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>

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 72a41e0..8b81cf9 100644 (file)
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -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

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index cce12e1..e302165 100644 (file)
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -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;