diff options
| author | Greentime Hu <greentime.hu@sifive.com> | 2020-01-09 11:17:40 +0800 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-02-18 09:41:24 -0800 |
| commit | c68a9032299e837b56d356de9250c93094f7e0e3 (patch) | |
| tree | c5bc94625a84d1d6f3568c344ab300a9b996f837 /arch/riscv/kernel/head.S | |
| parent | 11a48a5a18c63fd7621bb050228cebf13566e4d8 (diff) | |
| download | linux-stable-c68a9032299e837b56d356de9250c93094f7e0e3.tar.gz linux-stable-c68a9032299e837b56d356de9250c93094f7e0e3.tar.bz2 linux-stable-c68a9032299e837b56d356de9250c93094f7e0e3.zip | |
riscv: set pmp configuration if kernel is running in M-mode
When the kernel is running in S-mode, the expectation is that the
bootloader or SBI layer will configure the PMP to allow the kernel to
access physical memory. But, when the kernel is running in M-mode and is
started with the ELF "loader", there's probably no bootloader or SBI layer
involved to configure the PMP. Thus, we need to configure the PMP
ourselves to enable the kernel to access all regions.
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/kernel/head.S')
| -rw-r--r-- | arch/riscv/kernel/head.S | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 271860fc2c3f..85f2073e7fe4 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -58,6 +58,12 @@ _start_kernel: /* Reset all registers except ra, a0, a1 */ call reset_regs + /* Setup a PMP to permit access to all of memory. */ + li a0, -1 + csrw CSR_PMPADDR0, a0 + li a0, (PMP_A_NAPOT | PMP_R | PMP_W | PMP_X) + csrw CSR_PMPCFG0, a0 + /* * The hartid in a0 is expected later on, and we have no firmware * to hand it to us. |