From f4435980fa2da335fe388db431d4a7946a99a2b9 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Tue, 27 Oct 2020 23:36:21 +1030 Subject: [PATCH] Power10 libffi fixes (#585) Power10 pc-relative code doesn't use or preserve r2 as a TOC pointer. That means calling between pc-relative and TOC using code can't be done without intervening linker stubs, and a call from TOC code to pc-relative code must have a nop after the bl in order to restore r2. Now the PowerPC libffi assembly code doesn't use r2 except for the implicit use when making calls back to C, ffi_closure_helper_LINUX64 and ffi_prep_args64. So changing the assembly to interoperate with pc-relative code without stubs is easily done. * src/powerpc/linux64.S (ffi_call_LINUX64): Don't emit global entry when __PCREL__. Call using @notoc. Add nops. * src/powerpc/linux64_closure.S (ffi_closure_LINUX64): Likewise. (ffi_go_closure_linux64): Likewise. --- src/powerpc/linux64.S | 8 ++++++++ src/powerpc/linux64_closure.S | 14 +++++++++++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/src/powerpc/linux64.S b/src/powerpc/linux64.S index c99889c..e92d64a 100644 --- a/src/powerpc/linux64.S +++ b/src/powerpc/linux64.S @@ -36,8 +36,10 @@ .cfi_startproc # if _CALL_ELF == 2 ffi_call_LINUX64: +# ifndef __PCREL__ addis %r2, %r12, .TOC.-ffi_call_LINUX64@ha addi %r2, %r2, .TOC.-ffi_call_LINUX64@l +# endif .localentry ffi_call_LINUX64, . - ffi_call_LINUX64 # else .section ".opd","aw" @@ -89,9 +91,15 @@ ffi_call_LINUX64: /* Call ffi_prep_args64. */ mr %r4, %r1 # if defined _CALL_LINUX || _CALL_ELF == 2 +# ifdef __PCREL__ + bl ffi_prep_args64@notoc +# else bl ffi_prep_args64 + nop +# endif # else bl .ffi_prep_args64 + nop # endif # if _CALL_ELF == 2 diff --git a/src/powerpc/linux64_closure.S b/src/powerpc/linux64_closure.S index d67e4bb..3469a2c 100644 --- a/src/powerpc/linux64_closure.S +++ b/src/powerpc/linux64_closure.S @@ -37,8 +37,10 @@ .cfi_startproc # if _CALL_ELF == 2 ffi_closure_LINUX64: +# ifndef __PCREL__ addis %r2, %r12, .TOC.-ffi_closure_LINUX64@ha addi %r2, %r2, .TOC.-ffi_closure_LINUX64@l +# endif .localentry ffi_closure_LINUX64, . - ffi_closure_LINUX64 # else .section ".opd","aw" @@ -190,11 +192,19 @@ ffi_closure_LINUX64: # make the call # if defined _CALL_LINUX || _CALL_ELF == 2 +# ifdef __PCREL__ + bl ffi_closure_helper_LINUX64@notoc +.Lret: +# else bl ffi_closure_helper_LINUX64 +.Lret: + nop +# endif # else bl .ffi_closure_helper_LINUX64 -# endif .Lret: + nop +# endif # now r3 contains the return type # so use it to look up in a table @@ -460,8 +470,10 @@ ffi_closure_LINUX64: .cfi_startproc # if _CALL_ELF == 2 ffi_go_closure_linux64: +# ifndef __PCREL__ addis %r2, %r12, .TOC.-ffi_go_closure_linux64@ha addi %r2, %r2, .TOC.-ffi_go_closure_linux64@l +# endif .localentry ffi_go_closure_linux64, . - ffi_go_closure_linux64 # else .section ".opd","aw" -- 2.34.1