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-rw-r--r--arch/riscv/Kconfig3
-rw-r--r--arch/riscv/include/asm/cfi.h22
-rw-r--r--arch/riscv/include/asm/insn.h10
-rw-r--r--arch/riscv/include/asm/syscall.h5
-rw-r--r--arch/riscv/include/asm/syscall_wrapper.h87
-rw-r--r--arch/riscv/kernel/Makefile2
-rw-r--r--arch/riscv/kernel/cfi.c77
-rw-r--r--arch/riscv/kernel/compat_syscall_table.c8
-rw-r--r--arch/riscv/kernel/mcount.S9
-rw-r--r--arch/riscv/kernel/suspend_entry.S5
-rw-r--r--arch/riscv/kernel/sys_riscv.c6
-rw-r--r--arch/riscv/kernel/syscall_table.c8
-rw-r--r--arch/riscv/kernel/traps.c4
-rw-r--r--arch/riscv/purgatory/Makefile4
14 files changed, 238 insertions, 12 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index afa7160b136c..1494bca1b53a 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -35,6 +35,7 @@ config RISCV
select ARCH_HAS_SET_MEMORY if MMU
select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
+ select ARCH_HAS_SYSCALL_WRAPPER
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_HAS_VDSO_DATA
@@ -42,12 +43,14 @@ config RISCV
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
select ARCH_STACKWALK
select ARCH_SUPPORTS_ATOMIC_RMW
+ select ARCH_SUPPORTS_CFI_CLANG
select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
select ARCH_SUPPORTS_HUGETLBFS if MMU
select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
select ARCH_SUPPORTS_PER_VMA_LOCK if MMU
select ARCH_USE_MEMTEST
select ARCH_USE_QUEUED_RWLOCKS
+ select ARCH_USES_CFI_TRAPS if CFI_CLANG
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
diff --git a/arch/riscv/include/asm/cfi.h b/arch/riscv/include/asm/cfi.h
new file mode 100644
index 000000000000..56bf9d69d5e3
--- /dev/null
+++ b/arch/riscv/include/asm/cfi.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_CFI_H
+#define _ASM_RISCV_CFI_H
+
+/*
+ * Clang Control Flow Integrity (CFI) support.
+ *
+ * Copyright (C) 2023 Google LLC
+ */
+
+#include <linux/cfi.h>
+
+#ifdef CONFIG_CFI_CLANG
+enum bug_trap_type handle_cfi_failure(struct pt_regs *regs);
+#else
+static inline enum bug_trap_type handle_cfi_failure(struct pt_regs *regs)
+{
+ return BUG_TRAP_TYPE_NONE;
+}
+#endif /* CONFIG_CFI_CLANG */
+
+#endif /* _ASM_RISCV_CFI_H */
diff --git a/arch/riscv/include/asm/insn.h b/arch/riscv/include/asm/insn.h
index 4e1505cef8aa..9c23f598434c 100644
--- a/arch/riscv/include/asm/insn.h
+++ b/arch/riscv/include/asm/insn.h
@@ -63,6 +63,7 @@
#define RVG_RS1_OPOFF 15
#define RVG_RS2_OPOFF 20
#define RVG_RD_OPOFF 7
+#define RVG_RS1_MASK GENMASK(4, 0)
#define RVG_RD_MASK GENMASK(4, 0)
/* The bit field of immediate value in RVC J instruction */
@@ -129,6 +130,7 @@
#define RVC_C2_RS1_OPOFF 7
#define RVC_C2_RS2_OPOFF 2
#define RVC_C2_RD_OPOFF 7
+#define RVC_C2_RS1_MASK GENMASK(4, 0)
/* parts of opcode for RVG*/
#define RVG_OPCODE_FENCE 0x0f
@@ -278,6 +280,10 @@ static __always_inline bool riscv_insn_is_branch(u32 code)
#define RV_X(X, s, mask) (((X) >> (s)) & (mask))
#define RVC_X(X, s, mask) RV_X(X, s, mask)
+#define RV_EXTRACT_RS1_REG(x) \
+ ({typeof(x) x_ = (x); \
+ (RV_X(x_, RVG_RS1_OPOFF, RVG_RS1_MASK)); })
+
#define RV_EXTRACT_RD_REG(x) \
({typeof(x) x_ = (x); \
(RV_X(x_, RVG_RD_OPOFF, RVG_RD_MASK)); })
@@ -305,6 +311,10 @@ static __always_inline bool riscv_insn_is_branch(u32 code)
(RV_X(x_, RV_B_IMM_11_OPOFF, RV_B_IMM_11_MASK) << RV_B_IMM_11_OFF) | \
(RV_IMM_SIGN(x_) << RV_B_IMM_SIGN_OFF); })
+#define RVC_EXTRACT_C2_RS1_REG(x) \
+ ({typeof(x) x_ = (x); \
+ (RV_X(x_, RVC_C2_RS1_OPOFF, RVC_C2_RS1_MASK)); })
+
#define RVC_EXTRACT_JTYPE_IMM(x) \
({typeof(x) x_ = (x); \
(RVC_X(x_, RVC_J_IMM_3_1_OPOFF, RVC_J_IMM_3_1_MASK) << RVC_J_IMM_3_1_OFF) | \
diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index 0148c6bd9675..121fff429dce 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -75,7 +75,7 @@ static inline int syscall_get_arch(struct task_struct *task)
#endif
}
-typedef long (*syscall_t)(ulong, ulong, ulong, ulong, ulong, ulong, ulong);
+typedef long (*syscall_t)(const struct pt_regs *);
static inline void syscall_handler(struct pt_regs *regs, ulong syscall)
{
syscall_t fn;
@@ -87,8 +87,7 @@ static inline void syscall_handler(struct pt_regs *regs, ulong syscall)
