From 200036a8e802dee09103031eeeaea91dd212ec99 Mon Sep 17 00:00:00 2001
From: Helge Deller <deller@gmx.de>
Date: Tue, 14 May 2019 21:40:53 +0200
Subject: [PATCH] parisc: Allow building 64-bit kernel without -mlong-calls
compiler option
A 64-bit kernel built without CONFIG_MLONGCALLS (-mlong-calls compiler
option) usually fails to link because of unreachable functions. Try to
work around that linking issue by moving the *.init and *.exit text
segments closer to the main text segment. With that change those
segments now don't get freed at runtime any longer, but since we in most
cases run with huge-page enabled, we ignore the lost memory in
preference of better performance.
This change will not guarantee that every kernel config will now
sucessfully build with short calls and without linking issues.
Signed-off-by: Helge Deller <deller@gmx.de>
---
arch/parisc/Kconfig | 3 ++-
arch/parisc/kernel/vmlinux.lds.S | 21 ++++++++++++++-------
2 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 13b9512527c78..4860efa91d7bb 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -194,7 +194,8 @@ config PREFETCH
config MLONGCALLS
bool "Enable the -mlong-calls compiler option for big kernels"
- default y
+ default y if !MODULES || UBSAN || FTRACE
+ default n
depends on PA8X00
help
If you configure the kernel to include many drivers built-in instead
diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index c3b1b9c24ede7..cd33b4feacb16 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -35,6 +35,15 @@ OUTPUT_FORMAT("elf64-hppa-linux")
OUTPUT_ARCH(hppa:hppa2.0w)
#endif
+#define EXIT_TEXT_SECTIONS() .exit.text : { EXIT_TEXT }
+#if !defined(CONFIG_64BIT) || defined(CONFIG_MLONGCALLS)
+#define MLONGCALL_KEEP(x)
+#define MLONGCALL_DISCARD(x) x
+#else
+#define MLONGCALL_KEEP(x) x
+#define MLONGCALL_DISCARD(x)
+#endif
+
ENTRY(parisc_kernel_start)
#ifndef CONFIG_64BIT
jiffies = jiffies_64 + 4;
@@ -47,15 +56,11 @@ SECTIONS
__init_begin = .;
HEAD_TEXT_SECTION
- INIT_TEXT_SECTION(8)
+ MLONGCALL_DISCARD(INIT_TEXT_SECTION(8))
. = ALIGN(PAGE_SIZE);
INIT_DATA_SECTION(PAGE_SIZE)
- /* we have to discard exit text and such at runtime, not link time */
- .exit.text :
- {
- EXIT_TEXT
- }
+ MLONGCALL_DISCARD(EXIT_TEXT_SECTIONS())
.exit.data :
{
EXIT_DATA
@@ -73,11 +78,12 @@ SECTIONS
_text = .; /* Text and read-only data */
_stext = .;
+ MLONGCALL_KEEP(INIT_TEXT_SECTION(8))
.text ALIGN(PAGE_SIZE) : {
TEXT_TEXT
+ LOCK_TEXT
SCHED_TEXT
CPUIDLE_TEXT
- LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
@@ -92,6 +98,7 @@ SECTIONS
*(.lock.text) /* out-of-line lock text */
*(.gnu.warning)
}
+ MLONGCALL_KEEP(EXIT_TEXT_SECTIONS())
. = ALIGN(PAGE_SIZE);
_etext = .;
/* End of text section */
--
GitLab