linux.git/arch/powerpc/lib, branch v6.0

powerpc/ppc-opcode: Define and use PPC_RAW_SETB()

2022-07-27T11:36:05+00:00

We have PPC_INST_SETB then build the 'setb' instruction in the
user.

Instead, define PPC_RAW_SETB() and use it.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/b08a4f26919a8f8cdcf7544ab552d9c1c63418b5.1657205708.git.christophe.leroy@csgroup.eu

powerpc/64: Drop ppc_inst_as_str()

2022-06-29T09:37:07+00:00

The ppc_inst_as_str() macro tries to make printing variable length,
aka "prefixed", instructions convenient. It mostly succeeds, but it does
hide an on-stack buffer, which triggers stack protector.

More problematically it doesn't compile at all with GCC 12,
with -Wdangling-pointer, due to the fact that it returns the char buffer
declared inside the macro:

  arch/powerpc/kernel/trace/ftrace.c: In function '__ftrace_modify_call':
  ./include/linux/printk.h:475:44: error: using a dangling pointer to '__str' [-Werror=dangling-pointer=]
    475 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
    ...
  arch/powerpc/kernel/trace/ftrace.c:567:17: note: in expansion of macro 'pr_err'
    567 |                 pr_err("Not expected bl: opcode is %s\n", ppc_inst_as_str(op));
        |                 ^~~~~~
  ./arch/powerpc/include/asm/inst.h:156:14: note: '__str' declared here
    156 |         char __str[PPC_INST_STR_LEN];   \
        |              ^~~~~

This could be fixed by having the caller declare the buffer, but in some
places there'd need to be two buffers. In all cases where
ppc_inst_as_str() is used the output is not really meant for user
consumption, it's almost always indicative of a kernel bug.

A simpler solution is to just print the value as an unsigned long. For
normal instructions the output is identical. For prefixed instructions
the value is printed as a single 64-bit quantity, whereas previously the
low half was printed first. But that is good enough for debug output,
especially as prefixed instructions will be rare in kernel code in
practice.

Old:
  c000000000111170  60420000      ori     r2,r2,0
  c000000000111174  04100001 e580fb00     .long 0xe580fb0004100001

New:
  c00000000010f90c  60420000      ori     r2,r2,0
  c00000000010f910  e580fb0004100001      .long 0xe580fb0004100001

Reported-by: Bagas Sanjaya 
Reported-by: Petr Mladek 
Signed-off-by: Michael Ellerman 
Tested-by: Bagas Sanjaya 
Link: https://lore.kernel.org/r/20220531065936.3674348-1-mpe@ellerman.id.au

Merge tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2022-05-28T18:27:17+00:00

Pull powerpc updates from Michael Ellerman:

 - Convert to the generic mmap support (ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)

 - Add support for outline-only KASAN with 64-bit Radix MMU (P9 or later)

 - Increase SIGSTKSZ and MINSIGSTKSZ and add support for AT_MINSIGSTKSZ

 - Enable the DAWR (Data Address Watchpoint) on POWER9 DD2.3 or later

 - Drop support for system call instruction emulation

 - Many other small features and fixes

Thanks to Alexey Kardashevskiy, Alistair Popple, Andy Shevchenko, Bagas
Sanjaya, Bjorn Helgaas, Bo Liu, Chen Huang, Christophe Leroy, Colin Ian
King, Daniel Axtens, Dwaipayan Ray, Fabiano Rosas, Finn Thain, Frank
Rowand, Fuqian Huang, Guilherme G. Piccoli, Hangyu Hua, Haowen Bai,
Haren Myneni, Hari Bathini, He Ying, Jason Wang, Jiapeng Chong, Jing
Yangyang, Joel Stanley, Julia Lawall, Kajol Jain, Kevin Hao, Krzysztof
Kozlowski, Laurent Dufour, Lv Ruyi, Madhavan Srinivasan, Magali Lemes,
Miaoqian Lin, Minghao Chi, Nathan Chancellor, Naveen N. Rao, Nicholas
Piggin, Oliver O'Halloran, Oscar Salvador, Pali Rohár, Paul Mackerras,
Peng Wu, Qing Wang, Randy Dunlap, Reza Arbab, Russell Currey, Sohaib
Mohamed, Vaibhav Jain, Vasant Hegde, Wang Qing, Wang Wensheng, Xiang
wangx, Xiaomeng Tong, Xu Wang, Yang Guang, Yang Li, Ye Bin, YueHaibing,
Yu Kuai, Zheng Bin, Zou Wei, and Zucheng Zheng.

* tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (200 commits)
  powerpc/64: Include cache.h directly in paca.h
  powerpc/64s: Only set HAVE_ARCH_UNMAPPED_AREA when CONFIG_PPC_64S_HASH_MMU is set
  powerpc/xics: Include missing header
  powerpc/powernv/pci: Drop VF MPS fixup
  powerpc/fsl_book3e: Don't set rodata RO too early
  powerpc/microwatt: Add mmu bits to device tree
  powerpc/powernv/flash: Check OPAL flash calls exist before using
  powerpc/powermac: constify device_node in of_irq_parse_oldworld()
  powerpc/powermac: add missing g5_phy_disable_cpu1() declaration
  selftests/powerpc/pmu: fix spelling mistake "mis-match" -> "mismatch"
  powerpc: Enable the DAWR on POWER9 DD2.3 and above
  powerpc/64s: Add CPU_FTRS_POWER10 to ALWAYS mask
  powerpc/64s: Add CPU_FTRS_POWER9_DD2_2 to CPU_FTRS_ALWAYS mask
  powerpc: Fix all occurences of "the the"
  selftests/powerpc/pmu/ebb: remove fixed_instruction.S
  powerpc/platforms/83xx: Use of_device_get_match_data()
  powerpc/eeh: Drop redundant spinlock initialization
  powerpc/iommu: Add missing of_node_put in iommu_init_early_dart
  powerpc/pseries/vas: Call misc_deregister if sysfs init fails
  powerpc/papr_scm: Fix leaking nvdimm_events_map elements
  ...

powerpc/kasan: Don't instrument non-maskable or raw interrupts

2022-05-22T05:58:29+00:00

Disable address sanitization for raw and non-maskable interrupt
handlers, because they can run in real mode, where we cannot access
the shadow memory.  (Note that kasan_arch_is_ready() doesn't test for
real mode, since it is a static branch for speed, and in any case not
all the entry points to the generic KASAN code are protected by
kasan_arch_is_ready guards.)

The changes to interrupt_nmi_enter/exit_prepare() look larger than
they actually are.  The changes are equivalent to adding
!IS_ENABLED(CONFIG_KASAN) to the conditions for calling nmi_enter() or
nmi_exit() in real mode.  That is, the code is equivalent to using the
following condition for calling nmi_enter/exit:

	if (((!IS_ENABLED(CONFIG_PPC_BOOK3S_64) ||
			!firmware_has_feature(FW_FEATURE_LPAR) ||
			radix_enabled()) &&
		    !IS_ENABLED(CONFIG_KASAN) ||
		(mfmsr() & MSR_DR))

That unwieldy condition has been split into several statements with
comments, for easier reading.

The nmi_ipi_lock functions that call atomic functions (i.e.,
nmi_ipi_lock_start(), nmi_ipi_lock() and nmi_ipi_unlock()), besides
being marked noinstr, now call arch_atomic_* functions instead of
atomic_* functions because with KASAN enabled, the atomic_* functions
are wrappers which explicitly do address sanitization on their
arguments.  Since we are trying to avoid address sanitization, we have
to use the lower-level arch_atomic_* versions.

In hv_nmi_check_nonrecoverable(), the regs_set_unrecoverable() call
has been open-coded so as to avoid having to either trust the inlining
or mark regs_set_unrecoverable() as noinstr.

[paulus@ozlabs.org: combined a few work-in-progress commits of
 Daniel's and wrote the commit message.]

Signed-off-by: Daniel Axtens 
Signed-off-by: Paul Mackerras 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/YoTFGaKM8Pd46PIK@cleo

powerpc/inst: Remove PPC_INST_BRANCH

2022-05-22T05:58:27+00:00

Convert last users of PPC_INST_BRANCH to PPC_RAW_BRANCH()

And remove PPC_INST_BRANCH.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/fa8807108a2ef2287a2c9651d6e1ff7c051923d9.1652074503.git.christophe.leroy@csgroup.eu

powerpc/ftrace: Use patch_instruction() return directly

2022-05-19T13:11:28+00:00

Instead of returning -EPERM when patch_instruction() fails,
just return what patch_instruction returns.

