From mboxrd@z Thu Jan 1 00:00:00 1970 From: Deepak Gupta Date: Mon, 16 Sep 2024 11:23:57 -0700 Subject: [PATCH v6 4/4] lib: sbi: fwft: implement landing pad and shadow stack fwft interface In-Reply-To: <20240916182357.24545-1-debug@rivosinc.com> References: <20240916182357.24545-1-debug@rivosinc.com> Message-ID: <20240916182357.24545-5-debug@rivosinc.com> List-Id: To: opensbi@lists.infradead.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Supervisor software can enable control flow integrity features for itself using fwft feature `SBI_FWFT_LANDING_PAD` and `SBI_FWFT_SHADOW_STACK`. This patch implements the mechanism to enable both these fwft. Signed-off-by: Deepak Gupta Reviewed-by: Atish Patra Reviewed-by: Cl?ment L?ger --- lib/sbi/sbi_fwft.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/lib/sbi/sbi_fwft.c b/lib/sbi/sbi_fwft.c index ef881ef..88610aa 100644 --- a/lib/sbi/sbi_fwft.c +++ b/lib/sbi/sbi_fwft.c @@ -145,6 +145,68 @@ static int fwft_get_adue(struct fwft_config *conf, unsigned long *value) return SBI_OK; } +static int fwft_lpad_supported(struct fwft_config *conf) +{ + if (!sbi_hart_has_extension(sbi_scratch_thishart_ptr(), + SBI_HART_EXT_ZICFILP)) + return SBI_ENOTSUPP; + + return SBI_OK; +} + +static int fwft_enable_lpad(struct fwft_config *conf, unsigned long value) +{ + if (value == 1) + csr_set(CSR_MENVCFG, ENVCFG_LPE); + else if (value == 0) + csr_clear(CSR_MENVCFG, ENVCFG_LPE); + else + return SBI_EINVAL; + + return SBI_OK; +} + +static int fwft_get_lpad(struct fwft_config *conf, unsigned long *value) +{ + unsigned long cfg; + + cfg = csr_read(CSR_MENVCFG) & ENVCFG_LPE; + *value = cfg != 0; + + return SBI_OK; +} + +static int fwft_sstack_supported(struct fwft_config *conf) +{ + if (!sbi_hart_has_extension(sbi_scratch_thishart_ptr(), + SBI_HART_EXT_ZICFISS)) + return SBI_ENOTSUPP; + + return SBI_OK; +} + +static int fwft_enable_sstack(struct fwft_config *conf, unsigned long value) +{ + if (value == 1) + csr_set(CSR_MENVCFG, ENVCFG_SSE); + else if (value == 0) + csr_clear(CSR_MENVCFG, ENVCFG_SSE); + else + return SBI_EINVAL; + + return SBI_OK; +} + +static int fwft_get_sstack(struct fwft_config *conf, unsigned long *value) +{ + unsigned long cfg; + + cfg = csr_read(CSR_MENVCFG) & ENVCFG_SSE; + *value = cfg != 0; + + return SBI_OK; +} + static struct fwft_config* get_feature_config(enum sbi_fwft_feature_t feature) { int i; @@ -230,6 +292,18 @@ static const struct fwft_feature features[] = .set = fwft_set_misaligned_delegation, .get = fwft_get_misaligned_delegation, }, + { + .id = SBI_FWFT_LANDING_PAD, + .supported = fwft_lpad_supported, + .set = fwft_enable_lpad, + .get = fwft_get_lpad, + }, + { + .id = SBI_FWFT_SHADOW_STACK, + .supported = fwft_sstack_supported, + .set = fwft_enable_sstack, + .get = fwft_get_sstack, + }, { .id = SBI_FWFT_PTE_AD_HW_UPDATING, .supported = fwft_adue_supported, -- 2.45.0