kernel/arch/riscv/include/asm/extable.h, branch linux-rolling-stable

riscv: mm: stub extable related functions/macros for !MMU

2023-06-14T14:17:45Z

extable relies on the MMU to work properly, so it's useless to include __ex_table sections and build extable related functions for !MMU case. Signed-off-by: Jisheng Zhang Link: https://lore.kernel.org/r/20230509152641.805-1-jszhang@kernel.org Signed-off-by: Palmer Dabbelt

riscv: extable: add `type` and `data` fields

2022-01-06T01:52:54Z

This is a riscv port of commit d6e2cc564775 ("arm64: extable: add `type` and `data` fields"). Signed-off-by: Jisheng Zhang Signed-off-by: Palmer Dabbelt

riscv: extable: make fixup_exception() return bool

2022-01-06T01:52:29Z

The return values of fixup_exception() and riscv_bpf_fixup_exception() represent a boolean condition rather than an error code, so it's better to return `bool` rather than `int`. Signed-off-by: Jisheng Zhang Signed-off-by: Palmer Dabbelt

riscv: bpf: move rv_bpf_fixup_exception signature to extable.h

2022-01-06T01:52:24Z

This is to group riscv related extable related functions signature into one file. Signed-off-by: Jisheng Zhang Signed-off-by: Palmer Dabbelt

riscv: switch to relative exception tables

2022-01-06T01:52:20Z

Similar as other architectures such as arm64, x86 and so on, use offsets relative to the exception table entry values rather than absolute addresses for both the exception locationand the fixup. However, RISCV label difference will actually produce two relocations, a pair of R_RISCV_ADD32 and R_RISCV_SUB32. Take below simple code for example: $ cat test.S .section .text 1: nop .section __ex_table,"a" .balign 4 .long (1b - .) .previous $ riscv64-linux-gnu-gcc -c test.S $ riscv64-linux-gnu-readelf -r test.o Relocation section '.rela__ex_table' at offset 0x100 contains 2 entries: Offset Info Type Sym. Value Sym. Name + Addend 000000000000 000600000023 R_RISCV_ADD32 0000000000000000 .L1^B1 + 0 000000000000 000500000027 R_RISCV_SUB32 0000000000000000 .L0 + 0 The modpost will complain the R_RISCV_SUB32 relocation, so we need to patch modpost.c to skip this relocation for .rela__ex_table section. After this patch, the __ex_table section size of defconfig vmlinux is reduced from 7072 Bytes to 3536 Bytes. Signed-off-by: Jisheng Zhang Reviewed-by: Kefeng Wang Signed-off-by: Palmer Dabbelt