From mboxrd@z Thu Jan 1 00:00:00 1970 From: Helge Deller Date: Tue, 12 Oct 2021 06:48:56 +0000 Subject: Re: [PATCH v1 04/10] asm-generic: Use HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR to define associated stub Message-Id: List-Id: References: <8db2a3ca2b26a8325c671baa3e0492914597f079.1633964380.git.christophe.leroy@csgroup.eu> <91b38fce-8a5c-ccc7-fba5-b75b9769d4fc@gmx.de> <09bcd71a-baae-92b7-4c89-c8d446396d1c@csgroup.eu> In-Reply-To: <09bcd71a-baae-92b7-4c89-c8d446396d1c@csgroup.eu> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Christophe Leroy Cc: Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Andrew Morton , "James E.J. Bottomley" , Arnd Bergmann , Kees Cook , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org * Christophe Leroy : > > > Le 12/10/2021 à 08:02, Helge Deller a écrit : > > On 10/11/21 17:25, Christophe Leroy wrote: > > > Use HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR instead of 'dereference_function_descriptor' > > > to know whether arch has function descriptors. > > > > > > Signed-off-by: Christophe Leroy > > > --- > > > arch/ia64/include/asm/sections.h | 4 ++-- > > > arch/parisc/include/asm/sections.h | 6 ++++-- > > > arch/powerpc/include/asm/sections.h | 6 ++++-- > > > include/asm-generic/sections.h | 3 ++- > > > 4 files changed, 12 insertions(+), 7 deletions(-) > > > > > > diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h > > > index 35f24e52149a..80f5868afb06 100644 > > > --- a/arch/ia64/include/asm/sections.h > > > +++ b/arch/ia64/include/asm/sections.h > > > @@ -7,6 +7,8 @@ > > > * David Mosberger-Tang > > > */ > > > > > > +#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 > > > + > > > #include > > > #include > > > #include > > > @@ -27,8 +29,6 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b > > > extern char __start_unwind[], __end_unwind[]; > > > extern char __start_ivt_text[], __end_ivt_text[]; > > > > > > -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 > > > - > > > #undef dereference_function_descriptor > > > static inline void *dereference_function_descriptor(void *ptr) > > > { > > > diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h > > > index bb52aea0cb21..2e781ee19b66 100644 > > > --- a/arch/parisc/include/asm/sections.h > > > +++ b/arch/parisc/include/asm/sections.h > > > @@ -2,6 +2,10 @@ > > > #ifndef _PARISC_SECTIONS_H > > > #define _PARISC_SECTIONS_H > > > > > > +#ifdef CONFIG_64BIT > > > +#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 > > > +#endif > > > + > > > /* nothing to see, move along */ > > > #include > > > > > > @@ -9,8 +13,6 @@ extern char __alt_instructions[], __alt_instructions_end[]; > > > > > > #ifdef CONFIG_64BIT > > > > > > -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 > > > - > > > #undef dereference_function_descriptor > > > void *dereference_function_descriptor(void *); > > > > > > diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h > > > index 32e7035863ac..b7f1ba04e756 100644 > > > --- a/arch/powerpc/include/asm/sections.h > > > +++ b/arch/powerpc/include/asm/sections.h > > > @@ -8,6 +8,10 @@ > > > > > > #define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed > > > > > > +#ifdef PPC64_ELF_ABI_v1 > > > +#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 > > > +#endif > > > + > > > #include > > > > > > extern bool init_mem_is_free; > > > @@ -69,8 +73,6 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end) > > > > > > #ifdef PPC64_ELF_ABI_v1 > > > > > > -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 > > > - > > > #undef dereference_function_descriptor > > > static inline void *dereference_function_descriptor(void *ptr) > > > { > > > diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h > > > index d16302d3eb59..1db5cfd69817 100644 > > > --- a/include/asm-generic/sections.h > > > +++ b/include/asm-generic/sections.h > > > @@ -59,7 +59,8 @@ extern char __noinstr_text_start[], __noinstr_text_end[]; > > > extern __visible const void __nosave_begin, __nosave_end; > > > > > > /* Function descriptor handling (if any). Override in asm/sections.h */ > > > -#ifndef dereference_function_descriptor > > > +#ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR > > > +#else > > > > why not > > #ifndef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR > > instead of #if/#else ? > > To avoid changing it again in patch 6, or getting an ugly #ifndef/#else at > the end. Ok. Building on parisc fails at multiple files like this: CC mm/filemap.o In file included from /home/cvs/parisc/git-kernel/linus-linux-2.6/include/linux/interrupt.h:21, from /home/cvs/parisc/git-kernel/linus-linux-2.6/include/linux/trace_recursion.h:5, from /home/cvs/parisc/git-kernel/linus-linux-2.6/include/linux/ftrace.h:10, from /home/cvs/parisc/git-kernel/linus-linux-2.6/include/linux/perf_event.h:49, from /home/cvs/parisc/git-kernel/linus-linux-2.6/include/linux/trace_events.h:10, from /home/cvs/parisc/git-kernel/linus-linux-2.6/include/trace/syscall.h:7, from /home/cvs/parisc/git-kernel/linus-linux-2.6/include/linux/syscalls.h:87, from /home/cvs/parisc/git-kernel/linus-linux-2.6/init/initramfs.c:11: /home/cvs/parisc/git-kernel/linus-linux-2.6/arch/parisc/include/asm/sections.h:7:9: error: unknown type name ‘Elf64_Fdesc’ 7 | typedef Elf64_Fdesc funct_descr_t; | ^~~~~~~~~~~ So, you still need e.g. this patch: diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h index b041fb32a300..177983490e7c 100644 --- a/arch/parisc/include/asm/sections.h +++ b/arch/parisc/include/asm/sections.h @@ -4,6 +4,8 @@ #ifdef CONFIG_64BIT #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 +#include +#include typedef Elf64_Fdesc funct_descr_t; #endif In general to save space I think it would be beneficial if the dereference_kernel_function_descriptor() and dereference_kernel_function_descriptor() functions would go as real functions a c-file instead of just being inlined functions in the asm-generic/sections.h header file. Other than that it's a nice cleanup! Helge