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LoongArch/ftrace: Add recordmcount support 

Recordmcount utility under scripts is run, after compiling each object,
to find out all the locations of calling _mcount() and put them into
specific seciton named __mcount_loc.

Then the linker collects all such information into a table in the kernel
image (between __start_mcount_loc and __stop_mcount_loc) for later use
by ftrace.

This patch adds LoongArch specific definitions to identify such locations.
And on LoongArch, only the C version is used to build the kernel now that
CONFIG_HAVE_C_RECORDMCOUNT is on.

Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Qing Zhang 2022-12-10 22:40:15 +08:00 committed by Huacai Chen
parent dbe3ba3018
commit a0a458fbd6
2 changed files with 41 additions and 0 deletions
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2
arch/loongarch/Kconfig
View File

@ -85,11 +85,13 @@ config LOONGARCH
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
select HAVE_ASM_MODVERSIONS
select HAVE_CONTEXT_TRACKING_USER
select HAVE_C_RECORDMCOUNT
select HAVE_DEBUG_STACKOVERFLOW
select HAVE_DMA_CONTIGUOUS
select HAVE_EBPF_JIT
select HAVE_EXIT_THREAD
select HAVE_FAST_GUP
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
select HAVE_GENERIC_VDSO

39
scripts/recordmcount.c
View File

@ -38,6 +38,14 @@
#define R_AARCH64_ABS64 257
#endif
#ifndef EM_LOONGARCH
#define EM_LOONGARCH 258
#define R_LARCH_32 1
#define R_LARCH_64 2
#define R_LARCH_MARK_LA 20
#define R_LARCH_SOP_PUSH_PLT_PCREL 29
#endif
#define R_ARM_PC24 1
#define R_ARM_THM_CALL 10
#define R_ARM_CALL 28
@ -441,6 +449,28 @@ static int arm64_is_fake_mcount(Elf64_Rel const *rp)
return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26;
}
static int LARCH32_is_fake_mcount(Elf32_Rel const *rp)
{
switch (ELF64_R_TYPE(w(rp->r_info))) {
case R_LARCH_MARK_LA:
case R_LARCH_SOP_PUSH_PLT_PCREL:
return 0;
}
return 1;
}
static int LARCH64_is_fake_mcount(Elf64_Rel const *rp)
{
switch (ELF64_R_TYPE(w(rp->r_info))) {
case R_LARCH_MARK_LA:
case R_LARCH_SOP_PUSH_PLT_PCREL:
return 0;
}
return 1;
}
/* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
* http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
* We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
@ -558,6 +588,7 @@ static int do_file(char const *const fname)
break;
case EM_IA_64: reltype = R_IA64_IMM64; break;
case EM_MIPS: /* reltype: e_class */ break;
case EM_LOONGARCH: /* reltype: e_class */ break;
case EM_PPC: reltype = R_PPC_ADDR32; break;
case EM_PPC64: reltype = R_PPC64_ADDR64; break;
case EM_S390: /* reltype: e_class */ break;
@ -589,6 +620,10 @@ static int do_file(char const *const fname)
reltype = R_MIPS_32;
is_fake_mcount32 = MIPS32_is_fake_mcount;
}
if (w2(ehdr->e_machine) == EM_LOONGARCH) {
reltype = R_LARCH_32;
is_fake_mcount32 = LARCH32_is_fake_mcount;
}
if (do32(ehdr, fname, reltype) < 0)
goto out;
break;
@ -610,6 +645,10 @@ static int do_file(char const *const fname)
Elf64_r_info = MIPS64_r_info;
is_fake_mcount64 = MIPS64_is_fake_mcount;
}
if (w2(ghdr->e_machine) == EM_LOONGARCH) {
reltype = R_LARCH_64;
is_fake_mcount64 = LARCH64_is_fake_mcount;
}
if (do64(ghdr, fname, reltype) < 0)
goto out;
break;