diff options
Diffstat (limited to 'arch/riscv/kernel/head.S')
| -rw-r--r-- | arch/riscv/kernel/head.S | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 98a406474e7d..7ed1b22950fd 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -161,11 +161,20 @@ ENTRY(_start_kernel) /* Reset all registers except ra, a0, a1 */ call reset_regs - /* Setup a PMP to permit access to all of memory. */ + /* + * Setup a PMP to permit access to all of memory. Some machines may + * not implement PMPs, so we set up a quick trap handler to just skip + * touching the PMPs on any trap. + */ + la a0, pmp_done + csrw CSR_TVEC, a0 + li a0, -1 csrw CSR_PMPADDR0, a0 li a0, (PMP_A_NAPOT | PMP_R | PMP_W | PMP_X) csrw CSR_PMPCFG0, a0 +.align 2 +pmp_done: /* * The hartid in a0 is expected later on, and we have no firmware |