On Fri, Jun 8, 2018 at 07:35 Mark Johnston <ma...@freebsd.org> wrote:
> On Fri, Jun 08, 2018 at 04:58:03AM +0000, Matt Macy wrote: > > Author: mmacy > > Date: Fri Jun 8 04:58:03 2018 > > New Revision: 334827 > > URL: https://svnweb.freebsd.org/changeset/base/334827 > > > > Log: > > hwpmc: simplify calling convention for hwpmc interrupt handling > > > > pmc_process_interrupt takes 5 arguments when only 3 are needed. > > cpu is always available in curcpu and inuserspace can always be > > derived from the passed trapframe. > > > > While facially a reasonable cleanup this change was motivated > > by the need to workaround a compiler bug. > > What is the compiler bug? Do you have disassembly of the subroutines in > question? > We talked about this online. How would that help without engaging in a huge diversion in to the toolchain? There is nothing wrong with the C code so I resorted to a voodoo fix to get hwpmc working again. If you're volunteering mjg or I or you can disassemble the code prior to my change. > -M > > > > > core2_intr(cpu, tf) -> > > pmc_process_interrupt(cpu, ring, pmc, tf, inuserspace) -> > > pmc_add_sample(cpu, ring, pm, tf, inuserspace) > > > > In the process of optimizing the tail call the tf pointer was getting > > clobbered: > > > > (kgdb) up > > at /storage/mmacy/devel/freebsd/sys/dev/hwpmc/hwpmc_mod.c:4709 > > 4709 > pmc_save_kernel_callchain(ps->ps_pc, > > (kgdb) up > > 1205 error = pmc_process_interrupt(cpu, PMC_HR, pm, > tf, > > > > resulting in a crash in pmc_save_kernel_callchain. > _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
