Re: [PATCH v3 06/19] x86/vdso: Enable sframe generation in VDSO
Josh Poimboeuf <[email protected]>
| Newsgroups | org.kernel.vger.linux-toolchains,org.kernel.vger.linux-kernel,org.kernel.vger.linux-perf-users |
|---|---|
| Message-ID | <[email protected]> |
On Wed, Oct 30, 2024 at 07:20:08PM +0100, Jens Remus wrote: > > diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile > > index c9216ac4fb1e..75ae9e093a2d 100644 > > --- a/arch/x86/entry/vdso/Makefile > > +++ b/arch/x86/entry/vdso/Makefile > > @@ -47,13 +47,15 @@ quiet_cmd_vdso2c = VDSO2C $@ > > $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE > > $(call if_changed,vdso2c) > > +SFRAME_CFLAGS := $(call as-option,-Wa$(comma)-gsframe,) > > I have the impression this test might not work as expected. I suspect it works fine on x86-64, since that was the first arch supported, so --gsframe being supported also means x86-64 is supported. But yeah, other arches (and x86-32) are a different story. > Maybe the following would be an alternative test in the Makefile? > > SFRAME_CFLAGS := $(call as-instr,.cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_SFRAME=1) > ifneq ($(SFRAME_CFLAGS),) > SFRAME_CFLAGS += -Wa,--gsframe > endif Looks good, though the ifneq isn't needed: SFRAME_CFLAGS := $(call as-instr, \ .cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc, \ Wa$(comma)--gsframe -DCONFIG_AS_SFRAME=1) Though, if multiple arches are going to be using that, maybe it should just be a config option: diff --git a/arch/Kconfig b/arch/Kconfig index 33449485eafd..676dd45a7255 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -446,6 +446,9 @@ config HAVE_UNWIND_USER_SFRAME bool select UNWIND_USER +config AS_SFRAME + def_bool $(as-instr,.cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc) + config HAVE_PERF_CALLCHAIN_DEFERRED bool