Add fasttrap for PowerPC. This is the last piece of the dtrace/ppc puzzle.

It's incomplete, it doesn't contain full instruction emulation, but it should be
sufficient for most cases.

MFC after:	1 month

2 files changed, 215 insertions, 12 deletions

diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c
index 2d0428a..ee68479 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c
@@ -242,8 +242,14 @@ printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
 /* XXX */
 printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
 #elif defined(__powerpc__)
-/* XXX */
-printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+			/*
+			 * Add 4 bytes to hit the low half of this 64-bit
+			 * big-endian address.
+			 */
+			rel->r_offset = s->dofs_offset +
+			    dofr[j].dofr_offset + 4;
+			rel->r_info = ELF32_R_INFO(count + dep->de_global,
+			    R_PPC_REL32);
 #elif defined(__sparc)
 			/*
 			 * Add 4 bytes to hit the low half of this 64-bit
@@ -423,7 +429,10 @@ prepare_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf64_t *dep)
 #elif defined(__mips__)
 /* XXX */
 #elif defined(__powerpc__)
-/* XXX */
+			rel->r_offset = s->dofs_offset +
+			    dofr[j].dofr_offset;
+			rel->r_info = ELF64_R_INFO(count + dep->de_global,
+			    R_PPC64_REL64);
 #elif defined(__i386) || defined(__amd64)
 			rel->r_offset = s->dofs_offset +
 			    dofr[j].dofr_offset;
@@ -824,12 +833,84 @@ printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
 	return (0);
 }
 #elif defined(__powerpc__)
+/* The sentinel is 'xor r3,r3,r3'. */
+#define DT_OP_XOR_R3	0x7c631a78
+
+#define DT_OP_NOP		0x60000000
+#define DT_OP_BLR		0x4e800020
+
+/* This captures all forms of branching to address. */
+#define DT_IS_BRANCH(inst)	((inst & 0xfc000000) == 0x48000000)
+#define DT_IS_BL(inst)	(DT_IS_BRANCH(inst) && (inst & 0x01))
+
 /* XXX */
 static int
 dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
     uint32_t *off)
 {
-printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+	uint32_t *ip;
+
+	if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0)
+		return (-1);
+
+	/*LINTED*/
+	ip = (uint32_t *)(p + rela->r_offset);
+
+	/*
+	 * We only know about some specific relocation types.
+	 */
+	if (GELF_R_TYPE(rela->r_info) != R_PPC_REL24 &&
+	    GELF_R_TYPE(rela->r_info) != R_PPC_PLTREL24)
+		return (-1);
+
+	/*
+	 * We may have already processed this object file in an earlier linker
+	 * invocation. Check to see if the present instruction sequence matches
+	 * the one we would install below.
+	 */
+	if (isenabled) {
+		if (ip[0] == DT_OP_XOR_R3) {
+			(*off) += sizeof (ip[0]);
+			return (0);
+		}
+	} else {
+		if (ip[0] == DT_OP_NOP) {
+			(*off) += sizeof (ip[0]);
+			return (0);
+		}
+	}
+
+	/*
+	 * We only expect branch to address instructions.
+	 */
+	if (!DT_IS_BRANCH(ip[0])) {
+		dt_dprintf("found %x instead of a branch instruction at %llx\n",
+		    ip[0], (u_longlong_t)rela->r_offset);
+		return (-1);
+	}
+
+	if (isenabled) {
+		/*
+		 * It would necessarily indicate incorrect usage if an is-
+		 * enabled probe were tail-called so flag that as an error.
+		 * It's also potentially (very) tricky to handle gracefully,
+		 * but could be done if this were a desired use scenario.
+		 */
+		if (!DT_IS_BL(ip[0])) {
+			dt_dprintf("tail call to is-enabled probe at %llx\n",
+			    (u_longlong_t)rela->r_offset);
+			return (-1);
+		}
+
+		ip[0] = DT_OP_XOR_R3;
+		(*off) += sizeof (ip[0]);
+	} else {
+		if (DT_IS_BL(ip[0]))
+			ip[0] = DT_OP_NOP;
+		else
+			ip[0] = DT_OP_BLR;
+	}
+
 	return (0);
 }
 
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/powerpc/dt_isadep.c b/cddl/contrib/opensolaris/lib/libdtrace/powerpc/dt_isadep.c
index 1aeb95f..f4b02c9 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/powerpc/dt_isadep.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/powerpc/dt_isadep.c
@@ -35,14 +35,26 @@
 #include <dt_impl.h>
 #include <dt_pid.h>
 
+#include <libproc_compat.h>
+
 /*ARGSUSED*/
 int
 dt_pid_create_entry_probe(struct ps_prochandle *P, dtrace_hdl_t *dtp,
     fasttrap_probe_spec_t *ftp, const GElf_Sym *symp)
 {
+	ftp->ftps_type = DTFTP_ENTRY;
+	ftp->ftps_pc = (uintptr_t)symp->st_value;
+	ftp->ftps_size = (size_t)symp->st_size;
+	ftp->ftps_noffs = 1;
+	ftp->ftps_offs[0] = 0;
+
+	if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
+		dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
+		    strerror(errno));
+		return (dt_set_errno(dtp, errno));
+	}
 
