| Message ID | 1585668191-16287-1-git-send-email-vincent.chen@sifive.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | riscv: Add KGDB and KDB support | expand |
On Tue, Mar 31, 2020 at 11:23:06PM +0800, Vincent Chen wrote: > This patch set implements required ports to enable RISC-V kernel to support > KGDB and KDB features. Because there is no immediate value in the RISC-V > trap instruction, the kernel cannot identify the purpose of each trap > exception through the opcode. This makes the existing identification > schemes in other architecture unsuitable for the RISC-V kernel. In order > to solve this problem, this patch adds the kgdb_has_hit_break() to kgdb.c > to help the RISC-V kernel identify the KGDB trap exception. In addition, > the XML target description was introduced in this patch set to enable KGDB > to report the contents of the status, cause and steal registers. > > This patchset has passed the kgdbts test suite provided by Linux kernel on > HiFive unleashed board and QEMU. Can you share the defconfig and qemu boot lines used for testing. I'd like to see if they can easily be integrated into kgdbtest. Normally figuring out the qemu boot line is the hardest bit of adding support for an architecture one is not familar with. Daniel. PS At the moment it helps kgdbtest a lot if qemu is configured with two serial ports but I really should get round to relaxing that! > > Changes since v1: > 1. Replace the magic number with macro when filling the gdb_regs[]. > 2. Only support GDB XML packet instead of all query packets. > 3. Move the macros used to parse instrcuton to parse_asm.h > > > Vincent Chen (5): > kgdb: Add kgdb_has_hit_break function > riscv: Add KGDB support > kgdb: enable arch to support XML packet support. > riscv: Use the XML target descriptions to report 3 system registers > riscv: Add SW single-step support for KDB > > arch/riscv/Kconfig | 2 + > arch/riscv/include/asm/Kbuild | 1 - > arch/riscv/include/asm/gdb_xml.h | 117 ++++++++++++ > arch/riscv/include/asm/kdebug.h | 12 ++ > arch/riscv/include/asm/kgdb.h | 113 +++++++++++ > arch/riscv/include/asm/parse_asm.h | 214 +++++++++++++++++++++ > arch/riscv/kernel/Makefile | 1 + > arch/riscv/kernel/kgdb.c | 382 +++++++++++++++++++++++++++++++++++++ > arch/riscv/kernel/traps.c | 5 + > include/linux/kgdb.h | 9 + > kernel/debug/debug_core.c | 12 ++ > kernel/debug/gdbstub.c | 13 ++ > lib/Kconfig.kgdb | 5 + > 13 files changed, 885 insertions(+), 1 deletion(-) > create mode 100644 arch/riscv/include/asm/gdb_xml.h > create mode 100644 arch/riscv/include/asm/kdebug.h > create mode 100644 arch/riscv/include/asm/kgdb.h > create mode 100644 arch/riscv/include/asm/parse_asm.h > create mode 100644 arch/riscv/kernel/kgdb.c > > -- > 2.7.4 >
On Fri, Apr 3, 2020 at 6:12 PM Daniel Thompson <daniel.thompson@linaro.org> wrote: > > On Tue, Mar 31, 2020 at 11:23:06PM +0800, Vincent Chen wrote: > > This patch set implements required ports to enable RISC-V kernel to support > > KGDB and KDB features. Because there is no immediate value in the RISC-V > > trap instruction, the kernel cannot identify the purpose of each trap > > exception through the opcode. This makes the existing identification > > schemes in other architecture unsuitable for the RISC-V kernel. In order > > to solve this problem, this patch adds the kgdb_has_hit_break() to kgdb.c > > to help the RISC-V kernel identify the KGDB trap exception. In addition, > > the XML target description was introduced in this patch set to enable KGDB > > to report the contents of the status, cause and steal registers. > > > > This patchset has passed the kgdbts test suite provided by Linux