diff options
| author | Guo Ren | 2023-01-12 04:05:58 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-03-10 09:34:30 +0100 |
| commit | 8d4084ccdfceb16070562970489782e8a15eaed4 (patch) | |
| tree | ccffa26c4f9aa4b3c01f0e2e0cfbfe5d0ea6895d /arch/riscv | |
| parent | 6e433ccb6844b0315f38783bc04775b0cc0be0c8 (diff) | |
riscv: ftrace: Remove wasted nops for !RISCV_ISA_C
commit 409c8fb20c66df7150e592747412438c04aeb11f upstream.
When CONFIG_RISCV_ISA_C=n, -fpatchable-function-entry=8 would generate
more nops than we expect. Because it treat nop opcode as 0x00000013
instead of 0x0001.
Dump of assembler code for function dw_pcie_free_msi:
0xffffffff806fce94 <+0>: sd ra,-8(sp)
0xffffffff806fce98 <+4>: auipc ra,0xff90f
0xffffffff806fce9c <+8>: jalr -684(ra) # 0xffffffff8000bbec
<ftrace_caller>
0xffffffff806fcea0 <+12>: ld ra,-8(sp)
0xffffffff806fcea4 <+16>: nop /* wasted */
0xffffffff806fcea8 <+20>: nop /* wasted */
0xffffffff806fceac <+24>: nop /* wasted */
0xffffffff806fceb0 <+28>: nop /* wasted */
0xffffffff806fceb4 <+0>: addi sp,sp,-48
0xffffffff806fceb8 <+4>: sd s0,32(sp)
0xffffffff806fcebc <+8>: sd s1,24(sp)
0xffffffff806fcec0 <+12>: sd s2,16(sp)
0xffffffff806fcec4 <+16>: sd s3,8(sp)
0xffffffff806fcec8 <+20>: sd ra,40(sp)
0xffffffff806fcecc <+24>: addi s0,sp,48
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20230112090603.1295340-3-guoren@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/riscv')
| -rw-r--r-- | arch/riscv/Makefile | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index c8187867c5f4..7382398a0df2 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -11,7 +11,11 @@ LDFLAGS_vmlinux := ifeq ($(CONFIG_DYNAMIC_FTRACE),y) LDFLAGS_vmlinux := --no-relax KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY +ifeq ($(CONFIG_RISCV_ISA_C),y) CC_FLAGS_FTRACE := -fpatchable-function-entry=8 +else + CC_FLAGS_FTRACE := -fpatchable-function-entry=4 +endif endif ifeq ($(CONFIG_CMODEL_MEDLOW),y) |