
discovered with KASAN:

 BUG: KASAN: slab-out-of-bounds in vga_arbiter_add_pci_device+0x60/0xe00
 Read of size 4 at addr c000000264c26fdc by task swapper/0/1

 Call Trace:
   dump_stack_lvl+0x1bc/0x2b8 (unreliable)
   print_report+0x3f4/0xc60
   kasan_report+0x244/0x698
   __asan_load4+0xe8/0x250
   vga_arbiter_add_pci_device+0x60/0xe00
   pci_notify+0x88/0x444
   notifier_call_chain+0x104/0x320
   blocking_notifier_call_chain+0xa0/0x140
   device_add+0xac8/0x1d30
   device_register+0x58/0x80
   vio_register_device_node+0x9ac/0xce0
   vio_bus_scan_register_devices+0xc4/0x13c
   __machine_initcall_pseries_vio_device_init+0x94/0xf0
   do_one_initcall+0x12c/0xaa8
   kernel_init_freeable+0xa48/0xba8
   kernel_init+0x64/0x400
   ret_from_kernel_thread+0x5c/0x64

Fix this by creating separate notifier_block structs for each bus type.

Fixes: d6b9a81b2a45 ("powerpc: IOMMU fault injection")
Reported-by: Nageswara R Sastry 
Signed-off-by: Russell Currey 
Tested-by: Nageswara R Sastry 
Reviewed-by: Andrew Donnellan 
[mpe: Add #ifdef to fix CONFIG_IBMVIO=n build]
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230322035322.328709-1-ruscur@russell.cc
Signed-off-by: Sasha Levin

powerpc/32s: Fix assembler warning about r0

2023-09-23T08:46:54+00:00

commit b51ba4fe2e134b631f9c8f45423707aab71449b5 upstream.

The assembler says:
  arch/powerpc/kernel/head_32.S:1095: Warning: invalid register expression

It's objecting to the use of r0 as the RA argument. That's because
when RA = 0 the literal value 0 is used, rather than the content of
r0, making the use of r0 in the source potentially confusing.

Fix it to use a literal 0, the generated code is identical.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/2b69ac8e1cddff6f808fc7415907179eab4aae9e.1596693679.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman

powerpc/32: Include .branch_lt in data section

2023-09-23T08:46:54+00:00

commit 98ecc6768e8fdba95da1fc1efa0ef2d769e7fe1c upstream.

When building a 32 bit powerpc kernel with Binutils 2.31.1 this warning
is emitted:

 powerpc-linux-gnu-ld: warning: orphan section `.branch_lt' from
 `arch/powerpc/kernel/head_44x.o' being placed in section `.branch_lt'

As of binutils commit 2d7ad24e8726 ("Support PLT16 relocs against local
symbols")[1], 32 bit targets can produce .branch_lt sections in their
output.

Include these symbols in the .data section as the ppc64 kernel does.

[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=2d7ad24e8726ba4c45c9e67be08223a146a837ce
Signed-off-by: Joel Stanley 
Reviewed-by: Alan Modra 
Signed-off-by: Michael Ellerman 
Cc: Christophe Leroy 
Signed-off-by: Greg Kroah-Hartman

powerpc/rtas: use memmove for potentially overlapping buffer copy

2023-05-17T09:11:45+00:00

[ Upstream commit 271208ee5e335cb1ad280d22784940daf7ddf820 ]

Using memcpy() isn't safe when buf is identical to rtas_err_buf, which
can happen during boot before slab is up. Full context which may not
be obvious from the diff:

	if (altbuf) {
		buf = altbuf;
	} else {
		buf = rtas_err_buf;
		if (slab_is_available())
			buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
	}
	if (buf)
		memcpy(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);

This was found by inspection and I'm not aware of it causing problems
in practice. It appears to have been introduced by commit
033ef338b6e0 ("powerpc: Merge rtas.c into arch/powerpc/kernel"); the
old ppc64 version of this code did not have this problem.

