| Message ID | 20230511141211.2418-5-jszhang@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/tree_selection | fail | Failed to apply to next/pending-fixes or riscv/for-next |
On Thu, May 11, 2023 at 10:12:11PM +0800, Jisheng Zhang wrote: > diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S > index e5f9f4677bbf..492dd4b8f3d6 100644 > --- a/arch/riscv/kernel/vmlinux.lds.S > +++ b/arch/riscv/kernel/vmlinux.lds.S > @@ -85,11 +85,11 @@ SECTIONS > INIT_DATA_SECTION(16) > > .init.pi : { > - *(.init.pi*) > + KEEP(*(.init.pi*)) > } This section no longer exists in v6.4-rc1, it is now: /* Those sections result from the compilation of kernel/pi/string.c */ .init.pidata : { *(.init.srodata.cst8*) *(.init__bug_table*) *(.init.sdata*) } Cheers, Conor.
On Fri, May 12, 2023 at 02:58:49PM +0100, Conor Dooley wrote: > On Thu, May 11, 2023 at 10:12:11PM +0800, Jisheng Zhang wrote: > > > diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S > > index e5f9f4677bbf..492dd4b8f3d6 100644 > > --- a/arch/riscv/kernel/vmlinux.lds.S > > +++ b/arch/riscv/kernel/vmlinux.lds.S > > @@ -85,11 +85,11 @@ SECTIONS > > INIT_DATA_SECTION(16) > > > > .init.pi : { > > - *(.init.pi*) > > + KEEP(*(.init.pi*)) > > } > > This section no longer exists in v6.4-rc1, it is now: > /* Those sections result from the compilation of kernel/pi/string.c */ > .init.pidata : { > *(.init.srodata.cst8*) > *(.init__bug_table*) > *(.init.sdata*) > } Ahh, I see what has happened. This series was made on top of riscv/fixes, but none of the patches are marked as a fix, leading to the automation testing this as new content. Sorry for the noise on this patch.
On Fri, May 12, 2023 at 04:16:31PM +0100, Conor Dooley wrote: > On Fri, May 12, 2023 at 02:58:49PM +0100, Conor Dooley wrote: > > On Thu, May 11, 2023 at 10:12:11PM +0800, Jisheng Zhang wrote: > > > > > diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S > > > index e5f9f4677bbf..492dd4b8f3d6 100644 > > > --- a/arch/riscv/kernel/vmlinux.lds.S > > > +++ b/arch/riscv/kernel/vmlinux.lds.S > > > @@ -85,11 +85,11 @@ SECTIONS > > > INIT_DATA_SECTION(16) > > > > > > .init.pi : { > > > - *(.init.pi*) > > > + KEEP(*(.init.pi*)) > > > } > > > > This section no longer exists in v6.4-rc1, it is now: > > /* Those sections result from the compilation of kernel/pi/string.c */ > > .init.pidata : { > > *(.init.srodata.cst8*) > > *(.init__bug_table*) > > *(.init.sdata*) > > } > > Ahh, I see what has happened. This series was made on top of > riscv/fixes, but none of the patches are marked as a fix, leading to the I need to touch the sections, and there's a fix in Palmer's tree which will rename the section name, so rebased on the fix HEAD. > automation testing this as new content. > > Sorry for the noise on this patch. Thank you for your review.
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index f0663b52d052..a5feab2c3037 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -110,6 +110,7 @@ config RISCV select HAVE_KPROBES if !XIP_KERNEL select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL select HAVE_KRETPROBES if !XIP_KERNEL + select HAVE_LD_DEAD_CODE_DATA_ELIMINATION select HAVE_MOVE_PMD select HAVE_MOVE_PUD select HAVE_PCI diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index e5f9f4677bbf..492dd4b8f3d6 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -85,11 +85,11 @@ SECTIONS INIT_DATA_SECTION(16) .init.pi : { - *(.init.pi*) + KEEP(*(.init.pi*)) } .init.bss : { - *(.init.bss) /* from the EFI stub */ + KEEP(*(.init.bss*)) /* from the EFI stub */ } .exit.data : { @@ -112,7 +112,7 @@ SECTIONS . = ALIGN(8); .alternative : { __alt_start = .; - *(.alternative) + KEEP(*(.alternative)) __alt_end = .; } __init_end = .;
When trying to run linux with various opensource riscv core on resource limited FPGA platforms, for example, those FPGAs with less than 16MB SDRAM, I want to save mem as much as possible. One of the major technologies is kernel size optimizations, I found that riscv does not currently support HAVE_LD_DEAD_CODE_DATA_ELIMINATION, which passes -fdata-sections, -ffunction-sections to CFLAGS and passes the --gc-sections flag to the linker. This not only benefits my case on FPGA but also benefits defconfigs. Here are some notable improvements from enabling this with defconfigs: nommu_k210_defconfig: text data bss dec hex 1112009 410288 59837 1582134 182436 before 962838 376656 51285 1390779 1538bb after rv32_defconfig: text data bss dec hex 8804455 2816544 290577 11911576 b5c198 before 8692295 2779872 288977 11761144 b375f8 after defconfig: text data bss dec hex 9438267 3391332 485333 13314932 cb2b74 before 9285914 3350052 483349 13119315 c82f53 after Signed-off-by: Jisheng Zhang <jszhang@kernel.org> --- arch/riscv/Kconfig | 1 + arch/riscv/kernel/vmlinux.lds.S | 6 +++--- 2 files changed, 4 insertions(+), 3 deletions(-)