Messages in this thread |  | | Date | Fri, 24 Jul 2020 22:12:41 -0700 (PDT) | Subject | Re: [PATCH 3/4] RISC-V: Do not rely on initrd_start/end computed during early dt parsing | From | Palmer Dabbelt <> |
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On Wed, 15 Jul 2020 16:30:08 PDT (-0700), Atish Patra wrote: > Currently, initrd_start/end are computed during early_init_dt_scan > but used during arch_setup. We will get the following panic if initrd is used > and CONFIG_DEBUG_VIRTUAL is turned on. > > [ 0.000000] ------------[ cut here ]------------ > [ 0.000000] kernel BUG at arch/riscv/mm/physaddr.c:33! > [ 0.000000] Kernel BUG [#1] > [ 0.000000] Modules linked in: > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.8.0-rc4-00015-ged0b226fed02 #886 > [ 0.000000] epc: ffffffe0002058d2 ra : ffffffe0000053f0 sp : ffffffe001001f40 > [ 0.000000] gp : ffffffe00106e250 tp : ffffffe001009d40 t0 : ffffffe00107ee28 > [ 0.000000] t1 : 0000000000000000 t2 : ffffffe000a2e880 s0 : ffffffe001001f50 > [ 0.000000] s1 : ffffffe0001383e8 a0 : ffffffe00c087e00 a1 : 0000000080200000 > [ 0.000000] a2 : 00000000010bf000 a3 : ffffffe00106f3c8 a4 : ffffffe0010bf000 > [ 0.000000] a5 : ffffffe000000000 a6 : 0000000000000006 a7 : 0000000000000001 > [ 0.000000] s2 : ffffffe00106f068 s3 : ffffffe00106f070 s4 : 0000000080200000 > [ 0.000000] s5 : 0000000082200000 s6 : 0000000000000000 s7 : 0000000000000000 > [ 0.000000] s8 : 0000000080011010 s9 : 0000000080012700 s10: 0000000000000000 > [ 0.000000] s11: 0000000000000000 t3 : 000000000001fe30 t4 : 000000000001fe30 > [ 0.000000] t5 : 0000000000000000 t6 : ffffffe00107c471 > [ 0.000000] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003 > [ 0.000000] random: get_random_bytes called from print_oops_end_marker+0x22/0x46 with crng_init=0 > > To avoid the error, initrd_start/end can be computed from phys_initrd_start/size > in setup itself. It also improves the initrd placement by aligning the start > and size with the page size. > > Fixes: 6435f773d81f (riscv: mm: add support for CONFIG_DEBUG_VIRTUAL) > Signed-off-by: Atish Patra <atish.patra@wdc.com> > --- > arch/riscv/mm/init.c | 33 +++++++++++++++++++++++++++------ > 1 file changed, 27 insertions(+), 6 deletions(-) > > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 8d22973bde40..f818a47a72d1 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -95,19 +95,40 @@ void __init mem_init(void) > #ifdef CONFIG_BLK_DEV_INITRD > static void __init setup_initrd(void) > { > + phys_addr_t start; > unsigned long size; > > - if (initrd_start >= initrd_end) { > - pr_info("initrd not found or empty"); > + /* Ignore the virtul address computed during device tree parsing */ > + initrd_start = initrd_end = 0; > + > + if (!phys_initrd_size) > + return; > + /* > + * Round the memory region to page boundaries as per free_initrd_mem() > + * This allows us to detect whether the pages overlapping the initrd > + * are in use, but more importantly, reserves the entire set of pages > + * as we don't want these pages allocated for other purposes. > + */ > + start = round_down(phys_initrd_start, PAGE_SIZE); > + size = phys_initrd_size + (phys_initrd_start - start); > + size = round_up(size, PAGE_SIZE); > + > + if (!memblock_is_region_memory(start, size)) { > + pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region", > + (u64)start, size); > goto disable; > } > - if (__pa_symbol(initrd_end) > PFN_PHYS(max_low_pfn)) { > - pr_err("initrd extends beyond end of memory"); > + > + if (memblock_is_region_reserved(start, size)) { > + pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n", > + (u64)start, size); > goto disable; > } > > - size = initrd_end - initrd_start; > - memblock_reserve(__pa_symbol(initrd_start), size); > + memblock_reserve(start, size); > + /* Now convert initrd to virtual addresses */ > + initrd_start = (unsigned long)__va(phys_initrd_start); > + initrd_end = initrd_start + phys_initrd_size; > initrd_below_start_ok = 1; > > pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
I'm going to put this one on fixes, but I don't think that's the right: DEBUG_VIRTUAL just catches the bug, but as far as I can tell it's been there since the beginning. I'm going to replace this with
Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code")
It's not going to apply back that far, but we can always backport it where it fails.
Thanks!
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