Messages in this thread Patch in this message | | | Date | Thu, 22 Sep 2022 09:31:56 +0200 | Subject | Re: [PATCH 1/2] riscv: Fix crash during early errata patching | From | Alexandre Ghiti <> |
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Hi Samuel,
On 9/22/22 07:47, Samuel Holland wrote: > The patch function for the T-Head PBMT errata calls __pa_symbol() before > relocation. This crashes when CONFIG_DEBUG_VIRTUAL is enabled, because > __pa_symbol() forwards to __phys_addr_symbol(), and __phys_addr_symbol() > checks against the absolute kernel start/end address. > > Fix this by directly using the underlying kernel_mapping_va_to_pa().
I'd rather fix __phys_addr_symbol so that we can use __pa_symbol and then take advantage of the address range check. Instead of using _end in phys_addr_symbol, we have access to the size of the kernel mapping, so we could do something like that:
diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c index f981b1f95fa0..150691aef058 100644 --- a/arch/riscv/mm/physaddr.c +++ b/arch/riscv/mm/physaddr.c @@ -22,7 +22,7 @@ EXPORT_SYMBOL(__virt_to_phys); phys_addr_t __phys_addr_symbol(unsigned long x) { unsigned long kernel_start = kernel_map.virt_addr; - unsigned long kernel_end = (unsigned long)_end; + unsigned long kernel_end = kernel_map.virt_addr + kernel_map.size;
/* * Boundary checking aginst the kernel image mapping. Thanks,
Alex
> > Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head") > Signed-off-by: Samuel Holland <samuel@sholland.org> > --- > > arch/riscv/errata/thead/errata.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c > index 202c83f677b2..83174f13783e 100644 > --- a/arch/riscv/errata/thead/errata.c > +++ b/arch/riscv/errata/thead/errata.c > @@ -76,8 +76,9 @@ void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct al > if (cpu_req_errata & tmp) { > /* On vm-alternatives, the mmu isn't running yet */ > if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) > - memcpy((void *)__pa_symbol(alt->old_ptr), > - (void *)__pa_symbol(alt->alt_ptr), alt->alt_len); > + memcpy((void *)kernel_mapping_va_to_pa((unsigned long)alt->old_ptr), > + (void *)kernel_mapping_va_to_pa((unsigned long)alt->alt_ptr), > + alt->alt_len); > else > patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); > }
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