kernel on > > HiFive unleashed board and QEMU. > > Can you share the defconfig and qemu boot lines used for testing. > > I'd like to see if they can easily be integrated into kgdbtest. Normally > figuring out the qemu boot line is the hardest bit of adding support for > an architecture one is not familar with. > The process of building a RISC-V kernel is a bit different from other architecture. Maybe you can refer the steps in https://risc-v-getting-started-guide.readthedocs.io/en/latest/linux-qemu.html to build the kernel image and run it. For the Linux configuration used by KGDB, I just enable KGDB related configuration based on riscv defconfig. The riscv defconfig can founded in arch/riscv/configs/defconfig The QEMU boot lines are listed in the following. qemu-system-riscv64 -M virt -m 256M -nographic \ -kernel <bbl image>\ -append "debug root=/dev/vda rw console=ttyS0" \ -drive file=<root file system>,format=raw,id=hd0 \ -serial tcp:localhost:2345,server \ -gdb tcp::1133 \ -device virtio-blk-device,drive=hd0 \ > > Daniel. > > > PS At the moment it helps kgdbtest a lot if qemu is configured with two > serial ports but I really should get round to relaxing that! > > > > > Changes since v1: > > 1. Replace the magic number with macro when filling the gdb_regs[]. > > 2. Only support GDB XML packet instead of all query packets. > > 3. Move the macros used to parse instrcuton to parse_asm.h > > > > > > Vincent Chen (5): > > kgdb: Add kgdb_has_hit_break function > > riscv: Add KGDB support > > kgdb: enable arch to support XML packet support. > > riscv: Use the XML target descriptions to report 3 system registers > > riscv: Add SW single-step support for KDB > > > > arch/riscv/Kconfig | 2 + > > arch/riscv/include/asm/Kbuild | 1 - > > arch/riscv/include/asm/gdb_xml.h | 117 ++++++++++++ > > arch/riscv/include/asm/kdebug.h | 12 ++ > > arch/riscv/include/asm/kgdb.h | 113 +++++++++++ > > arch/riscv/include/asm/parse_asm.h | 214 +++++++++++++++++++++ > > arch/riscv/kernel/Makefile | 1 + > > arch/riscv/kernel/kgdb.c | 382 +++++++++++++++++++++++++++++++++++++ > > arch/riscv/kernel/traps.c | 5 + > > include/linux/kgdb.h | 9 + > > kernel/debug/debug_core.c | 12 ++ > > kernel/debug/gdbstub.c | 13 ++ > > lib/Kconfig.kgdb | 5 + > > 13 files changed, 885 insertions(+), 1 deletion(-) > > create mode 100644 arch/riscv/include/asm/gdb_xml.h > > create mode 100644 arch/riscv/include/asm/kdebug.h > > create mode 100644 arch/riscv/include/asm/kgdb.h > > create mode 100644 arch/riscv/include/asm/parse_asm.h > > create mode 100644 arch/riscv/kernel/kgdb.c > > > > -- > > 2.7.4 > >
On Mon, Apr 6, 2020 at 8:05 AM Vincent Chen <vincent.chen@sifive.com> wrote: > > On Fri, Apr 3, 2020 at 6:12 PM Daniel Thompson > <daniel.thompson@linaro.org> wrote: > > > > On Tue, Mar 31, 2020 at 11:23:06PM +0800, Vincent Chen wrote: > > > This patch set implements required ports to enable RISC-V kernel to support > > > KGDB and KDB features. Because there is no immediate value in the RISC-V > > > trap instruction, the kernel cannot identify the purpose of each trap > > > exception through the opcode. This makes the existing identification > > > schemes in other architecture unsuitable for the RISC-V kernel. In order > > > to solve this problem, this patch adds the kgdb_has_hit_break() to kgdb.c > > > to help the RISC-V kernel identify the KGDB trap exception. In addition, > > > the XML target description was introduced in this patch set to enable KGDB > > > to report the contents of the status, cause and steal registers. > > > > > > This patchset has passed the kgdbts test suite provided by Linux kernel on > > > HiFive unleashed board