* [binutils-gdb] ARM: Fix ld bloat introduced between binutils-2.38 and 2.39
@ 2023-01-12 16:28 Hans-Peter Nilsson
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From: Hans-Peter Nilsson @ 2023-01-12 16:28 UTC (permalink / raw)
To: bfd-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1a26a53a0dee39106ba58fcb15496c5f13074652
commit 1a26a53a0dee39106ba58fcb15496c5f13074652
Author: Hans-Peter Nilsson <hp@axis.com>
Date: Tue Jan 3 03:19:54 2023 +0100
ARM: Fix ld bloat introduced between binutils-2.38 and 2.39
Since commit 9833b7757d24, "PR28824, relro security issues",
ELF_MAXPAGESIZE matters much more, with regards to layout of
the linked file. That commit fixed an actual bug, but also
exposes a problem for targets were that value is too high.
For example, for ARM(32, a.k.a. "Aarch32") specifically
bfd_arch_arm, it's set to 64 KiB, making all Linux(/GNU)
targets pay an extra amount of up to 60 KiB of bloat in
DSO:s and executables. This matters when there are many
such files, and where storage is expensive.
It's *mostly* bloat when using a Linux kernel, as ARM(32) is
a good example of an target where ELF_MAXPAGESIZE is set to
an extreme value for an obscure corner-case. The ARM
(32-bit) kernel has 4 KiB pages, has had that value forever,
and can't be configured to any other value. The use-case is
IIUC "Aarch32" emulation on an "Aarch64" (arm64) kernel, but
not just that, but a setup where the Linux page-size is
configured to something other than the *default* 4 KiB. Not
sure there actually any such systems in use, again with
both Aarch32 compatibility support and a non-4KiB pagesize,
with all the warnings in the kernel config and requiring the
"EXPERT" level set on.
So, let's do like x86-64 in a2267dbfc9e1 "x86-64: Use only
one default max-page-size" and set ELF_MAXPAGESIZE to 4096.
bfd:
* elf32-arm.c (ELF_MAXPAGESIZE): Always set to 0x1000.
Diff:
---
bfd/elf32-arm.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 96ba509f505..a6d83b97c97 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -20290,11 +20290,7 @@ elf32_arm_backend_symbol_processing (bfd *abfd, asymbol *sym)
#define ELF_ARCH bfd_arch_arm
#define ELF_TARGET_ID ARM_ELF_DATA
#define ELF_MACHINE_CODE EM_ARM
-#ifdef __QNXTARGET__
#define ELF_MAXPAGESIZE 0x1000
-#else
-#define ELF_MAXPAGESIZE 0x10000
-#endif
#define ELF_COMMONPAGESIZE 0x1000
#define bfd_elf32_mkobject elf32_arm_mkobject
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2023-01-12 16:28 [binutils-gdb] ARM: Fix ld bloat introduced between binutils-2.38 and 2.39 Hans-Peter Nilsson
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