Merge tag 'riscv-for-linus-7.0-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Paul Walmsley:

 - Add support for control flow integrity for userspace processes.

   This is based on the standard RISC-V ISA extensions Zicfiss and
   Zicfilp

 - Improve ptrace behavior regarding vector registers, and add some
   selftests

 - Optimize our strlen() assembly

 - Enable the ISO-8859-1 code page as built-in, similar to ARM64, for
   EFI volume mounting

 - Clean up some code slightly, including defining copy_user_page() as
   copy_page() rather than memcpy(), aligning us with other
   architectures; and using max3() to slightly simplify an expression
   in riscv_iommu_init_check()

* tag 'riscv-for-linus-7.0-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (42 commits)
  riscv: lib: optimize strlen loop efficiency
  selftests: riscv: vstate_exec_nolibc: Use the regular prctl() function
  selftests: riscv: verify ptrace accepts valid vector csr values
  selftests: riscv: verify ptrace rejects invalid vector csr inputs
  selftests: riscv: verify syscalls discard vector context
  selftests: riscv: verify initial vector state with ptrace
  selftests: riscv: test ptrace vector interface
  riscv: ptrace: validate input vector csr registers
  riscv: csr: define vtype register elements
  riscv: vector: init vector context with proper vlenb
  riscv: ptrace: return ENODATA for inactive vector extension
  kselftest/riscv: add kselftest for user mode CFI
  riscv: add documentation for shadow stack
  riscv: add documentation for landing pad / indirect branch tracking
  riscv: create a Kconfig fragment for shadow stack and landing pad support
  arch/riscv: add dual vdso creation logic and select vdso based on hw
  arch/riscv: compile vdso with landing pad and shadow stack note
  riscv: enable kernel access to shadow stack memory via the FWFT SBI call
  riscv: add kernel command line option to opt out of user CFI
  riscv/hwprobe: add zicfilp / zicfiss enumeration in hwprobe
  ...

4 files changed, 36 insertions, 2 deletions

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 487b3bf2e1ea..8239cd95a005 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -229,4 +229,8 @@ static inline bool cpu_attack_vector_mitigated(enum cpu_attack_vectors v)
 #define smt_mitigations SMT_MITIGATIONS_OFF
 #endif
 
+int arch_get_indir_br_lp_status(struct task_struct *t, unsigned long __user *status);
+int arch_set_indir_br_lp_status(struct task_struct *t, unsigned long status);
+int arch_lock_indir_br_lp_status(struct task_struct *t, unsigned long status);
+
 #endif /* _LINUX_CPU_H_ */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2dbe1c2219ee..dc1ad71a2a70 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -361,7 +361,7 @@ enum {
 	DECLARE_VMA_BIT_ALIAS(PKEY_BIT2, HIGH_ARCH_2),
 	DECLARE_VMA_BIT_ALIAS(PKEY_BIT3, HIGH_ARCH_3),
 	DECLARE_VMA_BIT_ALIAS(PKEY_BIT4, HIGH_ARCH_4),
-#if defined(CONFIG_X86_USER_SHADOW_STACK)
+#if defined(CONFIG_X86_USER_SHADOW_STACK) || defined(CONFIG_RISCV_USER_CFI)
 	/*
 	 * VM_SHADOW_STACK should not be set with VM_SHARED because of lack of
 	 * support core mm.
@@ -462,7 +462,8 @@ enum {
 #define VM_PKEY_BIT4  VM_NONE
 #endif /* CONFIG_ARCH_PKEY_BITS > 4 */
 #endif /* CONFIG_ARCH_HAS_PKEYS */
-#if defined(CONFIG_X86_USER_SHADOW_STACK) || defined(CONFIG_ARM64_GCS)
+#if defined(CONFIG_X86_USER_SHADOW_STACK) || defined(CONFIG_ARM64_GCS) || \
+	defined(CONFIG_RISCV_USER_CFI)
 #define VM_SHADOW_STACK	INIT_VM_FLAG(SHADOW_STACK)
 #else
 #define VM_SHADOW_STACK	VM_NONE
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index 819ded2d39de..ee30dcd80901 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -545,6 +545,8 @@ typedef struct elf64_shdr {
 #define NT_RISCV_VECTOR	0x901		/* RISC-V vector registers */
 #define NN_RISCV_TAGGED_ADDR_CTRL "LINUX"
 #define NT_RISCV_TAGGED_ADDR_CTRL 0x902	/* RISC-V tagged address control (prctl()) */
+#define NN_RISCV_USER_CFI	"LINUX"
+#define NT_RISCV_USER_CFI	0x903		/* RISC-V shadow stack state */
 #define NN_LOONGARCH_CPUCFG	"LINUX"
 #define NT_LOONGARCH_CPUCFG	0xa00	/* LoongArch CPU config registers */
 #define NN_LOONGARCH_CSR	"LINUX"
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 79944b7ae50a..55b0446fff9d 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -396,4 +396,31 @@ struct prctl_mm_map {
  */
 # define PR_RSEQ_SLICE_EXT_ENABLE		0x01
 
+/*
+ * Get the current indirect branch tracking configuration for the current
+ * thread, this will be the value configured via PR_SET_INDIR_BR_LP_STATUS.
+ */
+#define PR_GET_INDIR_BR_LP_STATUS      80
+
+/*
+ * Set the indirect branch tracking configuration. PR_INDIR_BR_LP_ENABLE will
+ * enable cpu feature for user thread, to track all indirect branches and ensure
+ * they land on arch defined landing pad instruction.
+ * x86 - If enabled, an indirect branch must land on an ENDBRANCH instruction.
+ * arch64 - If enabled, an indirect branch must land on a BTI instruction.
+ * riscv - If enabled, an indirect branch must land on an lpad instruction.
+ * PR_INDIR_BR_LP_DISABLE will disable feature for user thread and indirect
+ * branches will no more be tracked by cpu to land on arch defined landing pad
+ * instruction.
+ */
+#define PR_SET_INDIR_BR_LP_STATUS      81
+# define PR_INDIR_BR_LP_ENABLE		   (1UL << 0)
+
+/*
+ * Prevent further changes to the specified indirect branch tracking
+ * configuration.  All bits may be locked via this call, including
+ * undefined bits.
+ */
+#define PR_LOCK_INDIR_BR_LP_STATUS      82
+
 #endif /* _LINUX_PRCTL_H */