#endif
fn = sys_call_table[syscall];
- regs->a0 = fn(regs->orig_a0, regs->a1, regs->a2,
- regs->a3, regs->a4, regs->a5, regs->a6);
+ regs->a0 = fn(regs);
}
static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
diff --git a/arch/riscv/include/asm/syscall_wrapper.h b/arch/riscv/include/asm/syscall_wrapper.h
new file mode 100644
index 000000000000..1d7942c8a6cb
--- /dev/null
+++ b/arch/riscv/include/asm/syscall_wrapper.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * syscall_wrapper.h - riscv specific wrappers to syscall definitions
+ *
+ * Based on arch/arm64/include/syscall_wrapper.h
+ */
+
+#ifndef __ASM_SYSCALL_WRAPPER_H
+#define __ASM_SYSCALL_WRAPPER_H
+
+#include <asm/ptrace.h>
+
+asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *);
+
+#define SC_RISCV_REGS_TO_ARGS(x, ...) \
+ __MAP(x,__SC_ARGS \
+ ,,regs->orig_a0,,regs->a1,,regs->a2 \
+ ,,regs->a3,,regs->a4,,regs->a5,,regs->a6)
+
+#ifdef CONFIG_COMPAT
+
+#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
+ asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs); \
+ ALLOW_ERROR_INJECTION(__riscv_compat_sys##name, ERRNO); \
+ static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
+ static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
+ asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs) \
+ { \
+ return __se_compat_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \
+ } \
+ static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
+ { \
+ return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \
+ } \
+ static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+
+#define COMPAT_SYSCALL_DEFINE0(sname) \
+ asmlinkage long __riscv_compat_sys_##sname(const struct pt_regs *__unused); \
+ ALLOW_ERROR_INJECTION(__riscv_compat_sys_##sname, ERRNO); \
+ asmlinkage long __riscv_compat_sys_##sname(const struct pt_regs *__unused)
+
+#define COND_SYSCALL_COMPAT(name) \
+ asmlinkage long __weak __riscv_compat_sys_##name(const struct pt_regs *regs); \
+ asmlinkage long __weak __riscv_compat_sys_##name(const struct pt_regs *regs) \
+ { \
+ return sys_ni_syscall(); \
+ }
+
+#define COMPAT_SYS_NI(name) \
+ SYSCALL_ALIAS(__riscv_compat_sys_##name, sys_ni_posix_timers);
+
+#endif /* CONFIG_COMPAT */
+
+#define __SYSCALL_DEFINEx(x, name, ...) \
+ asmlinkage long __riscv_sys##name(const struct pt_regs *regs); \
+ ALLOW_ERROR_INJECTION(__riscv_sys##name, ERRNO); \
+ static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
+ static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
+ asmlinkage long __riscv_sys##name(const struct pt_regs *regs) \
+ { \
+ return __se_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \
+ } \
+ static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
+ { \
+ long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \
+ __MAP(x,__SC_TEST,__VA_ARGS__); \
+ __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
+ return ret; \
+ } \
+ static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+
+#define SYSCALL_DEFINE0(sname) \
+ SYSCALL_METADATA(_##sname, 0); \
+ asmlinkage long __riscv_sys_##sname(const struct pt_regs *__unused); \
+ ALLOW_ERROR_INJECTION(__riscv_sys_##sname, ERRNO); \
+ asmlinkage long __riscv_sys_##sname(const struct pt_regs *__unused)
+
+#define COND_SYSCALL(name) \
+ asmlinkage long __weak __riscv_sys_##name(const struct pt_regs *regs); \
+ asmlinkage long __weak __riscv_sys_##name(const struct pt_regs *regs) \
+ { \
+ return sys_ni_syscall(); \
+ }
+
+#define SYS_NI(name) SYSCALL_ALIAS(__riscv_sys_##name, sys_ni_posix_timers);
+
+#endif /* __ASM_SYSCALL_WRAPPER_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 506cc4a9a45a..6ac56af42f4a 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -91,6 +91,8 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
+obj-$(CONFIG_CFI_CLANG) += cfi.o
+
obj-$(CONFIG_EFI) += efi.o
obj-$(CONFIG_COMPAT) += compat_syscall_table.o
obj-$(CONFIG_COMPAT) += compat_signal.o
diff --git a/arch/riscv/kernel/cfi.c b/arch/riscv/kernel/cfi.c
new file mode 100644
index 000000000000..820158d7a291
--- /dev/null
+++ b/arch/riscv/kernel/cfi.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Clang Control Flow Integrity (CFI) support.
