linux.git/arch/powerpc/kernel/trace, branch v6.0

powerpc64/ftrace: Fix ftrace for clang builds

2022-08-10T05:38:16+00:00

Clang doesn't support -mprofile-kernel ABI, so guard the checks against
CONFIG_DYNAMIC_FTRACE_WITH_REGS, rather than the elf ABI version.

Fixes: 23b44fc248f4 ("powerpc/ftrace: Make __ftrace_make_{nop/call}() common to PPC32 and PPC64")
Cc: stable@vger.kernel.org # v5.19+
Reported-by: Nick Desaulniers 
Reported-by: Ondrej Mosnacek 
Signed-off-by: Naveen N. Rao 
Tested-by: Ondrej Mosnacek 
Acked-by: Nick Desaulniers 
Signed-off-by: Michael Ellerman 
Link: https://github.com/llvm/llvm-project/issues/57031
Link: https://github.com/ClangBuiltLinux/linux/issues/1682
Link: https://lore.kernel.org/r/20220809095907.418764-1-naveen.n.rao@linux.vnet.ibm.com

powerpc: Fix all occurences of duplicate words

2022-07-25T02:05:15+00:00

Since commit 87c78b612f4f ("powerpc: Fix all occurences of "the the"")
fixed "the the", there's now a steady stream of patches fixing other
duplicate words.

Just fix them all at once, to save the overhead of dealing with
individual patches for each case.

This leaves a few cases of "that that", which in some contexts is
correct.

Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220718095158.326606-1-mpe@ellerman.id.au

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

powerpc/ftrace: Remove ftrace init tramp once kernel init is complete

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

Stop using the ftrace trampoline for init section once kernel init is
complete.

Fixes: 67361cf8071286 ("powerpc/ftrace: Handle large kernel configs")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Naveen N. Rao 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220516071422.463738-1-naveen.n.rao@linux.vnet.ibm.com

powerpc/ftrace: Minimise number of #ifdefs

2022-05-22T05:58:26+00:00

A lot of #ifdefs can be replaced by IS_ENABLED()

Do so.

Signed-off-by: Christophe Leroy 
[mpe: Fold in changes suggested by Naveen and Christophe on list]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/18ce6708d6f8c71d87436f9c6019f04df4125128.1652074503.git.christophe.leroy@csgroup.eu

powerpc/ftrace: Simplify expected_nop_sequence()

2022-05-22T05:58:26+00:00

Avoid ifdefs around expected_nop_sequence().

While at it make it a bool.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/305d22472f1f92127fba09692df6bb5d079a8cd0.1652074503.git.christophe.leroy@csgroup.eu

powerpc/ftrace: Use size macro instead of opencoding

2022-05-22T05:57:38+00:00

0x80000000 is SZ_2G. Use it.

Signed-off-by: Christophe Leroy 
[mpe: Fix comparison against unsigned -SZ_2G]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/bb6626e884acffe87b58736291df57db3deaa9b9.1652074503.git.christophe.leroy@csgroup.eu

powerpc/ftrace: Use PPC_RAW_xxx() macros instead of opencoding.

2022-05-19T13:11:29+00:00

PPC_RAW_xxx() macros are self explanatory and less error prone
than open coding.

Use them in ftrace.c

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/9292094c9a69cef6d29ee83f435a557b59c45065.1652074503.git.christophe.leroy@csgroup.eu

powerpc/ftrace: Use BRANCH_SET_LINK instead of value 1

2022-05-19T13:11:29+00:00

To make it explicit, use BRANCH_SET_LINK instead of value 1
when calling create_branch().

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/d57847063ac93660a5af620d4df1847f10edf61a.1652074503.git.christophe.leroy@csgroup.eu

powerpc/ftrace: Remove ftrace_plt_tramps[]

2022-05-19T13:11:29+00:00

ftrace_plt_tramps table is never filled so it is useless.

Remove it.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/daeeb618a6619e3a7e3f82f1bd83ca7c25af6330.1652074503.git.christophe.leroy@csgroup.eu