Messages in this thread | | | Date | Fri, 8 Feb 2019 01:11:33 -0800 | From | Christoph Hellwig <> | Subject | Re: [v3 PATCH 8/8] RISC-V: Assign hwcap only according to boot cpu. |
| |
> + * We don't support running Linux on hertergenous ISA systems. > + * But first "okay" processor might not be the boot cpu. > + * Check the ISA of boot cpu.
Please use up your available 80 characters per line in comments.
> + /* > + * All "okay" hart should have same isa. We don't know how to > + * handle if they don't. Throw a warning for now. > + */ > + if (elf_hwcap && temp_hwcap != elf_hwcap) > + pr_warn("isa mismatch: 0x%lx != 0x%lx\n", > + elf_hwcap, temp_hwcap); > + > + if (hartid == boot_cpu_hartid) > + boot_hwcap = temp_hwcap; > + elf_hwcap = temp_hwcap;
So we always set elf_hwcap to the capabilities of the previous cpu.
> + temp_hwcap = 0;
I think tmp_hwcap should be declared and initialized inside the outer loop instead having to manually reset it like this.
> + } > > + elf_hwcap = boot_hwcap;
And then reset it here to the boot cpu.
Shoudn't we only report the features supported by all cores? Otherwise we'll still have problems if the boot cpu supports a feature, but not others.
Something like:
for () { unsigned long this_hwcap = 0;
for (i = 0; i < strlen(isa); i++) this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
if (elf_hwcap) elf_hwcap &= this_hwcap; else elf_hwcap = this_hwcap; }
| |