+ *
+ * Copyright (C) 2023 Google LLC
+ */
+#include <asm/cfi.h>
+#include <asm/insn.h>
+
+/*
+ * Returns the target address and the expected type when regs->epc points
+ * to a compiler-generated CFI trap.
+ */
+static bool decode_cfi_insn(struct pt_regs *regs, unsigned long *target,
+ u32 *type)
+{
+ unsigned long *regs_ptr = (unsigned long *)regs;
+ int rs1_num;
+ u32 insn;
+
+ *target = *type = 0;
+
+ /*
+ * The compiler generates the following instruction sequence
+ * for indirect call checks:
+ *
+ *   lw t1, -4(<reg>)
+ * lui t2, <hi20>
+ * addiw t2, t2, <lo12>
+ * beq t1, t2, .Ltmp1
+ * ebreak ; <- regs->epc
+ * .Ltmp1:
+ * jalr <reg>
+ *
+ * We can read the expected type and the target address from the
+ * registers passed to the beq/jalr instructions.
+ */
+ if (get_kernel_nofault(insn, (void *)regs->epc - 4))
+ return false;
+ if (!riscv_insn_is_beq(insn))
+ return false;
+
+ *type = (u32)regs_ptr[RV_EXTRACT_RS1_REG(insn)];
+
+ if (get_kernel_nofault(insn, (void *)regs->epc) ||
+ get_kernel_nofault(insn, (void *)regs->epc + GET_INSN_LENGTH(insn)))
+ return false;
+
+ if (riscv_insn_is_jalr(insn))
+ rs1_num = RV_EXTRACT_RS1_REG(insn);
+ else if (riscv_insn_is_c_jalr(insn))
+ rs1_num = RVC_EXTRACT_C2_RS1_REG(insn);
+ else
+ return false;
+
+ *target = regs_ptr[rs1_num];
+
+ return true;
+}
+
+/*
+ * Checks if the ebreak trap is because of a CFI failure, and handles the trap
+ * if needed. Returns a bug_trap_type value similarly to report_bug.
+ */
+enum bug_trap_type handle_cfi_failure(struct pt_regs *regs)
+{
+ unsigned long target;
+ u32 type;
+
+ if (!is_cfi_trap(regs->epc))
+ return BUG_TRAP_TYPE_NONE;
+
+ if (!decode_cfi_insn(regs, &target, &type))
+ return report_cfi_failure_noaddr(regs, regs->epc);
+
+ return report_cfi_failure(regs, regs->epc, &target, type);
+}
diff --git a/arch/riscv/kernel/compat_syscall_table.c b/arch/riscv/kernel/compat_syscall_table.c
index 651f2b009c28..ad7f2d712f5f 100644
--- a/arch/riscv/kernel/compat_syscall_table.c
+++ b/arch/riscv/kernel/compat_syscall_table.c
@@ -9,11 +9,15 @@
#include <asm/syscall.h>
#undef __SYSCALL
-#define __SYSCALL(nr, call) [nr] = (call),
+#define __SYSCALL(nr, call) asmlinkage long __riscv_##call(const struct pt_regs *);
+#include <asm/unistd.h>
+
+#undef __SYSCALL
+#define __SYSCALL(nr, call) [nr] = __riscv_##call,
asmlinkage long compat_sys_rt_sigreturn(void);
void * const compat_sys_call_table[__NR_syscalls] = {
- [0 ... __NR_syscalls - 1] = sys_ni_syscall,
+ [0 ... __NR_syscalls - 1] = __riscv_sys_ni_syscall,
#include <asm/unistd.h>
};
diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S
index 8a6e5a9e842a..8818a8fa9ff3 100644
--- a/arch/riscv/kernel/mcount.S
+++ b/arch/riscv/kernel/mcount.S
@@ -3,6 +3,7 @@
#include <linux/init.h>
#include <linux/linkage.h>
+#include <linux/cfi_types.h>
#include <asm/asm.h>
#include <asm/csr.h>
#include <asm/unistd.h>
@@ -47,15 +48,19 @@
addi sp, sp, 4*SZREG
.endm
-ENTRY(ftrace_stub)
+SYM_TYPED_FUNC_START(ftrace_stub)
#ifdef CONFIG_DYNAMIC_FTRACE
.global MCOUNT_NAME
.set MCOUNT_NAME, ftrace_stub
#endif
ret
-ENDPROC(ftrace_stub)
+SYM_FUNC_END(ftrace_stub)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+SYM_TYPED_FUNC_START(ftrace_stub_graph)
