svn commit: r365626 - in head/sys/cddl/dev: dtrace/riscv fbt/riscv

[Kristof Provost]

Author: kp
Date: Fri Sep 11 09:15:49 2020
New Revision: 365626
URL: https://svnweb.freebsd.org/changeset/base/365626

Log:
  dtrace: fix fbt return probes on RISC-V
  
  Return values are passed in a0, so read it from there. We also pass a1 through
  to userspace, as the ABI allows small structs to be returned in registers
  a0/a1. While here read the register values directly from the trapframe rather
  than rtval, and remove the now unneeded argument from dtrace_invop().
  
  Set fbtp_roffset so that we get the correct return location in arg0.
  
  Reviewed by:	markj
  Sponsored by:	Axiado
  Differential Revision:	https://reviews.freebsd.org/D26389

Modified:
  head/sys/cddl/dev/dtrace/riscv/dtrace_subr.c
  head/sys/cddl/dev/fbt/riscv/fbt_isa.c

Modified: head/sys/cddl/dev/dtrace/riscv/dtrace_subr.c
==============================================================================
--- head/sys/cddl/dev/dtrace/riscv/dtrace_subr.c	Fri Sep 11 05:45:27 2020	(r365625)
+++ head/sys/cddl/dev/dtrace/riscv/dtrace_subr.c	Fri Sep 11 09:15:49 2020	(r365626)
@@ -53,7 +53,7 @@ extern dtrace_id_t	dtrace_probeid_error;
 extern int (*dtrace_invop_jump_addr)(struct trapframe *);
 extern void dtrace_getnanotime(struct timespec *tsp);
 
-int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
+int dtrace_invop(uintptr_t, struct trapframe *);
 void dtrace_invop_init(void);
 void dtrace_invop_uninit(void);
 
@@ -65,13 +65,13 @@ typedef struct dtrace_invop_hdlr {
 dtrace_invop_hdlr_t *dtrace_invop_hdlr;
 
 int
-dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
+dtrace_invop(uintptr_t addr, struct trapframe *frame)
 {
 	dtrace_invop_hdlr_t *hdlr;
 	int rval;
 
 	for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
-		if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
+		if ((rval = hdlr->dtih_func(addr, frame, 0)) != 0)
 			return (rval);
 
 	return (0);
@@ -254,7 +254,7 @@ dtrace_invop_start(struct trapframe *frame)
 	uint32_t imm;
 	int invop;
 
-	invop = dtrace_invop(frame->tf_sepc, frame, frame->tf_sepc);
+	invop = dtrace_invop(frame->tf_sepc, frame);
 	if (invop == 0)
 		return (-1);
 

Modified: head/sys/cddl/dev/fbt/riscv/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/riscv/fbt_isa.c	Fri Sep 11 05:45:27 2020	(r365625)
+++ head/sys/cddl/dev/fbt/riscv/fbt_isa.c	Fri Sep 11 09:15:49 2020	(r365626)
@@ -59,9 +59,14 @@ fbt_invop(uintptr_t addr, struct trapframe *frame, uin
 		if ((uintptr_t)fbt->fbtp_patchpoint == addr) {
 			cpu->cpu_dtrace_caller = addr;
 
-			dtrace_probe(fbt->fbtp_id, frame->tf_a[0],
-			    frame->tf_a[1], frame->tf_a[2],
-			    frame->tf_a[3], frame->tf_a[4]);
+			if (fbt->fbtp_roffset == 0) {
+				dtrace_probe(fbt->fbtp_id, frame->tf_a[0],
+				    frame->tf_a[1], frame->tf_a[2],
+				    frame->tf_a[3], frame->tf_a[4]);
+			} else {
+				dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset,
+				    frame->tf_a[0], frame->tf_a[1], 0, 0);
+			}
 
 			cpu->cpu_dtrace_caller = 0;
 			return (fbt->fbtp_savedval);
@@ -233,6 +238,7 @@ again:
 	fbt->fbtp_loadcnt = lf->loadcnt;
 	fbt->fbtp_symindx = symindx;
 	fbt->fbtp_rval = rval;
+	fbt->fbtp_roffset = (uintptr_t)instr - (uintptr_t)symval->value;
 	fbt->fbtp_savedval = *instr;
 	fbt->fbtp_patchval = patchval;
 	fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];