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| author | Segher Boessenkool <segher@kernel.crashing.org> | 2008-07-22 09:03:45 +1000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2008-07-22 10:39:37 +1000 |
| commit | c69cccc95fe4b90dde5fe33e6a3b77880b534fa4 (patch) | |
| tree | a66214423a1eb987ee0e54e8c8a67f9d955d6055 | |
| parent | f36c5227cd88b6340c40d62b05859e8213740a97 (diff) | |
| download | talos-op-linux-c69cccc95fe4b90dde5fe33e6a3b77880b534fa4.tar.gz talos-op-linux-c69cccc95fe4b90dde5fe33e6a3b77880b534fa4.zip | |
powerpc: Fix build bug with binutils < 2.18 and GCC < 4.2
binutils < 2.18 has a bug that makes it misbehave when taking an
ELF file with all segments at load address 0 as input. This
happens when running "strip" on vmlinux, because of the AT() magic
in this linker script. People using GCC >= 4.2 won't run into
this problem, because the "build-id" support will put some data
into the "notes" segment (at a non-zero load address).
To work around this, we force some data into both the "dummy"
segment and the kernel segment, so the dummy segment will get a
non-zero load address. It's not enough to always create the
"notes" segment, since if nothing gets assigned to it, its load
address will be zero.
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Tested-By: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/kernel/vmlinux.lds.S | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 87a72c66ce27..a914411bced5 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -9,6 +9,25 @@ ENTRY(_stext) +PHDRS { + kernel PT_LOAD FLAGS(7); /* RWX */ + notes PT_NOTE FLAGS(0); + dummy PT_NOTE FLAGS(0); + + /* binutils < 2.18 has a bug that makes it misbehave when taking an + ELF file with all segments at load address 0 as input. This + happens when running "strip" on vmlinux, because of the AT() magic + in this linker script. People using GCC >= 4.2 won't run into + this problem, because the "build-id" support will put some data + into the "notes" segment (at a non-zero load address). + + To work around this, we force some data into both the "dummy" + segment and the kernel segment, so the dummy segment will get a + non-zero load address. It's not enough to always create the + "notes" segment, since if nothing gets assigned to it, its load + address will be zero. */ +} + #ifdef CONFIG_PPC64 OUTPUT_ARCH(powerpc:common64) jiffies = jiffies_64; @@ -50,7 +69,7 @@ SECTIONS . = ALIGN(PAGE_SIZE); _etext = .; PROVIDE32 (etext = .); - } + } :kernel /* Read-only data */ RODATA @@ -62,7 +81,13 @@ SECTIONS __stop___ex_table = .; } - NOTES + NOTES :kernel :notes + + /* The dummy segment contents for the bug workaround mentioned above + near PHDRS. */ + .dummy : { + LONG(0xf177) + } :kernel :dummy /* * Init sections discarded at runtime @@ -74,7 +99,7 @@ SECTIONS _sinittext = .; INIT_TEXT _einittext = .; - } + } :kernel /* .exit.text is discarded at runtime, not link time, * to deal with references from __bug_table |