Use memmove() instead.

Fixes: 033ef338b6e0 ("powerpc: Merge rtas.c into arch/powerpc/kernel")
Signed-off-by: Nathan Lynch 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230220-rtas-queue-for-6-4-v1-2-010e4416f13f@linux.ibm.com
Signed-off-by: Sasha Levin

exit: Add and use make_task_dead.

2023-02-06T06:46:33+00:00

commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream.

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

powerpc/rtas: avoid scheduling in rtas_os_term()

2023-01-18T08:26:35+00:00

[ Upstream commit 6c606e57eecc37d6b36d732b1ff7e55b7dc32dd4 ]

It's unsafe to use rtas_busy_delay() to handle a busy status from
the ibm,os-term RTAS function in rtas_os_term():

Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
BUG: sleeping function called from invalid context at arch/powerpc/kernel/rtas.c:618
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0
preempt_count: 2, expected: 0
CPU: 7 PID: 1 Comm: swapper/0 Tainted: G      D            6.0.0-rc5-02182-gf8553a572277-dirty #9
Call Trace:
[c000000007b8f000] [c000000001337110] dump_stack_lvl+0xb4/0x110 (unreliable)
[c000000007b8f040] [c0000000002440e4] __might_resched+0x394/0x3c0
[c000000007b8f0e0] [c00000000004f680] rtas_busy_delay+0x120/0x1b0
[c000000007b8f100] [c000000000052d04] rtas_os_term+0xb8/0xf4
[c000000007b8f180] [c0000000001150fc] pseries_panic+0x50/0x68
[c000000007b8f1f0] [c000000000036354] ppc_panic_platform_handler+0x34/0x50
[c000000007b8f210] [c0000000002303c4] notifier_call_chain+0xd4/0x1c0
[c000000007b8f2b0] [c0000000002306cc] atomic_notifier_call_chain+0xac/0x1c0
[c000000007b8f2f0] [c0000000001d62b8] panic+0x228/0x4d0
[c000000007b8f390] [c0000000001e573c] do_exit+0x140c/0x1420
[c000000007b8f480] [c0000000001e586c] make_task_dead+0xdc/0x200

Use rtas_busy_delay_time() instead, which signals without side effects
whether to attempt the ibm,os-term RTAS call again.

Signed-off-by: Nathan Lynch 
Reviewed-by: Nicholas Piggin 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221118150751.469393-5-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin

powerpc/rtas: avoid device tree lookups in rtas_os_term()

2023-01-18T08:26:35+00:00

[ Upstream commit ed2213bfb192ab51f09f12e9b49b5d482c6493f3 ]

rtas_os_term() is called during panic. Its behavior depends on a couple
of conditions in the /rtas node of the device tree, the traversal of
which entails locking and local IRQ state changes. If the kernel panics
while devtree_lock is held, rtas_os_term() as currently written could
hang.

Instead of discovering the relevant characteristics at panic time,
cache them in file-static variables at boot. Note the lookup for
"ibm,extended-os-term" is converted to of_property_read_bool() since it
is a boolean property, not an RTAS function token.

Signed-off-by: Nathan Lynch 
Reviewed-by: Nicholas Piggin 
Reviewed-by: Andrew Donnellan 
[mpe: Incorporate suggested change from Nick]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221118150751.469393-4-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin

powerpc/pci_dn: Add missing of_node_put()

2022-10-26T11:17:07+00:00

[ Upstream commit 110a1fcb6c4d55144d8179983a475f17a1d6f832 ]

In pci_add_device_node_info(), use of_node_put() to drop the reference
to 'parent' returned by of_get_parent() to keep refcount balance.

