initial commit

src/jehanne/cmd/kpdump/kpdump.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"debug/elf"
+	"encoding/binary"
+	"flag"
+	"fmt"
+	"io"
+	"math"
+	"os"
+)
+
+const LRES = 3
+
+var kernel = flag.String("k", "9k", "kernel name")
+
+func main() {
+	flag.Parse()
+
+	n := flag.Args()[0]
+	d, err := os.Open(n)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
+	f, err := elf.Open(*kernel)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
+
+	var codeend uint64
+	var codestart uint64 = math.MaxUint64
+
+	for _, v := range f.Progs {
+		if v.Type != elf.PT_LOAD {
+			continue
+		}
+		fmt.Fprintf(os.Stderr, "processing %v\n", v)
+		// MUST alignt to 2M page boundary.
+		// then MUST allocate a []byte that
+		// is the right size. And MUST
+		// see if by some off chance it
+		// joins to a pre-existing segment.
+		// It's easier than it seems. We produce ONE text
+		// array and ONE data array. So it's a matter of creating
+		// a virtual memory space with an assumed starting point of
+		// 0x200000, and filling it. We just grow that as needed.
+
+		curstart := v.Vaddr
+		curend := v.Vaddr + v.Memsz
+		// magic numbers, BAH!
+		if curstart < uint64(0xffffffff00000000) {
+			curstart += 0xfffffffff0000000
+			curend += 0xfffffffff0000000
+		}
+		fmt.Fprintf(os.Stderr, "s %x e %x\n", curstart, curend)
+		if v.Flags&elf.PF_X == elf.PF_X {
+			if curstart < codestart {
+				codestart = curstart
+			}
+			if curend > codeend {
+				codeend = curend
+			}
+			fmt.Fprintf(os.Stderr, "code s %x e %x\n", codestart, codeend)
+		}
+	}
+	fmt.Fprintf(os.Stderr, "code s %x e %x\n", codestart, codeend)
+	s, err := f.Symbols()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
+	// maybe we should stop doing LRES ...
+	symname := make([]string, codeend-codestart)
+	for i := range symname {
+		symname[i] = fmt.Sprintf("[0x%x]", codestart+uint64(i))
+	}
+	for _, v := range s {
+		vstart := v.Value
+		vend := v.Value + v.Size
+		if v.Value > codeend {
+			continue
+		}
+		if v.Value+v.Size < codestart {
+			continue
+		}
+		if vstart < codestart {
+			v.Value = codestart
+		}
+		if vend > codeend {
+			vend = codeend
+		}
+		for i := vstart; i < vend; i++ {
+			symname[i-codestart] = v.Name
+		}
+	}
+	symname[0] = "Total ms"
+	symname[1<<LRES] = "Unknown"
+	// now dump the info ...
+	count := uint32(0)
+	pc := codestart
+	for {
+		if err := binary.Read(d, binary.BigEndian, &count); err != nil {
+			if err != io.EOF {
+				fmt.Fprintf(os.Stderr, "%v\n", err)
+			}
+			break
+		}
+		if count > 0 {
+			fmt.Printf("%s %d\n", symname[pc-codestart], count)
+		}
+		pc += (1 << LRES)
+	}
+}