On Sat, Sep 14, 2019 at 03:08:10PM -0400, George Koehler wrote:
> On Thu, 12 Sep 2019 16:19:18 +0200
> Otto Moerbeek <otto@drijf.net> wrote:
>
> > On Thu, Sep 12, 2019 at 12:54:47AM -0400, George Koehler wrote:
> > > The broken diff follows.
> >
> > The good news is that is is not broken for my use-case: PowerDNS
> > Recursor. It does not use ontop_fcontext. Thanks a lot for working on
> > this! I am wondering if there any users of ontop_fcontext in our tree...
> >
> > -Otto
>
> Here's a new diff with 3 more fixes:
>
> 1. It changes ontop_fcontext, so the fibonacci example now works.
>
> 2. It changes make_fcontext to align the stack pointer to 16 bytes.
> (Most code can run well or slightly slow with a 4-aligned stack
> pointer, but altivec vectors might cause a problem.)
>
> 3. Our patch-boost_context_pooled_fixedsize_stack_hpp used a wrong
> variable name, so any program that tried to #include
> <boost/context/pooled_fixedsize_stack.hpp> would get an error.
> The diff changes the variable name and bumps REVISION-main; this
> is the only part of the diff to affect arches other than powerpc.
>
> I have no code using pooled_fixedsize_stack, but one of the examples
> in boost includes the header via <boost/context/all.hpp>.
>
> I broke the fibonacci example because I caused ontop_fcontext to leave
> a stack frame, but didn't provide an .eh_frame for C++ exceptions.
> Then fibonacci threw an exception, but the unwinder can't remove the
> frame, so it didn't reach the code to catch the exception.
>
> To fix fibonacci, I go back to having ontop_fcontext make a tail call
> to the ontop-function without leaving a stack frame, like it does on
> Linux. I then cheat by placing an 8-byte transfer_t on the *other*
> stack; the existing code uses a similar cheat on Linux. This cheat
> will break if the program resumes the other stack before the
> ontop-function returns, but this is already broken on Linux.
>
> The diff doesn't fix 2 other bugs:
>
> 1. The handling of register %r13 is wrong, but this seems not to
> matter on OpenBSD, so I'm not trying to fix it.
>
> 2. The call to _exit(0) in make_fcontext is wrong for systems using
> the secure PLT, like OpenBSD. I have no code that reaches this
> call, but I would expect it to crash because it fails to set r30
> to the global offset table.
>
> I have stopped work on this diff. My next task is to report an issue
> to GitHub boost/context, about the multiple problems with ppc32.
This PowerDNS Recursor is still happy and the
boost_context_pooled_fixedsize_stack_hpp fix looks ok as well.
I'd say this is good to go in. Thanks,
-Otto
>
> Index: Makefile
> ===================================================================
> RCS file: /cvs/ports/devel/boost/Makefile,v
> retrieving revision 1.89
> diff -u -p -r1.89 Makefile
> --- Makefile 9 Aug 2019 11:25:29 -0000 1.89
> +++ Makefile 14 Sep 2019 00:56:15 -0000
> @@ -16,8 +16,8 @@ MASTER_SITES= ${MASTER_SITE_SOURCEFORGE:
> EXTRACT_SUFX= .tar.bz2
> FIX_EXTRACT_PERMISSIONS = Yes
>
> -REVISION-main= 6
> -REVISION-md= 1
> +REVISION-main= 7
> +REVISION-md= 2
>
> SO_VERSION= 9.0
> BOOST_LIBS= boost_atomic-mt \
> Index: patches/patch-boost_context_pooled_fixedsize_stack_hpp
> ===================================================================
> RCS file: /cvs/ports/devel/boost/patches/patch-boost_context_pooled_fixedsize_stack_hpp,v
> retrieving revision 1.1
> diff -u -p -r1.1 patch-boost_context_pooled_fixedsize_stack_hpp
> --- patches/patch-boost_context_pooled_fixedsize_stack_hpp 13 Dec 2018 19:52:46 -0000 1.1
> +++ patches/patch-boost_context_pooled_fixedsize_stack_hpp 14 Sep 2019 00:56:15 -0000
> @@ -18,7 +18,7 @@ Index: boost/context/pooled_fixedsize_st
> stack_context allocate() {
> - void * vp = storage_.malloc();
> - if ( ! vp) {
> -+ void * vp = mmap(NULL, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_STACK, -1, 0);
> ++ void * vp = mmap(NULL, stack_size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_STACK, -1, 0);
> + if ( vp == MAP_FAILED ) {
> throw std::bad_alloc();
> }
> Index: patches/patch-libs_context_build_Jamfile_v2
> ===================================================================
> RCS file: patches/patch-libs_context_build_Jamfile_v2
> diff -N patches/patch-libs_context_build_Jamfile_v2
> --- /dev/null 1 Jan 1970 00:00:00 -0000
> +++ patches/patch-libs_context_build_Jamfile_v2 14 Sep 2019 00:56:15 -0000
> @@ -0,0 +1,17 @@
> +$OpenBSD$
> +
> +ppc32_sysv_elf has 2 instances of "<toolset>clang".
> +The second "clang" should be "gcc".
> +
> +Index: libs/context/build/Jamfile.v2
> +--- libs/context/build/Jamfile.v2.orig
> ++++ libs/context/build/Jamfile.v2
> +@@ -326,7 +326,7 @@ alias asm_sources
> + <address-model>32
> + <architecture>power
> + <binary-format>elf
> +- <toolset>clang
> ++ <toolset>gcc
> + ;
> +
> + alias asm_sources
> Index: patches/patch-libs_context_src_asm_jump_ppc32_sysv_elf_gas_S
> ===================================================================
> RCS file: patches/patch-libs_context_src_asm_jump_ppc32_sysv_elf_gas_S
> diff -N patches/patch-libs_context_src_asm_jump_ppc32_sysv_elf_gas_S
> --- /dev/null 1 Jan 1970 00:00:00 -0000
> +++ patches/patch-libs_context_src_asm_jump_ppc32_sysv_elf_gas_S 14 Sep 2019 00:56:15 -0000
> @@ -0,0 +1,66 @@
> +$OpenBSD$
> +
> +ELF systems other than Linux use a different convention to return a
> +small struct like transfer_t.
> +
> +Index: libs/context/src/asm/jump_ppc32_sysv_elf_gas.S
> +--- libs/context/src/asm/jump_ppc32_sysv_elf_gas.S.orig
> ++++ libs/context/src/asm/jump_ppc32_sysv_elf_gas.S
> +@@ -78,6 +78,9 @@
> + .align 2
> + .type jump_fcontext,@function
> + jump_fcontext:
> ++ # Linux: jump_fcontext( hidden transfer_t * %r3, %r4, %r5)
> ++ # Other: transfer_t %r3:%r4 = jump_fcontext( %r3, %r4)
> ++
> + # reserve space on stack
> + subi %r1, %r1, 244
> +
> +@@ -121,7 +124,9 @@ jump_fcontext:
> + stw %r29, 216(%r1) # save R29
> + stw %r30, 220(%r1) # save R30
> + stw %r31, 224(%r1) # save R31
> ++#ifdef __Linux__
> + stw %r3, 228(%r1) # save hidden
> ++
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