and QEMU. > > > > Can you share the defconfig and qemu boot lines used for testing. > > > > I'd like to see if they can easily be integrated into kgdbtest. Normally > > figuring out the qemu boot line is the hardest bit of adding support for > > an architecture one is not familar with. > > > The process of building a RISC-V kernel is a bit different from other > architecture. Maybe you can refer the steps in > https://risc-v-getting-started-guide.readthedocs.io/en/latest/linux-qemu.html > to build the kernel image and run it. > > For the Linux configuration used by KGDB, I just enable KGDB related > configuration based on riscv defconfig. The riscv defconfig can > founded in arch/riscv/configs/defconfig > > The QEMU boot lines are listed in the following. > > qemu-system-riscv64 -M virt -m 256M -nographic \ > -kernel <bbl image>\ > -append "debug root=/dev/vda rw console=ttyS0" \ > -drive file=<root file system>,format=raw,id=hd0 \ > -serial tcp:localhost:2345,server \ > -gdb tcp::1133 \ > -device virtio-blk-device,drive=hd0 \ Majority of folks (including distros) have moved to OpenSBI instead of BBL. In fact, QEMU releases ship with OpenSBI as default M-mode firmware. To boot Linux on QEMU Virt with OpenSBI as M-mode firmware refer: https://github.com/riscv/opensbi/blob/master/docs/platform/qemu_virt.md Regards, Anup
On Tue, 31 Mar 2020 08:23:06 PDT (-0700), vincent.chen@sifive.com wrote: > This patch set implements required ports to enable RISC-V kernel to support > KGDB and KDB features. Because there is no immediate value in the RISC-V > trap instruction, the kernel cannot identify the purpose of each trap > exception through the opcode. This makes the existing identification > schemes in other architecture unsuitable for the RISC-V kernel. In order > to solve this problem, this patch adds the kgdb_has_hit_break() to kgdb.c > to help the RISC-V kernel identify the KGDB trap exception. In addition, > the XML target description was introduced in this patch set to enable KGDB > to report the contents of the status, cause and steal registers. > > This patchset has passed the kgdbts test suite provided by Linux kernel on > HiFive unleashed board and QEMU. > > Changes since v1: > 1. Replace the magic number with macro when filling the gdb_regs[]. > 2. Only support GDB XML packet instead of all query packets. > 3. Move the macros used to parse instrcuton to parse_asm.h > > > Vincent Chen (5): > kgdb: Add kgdb_has_hit_break function > riscv: Add KGDB support > kgdb: enable arch to support XML packet support. > riscv: Use the XML target descriptions to report 3 system registers > riscv: Add SW single-step support for KDB > > arch/riscv/Kconfig | 2 + > arch/riscv/include/asm/Kbuild | 1 - > arch/riscv/include/asm/gdb_xml.h | 117 ++++++++++++ > arch/riscv/include/asm/kdebug.h | 12 ++ > arch/riscv/include/asm/kgdb.h | 113 +++++++++++ > arch/riscv/include/asm/parse_asm.h | 214 +++++++++++++++++++++ > arch/riscv/kernel/Makefile | 1 + > arch/riscv/kernel/kgdb.c | 382 +++++++++++++++++++++++++++++++++++++ > arch/riscv/kernel/traps.c | 5 + > include/linux/kgdb.h | 9 + > kernel/debug/debug_core.c | 12 ++ > kernel/debug/gdbstub.c | 13 ++ > lib/Kconfig.kgdb | 5 + > 13 files changed, 885 insertions(+), 1 deletion(-) > create mode 100644 arch/riscv/include/asm/gdb_xml.h > create mode 100644 arch/riscv/include/asm/kdebug.h > create mode 100644 arch/riscv/include/asm/kgdb.h > create mode 100644 arch/riscv/include/asm/parse_asm.h > create mode 100644 arch/riscv/kernel/kgdb.c Looks like there's some comments on #3, so I'm going to drop this patch set and assum there will be another version coming. Thanks!