Alexandre Ghiti bb8958d5dc riscv: Flush current cpu icache before other cpus ... On SiFive Unmatched, I recently fell onto the following BUG when booting: [ 0.000000] ftrace: allocating 36610 entries in 144 pages [ 0.000000] Oops - illegal instruction [#1] [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5 [ 0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT) [ 0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae [ 0.000000] ra : __sbi_rfence_v02+0xc8/0x10a [ 0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10 [ 0.000000] gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000 [ 0.000000] t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60 [ 0.000000] s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10 [ 0.000000] a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 [ 0.000000] a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43 [ 0.000000] s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000 [ 0.000000] s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001 [ 0.000000] s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000 [ 0.000000] s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008 [ 0.000000] t5 : ffffffcf04000808 t6 : ffffffe3ffddf188 [ 0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002 [ 0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae [ 0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26 [ 0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a [ 0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32 [ 0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c [ 0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360 [ 0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130 [ 0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6 [ 0.000000] ---[ end trace f67eb9af4d8d492b ]--- [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! [ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- While ftrace is looping over a list of addresses to patch, it always failed when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the backtrace, the illegal instruction is encountered in this same function. However, patch_text_nosync, after patching the instructions, calls flush_icache_range. But looking at what happens in this function: flush_icache_range -> flush_icache_all -> sbi_remote_fence_i -> __sbi_rfence_v02 -> riscv_cpuid_to_hartid_mask The icache and dcache of the current cpu are never synchronized between the patching of riscv_cpuid_to_hartid_mask and calling this same function. So fix this by flushing the current cpu's icache before asking for the other cpus to do the same. Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Fixes: fab957c11e ("RISC-V: Atomic and Locking Code") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>		2021-10-04 18:24:15 -07:00
..
cacheflush.c	riscv: Flush current cpu icache before other cpus	2021-10-04 18:24:15 -07:00
context.c	riscv: add ASID-based tlbflushing methods	2021-06-30 20:55:39 -07:00
extable.c	riscv: abstract out CSR names for supervisor vs machine mode	2019-11-05 09:20:42 -08:00
fault.c	riscv: Enable KFENCE for riscv64	2021-06-30 20:55:41 -07:00
hugetlbpage.c	hugetlbfs: remove hugetlb_add_hstate() warning for existing hstate	2020-06-03 20:09:46 -07:00
init.c	RISC-V Patches for the 5.15 Merge Window, Part 1	2021-09-05 11:31:23 -07:00
kasan_init.c	riscv: Ensure BPF_JIT_REGION_START aligned with PMD size	2021-06-18 21:10:05 -07:00
Makefile	riscv: Fixup patch_text panic in ftrace	2021-01-14 15:09:04 -08:00
pageattr.c	RISC-V Patches for the 5.11 Merge Window, Part 1	2020-12-18 10:43:07 -08:00
physaddr.c	riscv: Introduce structure that group all variables regarding kernel mapping	2021-07-05 18:04:00 -07:00
ptdump.c	riscv: Fix PTDUMP output now BPF region moved back to module region	2021-07-06 15:21:27 -07:00
tlbflush.c	riscv: add ASID-based tlbflushing methods	2021-06-30 20:55:39 -07:00