From ca5420f1d8165b84aed97ec891cf01cf905b959b Mon Sep 17 00:00:00 2001 From: bdragon Date: Sat, 16 Nov 2019 20:33:46 +0000 Subject: [PATCH] [PowerPC] Fix *context on ELFv2 Due to ELFv1 specific code in _ctx_start.S and makecontext.c, userspace context switching was completely broken on ELFv2. With this change, we now pass the libthr test suite. Approved by: jhibbits (mentor) Differential Revision: https://reviews.freebsd.org/D22421 --- lib/libc/powerpc64/gen/_ctx_start.S | 6 ++++++ lib/libc/powerpc64/gen/makecontext.c | 5 +++++ 2 files changed, 11 insertions(+) diff --git a/lib/libc/powerpc64/gen/_ctx_start.S b/lib/libc/powerpc64/gen/_ctx_start.S index 17ec44e739cd..4d5f106c96cb 100644 --- a/lib/libc/powerpc64/gen/_ctx_start.S +++ b/lib/libc/powerpc64/gen/_ctx_start.S @@ -32,8 +32,14 @@ .globl CNAME(abort) ENTRY(_ctx_start) +#if !defined(_CALL_ELF) || _CALL_ELF == 1 + /* Load values from function descriptor */ ld %r2,8(%r14) ld %r14,0(%r14) +#else + /* Load global entry point */ + mr %r12,%r14 +#endif mtlr %r14 blrl /* branch to start function */ mr %r3,%r15 /* pass pointer to ucontext as argument */ diff --git a/lib/libc/powerpc64/gen/makecontext.c b/lib/libc/powerpc64/gen/makecontext.c index 8967ca96fa2a..c21e9140d38f 100644 --- a/lib/libc/powerpc64/gen/makecontext.c +++ b/lib/libc/powerpc64/gen/makecontext.c @@ -113,7 +113,12 @@ __makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...) * Use caller-saved regs 14/15 to hold params that _ctx_start * will use to invoke the user-supplied func */ +#if !defined(_CALL_ELF) || _CALL_ELF == 1 + /* Cast to ensure this is treated as a function descriptor. */ mc->mc_srr0 = *(uintptr_t *)_ctx_start; +#else + mc->mc_srr0 = (uintptr_t) _ctx_start; +#endif mc->mc_gpr[1] = (uintptr_t) sp; /* new stack pointer */ mc->mc_gpr[14] = (uintptr_t) start; /* r14 <- start */ mc->mc_gpr[15] = (uintptr_t) ucp; /* r15 <- ucp */