From ebae2f5a6f971a8f0b6c99e00f9c45ef7433924a Mon Sep 17 00:00:00 2001 From: Matheus Castanho Date: Fri, 9 Apr 2021 14:47:27 -0300 Subject: Add build option to disable usage of scv on powerpc Commit 68ab82f56690ada86ac1e0c46bad06ba189a10ef added support for the scv syscall ABI on powerpc. Since then systems that have kernel and processor support started using scv. However adding the proper support for a new syscall ABI requires changes to several other projects (e.g. qemu, valgrind, strace, kernel), which are gradually receiving support. Meanwhile, having a way to disable scv on glibc at build time can be useful for distros that may encounter conflicts with projects that still do not support the scv ABI, buying time until proper support is added. This commit adds a --disable-scv option that disables scv support and uses sc for all syscalls, like before commit 68ab82f56690ada86ac1e0c46bad06ba189a10ef. Reviewed-by: Raphael M Zinsly --- sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S | 14 +++++++++++--- sysdeps/unix/sysv/linux/powerpc/syscall.S | 2 +- sysdeps/unix/sysv/linux/powerpc/sysdep.h | 2 +- 3 files changed, 13 insertions(+), 5 deletions(-) (limited to 'sysdeps/unix') diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S index e9bd8cb960..777ead80b0 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S @@ -38,11 +38,13 @@ ENTRY (__clone) beq- cr0,L(badargs) /* Save some regs in the "red zone". */ +#ifdef USE_PPC_SCV std r28,-32(r1) + cfi_offset(r28,-32) +#endif std r29,-24(r1) std r30,-16(r1) std r31,-8(r1) - cfi_offset(r28,-32) cfi_offset(r29,-24) cfi_offset(r30,-16) cfi_offset(r31,-8) @@ -71,6 +73,7 @@ ENTRY (__clone) /* Do the call. */ li r0,SYS_ify(clone) +#ifdef USE_PPC_SCV CHECK_SCV_SUPPORT r28 0f /* This is equivalent to DO_CALL_SCV, but we cannot use the macro here because it uses CFI directives and we just called cfi_endproc. */ @@ -87,6 +90,7 @@ ENTRY (__clone) /* When using scv, error is indicated by negative r3. */ cmpdi cr1,r3,0 b 1f +#endif /* USE_PPC_SCV */ 0: DO_CALL_SC /* Check for child process. */ @@ -119,22 +123,26 @@ L(parent): cmpdi cr1,r28,0 /* Parent. Restore registers & return. */ +#ifdef USE_PPC_SCV cfi_offset(r28,-32) + ld r28,-32(r1) + cfi_restore(r28) +#endif cfi_offset(r29,-24) cfi_offset(r30,-16) cfi_offset(r31,-8) - ld r28,-32(r1) ld r29,-24(r1) ld r30,-16(r1) ld r31,-8(r1) - cfi_restore(r28) cfi_restore(r29) cfi_restore(r30) cfi_restore(r31) +#ifdef USE_PPC_SCV beq cr1,0f RET_SCV b 1f +#endif 0: RET_SC 1: TAIL_CALL_SYSCALL_ERROR diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall.S b/sysdeps/unix/sysv/linux/powerpc/syscall.S index d6ec87f006..a29652feaf 100644 --- a/sysdeps/unix/sysv/linux/powerpc/syscall.S +++ b/sysdeps/unix/sysv/linux/powerpc/syscall.S @@ -25,7 +25,7 @@ ENTRY (syscall) mr r6,r7 mr r7,r8 mr r8,r9 -#if !IS_IN(rtld) && (defined(__PPC64__) || defined(__powerpc64__)) +#if defined(USE_PPC_SCV) && !IS_IN(rtld) && (defined(__PPC64__) || defined(__powerpc64__)) CHECK_SCV_SUPPORT r9 0f DO_CALL_SCV RET_SCV diff --git a/sysdeps/unix/sysv/linux/powerpc/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/sysdep.h index 2f31f9177b..4b9d43c636 100644 --- a/sysdeps/unix/sysv/linux/powerpc/sysdep.h +++ b/sysdeps/unix/sysv/linux/powerpc/sysdep.h @@ -125,7 +125,7 @@ /* When inside the dynamic loader, the thread pointer may not have been initialized yet, so don't check for scv support in that case. */ -# if !IS_IN(rtld) +# if defined(USE_PPC_SCV) && !IS_IN(rtld) # undef TRY_SYSCALL_SCV # define TRY_SYSCALL_SCV(nr) \ CHECK_THREAD_POINTER && THREAD_GET_HWCAP() & PPC_FEATURE2_SCV ? \ -- cgit 1.4.1