Fixes: cca87d303c85 ("powerpc/pci: Refactor pci_dn")
Co-authored-by: Miaoqian Lin 
Signed-off-by: Liang He 
Signed-off-by: Michael Ellerman 
Reviewed-by: Tyrel Datwyler 
Link: https://lore.kernel.org/r/20220701131750.240170-1-windhl@126.com
Signed-off-by: Sasha Levin

powerpc/64: Init jump labels before parse_early_param()

2022-08-25T09:11:37+00:00

[ Upstream commit ca829e05d3d4f728810cc5e4b468d9ebc7745eb3 ]

On 64-bit, calling jump_label_init() in setup_feature_keys() is too
late because static keys may be used in subroutines of
parse_early_param() which is again subroutine of early_init_devtree().

For example booting with "threadirqs":

  static_key_enable_cpuslocked(): static key '0xc000000002953260' used before call to jump_label_init()
  WARNING: CPU: 0 PID: 0 at kernel/jump_label.c:166 static_key_enable_cpuslocked+0xfc/0x120
  ...
  NIP static_key_enable_cpuslocked+0xfc/0x120
  LR  static_key_enable_cpuslocked+0xf8/0x120
  Call Trace:
    static_key_enable_cpuslocked+0xf8/0x120 (unreliable)
    static_key_enable+0x30/0x50
    setup_forced_irqthreads+0x28/0x40
    do_early_param+0xa0/0x108
    parse_args+0x290/0x4e0
    parse_early_options+0x48/0x5c
    parse_early_param+0x58/0x84
    early_init_devtree+0xd4/0x518
    early_setup+0xb4/0x214

So call jump_label_init() just before parse_early_param() in
early_init_devtree().

Suggested-by: Michael Ellerman 
Signed-off-by: Zhouyi Zhou 
[mpe: Add call trace to change log and minor wording edits.]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220726015747.11754-1-zhouzhouyi@gmail.com
Signed-off-by: Sasha Levin

powerpc/pci: Fix get_phb_number() locking

2022-08-25T09:11:34+00:00

commit 8d48562a2729742f767b0fdd994d6b2a56a49c63 upstream.

The recent change to get_phb_number() causes a DEBUG_ATOMIC_SLEEP
warning on some systems:

  BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
  preempt_count: 1, expected: 0
  RCU nest depth: 0, expected: 0
  1 lock held by swapper/1:
   #0: c157efb0 (hose_spinlock){+.+.}-{2:2}, at: pcibios_alloc_controller+0x64/0x220
  Preemption disabled at:
  [<00000000>] 0x0
  CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0-yocto-standard+ #1
  Call Trace:
  [d101dc90] [c073b264] dump_stack_lvl+0x50/0x8c (unreliable)
  [d101dcb0] [c0093b70] __might_resched+0x258/0x2a8
  [d101dcd0] [c0d3e634] __mutex_lock+0x6c/0x6ec
  [d101dd50] [c0a84174] of_alias_get_id+0x50/0xf4
  [d101dd80] [c002ec78] pcibios_alloc_controller+0x1b8/0x220
  [d101ddd0] [c140c9dc] pmac_pci_init+0x198/0x784
  [d101de50] [c140852c] discover_phbs+0x30/0x4c
  [d101de60] [c0007fd4] do_one_initcall+0x94/0x344
  [d101ded0] [c1403b40] kernel_init_freeable+0x1a8/0x22c
  [d101df10] [c00086e0] kernel_init+0x34/0x160
  [d101df30] [c001b334] ret_from_kernel_thread+0x5c/0x64

This is because pcibios_alloc_controller() holds hose_spinlock but
of_alias_get_id() takes of_mutex which can sleep.

The hose_spinlock protects the phb_bitmap, and also the hose_list, but
it doesn't need to be held while get_phb_number() calls the OF routines,
because those are only looking up information in the device tree.

So fix it by having get_phb_number() take the hose_spinlock itself, only
where required, and then dropping the lock before returning.
pcibios_alloc_controller() then needs to take the lock again before the
list_add() but that's safe, the order of the list is not important.

Fixes: 0fe1e96fef0a ("powerpc/pci: Prefer PCI domain assignment via DT 'linux,pci-domain' and alias")
Reported-by: Guenter Roeck 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220815065550.1303620-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman