2020-12-03 07:26:29

by Xingxing Su

Subject: [PATCH] MIPS: Enable GCOV

Enable gcov profiling of the entire kernel on mips. Required changes
include disabling profiling for:

* arch/kernel/boot/compressed: not linked to main kernel.

Lightly tested on Loongson 3A3000 an 3A4000, seems to work as expected.

without "GCOV_PROFILE := n" in compressed Makefile,
build errors as follows:
...
ld: arch/mips/boot/compressed/string.o:(.data+0x88):
undefined reference to `__gcov_merge_add'
ld: arch/mips/boot/compressed/string.o:
in function `_GLOBAL__sub_I_00100_0_memcpy':
string.c:(.text.startup+0x4): undefined reference to `__gcov_init'
ld: arch/mips/boot/compressed/string.o:
in function `_GLOBAL__sub_D_00100_1_memcpy':
string.c:(.text.exit+0x0): undefined reference to `__gcov_exit'
...

Signed-off-by: Youling Tang <[email protected]>
Signed-off-by: Xingxing Su <[email protected]>
---
arch/mips/Kconfig | 1 +
arch/mips/boot/compressed/Makefile | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 2000bb2..52664a30 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -9,6 +9,7 @@ config MIPS
select ARCH_HAS_PTE_SPECIAL if !(32BIT && CPU_HAS_RIXI)
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UBSAN_SANITIZE_ALL
+ select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_SUPPORTS_UPROBES
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if 64BIT
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index d665118..405b47a 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -36,6 +36,7 @@ KBUILD_AFLAGS := $(KBUILD_AFLAGS) -D__ASSEMBLY__ \

# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
KCOV_INSTRUMENT := n
+GCOV_PROFILE := n

# decompressor objects (linked with vmlinuz)
vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o $(obj)/string.o
--
2.1.0

2020-12-04 12:13:48

by Thomas Bogendoerfer

Subject: Re: [PATCH] MIPS: Enable GCOV

On Thu, Dec 03, 2020 at 03:22:51PM +0800, Xingxing Su wrote:
> Enable gcov profiling of the entire kernel on mips. Required changes
> include disabling profiling for:
>
> * arch/kernel/boot/compressed: not linked to main kernel.
>
> Lightly tested on Loongson 3A3000 an 3A4000, seems to work as expected.
>
> without "GCOV_PROFILE := n" in compressed Makefile,
> build errors as follows:
> ...
> ld: arch/mips/boot/compressed/string.o:(.data+0x88):
> undefined reference to `__gcov_merge_add'
> ld: arch/mips/boot/compressed/string.o:
> in function `_GLOBAL__sub_I_00100_0_memcpy':
> string.c:(.text.startup+0x4): undefined reference to `__gcov_init'
> ld: arch/mips/boot/compressed/string.o:
> in function `_GLOBAL__sub_D_00100_1_memcpy':
> string.c:(.text.exit+0x0): undefined reference to `__gcov_exit'
> ...
>
> Signed-off-by: Youling Tang <[email protected]>
> Signed-off-by: Xingxing Su <[email protected]>
> ---
> arch/mips/Kconfig | 1 +
> arch/mips/boot/compressed/Makefile | 1 +
> 2 files changed, 2 insertions(+)

applied to mips-next.

Thomas.

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