MFC r273284:

 Allow libkvm to get the kernel va to pa delta without the need for
 physaddr. This should allow for a kernel where PHYSADDR and KERNPHYSADDR
 are both undefined.

 For now libkvm will use the old method of reading physaddr and kernaddr
 to allow it to work with old kernels. This could be removed in the future
 when enough time has passed.

3 files changed, 55 insertions, 12 deletions

diff --git a/lib/libkvm/kvm_arm.c b/lib/libkvm/kvm_arm.c
index b1274e9..2c686b2 100644
--- a/lib/libkvm/kvm_arm.c
+++ b/lib/libkvm/kvm_arm.c
@@ -128,8 +128,10 @@ _kvm_initvtop(kvm_t *kd)
 	u_long kernbase, physaddr, pa;
 	pd_entry_t *l1pt;
 	Elf32_Ehdr *ehdr;
+	Elf32_Phdr *phdr;
 	size_t hdrsz;
 	char minihdr[8];
+	int found, i;
 
 	if (!kd->rawdump) {
 		if (pread(kd->pmfd, &minihdr, 8, 0) == 8) {
@@ -154,19 +156,33 @@ _kvm_initvtop(kvm_t *kd)
 	hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
 	if (_kvm_maphdrs(kd, hdrsz) == -1)
 		return (-1);
-	nl[0].n_name = "kernbase";
+
+	phdr = (Elf32_Phdr *)((uint8_t *)ehdr + ehdr->e_phoff);
+	found = 0;
+	for (i = 0; i < ehdr->e_phnum; i++) {
+		if (phdr[i].p_type == PT_DUMP_DELTA) {
+			kernbase = phdr[i].p_vaddr;
+			physaddr = phdr[i].p_paddr;
+			found = 1;
+			break;
+		}
+	}
+
 	nl[1].n_name = NULL;
-	if (kvm_nlist(kd, nl) != 0)
-		kernbase = KERNBASE;
-	else
-		kernbase = nl[0].n_value;
+	if (!found) {
+		nl[0].n_name = "kernbase";
+		if (kvm_nlist(kd, nl) != 0)
+			kernbase = KERNBASE;
+		else
+			kernbase = nl[0].n_value;
 
-	nl[0].n_name = "physaddr";
-	if (kvm_nlist(kd, nl) != 0) {
-		_kvm_err(kd, kd->program, "couldn't get phys addr");
-		return (-1);
+		nl[0].n_name = "physaddr";
+		if (kvm_nlist(kd, nl) != 0) {
+			_kvm_err(kd, kd->program, "couldn't get phys addr");
+			return (-1);
+		}
+		physaddr = nl[0].n_value;
 	}
-	physaddr = nl[0].n_value;
 	nl[0].n_name = "kernel_l1pa";
 	if (kvm_nlist(kd, nl) != 0) {
 		_kvm_err(kd, kd->program, "bad namelist");
diff --git a/sys/arm/arm/dump_machdep.c b/sys/arm/arm/dump_machdep.c
index f37346c..b0e4b1b 100644
--- a/sys/arm/arm/dump_machdep.c
+++ b/sys/arm/arm/dump_machdep.c
@@ -246,6 +246,29 @@ cb_dumphdr(struct md_pa *mdp, int seqnr, void *arg)
 	return (error);
 }
 
+/*
+ * Add a header to be used by libkvm to get the va to pa delta
+ */
+static int
+dump_os_header(struct dumperinfo *di)
+{
+	Elf_Phdr phdr;
+	int error;
+
+	bzero(&phdr, sizeof(phdr));
+	phdr.p_type = PT_DUMP_DELTA;
+	phdr.p_flags = PF_R;			/* XXX */
+	phdr.p_offset = 0;
+	phdr.p_vaddr = KERNVIRTADDR;
+	phdr.p_paddr = pmap_kextract(KERNVIRTADDR);
+	phdr.p_filesz = 0;
+	phdr.p_memsz = 0;
+	phdr.p_align = PAGE_SIZE;
+
+	error = buf_write(di, (char*)&phdr, sizeof(phdr));
+	return (error);
+}
+
 static int
 cb_size(struct md_pa *mdp, int seqnr, void *arg)
 {
@@ -311,7 +334,7 @@ dumpsys(struct dumperinfo *di)
 
 	/* Calculate dump size. */
 	dumpsize = 0L;
-	ehdr.e_phnum = foreach_chunk(cb_size, &dumpsize);
+	ehdr.e_phnum = foreach_chunk(cb_size, &dumpsize) + 1;
 	hdrsz = ehdr.e_phoff + ehdr.e_phnum * ehdr.e_phentsize;
 	fileofs = MD_ALIGN(hdrsz);
 	dumpsize += fileofs;
@@ -328,7 +351,7 @@ dumpsys(struct dumperinfo *di)
 	mkdumpheader(&kdh, KERNELDUMPMAGIC, KERNELDUMP_ARM_VERSION, dumpsize, di->blocksize);
 
 	printf("Dumping %llu MB (%d chunks)\n", (long long)dumpsize >> 20,
-	    ehdr.e_phnum);
+	    ehdr.e_phnum - 1);
 
 	/* Dump leader */
 	error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
@@ -343,6 +366,8 @@ dumpsys(struct dumperinfo *di)
 
 	/* Dump program headers */
 	error = foreach_chunk(cb_dumphdr, di);
+	if (error >= 0)
+		error = dump_os_header(di);
 	if (error < 0)
 		goto fail;
 	buf_flush(di);
diff --git a/sys/sys/elf_common.h b/sys/sys/elf_common.h
index d34ee9b..2b9a759 100644
--- a/sys/sys/elf_common.h
+++ b/sys/sys/elf_common.h
@@ -339,6 +339,8 @@ typedef struct {
 #define	PT_GNU_EH_FRAME	0x6474e550
 #define	PT_GNU_STACK	0x6474e551
 #define	PT_GNU_RELRO	0x6474e552
+#define	PT_DUMP_DELTA	0x6fb5d000	/* va->pa map for kernel dumps
+					   (currently arm). */
 #define	PT_LOSUNW	0x6ffffffa
 #define	PT_SUNWBSS	0x6ffffffa	/* Sun Specific segment */
 #define	PT_SUNWSTACK	0x6ffffffb	/* describes the stack segment */