diff options
| author | Samuel Holland <[email protected]> | 2024-08-29 13:22:36 -0700 |
|---|---|---|
| committer | Anup Patel <[email protected]> | 2024-09-23 18:12:39 +0530 |
| commit | beef2f693785499153b00f330d0205f91c3add4e (patch) | |
| tree | 1f3a0985f4c3c763fb58ad8bc084eccb4d0cffd0 | |
| parent | 00093a20004baf6826d843ac3ff6e8e7c5d06b13 (diff) | |
lib: sbi: Respect scounteren when emulating the time CSR
This optimization creates a correctness issue, as it prevents supervisor
software from restricting VS-mode or U-mode access to the time CSR for
its own purposes.
Closes: https://github.com/riscv-software-src/opensbi/issues/370
Fixes: ebc8ebc0f846 ("lib: sbi: Improve HPM CSR read/write emulation")
Signed-off-by: Samuel Holland <[email protected]>
Reviewed-by: Anup Patel <[email protected]>
| -rw-r--r-- | lib/sbi/sbi_emulate_csr.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/lib/sbi/sbi_emulate_csr.c b/lib/sbi/sbi_emulate_csr.c index 869c81f4..3adec78d 100644 --- a/lib/sbi/sbi_emulate_csr.c +++ b/lib/sbi/sbi_emulate_csr.c @@ -66,12 +66,11 @@ int sbi_emulate_csr_read(int csr_num, struct sbi_trap_regs *regs, *csr_val = csr_read(CSR_MCYCLE); break; case CSR_TIME: + if (!hpm_allowed(csr_num - CSR_CYCLE, prev_mode, virt)) + return SBI_ENOTSUPP; /* * We emulate TIME CSR for both Host (HS/U-mode) and * Guest (VS/VU-mode). - * - * Faster TIME CSR reads are critical for good performance - * in S-mode software so we don't check CSR permissions. */ *csr_val = (virt) ? sbi_timer_virt_value(): sbi_timer_value(); |