| Message ID | 20250314-v5_user_cfi_series-v12-3-e51202b53138@rivosinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | riscv control-flow integrity for usermode | expand |
On 14/03/2025 22:39, Deepak Gupta wrote: > This patch adds support for detecting zicfiss and zicfilp. zicfiss and > zicfilp stands for unprivleged integer spec extension for shadow stack > and branch tracking on indirect branches, respectively. > > This patch looks for zicfiss and zicfilp in device tree and accordinlgy > lights up bit in cpu feature bitmap. Furthermore this patch adds detection > utility functions to return whether shadow stack or landing pads are > supported by cpu. > > Reviewed-by: Zong Li <zong.li@sifive.com> > Signed-off-by: Deepak Gupta <debug@rivosinc.com> > --- > arch/riscv/include/asm/cpufeature.h | 13 +++++++++++++ > arch/riscv/include/asm/hwcap.h | 2 ++ > arch/riscv/include/asm/processor.h | 1 + > arch/riscv/kernel/cpufeature.c | 13 +++++++++++++ > 4 files changed, 29 insertions(+) > > diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h > index 569140d6e639..69007b8100ca 100644 > --- a/arch/riscv/include/asm/cpufeature.h > +++ b/arch/riscv/include/asm/cpufeature.h > @@ -12,6 +12,7 @@ > #include <linux/kconfig.h> > #include <linux/percpu-defs.h> > #include <linux/threads.h> > +#include <linux/smp.h> > #include <asm/hwcap.h> > #include <asm/cpufeature-macros.h> > > @@ -137,4 +138,16 @@ static __always_inline bool riscv_cpu_has_extension_unlikely(int cpu, const unsi > return __riscv_isa_extension_available(hart_isa[cpu].isa, ext); > } > > +static inline bool cpu_supports_shadow_stack(void) > +{ > + return (IS_ENABLED(CONFIG_RISCV_USER_CFI) && > + riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICFISS)); I would use riscv_has_extension_unlikely() instead of the cpu specific variant, that would remove the need for #include <linux/smp.h>. Unless you have a good reason to do that? > +} > + > +static inline bool cpu_supports_indirect_br_lp_instr(void) > +{ > + return (IS_ENABLED(CONFIG_RISCV_USER_CFI) && > + riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICFILP)); > +} > + > #endif > diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h > index 869da082252a..2dc4232bdb3e 100644 > --- a/arch/riscv/include/asm/hwcap.h > +++ b/arch/riscv/include/asm/hwcap.h > @@ -100,6 +100,8 @@ > #define RISCV_ISA_EXT_ZICCRSE 91 > #define RISCV_ISA_EXT_SVADE 92 > #define RISCV_ISA_EXT_SVADU 93 > +#define RISCV_ISA_EXT_ZICFILP 94 > +#define RISCV_ISA_EXT_ZICFISS 95 > > #define RISCV_ISA_EXT_XLINUXENVCFG 127 > > diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h > index 5f56eb9d114a..e3aba3336e63 100644 > --- a/arch/riscv/include/asm/processor.h > +++ b/arch/riscv/include/asm/processor.h > @@ -13,6 +13,7 @@ > #include <vdso/processor.h> > > #include <asm/ptrace.h> > +#include <asm/hwcap.h> > > #define arch_get_mmap_end(addr, len, flags) \ > ({ \ > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c > index c6ba750536c3..82065cc55822 100644 > --- a/arch/riscv/kernel/cpufeature.c > +++ b/arch/riscv/kernel/cpufeature.c > @@ -150,6 +150,15 @@ static int riscv_ext_svadu_validate(const struct riscv_isa_ext_data *data, > return 0; > } > > +static int riscv_cfi_validate(const struct riscv_isa_ext_data *data, > + const unsigned long *isa_bitmap) > +{ > + if (!IS_ENABLED(CONFIG_RISCV_USER_CFI)) > + return -EINVAL; > + > + return 0; > +} > + > static const unsigned int riscv_zk_bundled_exts[] = { > RISCV_ISA_EXT_ZBKB, > RISCV_ISA_EXT_ZBKC, > @@ -333,6 +342,10 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = { > __RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts, > riscv_ext_zicboz_validate), > __RISCV_ISA_EXT_DATA(ziccrse, RISCV_ISA_EXT_ZICCRSE), > + __RISCV_ISA_EXT_SUPERSET_VALIDATE(zicfilp, RISCV_ISA_EXT_ZICFILP, riscv_xlinuxenvcfg_exts, > + riscv_cfi_validate), > + __RISCV_ISA_EXT_SUPERSET_VALIDATE(zicfiss, RISCV_ISA_EXT_ZICFISS, riscv_xlinuxenvcfg_exts, > + riscv_cfi_validate), > __RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR), > __RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND), > __RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR), > With the above comment fixed, you can add: Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Thanks, Alex
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h index 569140d6e639..69007b8100ca 100644 --- a/arch/riscv/include/asm/cpufeature.h +++ b/arch/riscv/include/asm/cpufeature.h @@ -12,6 +12,7 @@ #include <linux/kconfig.h> #include <linux/percpu-defs.h> #include <linux/threads.h> +#include <linux/smp.h> #include <asm/hwcap.h> #include <asm/cpufeature-macros.h> @@ -137,4 +138,16 @@ static __always_inline bool riscv_cpu_has_extension_unlikely(int cpu, const unsi return __riscv_isa_extension_available(hart_isa[cpu].isa, ext); } +static inline bool cpu_supports_shadow_stack(void) +{ + return (IS_ENABLED(CONFIG_RISCV_USER_CFI) && + riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICFISS)); +} + +static inline bool cpu_supports_indirect_br_lp_instr(void) +{ + return (IS_ENABLED(CONFIG_RISCV_USER_CFI) && + riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICFILP)); +} + #endif diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h index 869da082252a..2dc4232bdb3e 100644 --- a/arch/riscv/include/asm/hwcap.h +++ b/arch/riscv/include/asm/hwcap.h @@ -100,6 +100,8 @@ #define RISCV_ISA_EXT_ZICCRSE 91 #define RISCV_ISA_EXT_SVADE 92 #define RISCV_ISA_EXT_SVADU 93 +#define RISCV_ISA_EXT_ZICFILP 94 +#define RISCV_ISA_EXT_ZICFISS 95 #define RISCV_ISA_EXT_XLINUXENVCFG 127 diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index 5f56eb9d114a..e3aba3336e63 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -13,6 +13,7 @@ #include <vdso/processor.h> #include <asm/ptrace.h> +#include <asm/hwcap.h> #define arch_get_mmap_end(addr, len, flags) \ ({ \ diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index c6ba750536c3..82065cc55822 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -150,6 +150,15 @@ static int riscv_ext_svadu_validate(const struct riscv_isa_ext_data *data, return 0; } +static int riscv_cfi_validate(const struct riscv_isa_ext_data *data, + const unsigned long *isa_bitmap) +{ + if (!IS_ENABLED(CONFIG_RISCV_USER_CFI)) + return -EINVAL; + + return 0; +} + static const unsigned int riscv_zk_bundled_exts[] = { RISCV_ISA_EXT_ZBKB, RISCV_ISA_EXT_ZBKC, @@ -333,6 +342,10 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = { __RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts, riscv_ext_zicboz_validate), __RISCV_ISA_EXT_DATA(ziccrse, RISCV_ISA_EXT_ZICCRSE), + __RISCV_ISA_EXT_SUPERSET_VALIDATE(zicfilp, RISCV_ISA_EXT_ZICFILP, riscv_xlinuxenvcfg_exts, + riscv_cfi_validate), + __RISCV_ISA_EXT_SUPERSET_VALIDATE(zicfiss, RISCV_ISA_EXT_ZICFISS, riscv_xlinuxenvcfg_exts, + riscv_cfi_validate), __RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR), __RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND), __RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR),