The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=0e69c959150c0ba38459e9121158016ee34b0d92
commit 0e69c959150c0ba38459e9121158016ee34b0d92 Author: Mark Johnston <[email protected]> AuthorDate: 2022-10-31 23:11:36 +0000 Commit: Mark Johnston <[email protected]> CommitDate: 2022-10-31 23:11:36 +0000 dtrace: Fix up %rip for invop probes on x86 When a breakpoint exception is raised, the saved value of %rip points to the instruction following the breakpoint. However, when fetching the value of %rip using regs[], it's more natural to provide the address of the breakpoint itself, so modify the kinst and fbt providers accordingly. Reported by: khng Reviewed by: christos, khng MFC after: 2 months Differential Revision: https://reviews.freebsd.org/D37218 --- sys/cddl/dev/fbt/x86/fbt_isa.c | 8 ++++++++ sys/cddl/dev/kinst/amd64/kinst_isa.c | 8 +++++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/sys/cddl/dev/fbt/x86/fbt_isa.c b/sys/cddl/dev/fbt/x86/fbt_isa.c index 05ec87ab437f..b05ae4cb2c44 100644 --- a/sys/cddl/dev/fbt/x86/fbt_isa.c +++ b/sys/cddl/dev/fbt/x86/fbt_isa.c @@ -84,6 +84,12 @@ fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t scratch __unused) if ((uintptr_t)fbt->fbtp_patchpoint != addr) continue; fbtrval = fbt->fbtp_rval; + + /* + * Report the address of the breakpoint for the benefit + * of consumers fetching register values with regs[]. + */ + frame->tf_rip--; for (; fbt != NULL; fbt = fbt->fbtp_tracenext) { ASSERT(fbt->fbtp_rval == fbtrval); if (fbt->fbtp_roffset == 0) { @@ -143,6 +149,8 @@ fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t scratch __unused) cpu->cpu_dtrace_caller = 0; } } + /* Advance to the instruction following the breakpoint. */ + frame->tf_rip++; return (fbtrval); } diff --git a/sys/cddl/dev/kinst/amd64/kinst_isa.c b/sys/cddl/dev/kinst/amd64/kinst_isa.c index 6d8d5d521617..e47cfbbf4d4e 100644 --- a/sys/cddl/dev/kinst/amd64/kinst_isa.c +++ b/sys/cddl/dev/kinst/amd64/kinst_isa.c @@ -139,6 +139,12 @@ kinst_invop(uintptr_t addr, struct trapframe *frame, uintptr_t scratch) if (kp == NULL) return (0); + /* + * Report the address of the breakpoint for the benefit of consumers + * fetching register values with regs[]. + */ + frame->tf_rip--; + DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); cpu->cpu_dtrace_caller = stack[0]; DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT | CPU_DTRACE_BADADDR); @@ -162,7 +168,7 @@ kinst_invop(uintptr_t addr, struct trapframe *frame, uintptr_t scratch) if (kpmd->reg1 == -1 && kpmd->reg2 == -1) { /* rip-relative */ - rval = frame->tf_rip - 1 + kpmd->instlen; + rval = frame->tf_rip + kpmd->instlen; } else { /* indirect */ rval = kinst_regval(frame, kpmd->reg1) +
