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X-BeenThere: opensbi@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "opensbi" Errors-To: opensbi-bounces+opensbi=archiver.kernel.org@lists.infradead.org Expected trap must always clear MPRV. Currently it doesn't. There is a security issue here where if firmware was doing ld/st with MPRV=1 and since there would be a expected trap, opensbi will continue to run as MPRV=1. Security impact is DoS where opensbi will just keep trapping. Signed-off-by: Deepak Gupta --- lib/sbi/sbi_expected_trap.S | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/sbi/sbi_expected_trap.S b/lib/sbi/sbi_expected_trap.S index 99dede5f..8fbd2cb2 100644 --- a/lib/sbi/sbi_expected_trap.S +++ b/lib/sbi/sbi_expected_trap.S @@ -23,6 +23,8 @@ .global __sbi_expected_trap __sbi_expected_trap: /* Without H-extension so, MTVAL2 and MTINST CSRs and GVA not available */ + lui a4, 0x20 /* MSTATUS_MPRV */ + csrc CSR_MSTATUS, a4 csrr a4, CSR_MCAUSE REG_S a4, SBI_TRAP_INFO_OFFSET(cause)(a3) csrr a4, CSR_MTVAL @@ -39,6 +41,8 @@ __sbi_expected_trap: .global __sbi_expected_trap_hext __sbi_expected_trap_hext: /* With H-extension so, MTVAL2 and MTINST CSRs and GVA available */ + lui a4, 0x20 /* MSTATUS_MPRV */ + csrc CSR_MSTATUS, a4 csrr a4, CSR_MCAUSE REG_S a4, SBI_TRAP_INFO_OFFSET(cause)(a3) csrr a4, CSR_MTVAL -- 2.43.0 -- opensbi mailing list opensbi@lists.infradead.org http://lists.infradead.org/mailman/listinfo/opensbi