That simplifies ftrace_modify_code():

	   0:	94 21 ff c0 	stwu    r1,-64(r1)
	   4:	93 e1 00 3c 	stw     r31,60(r1)
	   8:	7c 7f 1b 79 	mr.     r31,r3
	   c:	40 80 00 30 	bge     3c 
	  10:	93 c1 00 38 	stw     r30,56(r1)
	  14:	7c 9e 23 78 	mr      r30,r4
	  18:	7c a4 2b 78 	mr      r4,r5
	  1c:	80 bf 00 00 	lwz     r5,0(r31)
	  20:	7c 1e 28 40 	cmplw   r30,r5
	  24:	40 82 00 34 	bne     58 
	  28:	83 c1 00 38 	lwz     r30,56(r1)
	  2c:	7f e3 fb 78 	mr      r3,r31
	  30:	83 e1 00 3c 	lwz     r31,60(r1)
	  34:	38 21 00 40 	addi    r1,r1,64
	  38:	48 00 00 00 	b       38 
				38: R_PPC_REL24	patch_instruction

Before:

	   0:	94 21 ff c0 	stwu    r1,-64(r1)
	   4:	93 e1 00 3c 	stw     r31,60(r1)
	   8:	7c 7f 1b 79 	mr.     r31,r3
	   c:	40 80 00 4c 	bge     58 
	  10:	93 c1 00 38 	stw     r30,56(r1)
	  14:	7c 9e 23 78 	mr      r30,r4
	  18:	7c a4 2b 78 	mr      r4,r5
	  1c:	80 bf 00 00 	lwz     r5,0(r31)
	  20:	7c 08 02 a6 	mflr    r0
	  24:	90 01 00 44 	stw     r0,68(r1)
	  28:	7c 1e 28 40 	cmplw   r30,r5
	  2c:	40 82 00 48 	bne     74 
	  30:	7f e3 fb 78 	mr      r3,r31
	  34:	48 00 00 01 	bl      34 
				34: R_PPC_REL24	patch_instruction
	  38:	80 01 00 44 	lwz     r0,68(r1)
	  3c:	20 63 00 00 	subfic  r3,r3,0
	  40:	83 c1 00 38 	lwz     r30,56(r1)
	  44:	7c 63 19 10 	subfe   r3,r3,r3
	  48:	7c 08 03 a6 	mtlr    r0
	  4c:	83 e1 00 3c 	lwz     r31,60(r1)
	  50:	38 21 00 40 	addi    r1,r1,64
	  54:	4e 80 00 20 	blr

It improves ftrace activation/deactivation duration by about 3%.

Modify patch_instruction() return on failure to -EPERM in order to
match with ftrace expectations. Other users of patch_instruction()
do not care about the exact error value returned.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/49a8597230713e2633e7d9d7b56140787c4a7e20.1652074503.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Inline create_branch()

2022-05-19T13:11:28+00:00

create_branch() is a good candidate for inlining because:
- Flags can be folded in.
- Range tests are likely to be already done.

Hence reducing the create_branch() to only a set of instructions.

So inline it.

It improves ftrace activation by 10%.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/69851cc9a7bf8f03d025e6d29e165f2d0bd3bb6e.1652074503.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Inline is_offset_in_{cond}_branch_range()

2022-05-19T13:11:28+00:00

Test in is_offset_in_branch_range() and is_offset_in_cond_branch_range()
are simple tests that are worth inlining.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/a05be0ccb7373e6a9789a1988fcd0c810f5f9269.1652074503.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Use jump_label to check if poking_init() is done

2022-05-11T13:06:39+00:00

It's only during early startup that poking_init() is not done yet,
for instance when calling ftrace_init().

Once poking_init() has been called there must be a poking area, no
need to check it everytime patch_instruction() is called.

ftrace activation time is reduced by 7% with the change on an 8xx.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/8d6088aca7b63247377b6d9e4897d08d935fbe93.1647962456.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Use jump_label for testing freed initmem

2022-05-11T13:06:39+00:00

Once init is done, initmem is freed forever so no need to
test system_state at every call to patch_instruction().

Use jump_label.

This reduces by 2% the time needed to activate ftrace on an 8xx.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/0aee964721cab7316cffde21a2ca223cee14d373.1647962456.git.christophe.leroy@csgroup.eu