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2025-04-16riscv: KGDB: Remove ".option norvc/.option rvc" for kgdb_compiled_breakWangYuli
[ Quoting Samuel Holland: ] This is a separate issue, but using ".option rvc" here is a bug. It will unconditionally enable the C extension for the rest of the file, even if the kernel is being built with CONFIG_RISCV_ISA_C=n. [ Quoting Palmer Dabbelt: ] We're just looking at the address of kgdb_compiled_break, so it's fine if it ends up as a c.ebreak. [ Quoting Alexandre Ghiti: ] .option norvc is used to prevent the assembler from using compressed instructions, but it's generally used when we need to ensure the size of the instructions that are used, which is not the case here as noted by Palmer since we only care about the address. So yes it will work fine with C enabled :) So let's just remove them all. Link: https://lore.kernel.org/all/4b4187c1-77e5-44b7-885f-d6826723dd9a@sifive.com/ Link: https://lore.kernel.org/all/mhng-69513841-5068-441d-be8f-2aeebdc56a08@palmer-ri-x1c9a/ Link: https://lore.kernel.org/all/23693e7f-4fff-40f3-a437-e06d827278a5@ghiti.fr/ Fixes: fe89bd2be866 ("riscv: Add KGDB support") Cc: Samuel Holland <samuel.holland@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: WangYuli <wangyuli@uniontech.com> Link: https://lore.kernel.org/r/8B431C6A4626225C+20250411073222.56820-2-wangyuli@uniontech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2025-04-16riscv: KGDB: Do not inline arch_kgdb_breakpoint()WangYuli
The arch_kgdb_breakpoint() function defines the kgdb_compiled_break symbol using inline assembly. There's a potential issue where the compiler might inline arch_kgdb_breakpoint(), which would then define the kgdb_compiled_break symbol multiple times, leading to fail to link vmlinux.o. This isn't merely a potential compilation problem. The intent here is to determine the global symbol address of kgdb_compiled_break, and if this function is inlined multiple times, it would logically be a grave error. Link: https://lore.kernel.org/all/4b4187c1-77e5-44b7-885f-d6826723dd9a@sifive.com/ Link: https://lore.kernel.org/all/5b0adf9b-2b22-43fe-ab74-68df94115b9a@ghiti.fr/ Link: https://lore.kernel.org/all/23693e7f-4fff-40f3-a437-e06d827278a5@ghiti.fr/ Fixes: fe89bd2be866 ("riscv: Add KGDB support") Co-developed-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: WangYuli <wangyuli@uniontech.com> Link: https://lore.kernel.org/r/F22359AFB6FF9FD8+20250411073222.56820-1-wangyuli@uniontech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-12-29RISC-V: rename parse_asm.h to insn.hHeiko Stuebner
The current parse_asm header should become a more centralized place for everything concerning parsing and constructing instructions. We already have a header insn-def.h similar to aarch64, so rename parse_asm.h to insn.h (again similar to aarch64) to show that it's meant for more than simple instruction parsing. Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20221223221332.4127602-8-heiko@sntech.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-12-29RISC-V: Move riscv_insn_is_* macros into a common headerHeiko Stuebner
Right now the riscv kernel has (at least) two independent sets of functions to check if an encoded instruction is of a specific type. One in kgdb and one kprobes simulate-insn code. More parts of the kernel will probably need this in the future, so instead of allowing this duplication to go on further, move macros that do the function declaration in a common header, similar to at least aarch64. Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20221223221332.4127602-7-heiko@sntech.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-12-29RISC-V: add prefix to all constants/macros in parse_asm.hHeiko Stuebner
Some of the constants and macros already have suitable RV_, RVG_ or RVC_ prefixes. Extend this to the rest of the file as well, as we want to use these things in a broader scope soon. Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20221223221332.4127602-3-heiko@sntech.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2020-07-09riscv: Fix "no previous prototype" compile warning in kgdb.c fileVincent Chen
Some functions are only used in the kgdb.c file. Add static properities to these functions to avoid "no previous prototype" compile warnings Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-06-18maccess: rename probe_kernel_address to get_kernel_nofaultChristoph Hellwig
Better describe what this helper does, and match the naming of copy_from_kernel_nofault. Also switch the argument order around, so that it acts and looks like get_user(). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-17maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofaultChristoph Hellwig
Better describe what these functions do. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-18riscv: Add SW single-step support for KDBVincent Chen
In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-05-18riscv: Use the XML target descriptions to report 3 system registersVincent Chen
The $status, $badaddr, and $cause registers belong to the thread context, so KGDB can obtain their contents from pt_regs in each trap. However, the sequential number of these registers in the gdb register list is far from the general-purpose registers. If riscv port uses the existing method to report these three registers, many trivial registers with sequence numbers in the middle of them will also be packaged to the reply packets. To solve this problem, the riscv port wants to introduce the GDB target description mechanism to customize the reported register list. By the list, the KGDB can ignore the intermediate registers and just reports the general-purpose registers and these three system registers. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-05-18riscv: Add KGDB supportVincent Chen
The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>