Messages in this thread Patch in this message | | | From | Jisheng Zhang <> | Subject | [PATCH 3/3] riscv: vdso.lds.S: remove hardcoded 0x800 .text start addr | Date | Thu, 27 Jul 2023 01:30:24 +0800 |
| |
I believe the hardcoded 0x800 and related comments come from the long history VDSO_TEXT_OFFSET in x86 vdso code, but commit 5b9304933730 ("x86 vDSO: generate vdso-syms.lds") and commit f6b46ebf904f ("x86 vDSO: new layout") removes the comment and hard coding for x86.
Similar as x86 and other arch, riscv doesn't need the rigid layout using VDSO_TEXT_OFFSET since it "no longer matters to the kernel". so we could remove the hard coding now, and removing it brings a small vdso.so and aligns with other architectures.
Also, having enough separation between data and text is important for I-cache, so similar as x86, move .note, .eh_frame_hdr, and .eh_frame between .rodata and .text.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org> --- arch/riscv/kernel/vdso/vdso.lds.S | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S index 671aa21769bc..cbe2a179331d 100644 --- a/arch/riscv/kernel/vdso/vdso.lds.S +++ b/arch/riscv/kernel/vdso/vdso.lds.S @@ -23,12 +23,8 @@ SECTIONS .gnu.version_d : { *(.gnu.version_d) } .gnu.version_r : { *(.gnu.version_r) } - .note : { *(.note.*) } :text :note .dynamic : { *(.dynamic) } :text :dynamic - .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr - .eh_frame : { KEEP (*(.eh_frame)) } :text - .rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) *(.got.plt) *(.got) @@ -37,13 +33,16 @@ SECTIONS *(.bss .bss.* .gnu.linkonce.b.*) } + .note : { *(.note.*) } :text :note + + .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr + .eh_frame : { KEEP (*(.eh_frame)) } :text + /* - * This linker script is used both with -r and with -shared. - * For the layouts to match, we need to skip more than enough - * space for the dynamic symbol table, etc. If this amount is - * insufficient, ld -shared will error; simply increase it here. + * Text is well-separated from actual data: there's plenty of + * stuff that isn't used at runtime in between. */ - . = 0x800; + . = ALIGN(16); .text : { *(.text .text.*) } :text . = ALIGN(4); -- 2.40.1
| |