-	dt_dprintf("%s: unimplemented\n", __func__);
-	return (DT_PROC_ERR);
+	return (1);
 }
 
 int
@@ -50,8 +62,74 @@ dt_pid_create_return_probe(struct ps_prochandle *P, dtrace_hdl_t *dtp,
     fasttrap_probe_spec_t *ftp, const GElf_Sym *symp, uint64_t *stret)
 {
 
-	dt_dprintf("%s: unimplemented\n", __func__);
-	return (DT_PROC_ERR);
+	uintptr_t temp;
+	uint32_t *text;
+	int i;
+	int srdepth = 0;
+
+	if ((text = malloc(symp->st_size + 4)) == NULL) {
+		dt_dprintf("mr sparkle: malloc() failed\n");
+		return (DT_PROC_ERR);
+	}
+
+	if (Pread(P, text, symp->st_size, symp->st_value) != symp->st_size) {
+		dt_dprintf("mr sparkle: Pread() failed\n");
+		free(text);
+		return (DT_PROC_ERR);
+	}
+
+	/*
+	 * Leave a dummy instruction in the last slot to simplify edge
+	 * conditions.
+	 */
+	text[symp->st_size / 4] = 0;
+
+	ftp->ftps_type = DTFTP_RETURN;
+	ftp->ftps_pc = symp->st_value;
+	ftp->ftps_size = symp->st_size;
+	ftp->ftps_noffs = 0;
+
+	for (i = 0; i < symp->st_size / 4; i++) {
+
+		if ((text[i] & 0xfc000001) != 0x48000000 &&
+		    text[i] != 0x4e800020)
+			continue;
+
+		/*
+		 * Check for a jump within this function.  If it's outside this
+		 * function then it's a tail-call, so a return point.
+		 */
+		if ((text[i] & 0xfc000000) == 0x48000000) {
+			temp = (text[i] & 0x03fffffc);
+			/* Bit 30 denotes an absolute address. */
+			if (!(text[i] & 0x02)) {
+				temp += symp->st_value + i * 4;
+			}
+			else {
+				/* Sign extend the absolute address. */
+				if (temp & 0x02000000) {
+					temp |= (UINTPTR_MAX - 0x03ffffff);
+				}
+			}
+			if (temp >= symp->st_value &&
+			    temp <= (symp->st_value + symp->st_size))
+				continue;
+		}
+		dt_dprintf("return at offset %x\n", i * 4);
+		ftp->ftps_offs[ftp->ftps_noffs++] = i * 4;
+	}
+
+	free(text);
+	if (ftp->ftps_noffs > 0) {
+		if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
+			dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
+			    strerror(errno));
+			return (dt_set_errno(dtp, errno));
+		}
+	}
+
+
+	return (ftp->ftps_noffs);
 }
 
 /*ARGSUSED*/
@@ -59,9 +137,22 @@ int
 dt_pid_create_offset_probe(struct ps_prochandle *P, dtrace_hdl_t *dtp,
     fasttrap_probe_spec_t *ftp, const GElf_Sym *symp, ulong_t off)
 {
+	if (off & 0x3)
+		return (DT_PROC_ALIGN);
+
+	ftp->ftps_type = DTFTP_OFFSETS;
+	ftp->ftps_pc = (uintptr_t)symp->st_value;
+	ftp->ftps_size = (size_t)symp->st_size;
+	ftp->ftps_noffs = 1;
+	ftp->ftps_offs[0] = off;
+
+	if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
+		dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
+		    strerror(errno));
+		return (dt_set_errno(dtp, errno));
+	}
 
-	dt_dprintf("%s: unimplemented\n", __func__);
-	return (DT_PROC_ERR);
+	return (1);
 }
 
 /*ARGSUSED*/
@@ -69,7 +160,38 @@ int
 dt_pid_create_glob_offset_probes(struct ps_prochandle *P, dtrace_hdl_t *dtp,
     fasttrap_probe_spec_t *ftp, const GElf_Sym *symp, const char *pattern)
 {
+	ulong_t i;
+
+	ftp->ftps_type = DTFTP_OFFSETS;
+	ftp->ftps_pc = (uintptr_t)symp->st_value;
+	ftp->ftps_size = (size_t)symp->st_size;
+	ftp->ftps_noffs = 0;
+
+	/*
+	 * If we're matching against everything, just iterate through each
+	 * instruction in the function, otherwise look for matching offset
+	 * names by constructing the string and comparing it against the
+	 * pattern.
+	 */
+	if (strcmp("*", pattern) == 0) {
+		for (i = 0; i < symp->st_size; i += 4) {
+			ftp->ftps_offs[ftp->ftps_noffs++] = i;
+		}
+	} else {
+		char name[sizeof (i) * 2 + 1];
+
+		for (i = 0; i < symp->st_size; i += 4) {
+			(void) sprintf(name, "%lx", i);
+			if (gmatch(name, pattern))
+				ftp->ftps_offs[ftp->ftps_noffs++] = i;
+		}
+	}
+
+	if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
+		dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
+		    strerror(errno));
+		return (dt_set_errno(dtp, errno));
+	}
 
-	dt_dprintf("%s: unimplemented\n", __func__);
-	return (DT_PROC_ERR);
+	return (ftp->ftps_noffs);
 }