+ ret
+SYM_FUNC_END(ftrace_stub_graph)
+
ENTRY(return_to_handler)
/*
* On implementing the frame point test, the ideal way is to compare the
diff --git a/arch/riscv/kernel/suspend_entry.S b/arch/riscv/kernel/suspend_entry.S
index 12b52afe09a4..f7960c7c5f9e 100644
--- a/arch/riscv/kernel/suspend_entry.S
+++ b/arch/riscv/kernel/suspend_entry.S
@@ -5,6 +5,7 @@
*/
#include <linux/linkage.h>
+#include <linux/cfi_types.h>
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
@@ -58,7 +59,7 @@ ENTRY(__cpu_suspend_enter)
ret
END(__cpu_suspend_enter)
-ENTRY(__cpu_resume_enter)
+SYM_TYPED_FUNC_START(__cpu_resume_enter)
/* Load the global pointer */
.option push
.option norelax
@@ -94,4 +95,4 @@ ENTRY(__cpu_resume_enter)
/* Return to C code */
ret
-END(__cpu_resume_enter)
+SYM_FUNC_END(__cpu_resume_enter)
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index 26ef5526bfb4..473159b5f303 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -335,3 +335,9 @@ SYSCALL_DEFINE5(riscv_hwprobe, struct riscv_hwprobe __user *, pairs,
return do_riscv_hwprobe(pairs, pair_count, cpu_count,
cpus, flags);
}
+
+/* Not defined using SYSCALL_DEFINE0 to avoid error injection */
+asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *__unused)
+{
+ return -ENOSYS;
+}
diff --git a/arch/riscv/kernel/syscall_table.c b/arch/riscv/kernel/syscall_table.c
index 44b1420a2270..dda913764903 100644
--- a/arch/riscv/kernel/syscall_table.c
+++ b/arch/riscv/kernel/syscall_table.c
@@ -10,9 +10,13 @@
#include <asm/syscall.h>
#undef __SYSCALL
-#define __SYSCALL(nr, call) [nr] = (call),
+#define __SYSCALL(nr, call) asmlinkage long __riscv_##call(const struct pt_regs *);
+#include <asm/unistd.h>
+
+#undef __SYSCALL
+#define __SYSCALL(nr, call) [nr] = __riscv_##call,
void * const sys_call_table[__NR_syscalls] = {
- [0 ... __NR_syscalls - 1] = sys_ni_syscall,
+ [0 ... __NR_syscalls - 1] = __riscv_sys_ni_syscall,
#include <asm/unistd.h>
};
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index f910dfccbf5d..212dc20631fb 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -21,6 +21,7 @@
#include <asm/asm-prototypes.h>
#include <asm/bug.h>
+#include <asm/cfi.h>
#include <asm/csr.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
@@ -271,7 +272,8 @@ void handle_break(struct pt_regs *regs)
== NOTIFY_STOP)
return;
#endif
- else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN)
+ else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN ||
+ handle_cfi_failure(regs) == BUG_TRAP_TYPE_WARN)
regs->epc += get_break_insn_length(regs->epc);
else
die(regs, "Kernel BUG");
diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index dc20e166983e..9e6476719abb 100644
--- a/arch/riscv/purgatory/Makefile
+++ b/arch/riscv/purgatory/Makefile
@@ -77,6 +77,10 @@ ifdef CONFIG_STACKPROTECTOR_STRONG
PURGATORY_CFLAGS_REMOVE += -fstack-protector-strong
endif
+ifdef CONFIG_CFI_CLANG
+PURGATORY_CFLAGS_REMOVE += $(CC_FLAGS_CFI)
+endif
+
CFLAGS_REMOVE_purgatory.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_purgatory.o += $(PURGATORY_CFLAGS)
generated by cgit (git 2.34.1) at 2025-04-23 19:16:52 +0000