| Message ID | 20210222085756.14396-5-frankja@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x: Cleanup exception register save/restore and implement backtrace | expand |
On 22/02/2021 09.57, Janosch Frank wrote: > After the stack changes we can finally use -mbackchain and have a > working backtrace. > > Signed-off-by: Janosch Frank <frankja@linux.ibm.com> > --- > lib/s390x/stack.c | 20 ++++++++++++++------ > s390x/Makefile | 1 + > s390x/macros.S | 5 +++++ > 3 files changed, 20 insertions(+), 6 deletions(-) Reviewed-by: Thomas Huth <thuth@redhat.com>
On Mon, 22 Feb 2021 03:57:53 -0500 Janosch Frank <frankja@linux.ibm.com> wrote: > After the stack changes we can finally use -mbackchain and have a > working backtrace. > > Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > lib/s390x/stack.c | 20 ++++++++++++++------ > s390x/Makefile | 1 + > s390x/macros.S | 5 +++++ > 3 files changed, 20 insertions(+), 6 deletions(-) > > diff --git a/lib/s390x/stack.c b/lib/s390x/stack.c > index 0fcd1afb..4cf80dae 100644 > --- a/lib/s390x/stack.c > +++ b/lib/s390x/stack.c > @@ -3,24 +3,32 @@ > * s390x stack implementation > * > * Copyright (c) 2017 Red Hat Inc > + * Copyright 2021 IBM Corp > * > * Authors: > * Thomas Huth <thuth@redhat.com> > * David Hildenbrand <david@redhat.com> > + * Janosch Frank <frankja@de.ibm.com> > */ > #include <libcflat.h> > #include <stack.h> > +#include <asm/arch_def.h> > > int backtrace_frame(const void *frame, const void **return_addrs, > int max_depth) { > - printf("TODO: Implement backtrace_frame(%p, %p, %d) > function!\n", > - frame, return_addrs, max_depth); > - return 0; > + int depth = 0; > + struct stack_frame *stack = (struct stack_frame *)frame; > + > + for (depth = 0; stack && depth < max_depth; depth++) { > + return_addrs[depth] = (void *)stack->grs[8]; > + stack = stack->back_chain; > + } > + > + return depth; > } > > int backtrace(const void **return_addrs, int max_depth) > { > - printf("TODO: Implement backtrace(%p, %d) function!\n", > - return_addrs, max_depth); > - return 0; > + return backtrace_frame(__builtin_frame_address(0), > + return_addrs, max_depth); > } > diff --git a/s390x/Makefile b/s390x/Makefile > index f3b0fccf..20bb5683 100644 > --- a/s390x/Makefile > +++ b/s390x/Makefile > @@ -39,6 +39,7 @@ CFLAGS += -ffreestanding > CFLAGS += -I $(SRCDIR)/lib -I $(SRCDIR)/lib/s390x -I lib > CFLAGS += -O2 > CFLAGS += -march=zEC12 > +CFLAGS += -mbackchain > CFLAGS += -fno-delete-null-pointer-checks > LDFLAGS += -nostdlib -Wl,--build-id=none > > diff --git a/s390x/macros.S b/s390x/macros.S > index 11f4397a..d4f41ec4 100644 > --- a/s390x/macros.S > +++ b/s390x/macros.S > @@ -22,6 +22,11 @@ > lgr %r2, %r15 > /* Allocate stack space for called C function, as specified > in s390 ELF ABI */ slgfi %r15, 160 > + /* > + * Save the address of the interrupt stack into the back > chain > + * of the called function. > + */ > + stg %r2, STACK_FRAME_INT_BACKCHAIN(%r15) > brasl %r14, \c_func > algfi %r15, 160 > RESTORE_REGS_STACK
diff --git a/lib/s390x/stack.c b/lib/s390x/stack.c index 0fcd1afb..4cf80dae 100644 --- a/lib/s390x/stack.c +++ b/lib/s390x/stack.c @@ -3,24 +3,32 @@ * s390x stack implementation * * Copyright (c) 2017 Red Hat Inc + * Copyright 2021 IBM Corp * * Authors: * Thomas Huth <thuth@redhat.com> * David Hildenbrand <david@redhat.com> + * Janosch Frank <frankja@de.ibm.com> */ #include <libcflat.h> #include <stack.h> +#include <asm/arch_def.h> int backtrace_frame(const void *frame, const void **return_addrs, int max_depth) { - printf("TODO: Implement backtrace_frame(%p, %p, %d) function!\n", - frame, return_addrs, max_depth); - return 0; + int depth = 0; + struct stack_frame *stack = (struct stack_frame *)frame; + + for (depth = 0; stack && depth < max_depth; depth++) { + return_addrs[depth] = (void *)stack->grs[8]; + stack = stack->back_chain; + } + + return depth; } int backtrace(const void **return_addrs, int max_depth) { - printf("TODO: Implement backtrace(%p, %d) function!\n", - return_addrs, max_depth); - return 0; + return backtrace_frame(__builtin_frame_address(0), + return_addrs, max_depth); } diff --git a/s390x/Makefile b/s390x/Makefile index f3b0fccf..20bb5683 100644 --- a/s390x/Makefile +++ b/s390x/Makefile @@ -39,6 +39,7 @@ CFLAGS += -ffreestanding CFLAGS += -I $(SRCDIR)/lib -I $(SRCDIR)/lib/s390x -I lib CFLAGS += -O2 CFLAGS += -march=zEC12 +CFLAGS += -mbackchain CFLAGS += -fno-delete-null-pointer-checks LDFLAGS += -nostdlib -Wl,--build-id=none diff --git a/s390x/macros.S b/s390x/macros.S index 11f4397a..d4f41ec4 100644 --- a/s390x/macros.S +++ b/s390x/macros.S @@ -22,6 +22,11 @@ lgr %r2, %r15 /* Allocate stack space for called C function, as specified in s390 ELF ABI */ slgfi %r15, 160 + /* + * Save the address of the interrupt stack into the back chain + * of the called function. + */ + stg %r2, STACK_FRAME_INT_BACKCHAIN(%r15) brasl %r14, \c_func algfi %r15, 160 RESTORE_REGS_STACK
After the stack changes we can finally use -mbackchain and have a working backtrace. Signed-off-by: Janosch Frank <frankja@linux.ibm.com> --- lib/s390x/stack.c | 20 ++++++++++++++------ s390x/Makefile | 1 + s390x/macros.S | 5 +++++ 3 files changed, 20 insertions(+), 6 deletions(-)