Improve PTDUMP and introduce new fields #51

Probing for misaligned access speed takes about 0.06 seconds. On a system with 64 cores, doing this in smp_callin() means it's done serially, extending boot time by 3.8 seconds. That's a lot of boot time. Instead of measuring each CPU serially, let's do the measurements on all CPUs in parallel. If we disable preemption on all CPUs, the jiffies stop ticking, so we can do this in stages of 1) everybody except core 0, then 2) core 0. The measurement call in smp_callin() stays around, but is now conditionalized to only run if a new CPU shows up after the round of in-parallel measurements has run. The goal is to have the measurement call not run during boot or suspend/resume, but only on a hotplug addition. Reported-by: Jisheng Zhang <jszhang@kernel.org> Closes: https://lore.kernel.org/all/mhng-9359993d-6872-4134-83ce-c97debe1cf9a@palmer-ri-x1c9/T/#mae9b8f40016f9df428829d33360144dc5026bcbf Fixes: 584ea65 ("RISC-V: Probe for unaligned access speed") Signed-off-by: Evan Green <evan@rivosinc.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Tested-by: Andrew Jones <ajones@ventanamicro.com> Tested-by: Jisheng Zhang <jszhang@kernel.org> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230920193801.3035093-1-evan@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Clément Léger <cleger@rivosinc.com> says: Since commit 61cadb9 ("Provide new description of misaligned load/store behavior compatible with privileged architecture.") in the RISC-V ISA manual, it is stated that misaligned load/store might not be supported. However, the RISC-V kernel uABI describes that misaligned accesses are supported. In order to support that, this series adds support for S-mode handling of misaligned accesses as well support for prctl(PR_UNALIGN). Handling misaligned access in kernel allows for a finer grain control of the misaligned accesses behavior, and thanks to the prctl() call, can allow disabling misaligned access emulation to generate SIGBUS. User space can then optimize its software by removing such access based on SIGBUS generation. This series is useful when using a SBI implementation that does not handle misaligned traps as well as detecting misaligned accesses generated by userspace application using the prctrl(PR_SET_UNALIGN) feature. This series can be tested using the spike simulator[1] and a modified openSBI version[2] which allows to always delegate misaligned load/store to S-mode. A test[3] that exercise various instructions/registers can be executed to verify the unaligned access support. [1] https://github.com/riscv-software-src/riscv-isa-sim [2] https://github.com/rivosinc/opensbi/tree/dev/cleger/no_misaligned [3] https://github.com/clementleger/unaligned_test * b4-shazam-merge: riscv: add support for PR_SET_UNALIGN and PR_GET_UNALIGN riscv: report misaligned accesses emulation to hwprobe riscv: annotate check_unaligned_access_boot_cpu() with __init riscv: add support for sysctl unaligned_enabled control riscv: add floating point insn support to misaligned access emulation riscv: report perf event for misaligned fault riscv: add support for misaligned trap handling in S-mode riscv: remove unused functions in traps_misaligned.c [Palmer: Evan pointed out an extra __init on unaligned_emulation_finish(), I've squashed it in as a merge conflict.] Link: https://lore.kernel.org/r/20231004151405.521596-1-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

RSW field can be used to encode 2 bits of software defined information. Currently, PTDUMP only prints "RSW" when its value is 1 or 3. To fix this issue and improve the debugging experience with PTDUMP, we redefine _PAGE_SPECIAL to its original value and use _PAGE_SOFT as the RSW mask, allow it to print the RSW with any non-zero value. This patch also removes the val from the struct prot_bits as it is no longer needed. Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>

This patch introduces the PBMT field to the PTDUMP, so it can display the memory attributes for NC or IO. Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>

This patch introduces the NAPOT field to PTDUMP, allowing it to display the letter "N" for pages that have the 63rd bit set. Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>

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Improve PTDUMP and introduce new fields #51

Improve PTDUMP and introduce new fields #51

Commits on Nov 2, 2023