Re: [PATCH v1 04/10] asm-generic: Use HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR to define associated stubs
From: Helge Deller <deller@gmx.de>
Date: 2021-10-12 06:50:06
Also in:
linux-arch, linux-mm, lkml
Subsystem:
parisc architecture, the rest · Maintainers:
"James E.J. Bottomley", Helge Deller, Linus Torvalds
* Christophe Leroy [off-list ref]:
Le 12/10/2021 à 08:02, Helge Deller a écrit :quoted
On 10/11/21 17:25, Christophe Leroy wrote:quoted
Use HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR instead of 'dereference_function_descriptor' to know whether arch has function descriptors. Signed-off-by: Christophe Leroy <redacted> --- 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 <davidm@hpl.hp.com> */ +#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1 + #include <linux/elf.h> #include <linux/uaccess.h> #include <asm-generic/sections.h>@@ -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 <asm-generic/sections.h>@@ -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 <asm-generic/sections.h> 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 +#elsewhy 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 <asm/elf.h> +#include <linux/uaccess.h> 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